Diodes PAM2309 User Manual
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Description
The PAM2309 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 PAM2309 provides a power-saving Pulse-
Skipping Modulation (PSM) mode to reduce quiescent current under
light load operation to save power.
The PAM2309 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. 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
0.1µA. Other key features include under-voltage lockout to prevent
deep battery discharge.
The PAM2309 is available in TSOT25, DFN2x2-6 Pin and QFN3x3-16
Pin packages.
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, DFN2x2-6 Pin and QFN3x3-16 Pin
Packages
• Pb-Free Package
Applications
Pin Assignments
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PAM2309
1A STEP-DOWN DC-DC CONVERTER
Top View
TSOT25
• Cellular Phone
• Portable Electronics
• Wireless Devices
• Cordless Phone
• Computer Peripherals
• Battery Powered Widgets
• Electronic Scales
• Digital Frame
PAM2309
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Typical Applications Circuit
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PAM2309
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Pin Descriptions
Pin
Name
VIN Chip main power supply pin.
GND Ground
EN
VOUT/FB
SW The drains of the internal main and synchronous power MOSFET.
NC Not connected
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.
FB: Feedback voltage to internal error amplifier, the threshold voltage is 0.5V.
Function
Functional Block Diagram
⎞
⎛
1R
⎟
⎜
15.0O
⎜
⎝
+×=
⎟
2R
⎠
PAM2309
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PAM2309
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 -0.3 to +6.0 V
EN, FB Pin Voltage
SW Voltage
Junction Temperature 150 °C
Storage Temperature Range -65 to +150 °C
Soldering Temperature 300, 5sec °C
Recommended Operating Conditions (@T
Parameter Rating Unit
Supply Voltage 2.5 to 5.5 V
Operation Temperature Range -40 to +85
Junction Temperature Range -40 to +125
= +25°C, unless otherwise specified.)
A
-0.3 to V
-0.3 to ( V
IN
+0.3)
IN
= +25°C, unless otherwise specified.)
A
V
V
°C
Thermal Information
Parameter
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
Internal Power Dissipation
Note: 1. The maximun output current for TSOT25 package is limited by internal power dissipation capacity as described in
Application Information hereinafter.
PAM2309
Document number: DSxxxxx Rev. 2 - 1
Package Symbol
TSOT25 (Note 1)
DFN2x2 20
QFN3x3 12
TSOT25
DFN2x2 68
QFN3x3 34
TSOT25
DFN2x2 980
QFN3x3 1470
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θ
JC
θ
JA
P
D
Max Unit
130
102
400
°C/W
mW
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PAM2309
Electrical Characteristics (@T
Parameter Symbol Test Conditions Min Typ Max Units
Input Voltage Range
Regulated Feedback Voltage
Reference Voltage Line Regulation
Regulated Output Voltage Accuracy
Peak Inductor Current
Output Voltage Line Regulation LNR
Output Voltage Load Regulation LDR
Quiescent Current
Shutdown Current
Oscillator Frequency
Drain-Source On-State Resistance
SW Leakage Current
High Efficiency η 96 %
EN Threshold High
EN Threshold Low
EN Leakage Current
Over Temperature Protection OTP 150 °C
OTP Hysteresis OTH 30 °C
PAM2309
Document number: DSxxxxx Rev. 2 - 1
= +25°C, VIN = 3.6V, VO = 1.8V, CIN = 10µF, CO = 10µF, L = 4.7µH, unless otherwise specified.)
A
V
IN
V
FB
ΔV
FB
V
I
O
I
V
PK
I
Q
I
V
SD
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OSC
R
I
DS(ON)
I
LSW
V
EH
V
EL
I
EN
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= 100mA
O
= 3V,VFB = 0.5V or VO = 90%
IN
V
= 2.5V to 5V, IO = 10mA
IN
I
= 1mA to 800mA
O
No load 40 70 µA
= 0V
EN
= 100%
V
O
VFB = 0V or VO = 0V
= 100mA
DS
P MOSFET 0.30 0.45 Ω
N MOSFET 0.35 0.50 Ω
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2.5 5.5 V
0.490 0.500 0.510 V
0.3 %/V
-3 +3 %
1.5 A
0.2 0.5 %/V
0.5 1.5 %
0.1 1.0 µA
1.2 1.5 1.8 MHz
500 kHz
±0.01 1 µA
1.5 V
0.3 V
±0.01 µA
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Typical Performance Characteristics (@T
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PAM2309
= +25°C, CIN = 10µF, CO = 10µF, L = 4.7µH, unless otherwise specified.)
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PAM2309
Document number: DSxxxxx Rev. 2 - 1
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Typical Performance Characteristics (cont.) (@T
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PAM2309
= +25°C, CIN = 10µF, CO = 10µF, L = 4.7µH, unless otherwise specified.)
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PAM2309
Document number: DSxxxxx Rev. 2 - 1
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