SC4212EVB [SEMTECH]
Very Low Input /Very Low Dropout 1Amp Regulator With Enable; 极低的输入/非常低压差稳压器1Amp具有使能
| 型号： | SC4212EVB |
| 厂家： | 
SEMTECH CORPORATION |
| 描述： | Very Low Input /Very Low Dropout 1Amp Regulator With Enable |
| 文件： | 总9页 (文件大小：554K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SC4212
Very Low Input /Very Low Dropout
1Amp Regulator With Enable
POWER MANAGEMENT
Features
Description
The SC4212 is a high performance positive voltage regu-
lator designed for applications requiring very low input
voltage and very low dropout voltage at up to 1 Ampere.
It operates with a VIN as low as 1.5V, with output voltage
programmable as low as 0.5V. The SC4212 features ultra
low dropout, ideal for applications where VOUT is very
close to VIN. Additionally, the SC4212 has an enable pin
to further reduce power dissipation while shutdown. The
SC4212 provides excellent regulation over variations in
line, load and temperature.
Input voltage as low as 1.5V
400mV dropout @ 1A
Adjustable output from 0.5V
Over current and over temperature protection
Enable pin
10μA quiescent current in shutdown
Low reverse leakage (output to input)
Full industrial temperature range
Available in MLPD-8 Pb-free package, fully WEEE and
RoHS compliant
The SC4212 is available in a 3 x 3 MLPD-8 package. The
output voltage can be set via external divider or to a
fixed setting of 0.5V depending upon how the FB pin
is configured.
Applications
Telecom/Networking cards
Motherboards/Peripheral cards
Industrial Applications
Wireless infrastructure
Set top boxes
Medical equipment
Notebook computers
Typical Application Circuit
SC4212
SC4212
VIN
VIN
EN
VOUT
FB
VOUT
VIN
VIN
EN
VOUT
FB
VOUT
ENABLE
R1
R2
ENABLE
C1
GND
C2
C1
GND
C2
0.5
R1+ R2
R2
Volts
VOUT =
(
)
VOUT = 0.5V
April 27, 2010
1
SC4212
Pin Configuration
Ordering Information
Part Number
Package
SC4212MLTRT(1)(2)
3mm x 3mm x 1mm MLPD-8
Evaluation Board
8
1
GND
FB
NC
TOP VIEW
SC4212EVB
Notes:
2
7
6
5
EN
(1) Only available in tape and reel packaging. A reel contains 3000 devices.
(2) Pb-free product. This product is fully WEEE and RoHS compliant.
3
VOUT
NC
VIN
T
4
NC
3mm x 3mm x 1mm MLPD-8
θJA = 36.3°C/W
Marking Information
Marking for the 3 x 3mm MLPD 8ld Lead Package:
yyww = Datecode ( Example : 0952 )
xxxx = Semtech Lot No. ( Example : E901 )
2
SC4212
Thermal Information
Absolute Maximum Ratings
Thermal Resistance, Junction to Ambient(1) .. 36.3°C/W
Thermal Resistance, Junction to Case............. 3.77°C/W
Operation Ambient Temperature Range...-40 to +85°C
Operation Junction Temperature Range ..-40 to+125°C
Storage Temperature …………………......-65 to +150°C
Peak IR Reflow Temperature (10s to 30s)……........+260°
VIN to GND ............………………………...… -0.3V to 7V
EN, FB, VOUT …………………..….... -0.3V to VIN +0.3V
ESD Rating (2)…......………………...……………… 3.5kV
Recommended Operating Conditions
Supply Input Voltage ………………......… 1.5 to 5.5V
Maximum Output Current ……………...……........... 1A
Junction Temperature …………….....… -40 to +125°C
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical
Characteristics section is not recommended.
NOTES:
(1)Calculated from package in still air, mounted to 3”x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
(2)Tested according to JEDEC standard JESD22-A114-B.
Electrical Characteristics
Unless specified otherwise: FB = VOUT, EN = VIN =, 1.5V to 5.5V, IOUT = 10μA to 1A,
TA = +25°C for Typ, -40 to +85 °C for Min and Max, TJ < 125°C.
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Input Supply
Input Supply Voltage
VIN
IQ
1.5
5.5
3
V
VIN = 3.3V, IOUT = 0A
VIN = 5.5V, EN = 0V
mA
µA
Quiescent Current
15
Output
VIN = 3.3V, IOUT = 10mA, TA = 25°C
-2%
-3%
VOUT
+2%
+3%
VOUT
Output Voltage(1)
V
1.5V < VIN < 5.5V, IOUT = 10mA
Line Regulation(1)
Load Regulation(1)
Minimum Load Current(3)
Current Limit
REG(LINE)
REG(LOAD)
IOUT
IOUT = 10mA
%/V
%/A
0.20
0.40
1.50
10
0.50
IOUT = 10mA to1A
VIN = VOUT + 0.5V
µA
A
1.10
1.5
ICL
IOUT = 500mA, TA = 25°C
IOUT = 500mA
100
250
300
400
Dropout Voltage(1)(2)
VDO
mV
IOUT = 1A, TA = 25°C
200
IOUT = 1A
500
3
SC4212
Electrical Characteristics (continued)
Parameter
Feedback
Symbol
Conditions
Min
Typ
Max
Units
V
0.495
0.490
0.505
0.510
200
VIN = 3.3V, FB = VOUT, IOUT = 10mA, TA = 25°C
Reference Voltage(1)
VREF
0.500
80
Feedback Pin Current
IFB
FB = VREF
nA
Enable
EN = 0V, VIN = 3.3V
VIN = 3.3V
1.5
10.0
0.5
µA
V
Enable Input High Current
Enable Input Threshold
IEN
VIH
VIL
1.6
VIN = 3.3V
Over Temperature Protection
High Trip Level
Hysteresis
TOT
160
10
°C
°C
TOT_HYS
Notes:
(1) Low duty cycle pulse testing with Kelvin connections required.
(2) VDO = VIN - VOUT when VOUT decreases by 1.5% of its nominal output voltage when VIN = VOUT + 0.8V.
(3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement.
4
SC4212
Typical Characteristics
Stability Curve, COUT = 100µF
Stability Curve, COUT = 10µF
IOUT (A)
IOUT (A)
Typical Dropout Voltage at VIN = 5.0 V
Typical Dropout Voltage at VIN = 1.5 V
350
300
250
200
150
100
50
450
400
350
300
250
200
150
100
50
T = 125°C
A
T = 125°C
A
T
A
= 25°C
TA = 25°C
T
A
= -40°C
T
A
= -40°C
0
0
0.0
0.1
0.2
0.3
0.4
0.5
IOUT (A)
0.6
0.7
0.8
0.9
1.0
0.0
0.1
0.2
0.3
0.4
0.5
IOUT (A)
0.6
0.7
0.8
0.9
1.0
Reference Voltage vs. Junction Temperature
Reference Voltage vs. Junction Temperature
506
505
504
503
502
501
500
499
498
497
496
495
505
504
503
502
501
500
499
498
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
TJ (ºC)
75
100
125
Tj (ºC)
5
SC4212
Pin Descriptions
Pin #
Pin Name Pin Function
1,4,5
NC
EN
No connect.
Enable Input. Pulling this pin below 0.5V turns the regulator off, reducing the quiescent current to a frac-
tion of its operating value. The device will be enabled if this pin is left open. Connect to VIN if the enable
feature is not being used.
2
Input voltage pin. For regulation at full load, the input to this pin must between ( VOUT + 0.5V ) and 5.5V.
Minimum VIN = 1.5V . A large bulk capacitance should be placed close to this pin to ensure that the input
supply does not sag below 1.5V. Also a minimum of 4.7µF ceramic capacitor should be placed directly at
this pin.
3
6
VIN
This pin is the power output of this device. A minimum 10µF capacitor should be placed directly at this
pin.
VOUT
When this pin is connected to the VOUT pin , the output voltage will be set to 0.5V . If external feedback
resistors are used , the output voltage will be determined by the resistor ratio (See Application Circuits on
page1):
0.5⋅(R1 + R2 )
R2
7
FB
VOUT
=
Volts
R1: The resistor connected from VOUT to FB.
R2: The resistor connected from FB to GND.
8
T
GND
Reference ground. The GND pin and the thermal pad must be connected together at the IC.
Thermal pad for heatsinking purposes. Not connected internally. Connect to ground plane using multiple
vias.
Thermal Pad
Block Diagram
RSENSE
VOUT
VIN
VPUMP
-
+
-
+
FB
VIN
0.5V
VIN
1.5uA
Reference
EN
Thermal
Shutdown
VOUT VIN
GND
+
-
Reverse Voltage
Shutdown
6
SC4212
Applications Information
Introduction
where an input voltage of < 1.9V is required. For applica-
tions with input voltages higher than 1.9V, the EN pin
could be left open or connected to VIN.
The SC4212 is intended for applications where high
current capability and very low dropout voltage are
required. It provides a very simple, low cost solution
that uses very little PCB real estate. Additional features
include an enable pin to allow for a very low power con-
sumption standby mode, and a fully adjustable output.
Thermal Considerations
The power dissipation in the SC4212 is approximately
equal to the product of the output current and the
input to output voltage differential:
Component Selection
PO = (VIN − VOUT)⋅IOUT
Input capacitor: A large bulk capacitance of ≥ 10µF
should be placed close to the input supply pin of the
SC4212 to ensure that VIN does not sag below 1.5V. Also
a minimum 4.7μF ceramic capacitor is recommended
to be placed directly next to the VIN pin. This allows
for the device being some distance fromany bulk ca-
pacitance on the rail. Additionally, input droop due to
load transients is reduced, improving load transient
response. Additional capacitance may be added if re-
quired by the application.
The absolute worst-case dissipation is given by:
PO(MAX) = (VIN(MAX) − VOUT(MIN) )⋅IOUT(MAX) + VIN(MAX) ⋅IQ(MAX)
For a typical scenario, VIN = 3.3V 5%, VOUT = 2.8V and
IOUT = 1A, therefore:
VIN(MAX) = 3.465V,
VOUT(MIN) = 2.744V and
IQ(MAX) = 3mA
Thus PD(MAX) = 0.731W.
Output capacitor: A minimum bulk capacitance of ≥
10μF, along with a 0.1μF ceramic decoupling capacitor
is recommended. Increasing the bulk capacitance will
improve the overall transient response.The use of mul-
tiple lower value ceramic capacitors in parallel to achieve
the desired bulk capacitance will not cause stability
issues. Although designed for use with ceramic output
capacitors, the SC4212 is extremely tolerant of output
capacitor ESR values and thus will also work comfortably
with tantalum output capacitors.
Using this figure, and assuming TA(MAX) = 70°C, we can
calculate the maximum thermal impedance allowable
to maintain TJ ≤ 125°C:
TJ(MAX) − T
125°C − 70°C
A(MAX)
°C
= 75
RTH(J−A)(MAX)
=
=
W
PO(MAX)
0.731W
This should be achievable with the 3mm x 3mm MLPD-8
package using PCB copper area to aid in conducting the
heat away, such as one square inch of copper connected
to the ground pins of the device. Internal ground/power
planes and air flow will also assist in removing heat. For
higher ambient tempertures it may be necessary to use
additional copper area.
Noise immunity: In very electrically noisy environments,
it is recommended that 0.1 μF ceramic capacitors be
placed from VIN to GND and VOUT to GND as close to the
device pins as possible.
External voltage selection resistors: The use of 1%
resistors designed for a current flow ≥ 10µA is recom-
mended to ensure a well-regulated output (thus R2 ≤
50kΩ).
Enable: Pulling the EN pin below 0.5V turns the regula-
tor off, reducing the quiescent current to a fraction of its
operating value. A pull up resistor up to 400kΩ should be
connected from the EN pin to the VIN pin in application
7
SC4212
Outline Drawing — 3mm x 3mm MLPD-8
Land Pattern — 3mm x 3mm MLPD-8
K
DIMENSIONS
INCHES MILLIMETERS
Y
DIM
C
G
H
K
P
X
Y
Z
(.116)
.087
.067
.102
.026
.016
.030
.146
(2.95)
2.20
1.70
2.58
0.65
0.40
0.75
3.70
H
X
(C)
G
Z
P
NOTES:
CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
1.
2. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
3.
THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD
SHALL BE CONNECTED TO A SYSTEM GROUND PLANE.
FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR
FUNCTIONAL PERFORMANCE OF THE DEVICE.
8
SC4212
© Semtech 2010
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rights. Semtech assumes no responsibility or liability whatsoever for any failure or unexpected operation resulting from
misuse, neglect improper installation, repair or improper handling or unusual physical or electrical stress including, but
not limited to, exposure to parameters beyond the specified maximum ratings or operation outside the specified range.
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Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805) 498-2111 Fax: (805) 498-3804
www.semtech.com
9
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