NCP5214MNR2G [ONSEMI]
2-in-1 Notebook DDR Power Controller;型号: | NCP5214MNR2G |
厂家: | ONSEMI |
描述: | 2-in-1 Notebook DDR Power Controller 双倍数据速率 开关 光电二极管 |
文件: | 总33页 (文件大小:419K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
NCP5214
2−in−1 Notebook DDR
Power Controller
The NCP5214 2−in−1 Notebook DDR Power Controller is
specifically designed as a total power solution for notebook DDR
memory system. This IC combines the efficiency of a PWM
controller for the VDDQ supply with the simplicity of linear
regulators for the VTT termination voltage and the buffered low
noise reference. This IC contains a synchronous PWM buck
controller for driving two external NFETs to form the DDR memory
supply voltage (VDDQ). The DDR memory termination regulator
output voltage (VTT) and the buffered VREF are internally set to
track at the half of VDDQ. An internal power good voltage monitor
tracks VDDQ output and notifies the user whether the VDDQ output
is within target range. Protective features include soft−start
circuitries, undervoltage monitoring of supply voltage, VDDQ
overcurrent protection, VDDQ overvoltage and undervoltage
protections, and thermal shutdown. The IC is packaged in DFN−22.
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MARKING
DIAGRAM
1
DFN−22
22
MN SUFFIX
NCP5214
AWLYYWW
G
CASE 506AF
1
NCP5214 = Specific Device Code
A
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
WL
YY
WW
G
Features
• Incorporates VDDQ, VTT Regulator, Buffered VREF
• Adjustable VDDQ Output
• VTT and VREF Track VDDQ/2
• Operates from Single 5.0 V Supply
• Supports VDDQ Conversion Rails from 4.5 V to 24 V
• Power−saving Mode for High Efficiency at Light Load
• Integrated Power FETs with VTT Regulator Sourcing/Sinking 1.5 A
DC and 2.4 A Peak Current
PIN CONNECTIONS
VDDQEN
VTTEN
FPWM
SS
VTTGND
VTT
PGND
BGDDQ
VCCP
SWDDQ
TGDDQ
BOOST
OCDDQ
PGOOD
VTTREF
FBDDQ
COMP
• Requires Only 20 mF Ceramic Output Capacitor for VTT
• Buffered Low Noise 15 mA VREF Output
• All External Power MOSFETs are N−channel
• <5.0 mA Current Consumption During Shutdown
• Fixed Switching Frequency of 400 kHz
• Soft−start Protection for VDDQ and VTT
• Undervoltage Monitor of Supply Voltage
• Overvoltage Protection and Undervoltage Protection for VDDQ
• Short−circuit Protection for VDDQ and VTT
• Thermal Shutdown
VTTI
FBVTT
AGND
DDQREF
VCCA
(Top View)
NOTE: Pin 23 is the thermal pad on
the bottom of the device.
• Housed in DFN−22
• This is a Pb−Free Device
ORDERING INFORMATION
Device
NCP5214MNR2G
Package
Shipping†
2500 Tape & Reel
Typical Applications
DFN−22
• Notebook DDR/DDR2 Memory Supply and Termination Voltage
• Active Termination Busses (SSTL−18, SSTL−2, SSTL−3)
(Pb−Free)
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
©
Semiconductor Components Industries, LLC, 2005
1
Publication Order Number:
December, 2005 − Rev. 0
NCP5214/D
NCP5214
CL1
RL1
VDDQEN
VTTEN
FPWM
VDDQEN
VTTEN
FPWM
OCDDQ
5VCC
VIN
SS
BOOST
VCCP
CSS
5VCC
4.5 V to 24 V
(Battery/
PWRGD
VTT
Adapter)
M1
M2
PGOOD
VDDQ
TGDDQ
L
1.8 V, 10 A
0.9 V, 1.5 A
VTT
1.8 mH
SWDDQ
BGDDQ
COUT2
Ceramic
10 mF x2
NCP5214
COUT1
POSCAP
150 mF x2
FBVTT
PGND1
VTTGND
5VCC
VREF
COMP
CZ1
VCCA
CP1
CZ2
R1
R2
RZ1
RZ2
VTTREF
FBDDQ
0.9 V, 15 mA
DDQREF
AGND
VTTI
Figure 1. Typical Application Diagram
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NCP5214
5VCC
VIN
VREF
VOLTAGE &
CURRENT
REFERENCE
VDDQEN
VREFGD
TSD
THERMAL
SHUTDOWN
CBULK
VDDQEN
VTTEN
5VCC
VCCP
VTTEN
FPWM
FPWM
VCCP
CONTROL
LOGIC
VCCAGD
VCCA
VBOOST
VOCDDQGD
VCCA
BOOST
FAULT
+
−
INREGDDQ
ILIM
RL1
VREF
+
−
IREF
VBOOST
OCDDQ
VOCDDQ
M3
VDDQ
TGDDQ
SWDDQ
PWM
LOGIC
FBDDQ
SWDDQ
+
−
VDDQ
L
VREF
VDDQEN
VTTEN
VCCA
Power−
Saving
Loop
VCCP
NEGATIVE CURRENT
DETECTION
SS
COUT1
M4
Control
BGDDQ
PGND
+
−
PGND
5VCC
VREF
VFBDDQ
OVLO
+
−
+
PWM−
COMP
PGOOD
−
UVLO
VREF
VFBDDQ
VREF
+
−
OSC
COMP
CZ1
PGND
CZ2
CP1
VOCDDQ
R1
R2
RZ1
RZ2
+
−
Adaptive
Ramp
A
FBDDQ
DDQREF
VTTI
Current
Limit &
Soft−Start
VCCA
+
−
M1
VDDQEN
VTTEN
SC2PWR
VTT
VTTI
VTTGND
VCCA
VTT
Regulation
Control
Deadband
Control
VTT
+
−
COUT2
INREGDDQ
VTTREF
M2
SC2GND
PGND
+
−
VTTGND
VTTREF
COUT3
VTTGND
VTTGND
FBVTT
GND
AGND
VTTGND
Figure 2. Detailed Block Diagram
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NCP5214
PIN FUNCTION DESCRIPTION
Pin
1
Symbol
VDDQEN
VTTEN
FPWM
SS
Description
VDDQ regulator enable input. High to enable.
2
VTT regulator enable input. High to enable.
3
Forced PWM enable input. Low to enable forced PWM mode and disable power−saving mode.
VDDQ Soft−start capacitor connection to ground.
4
5
VTTGND
VTT
Power ground for the VTT regulator.
6
VTT regulator output.
7
VTTI
Power input for VTT regulator which is normally connected to the VDDQ output of the buck regulator.
VTT regulator feedback pin for closed loop regulation.
Analog ground connection and remote ground sense.
External reference input which is used to regulate VTT and VTTREF to 1/2VDDQREF.
8
FBVTT
AGND
DDQREF
VCCA
9
10
11
5.0 V supply input for the IC’s control and logic section, which is monitored by undervoltage lock out
circuitry.
12
13
14
15
16
COMP
FBDDQ
VTTREF
PGOOD
OCDDQ
VDDQ error amplifier compensation node.
VDDQ regulator feedback pin for closed loop regulation.
DDR reference voltage output.
Power good signal open−drain output.
Overcurrent sense and program input for the high−side FET of VDDQ regulator. Also the battery
voltage input for the internal ramp generator to implement the voltage feedforward rejection to the input
voltage variation. This pin must be connected to the VIN through a resistor to perform the current limit
and voltage feedforward functions.
17
18
19
20
BOOST
TGDDQ
SWDDQ
VCCP
Positive supply input for high−side gate driver of VDDQ regulator and boost capacitor connection.
Gate driver output for VDDQ regulator high−side N−Channel power FET.
VDDQ regulator inductor driven node, return for high−side gate driver, and current limit sense input.
Power supply for the VDDQ regulator low−side gate driver and also supply voltage for the bootstrap
capacitor of the VDDQ regulator high−side gate driver supply.
21
22
23
BGDDQ
PGND
Gate driver output for VDDQ regulator low−side N−Channel power FET.
Power ground for the VDDQ regulator.
THPAD
Copper pad on bottom of IC used for heatsinking. This pin should be connected to the ground plane
under the IC.
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NCP5214
MAXIMUM RATINGS
Rating
Power Supply Voltage (Pin 11, 20) to AGND (Pin 9)
Symbol
, V
Value
Unit
V
V
−0.3, 6.0
−0.3, 6.0
CCA CCP
High−Side Gate Drive Supply: BOOST (Pin 17) to SWDDQ (Pin 19)
High−Side FET Gate Drive Voltage: TGDDQ (Pin 18) to SWDDQ (Pin 19)
V
V
−V
V
BOOST SWDDQ,
−V
TGDDQ SWDDQ
Input/Output Pins to AGND (Pin 9)
Pins 1−4, 6−8, 10, 12−15, 21
V
−0.3, 6.0
27
V
IO
Overcurrent Sense Input (Pin 16) to AGND (Pin 9)
Switch Node (Pin 19)
V
V
V
OCDDQ
V
−4.0 (<100 ns),
0.3 (dc), 32
SWDDQ
PGND (Pin 22), VTTGND (Pin 5) to AGND (Pin 9)
V
−0.3, 0.3
35
V
GND
Thermal Characteristics
DFN−22 Plastic Package
R
_C/W
q
JA
Thermal Resistance, Junction−to−Ambient
Operating Junction Temperature Range
Operating Ambient Temperature Range
Storage Temperature Range
T
T
0 to +150
−40 to +85
−55 to +150
2
_C
_C
_C
−
J
A
T
stg
Moisture Sensitivity Level
MSL
Maximumratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit values
(not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage
may occur and reliability may be affected.
1. This device series contains ESD protection and exceeds the following tests:
Human Body Model (HBM) ≤2.0 kV per JEDEC standard: JESD22–A114 except Pin 17 which is ≤500 V.
Machine Model (MM) ≤200 V per JEDEC standard: JESD22–A115 except Pin 17 which is ≤50 V.
2. Latchup Current Maximum Rating: ≤150 mA per JEDEC standard: JESD78.
3. Pin 16 (OCDDQ) must be pulled high to VIN through a resistor.
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NCP5214
ELECTRICAL CHARACTERISTICS (V = 12 V, T = −40 to 85_C, V
= V
= V
− V
= 5.0 V, L = 1.8 mH,
IN
A
CCA
CCP
BOOST
SWDDQ
C
OUT1
= 150 mF x 2, C
= 22 mF x 2, RL1 = 5.6 kW, R1 = 4.3 kW, R2 = 3.3 kW, RZ1 = 10 kW, RZ2 = 130 W, CP1 = 100 pF, CZ1 = 2.2 nF,
OUT2
CZ2 = 4.7 nF, for min/max values unless otherwise noted. Typical values are at T = 25_C.)
A
Characteristic
Symbol
Test Conditions
Min
Typ
Max
Unit
SUPPLY VOLTAGE
Input Voltage
V
−
−
−
4.5
4.5
4.5
−
24
5.5
5.5
V
V
V
IN
V
Operating Voltage
Operating Voltage
V
5.0
5.0
CCA
CCP
CCA
CCP
V
V
SUPPLY CURRENT
V
CCA
V
CCA
V
CCA
Quiescent Supply Current in S0
Quiescent Supply Current in S3
Shutdown Current
I
I
V
= 5.0 V, V = 5.0 V
TTEN
−
−
−
3.5
0.9
1.0
10
5.0
4.0
mA
mA
mA
VCCA_S0
VCCA_S3
VCCA_SD
DDQEN
V
= 5.0 V, V
= 0 V
DDQEN
TTEN
I
V
= 0 V, V
= 0 V,
DDQEN
TTEN
TA = 25°C
= 5.0 V, V = 5.0 V,
TTEN
V
CCP
V
CCP
V
CCP
Quiescent Supply Current in S0
Quiescent Supply Current in S3
Shutdown Current
I
I
V
−
−
−
−
−
20
20
mA
mA
mA
VCCP_S0
VCCP_S3
VCCP_SD
DDQEN
TGDDQ and BGDDQ Open
V
= 5.0 V, V = 0 V,
DDQEN
TTEN
TGDDQ and BGDDQ Open
I
V = 0 V, V = 0 V
1.0
2.0
DDQEN
TTEN
UNDERVOLTAGE MONITOR
V
V
V
V
UVLO Lower Threshold
UVLO Hysteresis
V
Falling Edge
−
−
−
−
3.7
0.35
3.0
4.1
−
V
V
V
V
CCA
CCAUV−
V
−
CCA
CCAUVHYS
OCDDQUV+
UVLO Upper Threshold
UVLO Hysteresis
V
Rising Edge
−
4.4
−
OCDDQ
OCDDQ
V
0.4
OCDDQUVHYS
THERMAL SHUTDOWN
Thermal Trip Point
T
(Note 4)
(Note 4)
−
−
150
25
−
−
_C
_C
SD
Hysteresis
T
SDHYS
V
DDQ
SWITCHING REGULATOR
FBDDQ Feedback Voltage, Control Loop in
Regulation
V
TA = 25°C
TA = −40 to 85°C
0.788
0.784
0.8
0.8
0.812
0.816
V
FBDDQ
Feedback Input Current
Oscillator Frequency
I
V
= 0.8 V
−
340
−
−
1.0
460
−
mA
kHz
V
fb
FBDDQ
F
SW
−
400
1.25
45
Ramp Amplitude Voltage
V
V
= 5.0 V (Note 4)
−
ramp
IN
Ramp Amplitude to V Ratio
dVRAMP/dVIN
−
−
mV/V
mA
IN
OCDDQ Pin Current Sink
I
V
= 4.0 V
26
−
31
36
−
OC
OCDDQ
OCDDQ Pin Current Sink Temperature
Coefficient
TC
TA = −40 to 85°C
3200
ppm/
_C
IOC
Minimum On Time
t
−
−
150
−
ns
onmin
Maximum Duty Cycle
D
max
V
V
V
= 5.0 V
= 15 V
= 24 V
−
−
−
90
50
32
−
−
−
%
IN
IN
IN
Soft−Start Current
I
V
= 5.0 V, Vss = 0 V
2.8
4.0
5.2
−
mA
ss
DDQEN
Overvoltage Trip Threshold
FBOVPth
With Respect to Error
115
130
%
Comparator Threshold of 0.8 V
Undervoltage Trip Threshold
FBUVPth
With Respect to Error
−
65
75
%
Comparator Threshold of 0.8 V
4. Guaranteed by design, not tested in production.
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NCP5214
ELECTRICAL CHARACTERISTICS (continued) (V = 12 V, T = −40 to 85_C, V
= V
= V
− V
= 5.0 V,
IN
A
CCA
CCP
BOOST
SWDDQ
L = 1.8 mH, C
= 150 mF x 2, C
= 22 mF x 2, RL1 = 5.6 kW, R1 = 4.3 kW, R2 = 3.3 kW, RZ1 = 10 kW, RZ2 = 130 W, CP1 = 100 pF,
OUT1
OUT2
CZ1 = 2.2 nF, CZ2 = 4.7 nF, for min/max values unless otherwise noted. Typical values are at T = 25_C.)
A
Characteristic
Symbol
Test Conditions
Min
Typ
Max
Unit
ERROR AMPLIFIER
DC Gain
GAIN
Ft
(Note 5)
−
−
70
−
−
dB
Unity Gain Bandwidth
COMP_GND = 220 nF,
2.0
MHz
1.0 W in Series (Note 5)
Slew Rate
SR
(Note 5)
−
−
3.0
1.8
−
V/mS
GATE DRIVERS
TGDDQ Gate Pull−HIGH Resistance
R
H_TG
V
V
− V
SWDDQ
= 5.0 V,
= 4.0 V
4.0
W
BOOST
− V
TGDDQ
SWDDQ
TGDDQ Gate Pull−LOW Resistance
R
L_TG
V
V
− V
− V
= 5.0 V,
= 1.0 V
−
1.8
4.0
W
BOOST
SWDDQ
TGDDQ
SWDDQ
BGDDQ Gate Pull−HIGH Resistance
BGDDQ Gate Pull−LOW Resistance
R
V
CCP
V
CCP
= 5.0 V, V
= 5.0 V, V
= 4.0 V
= 1.0 V
−
−
1.8
0.9
4.0
3.0
W
W
H_BG
BGDDQ
BGDDQ
R
L_BG
VTT0
V
TT
ACTIVE TERMINATOR
V
TT
with Respect to 1/2V
d
1/2VDDQREF – V ,
TT
mV
DDQREF
VDDQREF = 2.5 V,
I
= 0 to 2.4 A
VTT
(Sink Current)
−30
−
−
−
−
I
= 0 to –2.4 A
VTT
(Source Current)
30
1/2VDDQREF – V
,
TT
mV
VDDQREF = 1.8 V,
I
= 0 to 2.0 A
VTT
(Sink Current)
−30
−
−
I
= 0 to –2.0 A
VTT
(Source Current)
−
40
2.5
2.5
−
−
30
75
−
DDQREF Input Resistance
Source Current Limit
DDQREF_R
VDDQREF = 2.5 V
55
kW
A
I
−
−
−
−
3.0
3.0
1.0
0.32
LIMVTsrc
Sink Current Limit
I
−
A
LIMVTsnk
Soft−Start Source Current Limit
Maximum Soft−Start Time
I
−
A
LIMVTSS
t
−
−
ms
ssvttmax
V
TTREF
OUTPUT
V
Source Current
I
VDDQREF = 1.8 V or 2.5 V
1/2VDDQREF – V
15
−
−
−
mA
mV
TTREF
TTREF
VTTR
V
Accuracy Referred to 1/2V
d
,
TTR
−25
25
DDQREF
VTTR
VDDQREF = 2.5 V,
= 0 mA to 15 mA
I
VTTR
1/2VDDQREF – V
,
−18
−
18
mV
TTR
VDDQREF = 1.8 V,
= 0 mA to 15 mA
I
VTTR
5. Guaranteed by design, not tested in production.
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NCP5214
ELECTRICAL CHARACTERISTICS (continued) (V = 12 V, T = −40 to 85_C, V
= V
= V
− V
= 5.0 V,
IN
A
CCA
CCP
BOOST
SWDDQ
L = 1.8 mH, C
= 150 mF x 2, C
= 22 mF x 2, RL1 = 5.6 kW, R1 = 4.3 kW, R2 = 3.3 kW, RZ1 = 10 kW, RZ2 = 130 W, CP1 = 100 pF,
OUT1
OUT2
CZ1 = 2.2 nF, CZ2 = 4.7 nF, for min/max values unless otherwise noted. Typical values are at T = 25_C.)
A
Characteristic
Symbol
Test Conditions
Min
Typ
Max
Unit
CONTROL SECTION
VDDQEN Pin Threshold High
VDDQEN Pin Threshold Low
VDDQEN Pin Input Current
V
−
−
1.4
−
−
−
−
−
V
V
DDQEN_H
V
0.5
1.0
DDQEN_L
I
V
= 5.0 V
−
mA
IN_
DDQEN
VDDQEN
VTTEN Pin Threshold High
VTTEN Pin Threshold Low
VTTEN Pin Input Current
V
−
1.4
−
−
−
−
−
V
V
TTEN_H
V
−
0.5
1.0
TTEN_L
I
V
= V = 5.0 V
TTEN
−
mA
IN_VTTEN
DDQEN
FPWM Pin Threshold High
FPWM Pin Threshold Low
FPWM Pin Input Current
FPWM_H
FPWM_L
−
1.4
−
−
−
−
−
V
V
−
0.5
1.0
I
V
= V
=FPWM
−
mA
IN_FPWM
DDQEN
TTEN
= 5.0 V
PGOOD Pin ON Resistance
PGOOD_R
I
= 5.0 mA
−
−
−
70
−
−
W
mA
ms
_PGOOD
PGOOD Pin OFF Current
PGOOD_LK
−
1.0
200
PGOOD LOW−to−HIGH Hold Time, for S5 to S0
6. Guaranteed by design, not tested in production.
t
(Note 6)
−
hold
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NCP5214
TYPICAL OPERATING CHARACTERISTICS
4.0
3.8
3.6
1.0
0.8
0.6
3.4
3.2
0.4
0.2
3.0
0.0
−40
−15
10
35
60
85
85
85
−40
−15
10
35
60
85
85
85
T , AMBIENT TEMPERATURE (°C)
A
T , AMBIENT TEMPERATURE (°C)
A
Figure 3. VCCA Quiescent Current in S0
vs. Ambient Temperature
Figure 4. VCCA Quiescent Current in S3
vs. Ambient Temperature
10
8
450
425
6
400
375
4
2
0
−40
350
−40
−15
10
35
60
−15
10
35
60
T , AMBIENT TEMPERATURE (°C)
A
T , AMBIENT TEMPERATURE (°C)
A
Figure 5. VCCA Shutdown Current
vs. Ambient Temperature
Figure 6. Switching Frequency in S0
vs. Ambient Temperature
5.0
4.5
0.90
0.85
4.0
3.5
0.80
0.75
0.70
3.0
−40
−40
−15
10
35
60
−15
10
35
60
T , AMBIENT TEMPERATURE (°C)
A
T , AMBIENT TEMPERATURE (°C)
A
Figure 7. VDDQ Feedback Voltage
vs. Ambient Temperature
Figure 8. Soft−Start Current
vs. Ambient Temperature
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NCP5214
TYPICAL OPERATING CHARACTERISTICS
1.820
1.815
1.810
1.805
1.800
1.795
1.810
1.805
I
= 100 mA
= 10 A
VDDQ
1.800
1.795
V
IN
= 5 V
I
VDDQ
V
= 24 V
IN
1.790
1.785
V
= 1.8 V
DDQ
V
DDQ
= 1.8 V
S0 Mode
T = 25°C
A
T = 25°C
A
1.780
1.790
0
5
10
15
20
25
3.0
15
0
2
4
6
8
10
V
, INPUT VOLTAGE (V)
I
, VDDQ OUTPUT CURRENT (A)
IN
VDDQ
Figure 9. VDDQ Output Voltage
vs. Input Voltage
Figure 10. VDDQ Output Voltage
vs. VDDQ Output Current
1.29
1.28
1.27
1.26
1.25
1.24
1.23
1.22
1.21
0.94
0.93
0.92
0.91
0.90
0.89
0.88
0.87
0.86
V
IN
= 5 V
V
= 5 V
IN
V
IN
= 24 V
V
IN
= 24 V
1.0
V
= 2.5 V
V
= 1.8 V
T = 25°C
A
DDQ
DDQ
T = 25°C
A
−3.0
−2.0
−1.0
0.0
2.0
−2.0 −1.5 −1.0 −0.5 0.0
0.5
1.0
1.5 2.0
I
, VTT OUTPUT CURRENT (A)
I , VTT OUTPUT CURRENT (A)
VTT
VTT
Figure 11. VTT Output Voltage (DDR)
vs. VTT Output Current
Figure 12. VTT Output Voltage (DDR2)
vs. VTT Output Current
1.260
0.910
0.905
1.255
1.250
1.245
0.900
0.895
V
= 5 V
V
IN
= 5 V
IN
V
IN
= 24 V
V
IN
= 24 V
V
DDQ
= 2.5 V
V
DDQ
= 1.8 V
T = 25°C
A
T = 25°C
A
1.240
0.890
0
5
10
0
5
10
15
I , VTTR OUTPUT CURRENT (mA)
VTTR
I , VTTR OUTPUT CURRENT (mA)
VTTR
Figure 13. VTTR Output Voltage (DDR)
vs. VTTR Output Current
Figure 14. VTTR Output Voltage (DDR2)
vs. VTTR Output Current
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10
NCP5214
TYPICAL OPERATING CHARACTERISTICS
100
90
100
V
= 5 V
= 12 V
= 20 V
V
= 5 V
= 12 V
= 20 V
IN
IN
90
80
V
IN
V
IN
V
IN
V
IN
80
with power−saving
with power−saving
without power−saving
without power−saving
70
60
70
60
V
DDQ
= 2.5 V
V
DDQ
= 1.8 V
Freq = 400 kHz max
Freq = 400 kHz max
T = 25°C
T = 25°C
A
A
50
0.1
50
0.1
1.0
10
100
1.0
10
100
I , VDDQ OUTPUT CURRENT (A)
VDDQ
I , VDDQ OUTPUT CURRENT (A)
VDDQ
Figure 15. VDDQ Efficiency (DDR)
vs. VDDQ Output Current
Figure 16. VDDQ Efficiency (DDR2)
vs. VDDQ Output Current
VIN
20V/div
VIN
20V/div
1V/div
VDDQ
VTT
VDDQ
1V/div
1V/div
1V/div
VTT
1V/div
1V/div
VTTR
VTTR
VDDQEN = High; VTTEN = High; VIN = 0 V to 20 V
VDDQEN = High; VTTEN = High; VIN =20 V to 0 V
Figure 17. Power−Up Waveforms
Figure 18. Power−Down Waveforms
5V/div
5V/div
VDDQEN
VDDQ
VDDQEN
VDDQ
1V/div
1V/div
1V/div
5V/div
VTTR
VTTR
1V/div
5V/div
PGOOD
PGOOD
VDDQEN = 0 V to 5 V
VDDQEN = 5 V to 0 V
Figure 19. VDDQ, VTTR Start−Up Waveforms
Figure 20. VDDQ, VTTR Shutdown Waveforms
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11
NCP5214
TYPICAL OPERATING CHARACTERISTICS
VTTEN
VTT
VTTEN
5V/div
5V/div
1V/div
VTT
1V/div
500mA/div
IVTTI
IVTTI
500mA/div
VDDQEN = High; VTT Loaded with 4.7 W to GND
VDDQEN = High; VTT Loaded with 4.7 W to GND
Figure 21. VTT Start−Up Waveforms
Figure 22. VTT Shutdown Waveforms
100mV/div
VDDQ
100mV/div
VDDQ
VTT
1V/div
VTT
1V/div
50mV/div
VTTR
50mV/div
VTTR
5V/div
5V/div
FPWM
VTTEN
IVDDQ = 50 mA, IVTT = 100 mA, IVTTR = 5 mA
IVDDQ = 50mA, IVTT = 100mA, IVTTR = 5mA, VTTEN = 0V
Figure 23. S0−S3−S0 Transition Waveforms
Figure 24. PS−FPWM−PS Transition
Waveforms
100mV/div
50mV/div
VDDQ
VTT
100mV/div
50mV/div
50mV/div
VDDQ
VTT
50mV/div
5A/div
VTTR
VTTR
IVDDQ
IVDDQ
5A/div
IVDDQ = 0 A−7 A, IVTT = 1.5 A, IVTTR = 15 mA
IVDDQ = 7 A−0 A, IVTT = 1.5 A, IVTTR = 15 mA
Figure 25. VDDQ Load Transient
Figure 26. VDDQ Load Transient
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12
NCP5214
TYPICAL OPERATING CHARACTERISTICS
VDDQ
100mV/div
100mV/div
VDDQ
VTT
VTT
50mV/div
50mV/div
50mV/div
VTTR
VTTR
IVTT
50mV/div
2A/div
IVTT
2A/div
IVDDQ = 8 A, IVTT = 0 A to −2 A to 0 A, IVTTR = 15 mA
IVDDQ = 8 A, IVTT = 0 A to 2 A to 0 A, IVTTR = 15 mA
Figure 27. VTT Source Current Transient
Figure 28. VTT Sink Current Transient
VDDQ
VTT
100mV/div
50mV/div
50mV/div
10V/div
100mV/div
50mV/div
VDDQ
VTT
50mV/div
10V/div
VTTR
VIN
VTTR
VIN
IVDDQ = 0 A, IVTT = 0 A, IVTTR = 0 mA, VIN = 7 V to 20 V
IVDDQ = 0 A, IVTT = 0 A, IVTTR = 0 mA, VIN = 20 V to 7 V
Figure 29. Line Transient 7V to 20V at No Load
Figure 30. Line Transient 20V to 7V at No Load
100mV/div
VDDQ
VDDQ
100mV/div
VTT
50mV/div
VTT
50mV/div
50mV/div
10V/div
50mV/div
10V/div
VTTR
VIN
VTTR
VIN
IVDDQ = 10A, IVTT = 1.5A, IVTTR = 15mA, VIN = 20V to 7V
IVDDQ = 10A, IVTT = 1.5A, IVTTR = 15mA, VIN = 7V to 20V
Figure 31. Line Transient 7V to 20V at Full
Load
Figure 32. Line Transient 20V to 7V at Full
Load
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NCP5214
TYPICAL OPERATING CHARACTERISTICS
100mV/div
VDDQ
VDDQ
100mV/div
VTT
1V/div
50mV/div
5A/div
VTT
1V/div
VTTR
IVTT
VTTR
50mV/div
IVTT
5A/div
IVDDQ = 8 A, VTT shorts to VDDQ, IVTTR = 15 mA
IVDDQ = 8 A, VTT shorts to ground, IVTTR = 15 mA
Figure 33. VTT Short Circuit to Ground and
Recovery
Figure 34. VTT Short Circuit to VDDQ and
Recovery
VDDQ, 1V/div
VDDQ, 1V/div
VSWDDQ, 10V/div
VSWDDQ, 10V/div
VIN, 20V/div
IL, 10A/div
VIN, 20V/div
IL, 10A/div
Figure 35. VDDQ OCP by Short Circuit to
Ground
Figure 36. VDDQ OCP by Steady IVDDQ
Increase
VDDQ, 1V/div
VSWDDQ, 10V/div
VIN, 20V/div
IL, 10A/div
Figure 37. VDDQ OCP by Start into a Short
Circuit
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NCP5214
DETAILED OPERATING DESCRIPTION
General
VDDQ output voltage is divided down and fed back to the
The NCP5214 2−in−1 Notebook DDR Power Controller
inverting input of an internal error amplifier through
FBDDQ pin to close the loop at VDDQ = VFBDDQ ×
(1 + R1/R2). This amplifier compares the feedback voltage
with an internal VREF (= 0.800 V) to generate an error
signal for the PWM comparator. This error signal is further
compared with a fixed frequency RAMP waveform
derived from the internal oscillator to generate a
pulse−width−modulated signal. This PWM signal drives
the external N−Channel Power FETs via the TGDDQ and
BGDDQ pins. External inductor L and capacitor COUT1
filter the output waveform. The VDDQ output voltage
ramps up at a pre−defined soft−start rate when the IC enters
state S0 from S5. When in normal mode, and regulation of
VDDQ is detected, signal INREGDDQ will go HIGH to
notify the control logic block.
combines the efficiency of a PWM controller for the
VDDQ supply, with the simplicity of using a linear
regulator for the VTT termination voltage power supply.
The VDDQ output can be adjusted through the external
potential divider, while the VTT is internally set to track
half VDDQ.
The inclusion of VDDQ power good voltage monitor,
soft−start, VDDQ overcurrent protection, VDDQ
overvoltage and undervoltage protections, supply
undervoltage monitor, and thermal shutdown makes this
device a total power solution for high current DDR memory
system. The IC is packaged in DFN−22.
Control Logic
The internal control logic is powered by VCCA. The IC
is enabled whenever VDDQEN is high (exceed 1.4 V). An
internal bandgap voltage, VREF, is then generated. Once
VREF reaches its regulation voltage, an internal signal
VREFGD will be asserted. This transition wakes up the
supply undervoltage monitor blocks, which will assert
VCCAGD if VCCA voltage is within certain preset levels.
The control logic accepts external signals at VCCA,
OCDDQ, VDDQEN, VTTEN, and FPWM pins to control
the operating state of the VDDQ and VTT regulators in
accordance with Table 1. A timing diagram is shown in
Figure 38.
Input voltage feedforward is implemented to the RAMP
signal generation to reject the effect of wide input voltage
variation. With input voltage feedforward, the amplitude of
the RAMP is proportional to the input voltage.
For enhanced efficiency, an active synchronous switch is
used to eliminate the conduction loss contributed by the
forward voltage of a diode or Schottky diode rectifier.
Adaptive non−overlap timing control of the
complementary gate drive output signals is provided to
reduce large shoot−through current that degrades
efficiency.
Tolerance of VDDQ
VDDQ Switching Regulator in Normal Mode (S0)
The tolerance of VFBDDQ and the ratio of external
resistor divider R1/R2 both impact the precision of VDDQ.
With the control loop in regulation, VDDQ = VFBDDQ ×
(1 + R1/R2). With a worst case (for all valid operating
conditions) VFBDDQ tolerance of "1.5%, a worst case
range of "2.5% for VDDQ = 1.8 V will be assured if the
ratio R1/R2 is specified as 1.2500 "1%.
The VDDQ regulator is a switching synchronous
rectification buck controller directly driving two external
N−Channel power FETs. An external resistor divider sets
the nominal output voltage. The control architecture is
voltage mode fixed frequency PWM with external
compensation and with switching frequency fixed at
400 kHz " 15%. As can be observed from Figure 1, the
Table 1. State, Operation, Input and Output Condition Table
Input Conditions
Operating Conditions
Output Conditions
VCCA VOCDDQ VDDQEN VTTEN FPWM
VDDQ
VTTREF
H−Z
VTT
TGDDQ
BGDDQ
Low
PGOOD
Mode
S5
Low
X
X
X
X
X
X
H−Z
H−Z
H−Z
H−Z
Low
Low
Low
Low
H−Z
H−Z
S5
Low
High
High
X
X
H−Z
Low
S0
High
High
High
High
High
Low
X
Normal
Standby
Normal
Normal
Normal
H−Z
Normal
Standby
Normal
Standby
S3
High
(Power− (Power−
saving)
saving)
S3
S5
High
X
High
X
High
Low
Low
X
Low
X
Normal
H−Z
Normal
H−Z
H−Z
H−Z
Normal
Normal
H−Z
Low
Low
Low
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NCP5214
VDDQ Regulator in Standby Mode (S3)
current source to charge up the VTT output capacitor. The
current limit is initially 1.0 A during VTT soft−start. It is
then increased to 2.5 A after 128 internal clock cycles
which is typically 0.32 ms.
During state S3, a power−saving mode is activated when
the FPWM pin is pulled to VCCA. In power−saving mode,
the switching frequency is reduced with the VDDQ output
current and the low−side FET is turned off after the
detection of negative inductor current, so as to enhance the
efficiency of the VDDQ regulator at light loads. The
switching frequency can be reduced smoothly until it
reaches the minimum frequency at about 15 kHz.
Therefore, perceptible audible noise can be avoided at light
load condition.
In power−saving mode, the low−side MOSFET is turned
off after the detection of negative inductor current and the
converter cannot sink current. The power−saving mode can
be disabled by pulling the FPWM pin to ground. Then, the
converter operates in forced−PWM mode with fixed
switching frequency and ability to sink current.
VTT Active Terminator in Standby Mode (S3)
VTT output is high−impedance in S3 mode.
Fault Protection of VTT Active Terminator
To provide protection for the internal FETs, bidirectional
current limit is implemented, preset at the minimum of
2.5 A magnitude.
Thermal Consideration of VTT Active Terminator
The VTT terminator is designed to handle large transient
output currents. If large currents are required for very long
duration, then care should be taken to ensure the maximum
junction temperature is not exceeded. The 5x6 DFN−22 has
a thermal resistance of 35_C/W (dependent on air flow,
grade of copper, and number of vias). In order to take full
advantage from this thermal capability of this package, the
thermal pad underneath must be soldered directly onto a
PCB metal substrate to allow good thermal contact. It is
recommended that PCB with 2 oz. copper foil is used and
there should have 6 to 8 vias with 0.6 mm hole size
underneath the package’s thermal pad connecting the top
layer metal to the bottom layer metal and the internal layer
metal substrates of the PCB.
Fault Protection of VDDQ Regulator
During state S0 and S3, external resistor (RL1) between
OCDDQ and VIN sets the current limit for the high−side
switch. An internal 31 mA current sink (IOC) at OCDDQ
pin establishes a voltage drop across this resistor and
develops a voltage at the non−inverting input of the current
limit comparator. The voltage at the non−inverting input is
compared to the voltage at SWDDQ pin when the
high−side gate drive is high after a fixed period of blanking
time (150 ns) to avoid false current limit triggering. When
the voltage at SWDDQ is lower than that at the
non−inverting input for 4 consecutive internal clock
cycles, an overcurrent condition occurs, during which, all
VTTREF Output
The VTTREF output tracks VDDQREF/2 at "2%
accuracy. It has source current capability of up to 15 mA.
VTTREF should be bypassed to analog ground of the
device by 1.0 mF ceramic capacitor for stable operation.
The VTTREF is turned on as long as VDDQEN is pulled
high. In S0 mode, VTTREF soft−starts with VDDQ and
tracks VDDQREF/2. In S3 mode, VTTREF is kept on with
VDDQ. VTTREF is turned off only in S4/S5 like VDDQ
output.
outputs will be latched off to protect against
short−to−ground condition on SWDDQ or VDDQ. The IC
will be reset once VCCA or VDDQEN is cycled.
a
Feedback Compensation of VDDQ Regulator
The compensation network is shown in Figures 2 and 39.
VTT Active Terminator in Normal Mode (S0)
The VTT active terminator is a two−quadrant linear
regulator with two internal N−channel power FETs. It is
capable of sinking and sourcing at least 1.5 A continuous
current and up to 2.4 A transient peak current. It is activated
in normal mode in state S0 when the VTTEN pin is HIGH
and VDDQ is in regulation. Its input power path is from
VDDQ with the internal FETs gate drive power derived
from VCCA. The VTT internal reference voltage is derived
from the DDQREF pin. The VTT output is set to VDDQ/2
when VTT output is connecting to the FBVTT pin directly.
This regulator is stable with only a minimum 20 mF output
capacitor. The VTT regulator will have an internal
soft−start when it is transited from disable to enable.
During the VTT soft−start, a current limit is used as a
Output Voltages Sensing
The VDDQ output voltage is sensed across the FBDDQ
and AGND pins. FBDDQ should be connected through a
feedback resistor divider to the VDDQ point of regulation
which is usually the local VDDQ bypass capacitor for load.
The AGND should be connected directly through a sense
trace to the remote ground sense point which is usually the
ground of local VDDQ bypass capacitor for load.
The VTT output voltage is sensed between the FBVTT
and VTTGND pins. The FBVTT should be connected to
the VTT regulation point, which is usually the VTT local
bypass capacitor, via a direct sense trace. The VTTGND
should be connected via a direct sense trace to the ground
of the VTT local bypass capacitor for load.
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NCP5214
Supply Voltage Undervoltage Monitor
MOSFET to discharge the excessive output voltage. When
the VDDQ output voltage goes back down to the nominal
regulation voltage, normal switching cycles are resumed.
When the VDDQ output exceeds 130% (typ) of the
nominal regulation voltage for 4 consecutive internal clock
cycles, the controller sets overvoltage fault, the device is
latched off by turning off both the high−side and low−side
MOSFETs. The overvoltage fault latch can be reset and the
controller can be restarted by toggling VDDQEN, VCCA,
or VIN.
The IC continuously monitors VCCA and VIN through
VCCA pin and OCDDQ pin respectively. VCCAGD is set
HIGH if VCCA is higher than its preset threshold (derived
from VREF with hysteresis). The IC will enter S5 state if
VCCA fails while in S0 and both VDDQEN and VTTEN
remain HIGH.
Thermal Shutdown
When the chip junction temperature exceeds 150_C, the
entire IC is shutdown. The IC resumes normal operation
only after the junction temperature dropping below 125_C.
Undervoltage Protection
In S3 power−saving mode with reduced switching at
lighter loads, when the VDDQ falls below 94% of the
nominal regulation voltage, the reduced switching
frequency is raised up back to the maximum switching
frequency. When VDDQ voltage is back to nominal
regulation voltage, the normal S3 power−saving operation
is resumed. In both S0 and S3 modes, when the VDDQ falls
below 65% (typ) of the nominal regulation voltage for 4
consecutive internal clock cycles, the undervoltage fault is
set, the device is latched off by turning off both the
high−side and low−side MOSFETs. The output is
discharged by the load current. The load current and output
capacitance determine the discharge rate. Cycling
VDDQEN, VCCA, or VIN can reset the undervoltage fault
latch and restart the controller.
Power Good
The PGOOD is an open−drain output of a window
comparator which continuously monitors the VDDQ
output voltage. The PGOOD is pulled low when the VDDQ
rises 12% above or drops 12% below the nominal
regulation point. The PGOOD becomes high impedance
when the VDDQ is within 12% of the preset nominal
regulation voltage. A 100 kW resistor is recommended to
connect between PGOOD and VCCA as pull−up resistor
for logic level output.
Overvoltage Protection
When the VDDQ output is above 106% but below 130%
of the nominal regulation output voltage, the controller
turns off the high−side MOSFET and turns on the low−side
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NCP5214
VCCA
VIN
(VOCDDQ)
VDDQEN
VTTEN
VTTEN is
Don’t Care
in S5
VDDQ
Soft−start
VDDQ
VTT
VTT in H−Z
VTT Soft−start
VTT Soft−start
VTTREF
PGOOD
t
X 200 ms
hold
Operating
Mode
S5
S0
S3
S0
S5
VTTEN goes LOW
to activate S3 mode
and to turn off VTT.
PGOOD
goes HIGH.
Both VDDQEN and
VTTEN go LOW to
trigger S5 mode;
VCCA goes
above 4.0 V to
enable the IC.
VDDQ, VTT, VTTREF
are disabled, then
INREGDDQ and
INREGDDQ goes
HIGH, VTT goes into
normal mode.
VDDQEN goes HIGH,
VDDQ and VTTREF
are enabled but not
activated until VIN
goes above threshold
of 3.0 V. VTTEN goes
HIGH, VTT is enabled
but not activated until
VDDQ is good.
PGOOD goes LOW.
VTTEN goes
HIGH, VTT goes
into normal mode.
VIN goes above the
threshold, the VDDQ
and VTTREF go into
normal mode.
Figure 38. Powerup and Powerdown Timing Diagram
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NCP5214
APPLICATION INFORMATION
Input Capacitor Selection for VDDQ Buck Regulator
The input capacitor is important for proper regulation
operation of the buck regulator. It minimizes the input
voltage ripple and current ripple from the power source by
providing a local loop for switching current. The input
capacitor should be placed close to the drain of the
high−side MOSFET and source of the low−side MOSFET
with short, wide traces for connection. The input capacitor
must have large enough rms ripple current rating to
withstand the large current pulses present at the input of the
bulk regulator due to the switching current. The required
input capacitor rms ripple current rating can be estimated
V
+ I
L(ripple)
ESR, for small t
on
and large C
OUT
ripple
(eq. 3)
where I
and C
is the inductor ripple current, t is on−time,
on
L(ripple)
is the output capacitance.
OUT
The inductor ripple current can be calculated by the
equation:
(V −V
IN OUT
) V
OUT
V
(eq. 4)
I
+
L(ripple)
L f
SW
IN
where L is the inductance and f
is the switching
SW
frequency. The output ripple voltage can be reduced by
either using the inductor with larger inductance or the
output capacitor with smaller ESR. Thus, the ESR needed
to meet the ripple voltage requirement can be obtained by:
by the following with minimum V :
IN
2
V
V
V
OUT
OUT
IN
(eq. 1)
OUTǸ
* ǒ Ǔ
I
w I
CIN(RMS)
V
IN
V
ripple
L f
V
IN
SW
(eq. 5)
ESR v
Besides, the voltage rating of the input capacitor should
be at least 1.25 times of the maximum input voltage.
Capacitance of around 20 mF to 50 mF should be sufficient
for most DDR applications. Ceramic capacitors are the
most suitable choice of input capacitor for notebook
applications due to their low ESR, high ripple current, and
high voltage rating. POSCAP or OS−CON capacitors can
also be used since they have good ESR and ripple current
rating, but they are larger in size and more expensive.
Aluminum electrolytic capacitors are also a choice for their
high voltage rating and low cost, but several aluminum
capacitors in parallel should be used for the required ripple
current. If ceramic capacitors are used, X5R and X7R types
are preferred rather than the Y5V type since the X5R and
X7R types are ceramic capacitors and have smaller
tolerance and temperature coefficient.
(V −V
IN OUT
) V
OUT
The inductor ripple current is typically 30% of the
maximum load current and the ripple voltage is typically
2% of the output voltage. Thus, the above inequality can be
simplified to:
0.02 V
OUT
(eq. 6)
ESR v
0.3 I
LOAD(max)
For the load transient, the output capacitor contributes to
both the load−rise and the load−release responses. The
voltage undershoot during step−up load can be calculated
by the equation:
1−V
OUT
IN
DI
C
LOAD
OUT
V
V
+ DI
LOAD
ESR )
ǒ Ǔ
(eq. 7)
undershoot
f
SW
Output Capacitor Selection for VDDQ Buck Regulator
The output filter capacitor plays an important role in
steady state output ripple voltage, load transient
requirement, and loop compensation stability. The ESR
and the capacitance of the output capacitor are the most
important parameters needed to be considered. In general,
the output capacitor must have small enough ESR for
output ripple voltage and load transient requirement.
Besides, the capacitance of the output capacitor should be
large enough to meet the overshoot and undershoot during
load transient. Since steady state output ripple voltage,
transient load undershoot and overshoot are the largest at
where DI
is the change in output current. If the second
LOAD
term is ignored, then it becomes the following inequality:
V
undershoot
(eq. 8)
ESR v
DI
LOAD
The maximum ESR requires to meet voltage undershoot
requirement at step−up load transient can be estimated
from the above inequality.
Then, the required output capacitor capacitance can be
obtained by the following:
1−V
OUT
IN
DI
LOAD
V
C
OUT
w
ǒ Ǔ
(eq. 9)
V
−DI
ESR
f
SW
undershoot LOAD
maximum V , the ESR and capacitance of output
IN
capacitor should be estimated at the maximum V
condition.
IN
The output voltage overshoot during load−release is
because the excessive stored energy in the inductor is
absorbed by the output capacitor. The overshoot voltage
can be calculated by the following equation:
For steady output ripple voltage, both ESR and
capacitance of the output capacitor are the contributing
factors, however, the capacitor ESR is the dominant factor.
The output ripple voltage is calculated as follows:
2
LI
2
V
) C
OUT OUT
OUT
STEP(peak)
C
+ Ǹ
V
overshoot
−V
OUT
I
t
on
L(ripple)
(eq. 2)
V
ripple
+ I ESR )
L(ripple)
(eq. 10)
C
OUT
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NCP5214
Then the required output capacitor capacitance can be
estimated by:
current. Therefore, the maximum DC current rating of the
inductor can be obtained by:
(eq. 16)
2
I + 1.2 I
L(rating) L(peak)
L I
STEP(peak)
(eq. 11)
C
w
OUT
2 2
) V ) −V
OUT
(V
overshoot
where I
is the peak inductor current at maximum load
OUT
) V
L(peak)
current which is determined by:
(V −V
IN OUT
OUT
I
+ DI )
LOAD
STEP(peak)
I
L(ripple)
2
2L f
SW
V
IN
I
+ I
)
)
L(peak)
LOAD(max)
+ I
LOAD(max)
(eq. 12)
(V −V
IN OUT
) V
OUT
where I
is the load current step plus half of the
STEP(peak)
2 L f
SW
V
IN
ripple current at the load release and DI
in the output load current.
is the change
LOAD
(eq. 17)
Besides, the ESR and the capacitance of the output filter
capacitor also contribute to double pole and ESR zero
frequencies of the output filter, and the poles and zeros
frequencies of the compensation network for close loop
stability. The compensation network will be discussed in
more detail in the Loop Compensation section.
Other parameters about output filter capacitor that
needed to be considered are the voltage rating and ripple
current rating. The voltage rating should be at least 1.25
times the output voltage and the rms ripple current rating
should be greater than the inductor ripple current. Thus, the
voltage rating and ripple current rating can be obtained by:
Since the excessive energy stored in the inductor
contributed to the output voltage overshoot during load
release, the following inequality can be used to ensure that
the selected inductance value can meet the voltage
overshoot requirement at load release:
2
2
C
OUT
((V
) V
OUT
) −V
OUT
)
overshoot
L v
2
I
STEP(peak)
(eq. 18)
In addition, the inductor also needs to have low enough
DCR to obtain good conversion efficiency. In general,
inductors with about 2.0 mW to 3.0 mW per mH of
inductance can be used. Besides, larger inductance value
can be selected to achieve higher efficiency as long as it
still meets the targeted voltage overshoot at load release
and inductor DC current rating.
(eq. 13)
V
rating
w 1.25 V
OUT
(V −V
) V
V
IN OUT
OUT
I
w I +
L(ripple)
COUT(RMS)
L f
SW
IN
(eq. 14)
MOSFET Selection
SP−Cap, POSCAP and OS−CON capacitors are suitable
for the output capacitor since their ESR is low enough to
meet the ripple voltage and load transient requirements.
Usually, two or more capacitors of the same type,
capacitance and ESR can be used in parallel to achieve the
required ESR and capacitance without change the ESR
zero position for maintaining the same loop stability. Other
than the performance point of view, the physical size and
cost are also the concerned factors for output capacitor
selection.
External N−channel MOSFETs are used as the switching
elements of the buck controller. Both high−side and
low−side MOSFETs must be logic−level MOSFETs which
can be fully turned on at 5.0 V gate−drive voltage.
On−resistance (R
), maximum drain−to−source
DS(on)
voltage (V ), maximum drain current rating, and gate
DSS
charges (Q , Q , Q ) are the key parameters to be
G
GD
GS
considered when choosing the MOSFETs.
For on−resistance, it should be the lower; the better is the
performance in terms of efficiency and power dissipation.
Check the MOSFET’s rated R
at V = 4.5 Vwhen
GS
Inductor Selection
DS(on)
selecting the MOSFETs. The low−side MOSFET should
have lower R than the high−side MOSFET since the
turn−on time of the low−side MOSFET is much longer than
The inductor should be chosen according to the inductor
ripple current, inductance, maximum current rating,
transient load release, and DCR.
DS(on)
the high−side MOSFET in high V and low V
converter. Generally, high−side MOSFET with R
buck
In general, the inductor ripple current is 20% to 40% of
the maximum load current. A ripple current of 30% of the
maximum load current can be used as a typical value. The
required inductance can be estimated by:
IN
OUT
DS(on)
about
about 7.0 mW and low−side MOSFET with R
DS(on)
5.0 mW can achieve good efficiency.
The maximum drain current rating of the high−side
MOSFET and low−side MOSFET must be higher than the
peak inductor current at maximum load current. The
low−side MOSFET should have larger maximum drain
current rating than the high−side MOSFET since the
low−side MOSFET have longer turn−on time.
(V −V
IN OUT
0.3 I
LOAD(max)
) V
OUT
V f
IN SW
(eq. 15)
L w
where I
is the maximum load current.
The DC current rating of the inductor should be about 1.2
times of the peak inductor current at maximum output load
LOAD(max)
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20
NCP5214
The maximum drain−to−source voltage rating of the
MOSFETs used in buck converter should be at least 1.2 times
of the maximum input voltage. Generally, V of 30 V
left floating for normal operation. The voltage drop across
RL1 must be less than 1.0 V to allow enough headroom for
the voltage detection at the OCDDQ pin under low VIN
DSS
should be sufficient for both high−side MOSFET and
low−side MOSFET of the buck converter for notebook
application.
condition. In addition, since the MOSFET R
with temperature as current flows through the MOSFET
increases, the OCP trip point also varies with the MOSFET
varies
DS(on)
As a general rule of thumb, the gate charges are the
R
temperature variation.
DS(on)
smaller; the better is the MOSFET while R
is still low
Since the IOC and R
have device variations and
DS(on)
DS(on)
enough. MOSFETs are susceptible to false turn−on under
high dV/dt and high VDS conditions. Under high dV/dt and
MOSFET R
increase with temperature, to avoid false
DS(on)
triggering the overcurrent protection in normal operating
output load range, calculate the RL1 value from the
previous equation with the following conditions such that
minimum value of inductor current limit is set:
1. The minimum IOC value from the specification
table.
high V condition, current will flow through the C of
DS
GD
the capacitor divider formed by C and C , cause the
GD
GS
C
to charge up and the V to rise. If the V rises above
GS GS
GS
the threshold voltage, the MOSFET will turn on.
Therefore, it should be checked that the low−side MOSFET
have low Q to Q ratio. This indicates that the low−side
2. The maximum R
of the MOSFET used at
DS(on)
GD
GS
MOSFET have better immunity to short moment false
turn−on due to high dV/dt during the turn−on of the
high−side MOSFET. Such short moment false turn−on will
cause minor shoot−through current which will degrade
efficiency, especially at high input voltage condition.
the highest junction temperature.
3. Determine I for I > I +
LOAD(max)
LIMIT
LIMIT
I
I
2, where I
= I
+
L(ripple)/
LOAD(max)
VDDQ(max)
if VTT is powered by VDDQ.
VTT(max)
Besides, a decoupling capacitor CDCPL should be added
closed to the lead of the current limit setting resistor RL1
which connected to the drain of the high−side MOSFET.
Overcurrent Protection of VDDQ Buck Regulator
The OCP circuit is configured to set the current limit for
the current flowing through the high−side FET and
inductor during S0 and S3. The overcurrent tripping level
is programmed by an external resistor RL1 connected
between the OCDDQ pin and drain of the high−side FET.
An internal 31 mA current sink (IOC) at pin OCDDQ
establishes a voltage drop across the resistor RL1 at a
magnitude of RL1xIOC and develops a voltage at the
non−inverting input of the current limit comparator.
Another voltage drop is established across the high−side
Loop Compensation
Once the output LC filter components have been
determined, the compensation network components can be
selected. Since NCP5214 is a voltage mode PWM
converter with output LC filter, Type III compensation
network is required to obtain the desired close loop
bandwidth and phase boost with unconditional stability.
The NCP5214 PWM modulator, output LC filter and
Type III compensation network are shown in Figure 39.
The output LC filter has a double pole and a single zero.
The double pole is due to the inductance of the inductor and
capacitance of the output capacitor, while the single zero
is due to the ESR and capacitance of the output capacitor.
The Type III compensation has two RC pole−zero pairs.
The two zeros are used to compensate the LC double pole
and provide 180° phase boost. The two poles are used to
compensate the ESR zero and provide controlled gain
roll−off. For an ideally compensated system, the Bode plot
should have the close−loop gain roll−off with a slope of
−20 dB/decade crossing the 0 dB with the required
bandwidth and the phase margin larger than 45° for all
frequencies below the 0 dB frequency. The closed loop
gain is obtained by adding the modulator and filter gain (in
dB) to the compensation gain (in dB).The bandwidth is the
frequency at which the gain is 0 dB and the phase margin
is the difference between the close loop phase and 180°.
The goal of compensation is to achieve a stable close loop
system with the highest possible bandwidth, the gain
having −20 dB/decade slope at 0 dB gain crossing, and
sufficient phase margin for stability. The bandwidth of
close loop gain should be less than 50% of the switching
frequency and the compensation gain should be bounded
by the error amplifier open loop gain.
MOSFET R
at a magnitude of ILxR
and a
DS(on)
DS(on)
voltage is developed at SWDDQ when the high−side
MOSFET is turned on and the inductor current flows
through the R
of the MOSFET. The voltage at the
DS(on)
non−inverting input of the current limit comparator is then
compared to the voltage at SWDDQ pin when the
high−side gate drive is high after a fixed period of blanking
time (150 ns) to avoid false current limit triggering. When
the voltage at SWDDQ is lower than the voltage at the
non−inverting input of the current limit comparator for four
consecutive internal clock cycles, an overcurrent condition
occurs, during which, all outputs will be latched off to
protect against a short−to−ground condition on SWDDQ or
VDDQ. i.e., the voltage drop across the R
of
DS(on)
high−side FET developed by the drain current is larger than
the voltage drop across RL1, the OCP is triggered and the
device will be latched off.
The overcurrent protection will trip when a peak inductor
current hit the I
determined by the equation:
LIMIT
RL1 IOC
I
+
(eq. 19)
LIMIT
R
DS(on)
It should be noted that the OCDDQ pin must be pulled
high to VIN through a resistor RL1 and this pin cannot be
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NCP5214
VIN
CIN
NCP5214
VBOOST
Q1
Q2
TGDDQ
VDDQ
L
VDDQ
PWM
LOGIC
SWDDQ
BGDDQ
VCCP
PGND
ESR
OUTPUT
FILTER
COUT
PGND
PWM
COMP
OSC
COMP
C2
C3
R4
ERROR
AMP
VIN
C1
VREF
COMPENSATION
NETWORK
R1
R2
VRAMP
R3
ADAPTIVE
RAMP
A
FBDDQ
MODULATOR
Figure 39. Voltage Mode Buck Converter with Modulator, LC filter and Type III Compensation
Modulator DC Gain can be calculated by:
Type III compensation poles and zeros break frequencies
are defined by the below equations:
V
IN
(eq. 20)
G
+ 20 log
MOD(DC)
V
1
RAMP
(eq. 24)
f
+
Z1
2p R C
3
2
LC filter double pole and ESR zero break frequencies are
defined by:
1
ǒ
f
+
P1
(eq. 25)
C
1
C
1
C
)C
2
2
Ǔ
2p R
1
3
f
+
(eq. 21)
PLC
Ǹ
2p L C
OUT
1
(eq. 26)
(eq. 27)
f
+
Z2
2p (R ) R ) C
1
1
4
3
(eq. 22)
f
+
ZESR
2p ESR C
OUT
1
f
+
P2
Compensation network DC Gain can be calculated by the
equation:
2p R C
4
3
R
3
R
1
(eq. 23)
G
+ 20 log
COMP(DC)
100
f
Z1
f
Z2
f
80
60
40
20
P1
f
P2
Open Loop Error
Amp Gain
Compensation
Gain
0
R
R
3
1
20 log
20 log
−20
−40
Closed Loop Gain
V
IN
Modulator & Filter Gain
f
ZESR
PLC
V
RAMP
f
−60
10
100
1 k
10 k 100 k 1 M 10 M
FREQUENCY (Hz)
Figure 40. Asymptotic Bode Plot of the Converter Gain
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NCP5214
Close loop system bandwidth can be calculated by:
By using the above equations and guidelines, the
compensation components values can be determined by the
equations below:
R
R
V
3
1
IN
1
BW +
(eq. 28)
Ǹ
V
RAMP
2p L C
OUT
Ǹ
2p BW V
R L C
RAMP
V
1
OUT
Since the ramp amplitude of the PWM modulator has a
voltage feedforward function, the ramp amplitude is a
(eq. 30)
R
+
3
IN
function of V which can be determined by:
IN
Ǹ
2 L C
OUT
(eq. 31)
(eq. 32)
C
+
2
(eq. 29)
V
+ 1.25 V ) 0.045 (V −5.0 V)
IN
RAMP
R
3
Below are some guidelines for setting the compensation
components:
C
2
+ ǒ
Ǔ* 1
C
1
R
C
2
3
ESR C
1. Set a value for R between 2.0 kW and 5.0 kW.
OUT
1
2. Set a target for the close loop bandwidth which
should be less than 50% of the switching
frequency.
R
1
(eq. 33)
(eq. 34)
R
4
+
Ǹ
p f
SW
L C
* 1
OUT
1
3. Pick compensation DC gain (R /R ) for desired
3
1
C
3
+
p R f
4
SW
close loop bandwidth.
The modulator and filter gain, compensation gain, and
close loop gain asymptotic Bode plot can be drawn by the
calculated results to check the compensation gain and close
loop gain obtained. An example of asymptotic Bode plot is
shown in Figure 40.
4. Place 1st zero at half filter double pole.
5. Place 1st pole at ESR zero.
6. Place 2nd zero at filter double pole.
7. Place 2nd pole at half the switching frequency.
The phase of the output filter can be calculated by:
2pf ESR ) DCR C
OUT
−1
−1
ǒ
Ǔ
Phase
+ −tan (2pf ESR C
)−tan
(eq. 35)
(Filter)
OUT
2
2pf L C
−1
OUT
where the DCR of the inductor can be neglected if the DCR is small.
The phase of the Type III compensation network can be calculated by:
C C
C ) C
1
1
2
2
−1
−1
ǒ2pf R
Ǔ
Phase
+ −90° ) tan (2pf R C )−tan
(TypeIII)
3
2
3
(eq. 36)
(eq. 39)
−1
−1
) tan (2pf (R ) R ) C )−tan (2pf R C )
1
4
3
4
3
The close loop phase can be calculated by summing the
filter phase and compensation phase:
0.8 R
1
R
2
+
V
OUT
−0.8
Phase
+ Phase
) Phase
(Filter) (TypeIII)
It is recommended to adjust the value of R to fine−tune
(CloseLoop)
2
the output voltage when it is necessary. The value of R
1
(eq. 37)
should not be changed since the compensation DC gain and
the 2 zero break frequency of the compensation gain are
Then the close loop phase margin can be estimated by:
nd
Phase
+ Phase
* (*180°)
(Margin)
(CloseLoop)
contributed by R . If the value of R is changed, the
1
1
(eq. 38)
compensation, the close loop bandwidth and phase margin,
and the system stability will be affected. Besides, it is
recommended to use resistors with at least 1% tolerance for
It should be checked that closed loop gain has a 0 dB gain
crossing with −20 dB/decade slope and a phase margin of
45° or greater. The compensation components values may
require some adjustment to meet these requirements.
Besides, the compensation gain should be checked with the
error amplifier open loop gain to make sure that it is
bounded by the error amplifier open loop gain.
The poles and zeros locations and hence the
compensation network components values may need to be
further fine tuned after actual system testing and analysis.
R and R .
1
2
Soft−Start of Buck Regulator
A VDDQ soft−start feature is incorporated in the device
to prevent surge current from power supply and output
voltage overshoot during power up. When VDDQEN,
VCCA, and VOCDDQ rise above their respective upper
threshold voltages, the external soft−start capacitor C
SS
will be charged up by a constant current source, I . When
ss
Feedback Resistor Divider
The output voltage of the buck regulator can be adjusted
by the feedback resistor divider formed by R and R . Once
the soft−start voltage (Vcss) rises above the SS_EN voltage
(X50 mV), the BGDDQ and TGDDQ will start switching
and VDDQ output will ramp up with VFBDDQ following
the soft−start voltage. When the soft−start voltage reaches
the SS_OK voltage (XVref + 50 mV), the soft−start of
1
2
the value of R is selected when determining the
1
compensation components, the value of R can be obtained
2
by:
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23
NCP5214
VDDQ is finished. The C will continue to charge up until
it reaches about 2.5 V to 3.0 V.
to VTTGND with at least a 10 mF capacitor if external
voltage source is used.
ss
The soft−start time t can be programmed by the
ss
Design Example
soft−start capacitor according to the following equation:
A design example of a VDDQ bulk converter with the
following design parameters is shown below:
0.8 C
ss
(eq. 40)
t
ss
[
I
ss
DDR2 VDDQ bulk converter design parameters:
1. Input voltage range: 7.0 V to 20 V.
Ceramic capacitors with low tolerance and low
temperature coefficient, such as B, X5R, X7R ceramic
capacitors are recommended to be used as the C . Ceramic
capacitors with Y5V temperature characteristic are not
recommended.
2. Nominal V : 1.8 V.
OUT
SS
3. Static tolerance: 2% ("36 mV).
4. Transient tolerance: "100 mV.
5. Maximum output current: 10 A
(I
= 8.0 A, I
= 2.0 A).
Soft−Start of VTT Active Terminator
VDDQ(max)
VTT(max)
6. Load transient step: 1.0 A to 8.0 A.
7. Switching frequency: 400 kHz.
8. Bandwidth: 100 kHz.
The VTT source current limit is used as a constant
current source to charge up the VTT output capacitor
during VTT soft−start. Besides, the VTT source current
limit is reduced to about 1.0 A for 128 internal clock cycles
to minimize the inrush current during VTT soft−start.
9. Soft−start time: 400 ms.
a. Calculate input capacitor rms ripple current rating and
voltage rating:
Therefore, the VTT soft−start time t
by the equation:
can be estimated
SSVTT
2
1.836 V
8.0 V
1.836 V
8.0 V
Ǹ
* ǒ
Ǔ
I
w 10 A
+ 4.2 A
CIN(RMS)
C
VTT
OUTVTT
I
(eq. 41)
t
[
SSVTT
(eq. 42)
LIMVTSS
(eq. 43)
V
w 20 1.25 V + 25 V
where C
is the capacitance of VTT output capacitor
CIN(rating)
OUTVTT
and I
is the VTT soft−start source current limit.
LIMVTSS
Therefore, two 10 mF 25 V ceramic capacitors with 1210
size in parallel are used.
Boost Supply Diode and Capacitor
b. Calculate inductance, rated current and DCR of
inductor:
First, suppose ripple current is 0.3 times the maximum
output current, such that:
An external diode and capacitor are used to generate the
boost voltage for the supply of the high−side gate driver of
the bulk regulator. Schottky diode with low forward
voltage should be used to ensure higher floating gate drive
voltage can be applied across the gate and the source of the
high−side MOSFET. A Schottky diode with 30 V reverse
voltage and 0.5 A DC current ratings can be used as the
boost supply diode for most applications. A 0.1 mF to
0.22 mF ceramic capacitor should be sufficient as the boost
capacitor.
(20 V−1.836 V) 1.836 V
0.3 10 A 20 V 400 kHz
(eq. 44)
+ 1.39 mH
L w
Second, the overshoot requirement at load release is then
considered and supposes two 220 mF capacitors in parallel
are used as an initially guess, such that:
2
2
)
(
440 mF (100 mV )1.836 V) −(1.836 V)
Lv
+2.56 mH
0.3 7 A
2
Ǔ
ǒ7 A )
VTTI Input Power Supply for VTT and VTTR
2
(eq. 45)
Both VTT and VTTR are supplied by VTTI for sourcing
current. VTTI is normally connected to the VDDQ output
for optimum performance. If VTTI is connected to VDDQ,
no bypass capacitor is required to add to VTTI since the
bulk capacitor at VDDQ output is sufficiently large.
Besides, the maximum load current of VDDQ is the sum of
Thus, inductors with standard inductance values of
1.5 mH, 1.8 mH and 2.2 mH can be used. As a trade−off
between smaller overshoot and better efficiency, the
average value of 1.8 mH inductor is selected.
Then, the maximum rated DC current is calculated by:
I
and I
when making electrical design
(20 V−1.836 V) 1.836 V
2 1.8 mH 400 kHz 20
VDDQ(max)
VTT(max)
+ 1.2 ǒ10 A )
Ǔ
I
L(rated)
and components selection of the VDDQ buck regulator.
VTTI can also be connected to an external voltage source.
However, extra power dissipation will be generated from
the internal VTT high−side MOSFET and more
heatsinking is required if the external voltage is higher than
+ 13.39 A
(eq. 46)
Therefore, inductor with maximum rated DC current of
14 A or larger can be used.
Finally, the DCR of inductor is 2.0 mW per mH of
inductance as a rule of thumb, then:
VDDQ. Whereas, the headroom will be limit by the R
DS(on)
of the VTT linear regulator high−side MOSFET, and the
maximum VTT output current with VTT within regulation
window will also be reduced if the external voltage is lower
than VDDQ. Besides, the VTTI pin input must be bypassed
2 mW
(eq. 47)
DCR +
1.8 mH + 3.6 mW
1 mH
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NCP5214
Thus, inductor with 1.8 mH inductance, 14 A maximum
Second, the ESR required to meet the transient load
undershoot requirement is considered, such that:
rated DC current and 3.5 mW DCR is chosen.
c. Calculate ESR and capacitance of output filter
capacitor:
100 mV
(eq. 49)
ESR v
+ 14.3 mW
7 A
First, the ESR required to achieve the desired output
ripple voltage is considered. Suppose the output ripple
voltage is 2% of the nominal output voltage.
Therefore, the suitable ESR is 12 mW or smaller, and the
value of 7.5 mW is selected for more design margin and
better performance. Then, two same SP−Caps or POSCAPs
each with 15 mW ESR in parallel having a resultant ESR
of 7.5 mW should be good enough to meet the
requirements.
Then, check that whether the previously supposed
capacitance meets the undershoot and overshoot
requirements.
(0.02 1.8 V) 1.8 mH 400 kHz 20 V
ESR v
(20 V−1.8 V) 1.8 V
+ 15.8 mW
(eq. 48)
To ensure that undershoot requirement of less than 100 mV is achieved, the capacitance must be:
1.8 V−36 mV
ǒ1−
Ǔ
20 V
7 A
(eq. 50)
(eq. 51)
C
w
+ 335.9 mF
ǒ Ǔ
OUT
100 mV−7 A 7.5 mW
400 kHz
To make sure that overshoot requirement of less than 100 mV is fulfilled, capacitance must be:
(20 V−1.836 V) 1.836 V
1.8 mH ǒ7 A )
(100 mV ) 1.836 V) − (1.836 V)
Ǔ2
2
2 1.8 mH 400 kHz 20 V
C
w
+ 317.6 mF
OUT
2
Therefore, output capacitor with capacitance of 440 mF
should meet both undershoot and overshoot requirements.
Sometimes, it may take several times of iterations between
the process of selecting inductance of the inductor and ESR
and capacitance of the output capacitor.
d. Calculate the resistance value of OCP current limit
setting resistor:
First, the OCP current limit is estimated at maximum
load condition, such that:
(20 V−1.836 V) 1.836 V
2 1.8 mH 400 kHz 20 V
I
u 8 A ) 2 A )
+ 11.16 A
LIMIT
Then, the voltage rating of the output capacitor is
estimated by:
(eq. 54)
(eq. 52)
V
rated
w 1.25 1.836 V + 2.3 V
Thus, I
is set to 11.5 A. Suppose from the high−side
LIMIT
Thus, output capacitor with 2.5 V or larger rated voltage
is used.
Finally, the rated rms ripple current of the output
capacitor is considered:
MOSFET data sheet, the maximum R
is 10 mW.
DS(on)
Then, the value of RL1 is calculated by:
11.5 A 10 mW
(eq. 55)
RL1 +
+ 4.4 kW
26 mA
(20 V−1.836 V) 1.836 V
1.8 mH 400 kHz 20 V
Therefore, the resistor with standard value of 4.7 kW is
selected for RL1.
I
w
+ 2.3 A
COUT(rms)
(eq. 53)
e. Calculate the RC values of the compensation network:
Thus, capacitor with rated rms ripple current of 3.0 A or
larger should be selected. Two capacitors each with 1.5 A
rated ripple current can be connected in parallel to provide
a total of 3.0 A rated rms ripple current.
Therefore, two same capacitors in parallel each with
capacitance of 220 mF, ESR of 15 mW, rated voltage of
2.5 V, and rated rms ripple current of 1.5 A are used.
First, 4.3 kW is chosen as the value of R which is in the
1
range between 2.0 kW and 5.0 kW.
Since the worst case of stability is at the maximum V ,
IN
the close loop compensation should be considered at
maximum V . Then the ramp amplitude can be calculated
IN
as below:
V
+ 1.25 V ) 0.045 (20 V−5 V) + 1.925 V
RAMP
(eq. 56)
Since the L = 1.8 mH, C
= 440 mF, and the target close loop bandwidth is 100 kHz, the value of R can be
3
OUT
calculated as:
Ǹ
2p 100 kHz 1.925 V 4.3 kW 1.8 mH 440 mF
(eq. 57)
R
3
+
+ 7.3 kW
20 V
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NCP5214
Thus, standard value of 7.5 kW is selected for R .
Then, if the second zero break frequency is placed at the LC
filter’s double pole and the second pole is placed at half the
3
If the first zero break frequency is placed at half the LC
filter’s double pole, the value of C can be calculated by:
switching frequency, the value of R can be calculated by:
2
4
4.3 kW
Ǹ
2 1.8 mH 440 mF
R
4
+
+ 125 W
(eq. 58)
C
2
+
+ 7.5 nF
Ǹ
p 400 kHz 1.8 mH 440 mF−1
7.5 kW
(eq. 60)
Thus, standard value of 8.2 nF is chosen for C2.
If the 1st pole break frequency is placed at the LC filter’s
Thus, standard value of 130 W is selected for R .
4
Then, C can be calculated by:
3
ESR zero, the value of C can be calculated by:
1
1
(eq. 61)
+ 6.12 nF
C
3
+
8.2 nF
7.5 kW 8.2 nF
7.5 mW 440 mF
C
1
+
+ 464.9 pF
p 130 W 400 kHz
(eq. 59)
* 1
Therefore, standard value of 5.6 nF is selected for C .
3
Thus, standard value of 470 pF can be chosen for C .
1
However, 180 pF is selected for more phase boost at the
0 dB gain crossing.
Then, the close loop phase margin can be estimated by the following:
−1
+ −tan (2p 100 kHz 7.5 mW 440 mF)
Phase
(Filter)
2p 100 kHz 7.5 mW
−1
ǒ
Ǔ
−tan
2
2p (100 kHz) 1.8 mH 440 mF−1
+ −153.66°
−1
+ −90 ) tan (2p 100 kHz 7.5 kW 8.2 nF)
Phase
(TypeIII)
180 pF 8.2 nF
180 pF ) 8.2 nF
) tan (2p 100 kHz (4.3 kW ) 130 W) 5.6 nF)
−1
ǒ2p 100 kHz 7.5 kW
Ǔ
−tan
(eq. 62)
−1
−1
−tan (2p 100 kHz 130 W 5.6 nF)
+ 20.57°
Phase
Phase
+ −153.66° ) 20.57° + −133.09°
(closeloop)
+ Phase
−(−180°) + −133.09°−(−180°) + 46.91°
(closeloop)
(margin)
Therefore, the phase margin is large enough for stability.
f. Calculate the resistance value of feedback resistor
divider:
Therefore, a 3.44 kW resistor is selected for the low−side
feedback resistor R .
2
g. Calculate soft−start capacitor value for the desired
Since a 4.3 kW resistor is chosen as the high−side resistor
400 ms VDDQ soft−start time:
R , the resistance value of low−side resistor R can be
calculated by:
1
2
4.0 mA 400 ms
(eq. 64)
C
SS
+
+ 2.0 nF
0.8 V
0.8 4.3 kW
1.8 V−0.8 V
Therefore, 2.0 nF X5R ceramic capacitor is selected for
the soft−start capacitor.
(eq. 63)
R
2
+
+ 3.44 kW
http://onsemi.com
26
NCP5214
PCB Layout Guidelines
vias with 0.6 mm hole−diameter to help heat
dissipation and ensure good thermal capability. It
is recommended to use PCB with 1 oz or 2 oz
copper foil. The thermal pad can be connected to
either PGND ground plane or AGND ground
plane but not both.
Cautious PCB layout design is very critical to ensure
high performance and stable operation of the DDR power
controller. The following items must be considered when
preparing PCB layout:
1. All high−current traces must be kept as short and
wide as possible to reduce power loss.
5. The input capacitor ground terminal, the VDDQ
output capacitor ground terminal and the source
of the low−side MOSFET must be connected to
the PGND ground plane through multiple vias.
6. Sensitive traces like trace from FBDDQ, trace
from COMP, trace from OCDDQ, trace from
FBVTT and trace from VTTREF should be
avoided from the high−voltage switching nodes
like SWDDQ, BOOST, TGDDQ and BGDDQ.
7. Separate sense trace should be used to connect
the VDDQ point of regulation, which is usually
the local bypass capacitor for load, to the
feedback resistor divider to ensure accurate
voltage sensing. The feedback resistor divider
should be place close to the FBDDQ pin.
8. Separate sense trace should be used to connect the
VTT point of regulation, which is usually the local
bypass capacitor for load, to the FBVTT pin.
9. Separate sense trace should be used to connect
the VDDQ point of regulation to the DDQREF
pin to ensure that the reference voltage to VTT is
accurately half of the VDDQ voltage.
10. The traces length between the gate driver outputs
and gates of the MOSFETs must be minimized to
avoid parasitic impedance.
11. To ensure normal function of the device, an RC
filter should be placed close to the VCCA pin and
a decoupling capacitor should be placed close to
the VCCP pin.
12. The copper trace area of the switching node which
includes the source of the high−side MOSFET,
drain of the low−side MOSFET and high voltage
side of the inductor should be minimized by using
short wide trace to reduce EMI.
13. A snubber circuit consists of a 3.3 W resistor and
1.0 nF capacitor may need to be connected across
the switching node and PGND to reduce the
high−frequency ringing occurring at the rising
edge of the switching waveform to obtain more
accurate inductor current limit sensing of the
VDDQ buck converter. However, adding this
snubber circuit will slightly reduce the conversion
efficiency.
High−current traces are the trace from the input
voltage terminal to the drain of the high−side
MOSFET, the trace from the source of the
high−side MOSFET to the inductor, the trace
from inductor to the VDDQ output terminal, the
trace from the input ground terminal to the
VDDQ output ground terminal, the trace from
VDDQ output to VTTI pin, the trace from VTT
pin to VTT output terminal, and the trace from
VTT output ground terminal to the VTTGND pin.
Power handling and heaksinking of high−current
traces can be improved by also routing the same
high−current traces in the other layers and joined
together with multiple vias.
2. Power components which include the input
capacitor, high−side MOSFET, low−side
MOSFET and VDDQ output capacitor of the
buck converter section must be positioned close
together to minimize the current loop. The input
capacitor must be placed close to the drain of the
high−side MOSFET and the source of the
low−side MOSFET.
3. To ensure the proper function of the device,
separated ground connections should be used for
different parts of the application circuit according
to their functions. The input capacitor ground, the
low−side MOSFET source, the VDDQ output
capacitor ground, the VCCP decoupling capacitor
ground should be connected to the PGND. The
trace path connecting the source of the low−side
MOSFET and PGND pin should be minimized.
The VTT output capacitor ground should be
connected to the VTTGND first with a short
trace, it is then connected to the ground plane of
PGND. The VCCA decoupling capacitor ground,
the ground of the VDDQ feedback resistor, the
soft−start capacitor ground, the VTTREF output
capacitor ground should be connected to the
AGND. The AGND pin is then connected directly
through a sense trace to the remote ground sense
point of the PGND, which is usually the ground
of the local bypass capacitor for the load. Never
connect the AGND, PGND and VTTGND
together just under the thermal pad.
14. VTTI should be connected to VDDQ output with
wide and short trace if VDDQ is used as the
sourcing supply for VTT. An input capacitor of at
4. The thermal pad of the DFN−22 package should
be connected to the ground planes in the internal
layer and bottom layer from the copper pad at top
layer underneath the package through six to eight
least 10 mF should be added close to the VTTI
pin and bypassed to VTTGND if external voltage
supply is used as the VTT sourcing supply.
http://onsemi.com
27
NCP5214
VCCA
C5
U1
NCP5214
(option)
0.1 mF
16
R1
R2
R3
100 k 100 k 100 k 100 k
R4
1
2
VDDQEN OCDDQ
R6
TP5
5 V
20
17
5.6 kW
VTTEN
VCCP
BIAS SUPPLY
JP1 JP2 JP3
4.7 mF
C6
MBR0530T1
2
3
4
1
BOOST
FPWM
SS
D1
Q1
TP6
TP7
NTMS4700N
VIN
(4.5 V TO 24 V)
C7
C1
1.8 nF
C10
10 mF
C8
C9
10 mF *33 mF
ON Semiconductor
NCP5214
0.1 mF
GND
R7
18
19
TP1
TP4
15
TGDDQ
SWDDQ
(option for Vin < 8 V)
PGOOD
VTTREF
PGOOD
0 W
N−CHANNEL
30 V, 7.3 mW
NTMS4107N
14
1.8 mH, 14 A, 3.4 mW
VREF
0.9 V/15 mA
1.25 V/15 mA
AGND
VDDQ
C13
1 mF
TP8
1.8 V/10 A
2.5 V/12 A
VDDQ
C18
1 mF
TP10
TP2
L1
(option)
6
8
5
Q2
VTT
C12
150 mF
C11
150 mF
R14
3.3 W
VTT
0.9 V/ 1.5 A
1.25 V/ 1.5 A
FBVTT
VTTGND
R8
TP9
C19
C17
10 mF
21
22
12
C2
10 mF
BGDDQ
PGND
(option)
TP3
VDDQGND
0 W
1 nF
N−CHANNEL
VTTGND
5 V
C14
30 V, 4.7 mW
100 pF
R5
COMP
11
VCCA
C16
4.7 nF
C15
R11
4.3 k
C11, C12
(150 mF, 4 V, 15 mW)
R9
10 W
C4
1 mF
10 k
R10
130
LOW ESR SP−CAP UD Series
Panasonic EEFUD0G151R
(150 mF, 4 V, 18 mW)
LOW−ESR POSCAP TPE Series
SANYO 4TPE150MI
2.2 nF
10
13
7
FBDDQ
VTTI
DDQREF
AGND
(option)
C3
10 mF
* Install R12 = 3.44 k for VDDQ = 1.8 V
Install R12 = 2.02 k for VDDQ = 2.5 V
9
*
R12
3.44 k
C20
THPAD
23
10 mF
(option)
VTTGND
JP4
R13
0 W
Figure 41. Schematic Diagram of Evaluation Board
http://onsemi.com
28
NCP5214
PCB Layout of Evaluation Board
Figure 42. Silkscreen of Evaluation Board PCB
Figure 43. Top Layer of Evaluation Board
PCB Layout
Figure 45. Middle Layer2 of Evaluation
Board PCB Layout
Figure 44. Middle Layer1 of Evaluation
Board PCB Layout
Figure 46. Bottom Layer of Evaluation Board
PCB Layout
http://onsemi.com
29
NCP5214
Table 2. Bill of Materials of the Evaluation Board
Item
Qty
1
Designators
C1
Part Description
Mfg. & P/N
Remark
1
2
3
Capacitor, Ceramic, 1.8 nF/50 V 0603
Capacitor, Ceramic, 10 μF/6.3 V 0805
Capacitor, Ceramic, 10 μF/6.3 V 0805
Panasonic ECJ1VB1H182K
Panasonic ECJ2FB0J106M
Panasonic ECJ2FB0J106M
2
C2, C17
C3, C20
2
C3 & C20 are
optional
4
5
6
7
8
9
3
2
1
2
1
2
C4, C13, C18
C5, C7
C6
Capacitor, Ceramic, 1 μF/10 V 0805
Capacitor, Ceramic, 0.1 μF/25 V 0603
Capacitor, Ceramic, 4.7 μF/10 V 0603
Capacitor, Ceramic, 10 μF/25 V 1210
Capacitor, Electrolytic, 33 μF/35 V Size D
Panasonic ECJ1VB1A105M
Panasonic ECJ1VB1E104K
Panasonic ECJ2FB1C475M
Panasonic ECJ4YB1E106M
Panasonic EEVFK1V330P
C5 is optional
C9 is optional
C8, C10
C9
C11, C12
Capacitor, SP−CAP, 150 μF/4 V Size D /
Capacitor, POSCAP, 150 μF/4 V Size D
Panasonic EEFUD0G151R /
Sanyo 4TPE150MI
10
11
12
13
14
15
16
17
1
1
1
1
1
3
1
1
C14
Capacitor, Ceramic, 100 pF/50 V 0603
Capacitor, Ceramic, 2.2 nF/50 V 0603
Capacitor, Ceramic, 4.7 nF/50 V 0603
Capacitor, Ceramic, 1 nF/50 V 0603
Diode, 0.5 A 30 V schottky SOD−123
Header, 3−pin, 100 mil spacing
Panasonic ECJ1VC1H101K
Panasonic ECJ1VB1H222K
Panasonic ECJ1VB1H472K
Panasonic ECJ1VB1H102K
ON Semiconductor MBR0530T1
Any
C15
C16
C19
C19 is optional
D1
JP1, JP2, JP3
JP4
Header, 2−pin, 100 mil spacing
Any
L1
Inductor, SMD, 1.8 μH/14 A /
Inductor, SMD, 1.5 μH/17 A
Panasonic ETQP2H1R8BFA /
TOKO FDA1055−1R5M=P3
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
1
1
4
1
1
1
2
1
1
1
1
1
8
1
4
1
Q1
MOSFET, N−Channel SO−8, 30 V/14.5 A
MOSFET, N−Channel SO−8, 30 V/19 A
Resistor, 100 kW 5% 0603
Resistor, 10 W 5% 0603
ON Semiconductor NTMS4700N
ON Semiconductor NTMS4107N
Panasonic ERJ3GEYJ104V
Panasonic ERJ3GEYJ100V
Panasonic ERJ3EKF5602V
Panasonic ERJ3GEYJ0R0V
Panasonic ERJ3GEYJ0R0V
Panasonic ERJ3EKF1002V
Panasonic ERJ3EKF1300V
Panasonic ERJ3EKF4301V
Panasonic ERJ3EKF3441V
Panasonic ERJ3GEYJ3R3V
Any
Q2
R1, R2, R3, R4
R5
R6
Resistor, 5.6 kW 1% 0603
Resistor, 0 W 5% 0603
R7
R8, R13
R9
Resistor, 0 W 5% 0603
Resistor, 10 kW 1% 0603
R10
Resistor, 130 W 1% 0603
R11
Resistor, 4.3 kW 1% 0603
Resistor, 3.44 kW 1% 0603
Resistor, 3.3 W 5% 0603
R12
R14
R14 is optional
TP1 − TP8
U1
Header, single pin
2−in−1 Notebook DDR Power Controller
Shunt, 100 mil jumper
ON Semiconductor NCP5214
Any
Test Pin, 0.7 mm Diameter, 12 mm Height
Any
Place at the
GND between
C11 and C8
34
35
4
1
Bumpon, 4.44 x 0.20 transparent
4−layered PCB 2500 mil x 2000 mil
3M
Any
http://onsemi.com
30
MECHANICAL CASE OUTLINE
PACKAGE DIMENSIONS
DFN22 6*5*0.9 MM, 0.5 P
CASE 506AF−01
ISSUE A
22
DATE 15 AUG 2005
1
A
SCALE 2:1
D
B
NOTES:
1. DIMENSIONS AND TOLERANCING PER
ASME Y14.5M, 1994.
2. DIMENSIONS IN MILLIMETERS.
3. DIMENSION b APPLIES TO PLATED
TERMINALS AND IS MEASURED BETWEEN
0.25 AND 0.30 MM FROM TERMINAL
4. COPLANARITY APPLIES TO THE EXPOSED
PAD AS WELL AS THE TERMINALS.
PIN 1 LOCATION
E
0.15
C
MILLIMETERS
DIM MIN
MAX
1.00
0.05
A
A1
A3
b
0.80
0.00
0.20 REF
TOP VIEW
SIDE VIEW
0.15
C
0.18
0.30
0.10
0.08
C
C
D
D2
E
E2
e
K
6.00 BSC
3.98
4.28
A
5.00 BSC
2.98
3.28
A1
(A3)
0.50 BSC
C
0.20
0.50
−−−
0.60
SEATING
PLANE
L
D2
e
GENERIC
22 X L
1
11
MARKING DIAGRAM*
1
E2
22 X K
XXXXXXXX
XXXXXXXX
AWLYYWW
G
22
12
22 X b
0.10 C A
B
0.05
C
NOTE 3
XXXXX = Specific Device Code
A
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
BOTTOM VIEW
WL
YY
WW
G
SOLDERING FOOTPRINT
4.300
0.169
0.980
0.039
*This information is generic. Please refer to
device data sheet for actual part marking.
Pb−Free indicator, “G” or microdot “ G”,
may or may not be present.
5.770
0.227
3.130
0.123
0.340
0.013
0.280
0.011
mm
0.500
0.020
22X
20X
ǒ
Ǔ
SCALE 8:1
inches
98AON12565D
ON SEMICONDUCTOR STANDARD
DOCUMENT NUMBER:
STATUS:
Electronic versions are uncontrolled except when
accessed directly from the Document Repository. Printed
versions are uncontrolled except when stamped
“CONTROLLED COPY” in red.
NEW STANDARD:
DESCRIPTION: DFN22 6*5*0.9 MM, 0.5 P
PAGE 1 OF2
DOCUMENT NUMBER:
98AON12565D
PAGE 2 OF 2
ISSUE
REVISION
RELEASED TO PRODUCTION. REQ. BY P. CELAYA.
MODIFIED SOLDERING FOOTPRINT. REQ. BY
DATE
O
A
27 OCT 2004
15 AUG 2005
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
© Semiconductor Components Industries, LLC, 2005
Case Outline Number:
August, 2005 − Rev. 01A
506AF
onsemi,
, and other names, marks, and brands are registered and/or common law trademarks of Semiconductor Components Industries, LLC dba “onsemi” or its affiliates
and/or subsidiaries in the United States and/or other countries. onsemi owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property.
A listing of onsemi’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. onsemi reserves the right to make changes at any time to any
products or information herein, without notice. The information herein is provided “as−is” and onsemi makes no warranty, representation or guarantee regarding the accuracy of the
information, product features, availability, functionality, or suitability of its products for any particular purpose, nor does onsemi assume any liability arising out of the application or use
of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its products
and applications using onsemi products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information
provided by onsemi. “Typical” parameters which may be provided in onsemi data sheets and/or specifications can and do vary in different applications and actual performance may
vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. onsemi does not convey any license
under any of its intellectual property rights nor the rights of others. onsemi products are not designed, intended, or authorized for use as a critical component in life support systems
or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should
Buyer purchase or use onsemi products for any such unintended or unauthorized application, Buyer shall indemnify and hold onsemi and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that onsemi was negligent regarding the design or manufacture of the part. onsemi is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
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