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3A ADJUSTABLE LOW VOLTAGE LOW DROPOUT CMOS REGULATOR
Description
The PAM3131 is a 3A CMOS adjustable LDO regulator that features
a low quiescent current, ultra low input, output, and dropout voltages,
as well as over temperature protection. It is available in TO-263 and
PSOP-8 (Exposed Pad) packages. The output voltage is adjustable
from 0.9V to 3.3V. The PAM3131 is stable with a ceramic output
capacitor of 1.0μF or higher.
This family of regulators can provide either a stand alone power
supply solution or act as a post regulator for switch mode power
supplies. They are particularly well suited for applications requiring
low input and output voltages.
Features
• Low-Dropout Regulator Supports Input Voltages Down to 1.4V
• Low Dropout Voltage: 300mV@ 3A
• Output Voltage Adjustable from 0.9V-3.3V
• Stable with a Ceramic Output Capacitor of 1.0μF or Higher
• Low Quiescent Current
• Current Limit
• Over Temperature Shutdown
• Short Circuit Current Protection
• Low Temperature Coefficient
• Standard TO-263 and PSOP-8 (Exposed Pad) Packages
• Pb-Free Package
Pin Assignments
Applications
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PAM3131
Typical Applications Circuit
• DSP, FPGA, and Microprocessor Power Supplies
• 1.2V Core Voltage for DSPs
• SATA Power Supply
• LCD TV/ Monitors
• Wireless Devices
• Communication Devices
• Portable Electronics
• Post Regulator for SMPS
PAM3131
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Pin Description
Pin Name
VIN
EN
ADJ
VOUT
GND 3 1, 4, 8 Ground
PWRGD — 5 Power Good
Pin Number
TO263-5L PSOP-8(EPD)
1 2 Input
2 3 Enable Pin
4 6 Adjustable Pin
5 7 Output
Function
Functional Block Diagram
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PAM3131
Absolute Maximum Ratings (@T
These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may
affect device reliability. All voltages are with respect to ground.
Parameter Rating Unit
Input Voltage 4.0 V
Output Pin Voltage
Operation Temperature Range -40 to +85 °C
Operation Junction Range -40 to +125 °C
Maximum Output Current
Storage Temperature -65 to +150 °C
Maximum Junction Temperature 150 °C
Soldering Temperature 300, (5sec) °C
PAM3131
Document number: DSxxxxx Rev. 1 - 1
= +25°C, unless otherwise specified.)
A
-0.3 to V
P
/(VIN–VO)
D
+0.3
IN
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V
—
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Diodes Incorporated
Recommended Operating Conditions (@T
Parameter Rating Unit
Supply Voltage Range 1.4 to 3.6 V
Operation Temperature Range -40 to +85
Junction Temperataure Range -40 to +125
= +25°C, unless otherwise specified.)
A
Thermal Information
Parameter Symbol Package Max Unit
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
Internal Power Dissipation (TA = 25°C) PD
θ
θ
PAM3131
Document number: DSxxxxx Rev. 1 - 1
JC
JA
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TO-263 7
PSOP-8 10
TO-263 35
PSOP-8 50
TO-263 2800
PSOP-8 2000
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°C
°C/W
mW
PAM3131
October 2012
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PAM3131
Electrical Characteristics (@T
Parameter Symbol Test Conditions Min Typ Max Units
Input Voltage Range
ADJ Reference Voltage
Dropout Voltage
Short Circuit Current
Output Current
Quiescent Current
Ground Pin Current
Line Regulation LNR
Load Regulation LDR
Over Temperature Shutdown OTS 150 °C
Over Temperature Hysteresis OTH 50 °C
Temperature Coefficient
Power Supply Ripple Rejection PSRR
Output Noise Vn f = 10Hz to 100kHz 40
Notes: 1. The minimum input voltage ( ) of the PAM3131 is determined by output voltage and dropout voltage. The minimum input voltage is defined as:
2. Output current is limited by P
PAM3131
Document number: DSxxxxx Rev. 1 - 1
D
= +25°C, VIN = VO +1V, CIN = 4.7µF, CO = 4.7µF, unless otherwise specified.)
A
V
IN
IO = 100mA
V
REF
= 500mA
I
O
V
DROP
IO = 3.0A
I
VO < 0.3V
SC
3.0 Note 2 A
IO = 0mA
VO > 0.8V
V
≤ 2.5V, IO = 10mA
O
= VO +0.5V to VO +1.5V
V
IN
I
GND
I
O
I
Q
VO > 2.5V, IO = 10mA
= 3.3V to 3.6V
V
IN
I
= 1mA to 3.0A, VIN = V
O
T
, maximum IO = PD/(V
40 ppm/°C
C
= 100mA, VO = 1.5V
I
O
IN(MAX)
-VO).
V
= 0.9V
O
VO = 1.0V
2.5V > VO ≥ 1.2V
VO ≥ 2.5V
= 0.9V
V
O
VO = 1.0V
2.5V > VO ≥ 1.2V
VO ≥ 2.5V
+0.5A
O
f = 100Hz 64
f = 1kHz 58
Note 1 3.6 V
0.882 0.900 0.918 V
330 500
220 400
50 200
40 150
500
400
350
300
1.0 A
90 150 µA
1.0 mA
0.2 1.0 %/V
0.5 2 %/A
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µV
mV
dB
RMS
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Typical Performance Characteristics (@T
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= +25°C, CIN =4.7µF, CO = 2.2µF, unless otherwise specified.)
A
PAM3131
PAM3131
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Typical Performance Characteristics (cont.) (@T
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PAM3131
= +25°C, CIN =4.7µF, CO = 2.2µF, unless otherwise specified.)
A
PAM3131
Document number: DSxxxxx Rev. 1 - 1
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Typical Performance Characteristics (cont.) (@T
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PAM3131
= +25°C, CIN =4.7µF, CO = 2.2µF, unless otherwise specified.)
A
PAM3131
Document number: DSxxxxx Rev. 1 - 1
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Typical Performance Characteristics (cont.) (@T
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PAM3131
= +25°C, CIN =4.7µF, CO = 2.2µF, unless otherwise specified.)
A
PAM3131
Document number: DSxxxxx Rev. 1 - 1
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Typical Performance Characteristics (cont.) (@T
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PAM3131
= +25°C, CIN =4.7µF, CO = 2.2µF, unless otherwise specified.)
A
PAM3131
Document number: DSxxxxx Rev. 1 - 1
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PAM3131
Application Information
The PAM3116 family of low-dropout (LDO) regulators have several features that allow them to apply to a wide range of applications. The family
operates with very low input voltage and low dropout voltage (typically 300mV at full load), making it an efficient stand-alone power supply or
post regulator for battery or switch mode power supplies. The 1.5A output current make the PAM3116 family suitable for powering many
microprocessors and FPGA suppl ies. The PAM3116 family also has low output noise (typically 50μVRMS with 4.7μF output capacitor), making it
ideal for use in telecom equipment.
External Capacitor Requirements
A 4.7μF or larger ceramic input bypass capacitor, connected between VIN and GND and located close to the PAM3116, is required for stability. A
4.7µF minimum value capacitor from V
additional 1 0μF or larger, low ESR capacitor is recommended at the output. A higher-value, low ESR output capacitor may be necessary if large,
fast-rise-time load transients are anticipated and the device is located several inches from the power source, especially if the minimum input
voltage of 2.5V is used.
Regulator Protection
The PAM3116 features internal current limiting, thermal protection and short circuit protection. During normal operation, the PAM3116 limits
output current to about 2.5A. When current limiting engages, the output voltage scales back linearly until the over current condition ends. While
current limiting is designed to prevent gross device failure, care should be taken not to exceed the power dissipation ratings of the package. If the
temperature of the device exceeds +150°C, thermal-protection circuitry will shut down. Once the device has cooled down to approximatel y +40°C
below the high temp trip point, regulator operation resumes. The short circuit current of the PAM3116 is about 0.7A when its output pin is shorted
to ground.
Thermal Information
The amount of heat that an LDO linear regulator generates is:
All integrated circuits have a maximum allowable junction temperature (T
must design the operating environment so that the operating junction temperature (T
). The two main environmental variables that a designer can use to improve thermal performance are air flow and external heat sinks.
(T
J(MAX)
The purpose of thi s information is to aid the designer in determining the proper operating environment for a linear regulator that is operating at a
specific power level.
In general, the maximum expected power (P
Where:
• V
• V
• I
• I
For most LDO regulators, the quiescent current is insignificant compared to the average output current; therefore, the term V
neglected. The operating junction temperature is computed by adding the ambient temperature (T
regulator's power dissipation. The temperature rise is computed by multiplying the maximum expected power dissipation by the sum of the
thermal resistances between the junction and the case R
resistances are measures of how effectively an object dissipates heat. Typically, the larger the device, the more surface area available for power
dissipation so that the object’s thermal resistance will be lowers.
()
−=
IVVP
OOIND
is the average input voltage.
I(AVG)
is the average output voltage.
O(AVG)
is the average output current.
O(AVG)
is the quiescent current.
(Q)
to GND is also required. To improve transient response, noise rejection, and ripple rejection, an
O
) above which normal operation is not assured. A system designer
J(MAX)
) does not exceed the maximum junction temperature
J
) consumed by a linear regulator is computed as:
D(MAX)
xIQ can be
I(AVG)
) and the increase in temperature due to the
A
), the case to heatsink (R
θJC
), and the heatsink to ambient (R
θCS
). Thermal
θSA
PAM3131
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Ordering Information
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PAM3131
Part Number Package Type Standard Package
PAM3131AMBR TO236-5L 800 Units/Tape&Reel
PAM3131BECR PSOP-8 2500 Units/Tape&Reel
Marking Information
PAM3131
Document number: DSxxxxx Rev. 1 - 1
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Package Outline Dimensions (All dimensions in mm.)
TO263-5L
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PAM3131
PAM3131
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Package Outline Dimensions (cont.) (All dimensions in mm.)
PSOP-8
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PAM3131
PAM3131
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PAM3131
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IMPORTANT NOTICE
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PAM3131
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