Diodes PAM2305 User Manual

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Description

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PAM2305

1A STEP-DOWN DC-DC CONVERTER

Pin Assignments

The PAM2305 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 PAM2305 provides a power-saving Pulse-

Skipping Modulation (PSM) mode to reduce quiescent current under

light load operation to save power.

The PAM2305 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

PAM2305-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 0.1µA. Other

key features include under-voltage lockout to prevent deep battery

discharge.

The PAM2305 is available in TSOT25, DFN2x2-6 Pin and QFN3x3-16 Pin packages.

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

PAM2305

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Typical Applications Circuit

Fixed Output Voltage Adjustable Output Voltage

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1R

⎛

V

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⎜ ⎝

⎞

+×=

16.0

⎟

2R

⎠

PAM2305

Pin Descriptions

Name

TSOT25 DFN2x2-6L QFN3x3-16L

Package Name

VIN 1 3 9, 10, 11, 12

GND 2 5 1, 2, 3, 5

EN 3 2 7

VOUT/FB 4 6 4

SW 5 4 13, 14, 15 NC — 1 6, 8, 16

Functional Block Diagram

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 0.6V.

The drains of the internal main and synchronous power MOSFET.

No connection.

PAM2305

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PAM2305

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 Pin Voltage

Junction Temperature

Storage Temperature Range

Soldering Temperature

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

-65 to +150 °C

300, 5sec °C

IN

+0.3)

IN

150 °C

= +25°C, unless otherwise specified.)

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V

°C

Thermal Information

Parameter Package Symbol Max Unit

TSOT25 (Note 1)

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 here inafter.

DFN2x2-6 25

QFN3x3-16 14

TSOT25

DFN2x2-6 68

QFN3x3-16 35

TSOT25

DFN2x2-6 980

QFN3x3-16 1470

θ

JC

θ

JA

P

D

130

250

400

°C/W

mW

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PAM2305

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

PAM2305

Document number: DSxxxxx Rev. 2 - 6

= +25°C, VIN = 3.6V, VO = 1.8V, CIN = 10µF, C

A

IN

FB

IO = 100mA

O

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

V

= 2.5V to 5V, IO = 10mA

IN

I

= 1mA to 800mA

O

No load 40 70 µA

Q

VEN = 0V

= 100%

V

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

V

ΔV

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R

DS(ON)

I

V

I

PK

I

SD

OSC

LSW

I

EN

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= 10µF, L = 4.7µH, unless otherwise specified.)

OUT

2.5 5.5 V

0.588 0.6 0.612 V

0.3 %/V

-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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Typical Performance Characteristics (@T

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PAM2305

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

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PAM2305

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Typical Performance Characteristics (cont.) (@T

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PAM2305

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

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PAM2305

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