Document
A Product Line of Diodes Incorporated
PAM2309
1A STEP-DOWN DC-DC CONVERTER
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 PulseSkipping 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.
Pin Assignments
Top View TSOT25
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
• Cellular Phone • Portable Electronics • Wireless Devices • Cordless Phone • Computer Peripherals • Battery Powered Widgets • Electronic Scales • Digital Frame
PAM2309
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© Diodes Incorporated
Typical Applications Circuit
A Product Line of Diodes Incorporated
PAM2309
VO
=
0.5
×
⎜⎜⎛1 +
⎝
R1 ⎟⎞
R2
⎟ ⎠
Pin Descriptions
Pin Name
VIN GND EN
VOUT/FB
SW NC
Function
Chip main power supply pin. Ground 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. The drains of the internal main and synchronous power MOSFET. Not connected
Functional Block Diagram
PAM2309
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© Diodes Incorporated
A Product Line of Diodes Incorporated
PAM2309
Absolute Maximum Ratings (@TA = +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 Input Voltage EN, FB Pin Voltage
SW Voltage
Junction Temperature Storage Temperature Range Soldering Temperature
Rating -0.3 to +6.0
-0.3 to VIN -0.3 to ( VIN +0.3)
150 -65 to +150 300, 5sec
Unit V V
V °C °C °C
Recommended Operating Conditions (@TA = +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
Package TSOT25 (Note 1)
DFN2x2 QFN3x3 TSOT25 DFN2x2 QFN3x3 TSOT25 DFN2x2 QFN3x3
Symbol θJC θJA PD
Max 130 20 12 102 68 34 400 980 1470
Unit °C/W mW
Note:
1. The maximun output current for TSOT25 package is limited by internal power dissipation capacity as described in Application Information hereinafter.
PAM2309
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© Diodes Incorporated
A Product Line of Diodes Incorporated
PAM2309
Electrical Characteristics (@TA = +25°C, VIN = 3.6V, VO = 1.8V, CIN = 10µF, CO = 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 Output Voltage Line Regulation Output Voltage Load Regulation Quiescent Current Shutdown Current
Oscillator Frequency
Drain-Source On-State Resistance
SW Leakage Current High Efficiency EN Threshold High EN Threshold Low EN Leakage Current Over Temperature Protection OTP Hysteresis
Symbol VIN VFB ΔVFB VO IPK LNR LDR IQ ISD
fOSC
RDS(ON)
ILSW η
VEH VEL IEN OTP OTH
Test Conditions
IO = 100mA
VIN = 3V,VFB = 0.5V or VO = 90%
VIN = 2.5V to 5V, IO = 10mA
IO = 1mA to 800mA No load
VEN = 0V
VO = 100%
VFB = 0V or VO = 0V
IDS = 100mA
P MOSFET N MOSFET
Min 2.5 0.490 -3
1.2
1.5
Typ
0.500 0.3
1.5 0.2 0.5 40 0.1 1.5 500 0.30 0.35 ±0.01 96
±0.01 150 30
Max 5.5 0.510
+3
0.5 1.5 70 1.0 1.8
0.45 0.50
1
0.3
Units V V
%/V % A %/V % µA µA MHz kHz Ω Ω µA % V V µA °C °C
PAM2309
Document number: DSxxxxx Rev. 2 - 1
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January 2013
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