Diodes PAM2321 User Manual

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PAM2321

3MHz, FAST TRANSIENT 2A STEP-DOWN CONVERTER

Description

The PAM2321 is a 2A step-down converter with a typical input

voltage of 3.3V and a fixed output voltage of 1.2V or an adjustable

output. The 3MHz switching frequency enables the use of small

external components. The ultra-small 3mmx3mm footprint and high

efficiency make the PAM2321 an ideal choice for portable

applications.

The PAM2321 delivers 2A maximum output current while consuming

only 55µA no-load quiescent current. Low R

MOSFETs and 100% duty cycle operation make the PAM2321 the

ideal choice for high output voltage, high current applications which

require a low dropout threshold.

The PAM2321 provides excellent transient response and output

accuracy across the operating range.

The PAM2321 maintains high efficiency throughout the load range.

The PAM2321 automatically optimizes efficiency during light load

mode (PSM) and maintains constant frequency and low output ripple

during PWM mode.

Over-temperature and short circuit protection safeguard the PAM2321

and system components from damage.

The PAM2321 are available in Pb-free, ultrasmall, low profile,

TDFN3X3-10 package. The product is rated over a temperature range

of -40°C to +85°C.

DS(ON)

integrated

Features

• 2A Maximum Output Current

• Tiny 0.47µH Chip Inductor

• Excellent Transient Response

• Input Voltage: 2.7V to 5.5V

• Fixed or Adjustable Output Voltage Options:

 Fixed Output Voltage: 1.2V

 Adjustable Output Voltage: 1.0V to V

• High Efficiency with 3MHz Switching Frequency

• 55µA No Load Quiescent Current

• 100% Duty Cycle Low-Dropout Operation

• Internal Soft-Start

• Over-Temperature and Current Limit Protection

• <1µA Shutdown Current

• -40°C to +85°C Temperature Range

• Pb-Free/Halogen Free Package

IN

Pin Assignments

Applications

• Cellular Phone

• Digital Cameras

• Hard Disk Drives

• MP3 Players

• PDAs and Handheld Computers

• Portable Media Players

• USB Devices

• Wireless Network Cards

• RoHS/REACH Compliant

PAM2321

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Typical Applications Circuit

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PAM2321

Pin Descriptions

Name

PGND

PVIN

AGND

Main power ground return pin. Connect to the output and input capacitor return.

Input power supply tied to the source of the high side P-Channel MOSFET.

Power supply; supplies power for the internal circuitry.

VIN

Feedback input pin. This pin is connected directly to the converter output for the 1.2V fixed output version, or connected to an

FB

external resistor divider for the adjustable output version. Analog ground. This pin is internally connected to the analog ground of the control circuitry. Enable pin. A logic low disables the converter and it consumes less than 1μA of current. When connected high, it resumes normal

EN

operation. Switching node. Connect the inductor to this pin. It is internally connected to the drain of both high and low side MOSFETs.

SW

Exposed pad of the package provides both electrical contact to the ground and good thermal

EP

contact to the PCB. This pad must be soldered to the PCB for proper operation.

Functional Block Diagram

V

OUT

+=

Function

)

2R/1R1*6.0

PAM2321

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PAM2321

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

EN, FB Pin Voltage

SW Pin 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

+0.3)

IN

= +25°C, unless otherwise specified.)

A

V

°C

Thermal Information

Parameter Symbol Package Max Unit

Thermal Resistance (Junction to Case)

Thermal Resistance (Junction to Ambient)

Internal Power Dissipation

θ

JC

θ

JA

P

D

TDFN3x3-10 8.5

TDFN3x3-10 60

TDFN3x3-10 1.66 W

°C/W

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PAM2321

Electrical Characteristics

(@TA = +25°C, VIN = 3.3V, V

Parameter Symbol Test Conditions Min Typ Max Units

Input Voltage Range

UVLO Threshold

Output Voltage Range

Output Voltage Accuracy

Regulated Feedback Voltage

PMOS Current Limit

Output Voltage Line Regulation LNR

Output Voltage Load Regulation LDR

Quiescent Current

Shutdown Current

Oscillator Frequency

Drain-Source On-State Resisitance

SW Leakage Current

Start-Up Time

PSM Threshold

EN Threshold High

EN Threshold Low

EN Leakage Current

Over Temperature Protection OTP 150 °C

OTP Hysteresis OTH 30 °C

PAM2321

Document number: DSxxxxx Rev. 2 - 1

= 1.2V, CIN = 10µF, CO = 10µF, L = 0.47µH, unless otherwise specified.)

OUT

IN

Rising

V

IN

Hysteresis 250 mV

V

UVLO

VIN Falling

V

f

R

DS(ON)

I

OUT

V

I

LIM

I

SD

OSC

LSW

t

I

TH

V

I

EN

IO = 0mA

No Load 0.588 0.600 0.612 V

FB

V

= 3.3V to 4V

IN

I

= 1mA to 2A

O

No Load 55 90 µA

Q

VEN = 0V

IDS = 100mA

1 µA

VIN = 3.3V, VO = 1.2V

S

200 mA

1.4 V

EH

0.4 V

EL

±0.01 µA

P MOSFET 130 mΩ

N MOSFET 90 mΩ

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2.7 3.3 5.5 V

2.6 2.7 V

2 V

1 1.2

VIN

V

-3.0 +3.0 %

3.0 A

0.3 %/V

1 %/A

1 µA

3 MHz

200 µs

January 2013