MIC2810-4GKYMLTR [MICROCHIP]
2-CHANNEL POWER SUPPLY SUPPORT CKT, QCC16, 3 X 3 MM, GREEN, MLF-16;
| 型号： | MIC2810-4GKYMLTR |
| 厂家： | 
MICROCHIP |
| 描述： | 2-CHANNEL POWER SUPPLY SUPPORT CKT, QCC16, 3 X 3 MM, GREEN, MLF-16 |
| 文件： | 总18页 (文件大小：508K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC2810
Digital Power Management IC
2MHz, 600mA DC/DC w/Dual
300mA/300mA Low VIN LDOs
General Description
DC/DC Converter
• 2.7V to 5.5V input voltage range
The MIC2810 is a high performance power management
IC, integrating a 2MHz DC/DC switcher with two 300mA
LDOs. The MIC2810 features a LOWQ® mode, reducing
the total current draw while in this mode to less than 30µA.
In LOWQ® mode, the output noise of the DC/DC converter
is 53µVRMS, significantly lower than other converters that
use a PFM light load mode that can interfere with sensitive
RF circuitry.
• Output current to 600mA in PWM mode
•
LOWQ® Mode: NO NOISE light load mode
– 53µVRMS Output noise in LOWQ® mode
• 2MHz PWM operation in normal mode
LDOs
• LDO1
– 1.65V to 5.5V input voltage range
– 300mA Output current
– Output voltage down to 0.8V
• LDO2
The MIC2810 is a µCap design, operating with very small
ceramic output capacitors and inductors for stability,
therefore, reducing required board space and component
cost. It is available with fixed output voltages in a 16-pin
3mm x 3mm MLF® leadless package.
– 2.7V to 5.5V input voltage range
– 300mA Output current
– Output voltage down to 0.8V
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Applications
• Mobile phones
• PDAs
• GPS receivers
• Digital still cameras
• Portable media players
Features
• 2MHz DC/DC converter and two LDOs
• Integrated power-on reset (OR function for all outputs)
– Adjustable delay time
•
LOWQ® mode
– 30µA Total IQ when in LOWQ® mode
• Tiny 16-pin 3mm x 3mm MLF® package
• Thermal shutdown protection
• Current limit protection
Typical Application
1.2V
Efficiency
OUT
MIC2810-xxxYML
90
80
70
60
50
40
30
20
10
VIN
VIN
VIN1
VIN2
EN
LDO
SW
VOUT
2.7V to 5.5V
Memory/DSP
Baseband
V =3V
IN
4.7µF
2.2µH
2.2µF
V =3.6V
IN
V =4.2V
IN
EN1
LDO1
LDO2
POR
LOWQ
EN2
BIAS
CSET
2.2µF
ceramic
2.2µF
ceramic
PGND
SGND
0.1µF
0.01µF
0
100 200 300 400 500 600
OUTPUT CURRENT (mA)
GND
GND
LOWQ is a registered trademark of Micrel, Inc.
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
M9999-022008-C
February 2008
Micrel, Inc.
MIC2810
Ordering Information
Part Number
Marking
Code
Voltage*
Junction
Temperature Range
Package
Lead Finish
MIC2810-44MYML
MIC2810-4GKYML
MIC2810-4GMYML
MIC2810-4GPYML
MIC2810-4GSYML
MIC2810-4LSYML
MIC2810-4MSYML
MIC2810-CGJYML
MIC2810-FGSYML
Notes:
YD44M
YD4GK
YD4GM
YD4GP
YD4GS
YD4LS
YD4MS
YDCGJ
YDFGS
1.2V/1.2V/2.8V
1.2V/1.8V/2.6V
1.2V/1.8V/2.8V
1.2V/1.8V/3.0V
1.2V/1.8V/3.3V
1.2V/2.7V/3.3V
1.2V/2.8V/3.3V
1.2V/1.8V/2.5V
1.5V/1.8V/3.3V
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
16-Pin 3x3 MLF®
16-Pin 3x3 MLF®
16-Pin 3x3 MLF®
16-Pin 3x3 MLF®
16-Pin 3x3 MLF®
16-Pin 3x3 MLF®
16-Pin 3x3 MLF®
16-Pin 3x3 MLF®
16-Pin 3x3 MLF®
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
MLF® is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Other voltage options available. Please contact Micrel for details.
DC/DC –Output Voltage Range of 1.0V to 2.0V.
LDO1 – Output Voltage Range of 0.8V to 3.6V.
LDO2 – Output Voltage Range of 0.8V to 3.6V.
* Refers to nominal output voltage of DC/DC, LDO1, and LDO2 respectively.
M9999-022008-C
February 2008
2
Micrel, Inc.
MIC2810
Pin Configuration
16-Pin 3mm x 3mm MLF® (ML)
Pin Description
Pin Number
Pin Name
Pin Function
LOWQ Mode. Active Low Input. Logic High = Full Power (Normal) Mode;
Logic Low = LOWQ Mode; Do not leave floating.
1
/LOWQ
BIAS
Internal circuit bias supply. It must be de-coupled to signal ground with a 0.1µF
capacitor and should not be loaded.
2
3
4
5
SGND
PGND
SW
Signal ground.
Power ground.
Switch: Internal power MOSFET output switches.
Supply Input – DC/DC and other circuitry shared with LDO1 and LDO2. Must be
connected to PIN 7.
6
VIN
7
8
VIN2
LDO2
LDO
Supply Input – LDO2. Must be connected to PIN 6.
Output of LDO2
9
LDO Output: Connect to VOUT of the DC/DC for LOWQ mode operation.
Supply Input – LDO1.
10
11
VIN1
LDO1
Output of LDO1
Power-On Reset Output: Open-drain output. Active low indicates an output
undervoltage condition on either one of the three regulated outputs.
12
13
14
15
16
POR
CSET
EN1
EN
Delay Set Input: Connect external capacitor to GND to set the internal delay for the
POR output. When left open, there is minimum delay. This pin cannot be grounded.
Enable Input (LDO 1). Active High Input. Logic High = On; Logic Low = Off; Do not
leave floating
Enable Input (DC/DC). Active High Input. Logic High = On; Logic Low = Off; Do not
leave floating.
Enable Input (LDO 2). Active High Input. Logic High = On; Logic Low = Off; Do not
leave floating
EN2
M9999-022008-C
February 2008
3
Micrel, Inc.
MIC2810
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN, VIN1, VIN2)............................... 0V to 6V
Enable Input Voltage (VEN, VEN1, VEN2)...................0V to VIN
Power Dissipation ..................................Internally Limited(3)
Lead Temperature (soldering, 10 sec.)...................... 260°C
Storage Temperature (Ts) .........................–65°C to +150°C
ESD Rating(4)..................................................................2kV
Supply Voltage (VIN, VIN2)................................. 2.7V to 5.5V
Supply Voltage (VIN1)...................................... 1.65V to 5.5V
Enable Input Voltage (VEN, VEN1, VEN2)................... 0V to VIN
Junction Temperature (TJ) ........................–40°C to +125°C
Junction Thermal Resistance
MLF-16 (θJA) ......................................................56°C/W
Electrical Characteristics(5)
VIN = VIN1 = VIN2 = EN1 = EN2 = EN = /LOWQ = VOUT(6) + 1V; COUTDC/DC = 2.2µF, CLDO1 = CLDO2 = 2.2µF; IOUTDC/DC = 100mA;
IOUTLDO1 = IOUTLDO2 = 100µA; TJ = 25°C, bold values indicate –40°C < TJ < +125°C; unless noted.
Parameter
Conditions
Rising input voltage during turn-on
Min
2.45
Typ
2.55
100
800
Max
2.65
Units
V
mV
µA
UVLO Threshold
UVLO Hysteresis
Ground Pin Current
VFB = GND (not switching);
1100
LDO1 or LDO2 (EN = GND; EN1 or EN2 = GND)
EN = EN1 = EN2 = 0V
55
0.2
38
20
85
95
5
µA
µA
µA
Ground Pin Current in
Shutdown
Ground Pin Current
(LOWQ® mode)
IDC/DC < ILDO1 < ILDO2 < 10mA (/LOWQ = GND)
60
80
70
µA
µA
µA
LDO1 or LDO2 (EN = GND; EN1 or EN2 = GND);
IOUT < 10mA (/LOWQ = GND)
Over-temperature Shutdown
160
23
°C
°C
Over-temperature Shutdown
Hysteresis
Enable Inputs (EN; EN1; EN2; /LOWQ )
Enable Input Voltage
Enable Input Current
Logic Low
0.2
V
V
Logic High
VIL < 0.2V
VIH > 1.0V
1.0
0.1
0.1
1
1
µA
µA
Turn-on Time
Turn-on Time
(LDO1 and LDO2)
Turn-on Time (DC/DC)
240
83
500
350
µs
µs
(/LOWQ = VIN; ILOAD = 300mA); (/LOWQ = GND; ILOAD
10mA)
=
POR Output
VTH
Low Threshold, % of nominal (VDC/DC or VLDO1 or VLDO2) (Flag
ON)
High Threshold, % of nominal (VDC/DC AND VLDO1 AND
VLDO2) (Flag OFF)
90
91
96
%
%
99
VOL
POR Output Logic Low Voltage; IL = 250µA
Flag Leakage Current, Flag OFF
10
100
1
mV
µA
IPOR
0.01
SET INPUT
SET Pin Current Source
SET Pin Threshold Voltage
VSET = 0V
POR = High
0.75
1.25
1.25
1.75
µA
V
M9999-022008-C
February 2008
4
Micrel, Inc.
MIC2810
Electrical Characteristics - DC/DC Converter
VIN = VOUTDC/DC + 1; EN = VIN; EN2 = EN1 = GND; IOUTDC/DC = 100mA ;L = 2.2µH; COUTDC/DC = 2.2µF; TJ = 25°C,
bold values indicate –40°C to + 125°C; unless noted.
Parameter
Conditions
Min
Typ
Max
Units
LOWQ = High (Full Power Mode)
Nominal VOUT tolerance
–2
–3
+2
+3
%
%
Fixed Output Voltages
Output Voltage Line Regulation
VOUT > 2.4V; VIN = VOUT + 300mV to 5.5V, ILOAD= 100mA
VOUT < 2.4V; VIN = 2.7V to 5.5V, ILOAD= 100mA
0.2
0.1
%/V
Output Voltage Load Regulation 20mA < ILOAD < 600mA
Maximum Duty Cycle
%
%
100
VFB ≤ 0.4V
PWM Switch ON-Resistance
ISW = 150mA VFB = 0.7VFB_NOM PMOS
ISW = -150mA VFB = 1.1VFB_NOM NMOS
0.5
0.6
2
Ω
Ω
MHz
A
Oscillator Frequency
Current Limit in PWM Mode
1.8
0.75
2.2
1.6
VFB = 0.9*VNOM
1
LOWQ = Low (Light Load Mode)
Output Voltage Accuracy
Variation from nominal VOUT
Variation from nominal VOUT; –40°C to +125°C
VIN = VOUT + 1V to 5.5V; IOUT = 100µA
–2
–3
+2
+3
0.3
0.6
1.5
%
%
%/V
%/V
Line Regulation
0.02
Load Regulation
Ripple Rejection
Current Limit
IOUT = 100µA to 50mA
f = up to 1kHz
VOUT = 0V
0.4
45
120
%
dB
mA
80
220
Output Voltage Noise
10Hz to 100KHz
53
µVRMS
M9999-022008-C
February 2008
5
Micrel, Inc.
MIC2810
Electrical Characteristics – LDO1/LDO2
VIN1 = VIN2 = VOUTLDO1 + 1.0V or VIN1 = VIN2 = VOUTLDO2 + 1.0V; EN = GND; EN1 = EN2 = VIN1 = VIN2; CLDO1 = CLDO2 = 2.2µF;
IOUTLDO1 = 100µA; TJ = 25°C, bold values indicate –40°C< TJ < +125°C; unless noted.
Parameter
Conditions
Min
Typ
Max
Units
LOWQ = High (Full Power Mode)
Output Voltage Accuracy
Variation from nominal VOUT
Variation from nominal VOUT; –40°C to +125°C
VIN = VOUT +1V to 5.5V
–2
–3
+2
+3
0.3
0.6
%
%
%/V
Line Regulation
Load Regulation
0.02
IOUT = 100µA to 150mA
IOUT = 100µA to 200mA
IOUT = 100µA to 300mA
IOUT = 150mA
IOUT = 200mA
IOUT = 300mA
f = up to 1kHz
VOUT = 0V
10Hz to 100kHz
0.20
0.25
0.40
70
94
142
35
%
%
%
mV
mV
mV
dB
mA
µVRMS
1.5
Dropout Voltage
300
Ripple Rejection
Current Limit
Output Voltage Noise
400
600
91
850
LOWQ = Low (Light Load Mode)
Output Voltage Accuracy
Variation from nominal VOUT
Variation from nominal VOUT; –40°C to +125°C
VIN = VOUT +1V to 5.5V
–3
–4
+3
+4
0.3
0.6
1.0
%
%
%/V
Line Regulation
0.02
Load Regulation
Dropout Voltage
IOUT = 100µA to 10mA
IOUT = 10mA
0.2
22
%
mV
mV
35
50
Ripple Rejection
Current Limit
f = up to 1kHz
VIN = 2.7V; VOUT = 0V
35
85
dB
mA
50
125
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max) – TA) / θJA. Exceeding the maximum allowable power
dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
5. Specification for packaged product only.
M9999-022008-C
February 2008
6
Micrel, Inc.
MIC2810
Typical Characteristics ― DC/DC Normal Mode (/LOWQ = VIN)
1.2V
Efficiency
Switching Frequency
vs. Input Voltage
Switching Frequency
vs. Temperature
OUT
90
80
70
60
50
40
30
20
10
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
V
=3V
IN
V
IN
=3.6V
V
IN
=4.2V
L = 2.2µH
C
I
= 2.2µF
OUT
OUT
/LowQ = V
V
OUT
/LowQ = V
= 3.6V
IN
= 300mA
I
= 400mA
IN
IN
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
0
100 200 300 400 500 600
OUTPUT CURRENT (mA)
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
INPUT CURRENT (V)
Load Regulation
Line Regulation
Current Limit
vs. Input Voltage
1.22
1.21
1.20
1.19
1.18
1.200
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
1.198
1.196
1.194
1.192
L = 2.2µH
L = 2.2µH
C
I
= 2.2µF
OUT
C
= 2.2µF
OUT
IN
/LowQ = V
= 300mA
OUT
V
= 3.6V
/LowQ = V
/LowQ = V
IN
IN
IN
0
100 200 300 400 500 600
OUTPUT CURRENT (mA)
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
INPUT VOLTAGE (V)
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
INPUT VOLTAGE (V)
M9999-022008-C
February 2008
7
Micrel, Inc.
MIC2810
Typical Characteristics ― DC/DC LOWQ Mode (/LOWQ = GND)
Power Supply
Load Regulation
Line Regulation
Rejection Ratio
80
70
60
50
40
30
20
10
0
1.24
1.23
1.22
1.21
1.20
1.19
1.18
1.17
1.16
1.30
1.25
1.20
1.15
1.10
V
= 3.6V
IN
OUT
OUT
C
V
OUT
= 2.2µF
V
= 1.2V
= 2.2µF
= 5mA
OUT
C
V
= 2.2µF
= 3.6V
C
I
OUT
IN
IN
= 3.6V
I
= 20mA
OUT
/LowQ = GND
/LowQ = GND
/LowQ = GND
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
INPUT VOLTAGE (V)
0.01 0.1
1
10
100 1000
0
10 20 30 40 50 60 70 80
OUTPUT CURRENT (mA)
FREQUENCY (kHz)
Current Limit
Output Noise
vs. Input Voltage
Spectral Density
380
340
300
260
220
180
140
100
60
10
1
0.1
V
V
= 4.2V
0.01
IN
= 1.2V
OUT
OUT
C
= 2.2µF
/LowQ = GND
/LowQ = GND
20
0.001
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
INPUT VOLTAGE (V)
0.01 0.1
1
10 100 1,000 10,000
FREQUENCY (kHz)
M9999-022008-C
February 2008
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Micrel, Inc.
MIC2810
Typical Characteristics ― LDO1/LDO2
Power Supply Rejection Ratio
Power Supply Rejection Ratio
LDO1 Line Regulation
LDO1[LOWQ Mode]
LDO1[Normal Mode]
80
70
2.0
1.9
1.8
1.7
1.6
V
V
= 3.6V
V
= 3.6V
IN
OUT
IN
V
= 1.2V
= 2.2µF
= 25mA
= 1.2V
70
60
50
40
30
20
10
OUT
60
50
40
30
20
10
C
I
C
I
= 2.2µF
OUT
OUT
= 100mA
OUT
OUT
/LowQ = GND
/LowQ = V
IN
C
= 2.2µF
OUT
= 3.6V
V
IN
OUT
I
= 150mA
/LowQ = V
IN
0
0
0.01 0.1
1
10
100 1000
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
INPUT VOLTAGE (V)
0.01 0.1
1
10
100 1000
FREQUENCY (kHz)
FREQUENCY (kHz)
Power Supply Rejection Ratio
Power Supply Rejection Ratio
LDO2 Load Regulation
LDO2[LOWQ Mode]
LDO2[Normal Mode]
90
80
2.85
V
V
= 3.6V
V
= 3.6V
IN
OUT
IN
V
80
70
60
50
40
30
20
10
= 2.8V
= 2.2µF
= 25mA
= 2.8V
70
60
50
40
30
20
10
OUT
C
I
C
I
= 2.2µF
OUT
OUT
= 100mA
OUT
OUT
/LowQ = GND
/LowQ = V
2.80
2.75
2.70
IN
C
IN
/LowQ = V
= 2.2µF
OUT
V
= 3.6V
IN
0
0
0.01 0.1
1
10
100 1000
0
50 100 150 200 250 300
OUTPUT CURRENT (mA)
0.01 0.1
1
10
100 1000
FREQUENCY (kHz)
FREQUENCY (kHz)
LDO2 Ground Current
vs. Output Current
LDO2 Ground Current
vs. Temperature
LDO2 Dropout Voltage
vs. Output Current
80
75
70
65
60
55
80
70
60
50
40
30
140
120
100
80
60
40
V
I
= 3.6V
OUT
V
V
= 3.6V
IN
IN
OUT
20
V
= 2.8V
= 200mA
= 2.8V
OUT
/LowQ = V
/LowQ = V
/LowQ = V
IN
IN
IN
0
0
50 100 150 200 250 300
OUTPUT CURRENT (mA)
0
50 100 150 200 250 300
OUTPUT CURRENT (mA)
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
LDO2 Dropout Voltage
vs. Temperature
LDO2 Output Noise
Spectral Density
110
100
90
10
1
0.1
80
V
= 4.2V
0.01
IN
V
OUT
/LowQ = V
= 2.8V
70
OUT
V
= 2.8V
OUT
OUT
I
= 200mA
C
= 2.2µF
IN
/LowQ = V
IN
60
0.001
-40 -20
0
20 40 60 80 100 120
0.01 0.1
1
10 100 1,000 10,000
TEMPERATURE (°C)
FREQUENCY (kHz)
M9999-022008-C
February 2008
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Micrel, Inc.
MIC2810
Functional Characteristics
LDO2[LOWQ Mode] Load Transient
LDO2[Normal Mode] Load Transient
V
V
= 3.6V
IN
= 2.8V
OUT
C
= 2.2µF
OUT
/LowQ = V
IN
45mA
200mA
V
V
= 3.6V
= 2.8V
IN
OUT
C
= 2.2µF
OUT
/LowQ = GND
1mA
10mA
Time (40µs/div)
Time (100µs/div)
DC/DC[LOWQ Mode] Load Transient
DC/DC[LOWQ Mode] Start-Up Waveforms
50mA
V
V
= 3.6V
= 1.2V
V
V
= 3.6V
IN
OUT
IN
= 1.2V
OUT
C
= 2.2µF
C
= 2.2µF
OUT
OUT
/LowQ = GND
/LowQ = GND
= 20mA
1mA
I
OUT
Time (20µs/div)
Time (40µs/div)
M9999-022008-C
February 2008
10
Micrel, Inc.
MIC2810
Functional Characteristics (cont.)
DC/DC PWM Waveforms
DC/DC Load Transient
L = 2.2µH
/LowQ = V
I = 300mA
OUT
V
V
C
= 3.6V
= 1.2V
IN
OUT
IN
= 2.2µF
OUT
V
= 3.6V
IN
V
= 1.2V
OUT
C
= 2.2µF
OUT
L = 2.2µH
/LowQ = V
300mA
IN
10mA
Time (20µs/div)
Time (400ns/div)
DC/DC Start-Up Waveforms
V
V
= 3.6V
= 1.2V
IN
OUT
C
= 2.2µF
OUT
L = 2.2µH
/LowQ = V
IN
I
= 300mA
OUT
Time (20µs/div)
M9999-022008-C
February 2008
11
Micrel, Inc.
MIC2810
Functional Diagram
MIC2810 Block Diagram
M9999-022008-C
February 2008
12
Micrel, Inc.
MIC2810
LDO1
Device Functional Description
Regulated output voltage of LDO1. Power is provided by
VIN1. Recommended output capacitance is 2.2µF.
The MIC2810 is a power management IC with a single
integrated step-down regulator and two low dropout
regulators. LDO1 and LDO2 are 300mA low dropout
regulators supplied from the input voltage pins. The
step-down regulator is a 600mA PWM power supply. All
three regulators utilize a /LOWQ light load mode to
maximize battery efficiency under light load conditions.
This is achieved with a /LOWQ control pin that when
pulled low shuts down all the biasing and drive current
for the PWM regulator, along with reducing the current
limit of the two independent LDOs. When the /LOWQ pin
is pulled low, the MIC2810 draws only 30µA of operating
current. This mode allows the output to be regulated
through the LDO output which is capable of providing
60mA of output current. This method has the advantage
of producing a clean, low current, ultra-low noise output
in /LOWQ mode. During /LOWQ mode, the SW node
becomes high impedance, blocking current flow. Other
methods of reducing quiescent current, such as pulse
frequency modulation (PFM) or bursting techniques
create large amplitude and low frequency ripple voltages
that can be detrimental to system operation.
LDO2
Regulated output voltage of LDO2. Power is provided by
VIN2. Recommended output capacitance is 2.2µF.
EN/EN1/EN2
All enable inputs are active high, requiring 1.0V for
guaranteed operation. EN provides logic control for the
DC/DC regulator. EN2 provides logic control for LDO2,
and EN1 provides logic control for LDO1. The enable
inputs are CMOS logic and cannot be left floating.
The enable pins provide logic level control of the
specified outputs. When all enable pins are in the off
state, supply current of the device is greatly reduced
(typically <1µA). When the DC/DC regulator is in the off
state, the output drive is placed in a "tri-stated" condition,
where both the high side P-channel MOSFET and the
low-side N-channel are in an “off” or non-conducting
state. Do not drive any of the enable pins above the
supply voltage.
When more than 60mA is required, the /LOWQ pin can
be forced high, causing the MIC2810 to enter PWM
mode. In this case, the LDO output makes a "hand-off"
to the PWM regulator with virtually no variation in output
voltage. The LDO output then turns off allowing up to
600mA of current to be efficiently supplied through the
PWM output to the load.
Power-On Reset (POR)
The power-on reset output is an open-drain N-Channel
device, requiring a pull-up resistor to either the input
voltage or output voltage for proper voltage levels. The
POR output has a delay time that is programmable with
a capacitor from the CSET pin to ground. The delay time
can be programmed to be as long as 1 second.
Pin Functional Description
/LOWQ
VIN/VIN1/VIN2
The /LOWQ pin provides a logic level control between
the internal PWM switching regulator mode, and the low
noise linear regulator mode. With /LOWQ pulled low
(≤0.2V), quiescent current of the device is greatly
reduced by switching to a low noise linear regulator
mode that has a typical supply current of 38µA. In linear
(LDO) mode the output can deliver 60mA of current to
the output. By placing /LOWQ high (≥1V), the device
transitions into a constant frequency PWM step-down
regulator mode. This allows the device the ability to
efficiently deliver up to 600mA of output current at the
same output voltage.
Three input voltage pins provide power to the switch
mode regulator, LDO1, and LDO2. VIN provides power
to the control circuitry of the DC/DC converter and
voltage reference circuitry shared by all the regulators in
the MIC2810. LDO1’s input voltage (VIN1) can go down
to 1.65V but LDO2 and the DC/DC converter input
voltages are limited to 2.7V minimum.
For the switch mode regulator VIN provides power to the
MOSFET along with current limiting sense circuitry. Due
to the high switching speeds, a 4.7µF capacitor is
recommended close to VIN and the power ground
(PGND) pin for bypassing. Please refer to the PCB
layout section for an example of an appropriate circuit
layout.
/LOWQ mode also limits the output load of both LDO1
and LDO2 to <50mA.
BIAS
LDO
The BIAS pin supplies the power to the internal control
and reference circuitry. The bias is powered from VIN
through an internal 6ꢀ resistor. A small 0.1µF capacitor
is recommended for bypassing.
The LDO pin is the output of the linear regulator and
should be connected to the output of the step-down
PWM regulator. In /LOWQ mode (/LOWQ <0.2V), the
LDO provides the output voltage of the DC/DC regulator.
M9999-022008-C
February 2008
13
Micrel, Inc.
SW
MIC2810
Input Capacitor
The switch (SW) pin connects directly to the inductor
and provides the switching current necessary to operate
in PWM mode. Due to the high speed switching on this
pin, the switch node should be routed away from
sensitive nodes.
A minimum 1µF ceramic, 4.7µF recommended, should
be placed as close as possible to the VIN pin for optimal
bypassing. X5R or X7R dielectrics are recommended for
the input capacitor. Y5V dielectrics lose most of their
capacitance over temperature and are therefore, not
recommended. A minimum 1µF is recommended close
to the VIN and PGND pins for high frequency filtering.
Smaller case size capacitors are recommended due to
their lower ESR and ESL. Please refer to the PCB layout
section for an example of an appropriate circuit layout.
PGND
Power ground (PGND) is the ground path for the high
current PWM mode. The current loop for the power
ground should be as small as possible.
Inductor Selection
SGND
The MIC2810 is designed for use with a 2.2µH inductor.
Proper selection should ensure the inductor can handle
the maximum average and peak currents required by the
load. Maximum current ratings of the inductor are
generally given in two methods; permissible DC current
and saturation current. Permissible DC current can be
rated either for a 40°C temperature rise or a 10% to 20%
loss in inductance. Ensure that the inductor selected can
handle the maximum operating current. When saturation
current is specified, make sure that there is enough
margin that the peak current will not saturate the
inductor. Peak inductor current can be calculated as
follows:
Signal ground (SGND) is the ground path for the biasing
and control circuitry. The current loop for the signal
ground should be as small as possible.
CSET
The CSET pin is a current source output that charges a
capacitor that sets the delay time for the power-on reset
output from low to high. The delay for POR high to low
(detecting an undervoltage on any of the outputs) is
always minimal. The current source of 1.25µA charges a
capacitor up from 0V. When the capacitor reaches
1.25V, the output of the POR is allowed to go high. The
delay time in microseconds is equal to the Cset in
picofarads.
⎛
⎞
VOUT
⎜
⎟
⎟
VOUT 1−
POR Delay (µs) = CSET (pF)
⎜
V
IN
⎝
⎠
IPK = IOUT
+
2× f ×L
Component Selection
Output Capacitor
IPK:
IOUT
VIN:
Peak Inductor Current
Output/Load Current
Input Voltage
:
LDO1 and LDO2 outputs require a 2.2µF ceramic output
capacitor for stability. The DC/DC switch mode regulator
also requires a 2.2µF ceramic output capacitor to be
stable. All output capacitor values can be increased to
improve transient response, but performance has been
optimized for a 2.2µF ceramic on the LDOs and the
DC/DC regulator. X7R/X5R dielectric-type ceramic
capacitors are recommended because of their
temperature performance. X5R/X7R-type capacitors
change capacitance by 15% over their operating
temperature range and are the most stable type of
ceramic capacitors. Z5U and Y5V dielectric capacitors
change value by as much as 50% to 60% respectively
over their operating temperature ranges.
VOUT
f:
:
Output Voltage
Switching Frequency of PWM Regulator
Inductor Value
L:
M9999-022008-C
February 2008
14
Micrel, Inc.
MIC2810
PCB Layout
EN1
J10
R2
EN
J9
Vin
R3
R4
Vin
EN2
J11
R1
C4
POR
J8
16 15 14 13
/LowQ
J12
LD01
J4
12
11
1
2
/LowQ
POR
JP1
C3
C2
LDO1
BIAS
R5
Vin
Vo
C5
3
4
10
9
SGND
VIN1
LDO
LD0
J3
PGND
5
6
7
8
Vo
VO
J6
C6
Vin
LD02
J5
L1
VIN
J1
C7
C1
GND
J7
GND
J2
Layout Schematic
M9999-022008-C
February 2008
15
Micrel, Inc.
MIC2810
Top Layer
M9999-022008-C
February 2008
16
Micrel, Inc.
MIC2810
Bottom Layer
M9999-022008-C
February 2008
17
Micrel, Inc.
MIC2810
Package Information
16-Pin 3mm x 3mm MLF® (ML)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2006 Micrel, Incorporated.
M9999-022008-C
February 2008
18
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