A Product Line of
Diodes Incorporated
PAM2312
1A STEP-DOWN DC-DC CONVERTER
Description
The PAM2312 is a step-down current-mode, DC-DC converter. At
heavy load, the constant frequency PWM control performs excellent
stability and transient response. To ensure the longest battery life in
portable applications, the PAM2312 provides a power-saving
Pulse- Skipping Modulation (PSM) mode to reduce quiescent current
under light load operation to save power.
The PAM2312 supports a range of input voltages from 2.5V to 5.5V,
allowing the use of a single Li+/Li-polymer cell, multiple Alkaline/NiMH
cell, USB, and other standard power sources. The output voltage is
adjustable from 0.6V to the input voltage, while the part number suffix
PAM2312-XX indicates pre-set output voltage of 3.3V, 2.8V, 2.5V,
1.8V, 1.5V, 1.2V or adjustable. All versions employ internal power
switch and synchronous rectifier to minimize external part count and
realize high efficiency. During shutdown, the input is disconnected
from the output and the shutdown current is less than 1µA. Other key
features include under-voltage lockout to prevent deep battery
discharge.
The PAM2312 is available in TSOT25 packages.
Pin Assignments
Top View
TSOT25
Applications
•
•
•
•
•
•
•
•
Cellular Phone
Portable Electronics
Wireless Devices
Cordless Phone
Computer Peripherals
Battery Powered Widgets
Electronic Scales
Digital Frame
Features
•
•
•
•
•
•
•
•
•
•
•
Efficiency up to 96%
Only 40µA (typ) Quiescent Current
Output Current: Up to 1A
Internal Synchronous Rectifier
1.5MHz Switching Frequency
Soft Start
Under-Voltage Lockout
Short Circuit Protection
Thermal Shutdown
5-pin Small TSOT25 Packages
Pb-Free Package
Typical Applications Circuit
Fixed Output Voltage
Adjustable Output Voltage
R1
⎞
⎛
⎟
V
O
=
0 .6 x
⎜
1
+
R2
⎠
⎝
PAM2312
Document number: DSxxxxx Rev. 2 - 0
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January 2013
© Diodes Incorporated
A Product Line of
Diodes Incorporated
PAM2312
Pin Descriptions
Pin
Name
TSOT25
Pin Name
Function
Chip main power supply pin.
Ground
4
2
1
5
3
VIN
GND
EN
Enable Control Input. Force this pin voltage above 1.5V, enables the chip, and below
0.3V shuts down the device.
VOUT: Output voltage feedback pin, an internal resistive divider divides the output
voltage down for comparison to the internal reference voltage.
VOUT/FB
FB:
Feedback voltage to internal error amplifier, the threshold voltage is 0.6V.
SW
The drains of the internal main and synchronous power MOSFET.
Functional Block Diagram
Absolute Maximum Ratings
(@T
A
= +25°C, unless otherwise specified.)
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
Inout Voltage
EN, FB Pin Voltage
SW Pin Voltage
Junction Temperature
Storage Temperature Range
Soldering Temperature
Rating
-0.3 to +6.0
-0.3 to V
IN
-0.3 to (V
IN
+0.3)
150
-65 to +150
300, 5sec
Unit
V
V
V
°C
°C
°C
PAM2312
Document number: DSxxxxx Rev. 2 - 0
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January 2013
© Diodes Incorporated
A Product Line of
Diodes Incorporated
PAM2312
Recommended Operating Conditions
(@T
A
= +25°C, unless otherwise specified.)
Parameter
Supply Voltage
Operation Temperature Range
Junction Temperature Range
Rating
2.5 to 5.5
-40 to +85
-40 to +125
Unit
V
°C
Thermal Information
Parameter
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
Internal Power Dissipation
Note:
Package
TSOT25 (Note 1)
TSOT25
TSOT25
Symbol
θ
JC
θ
JA
P
D
Max
130
250
400
Unit
°C/W
mW
1. The maximun output current for TSOT25 package is limited by internal power dissipation capacity as described in
Application Information here inafter.
PAM2312
Document number: DSxxxxx Rev. 2 - 0
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January 2013
© Diodes Incorporated
A Product Line of
Diodes Incorporated
PAM2312
Electrical Characteristics
(@T
A
= +25°C, V
IN
= 3.6V, V
O
= 1.8V, C
IN
= 10µF, C
OUT
= 10µF, L = 4.7µH, unless otherwise specified.)
Parameter
Input Voltage Range
Regulated Feedback Voltage
Reference Voltage Line Regulation
Regulated Output Voltage Accuracy
Peak Inductor Current
Putput Voltage Line Regulation
Output Voltage Load Regulation
Quiescent Current
Shutdown Current
Oscillator Frequency
Drain-Source On-State Resistance
SW Leakage Current
High Effiency
EN Threshold High
EN Threshold Low
EN Leakage Current
Over Temperature Protection
OTP Hysteresis
Symbol
V
IN
V
FB
ΔV
FB
V
O
I
PK
LNR
LDR
I
Q
I
SD
f
OSC
R
DS(ON)
I
LSW
η
V
EH
V
EL
I
EN
OTP
OTH
±0.01
150
30
1.5
0.3
I
O
= 100mA
V
IN
= 3V, V
FB
= 0.5V or V
O
= 90%
V
IN
= 2.5V to 5v, I
O
= 10mA
I
O
= 800mA
No Load
V
EN
= 0V
V
O
= 100%
V
FB
= 0V or V
O
= 0V
I
DS
= 100mA
P MOSFET
N MOSFET
1.2
1.5
500
0.3
0.35
±0.01
96
0.45
0.5
1
-3
1.5
0.2
0.5
40
0.5
1.5
70
1
1.8
Test Conditions
Min
2.5
0.588
0.6
0.3
+3
Typ
Max
5.5
0.612
Units
V
V
%/V
%
A
%/V
%
µA
µA
MHz
KHz
Ω
Ω
µA
%
V
V
µA
°C
°C
PAM2312
Document number: DSxxxxx Rev. 2 - 0
4 of 14
www.diodes.com
January 2013
© Diodes Incorporated
A Product Line of
Diodes Incorporated
PAM2312
Typical Performance Characteristics
(@T
A
= +25°C, C
IN
= 10µF, C
O
= 10µF, L = 4.7µH, unless otherwise specified.)
PAM2312
Document number: DSxxxxx Rev. 2 - 0
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www.diodes.com
January 2013
© Diodes Incorporated
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