Diodes PAM2308 User Manual

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DUAL HIGH-EFFICIENCY PWM STEP-DOWN DC-DC CONVERTER

Description

The PAM2308 is a dual 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 PAM2308 provides a power-

saving Pulse- Skipping Modulation (PSM) mode to reduce quiescent

current under light load operation.

The PAM2308 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 dual output

voltages are available for 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 0.1µA. Other key features

include under-voltage lockout to prevent deep battery discharge.

Features

• Efficiency up to 96%

• Only 40μA (typ per channel) Quiescent Current

• Output Current: Up to 1A per Channel

• Internal Synchronous Rectifier

• 1.5MHz Switching Frequency

• Soft-Start

• Under-Voltage Lockout

• Short Circuit Protection

• Thermal Shutdown

• Small WDFN3x3-10L Packages

• Pb-Free Package and RoHS Compliant

Typical Applications Circuit

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Pin Assignments

Applications

• Cellular Phone

• Portable Electronics

• Personal Information Appliances

• Wireless and DSL Modems

• MP3 Players

PAM2308

1Rx

⎛

1

⎜

VV

REFOUTx

⎝

PAM2308

Document number: DSxxxxx Rev. 1 - 1

⎞

+=

Figure 1. Adjustable Voltage Regulator

⎟

2Rx

⎠

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Typical Applications Circuit (cont.)

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PAM2308

V

= 1.2V, 1.5V, 1.8V, 2.5V, 2.8V or 3.3V

OUTx

Figure 2. Fixed Voltage Regulator

Pin Descriptions

Pin

Name

EN1 1 Chip Enable of Channel 1(Active High). V
FB1 2

VIN2 3

GND 4, 9

LX2 5
EN2 6 Chip Enable of Channel 2 (Active High).V
FB2 7

VIN1 8

LX1 10

PAM2308

Document number: DSxxxxx Rev. 1 - 1

Pin

Number

Function

≤ V

≤ V

IN1

IN2

.

.

January 2013

© Diodes Incorporated

EN1

Feedback of Channel 1.

Power Input of Channel 2.

Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power
dissipation.

Pin for Switching of Channel 2.

EN2

Feedback of Channel 2.

Power Input of Channel 1.

Pin for Switching of Channel 1.

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Functional Block Diagram

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PAM2308

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 +6.5 V

EN1, FB1, LX1, EN2, FB2 AND LX2 Pin Voltage

Maximum Junction Temperature 150 °C

Storage Temperature Range -65 to +150 °C

Soldering Temperature 260, 10sec °C

Recommended Operating Conditions (@T

Parameter Rating Unit

Supply Voltage 2.5 to 5.5 V

Ambient Temperature Range -40 to +85

Junction Temperature Range -40 to +125

= +25°C, unless otherwise specified.)

A

-0.3 to (V

= +25°C, unless otherwise specified.)

A

+0.3)

IN

V

°C

Thermal Information

Parameter Symbol Package Max Unit

Thermal Resistance (Junction to Ambient)

Thermal Resistance (Junction to Case)

Thermal Resistance (Junction to Case)

θ

JA

θ

JC

P

D

PAM2308

Document number: DSxxxxx Rev. 1 - 1

W-DFN3x3-10 60

W-DFN3x3-10 8.5

W-DFN3x3-10 1.66 W

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°C/W

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PAM2308

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 (per channel)

Shutdown Current (per channel)

Oscillator Frequency fosc

Drain-Source On-State Resisitance

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

PAM2308

Document number: DSxxxxx Rev. 1 - 1

= +25°C, VIN = 3.6V, VO = 1.8V, CIN = 10µF, CO = 10µF, L = 2.2µH, unless otherwise specified.)

A

2.5 5.5 V

IN

0.588 0.6 0.612 V

FB

0.3 %/V

FB

IO = 100mA

O

VIN = 3V, VFB = 0.5V or VO = 90%

V

= 2.5V TO 5V, IO = 10mA

IN

I

= 1mA to 1A

O

No load 40 70 µA

Q

VEN = 0V

V

= 100%

O

VFB = 0V or VO = 0V

IDS = 100mA

±0.01 1 µA

1.5 V

EH

0.3 V

EL

±0.01 µA

P MOSFET 0.3 0.45 Ω

N MOSFET 0.35 0.5 Ω

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-3 +3 %

1.5 A

0.2 0.5 %/V

0.5 1.5 %

0.1 1 µA

1.2 1.5 1.8 MHz

500 kHz

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© Diodes Incorporated

V

ΔV

R

DS(ON)

I

V

V

V

V

I

PK

I

I

SD

LSW

I

EN

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Typical Performance Characteristics (@T

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PAM2308

= +25°C, CIN = 10µF, CO = 10µF, L = 4.7µH, unless otherwise specified.)

A

PAM2308

Document number: DSxxxxx Rev. 1 - 1

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