AP2003SLA - Anachip Corporation

AP2003

Synchronous PWM Controller (Preliminary)

This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of

this product. No rights under any patent accompany the sale of the product.

Rev. 0.1 Feb.10, 2004

1/6

 Features

- Single or Dual Supply Application

- 0.8V + 1.0% Voltage Reference.

- Fast transient response.

- Synchronous operation for high efficiency (95%)

- Soft Start functions

- Small size with minimum external components

- Industrial temperature range

- Under Voltage Lockout function

- SOP-8L package

 Applications

- Microprocessor core supply

- Low cost synchronous applications

- Voltage Regulator Modules (VRM)

- DDR termination supplies

- Networking power supplies

- Sequenced power supplies

 General Description

The AP2003 is a low-cost, full featured, and

synchronous voltage-mode controller designed for

use in single ended power supply applications

where efficiency is of the primary concern. This

synchronous operation allows the elimination of

heat sinks in many applications. The AP2003 is

ideal for implementing DC/DC converters needed to

power advanced microprocessors in low cost

systems, or in distributed power applications where

efficiency is important. Internal level-shift,

high-side drive circuitry, and preset shoot-thru

control, allows the use of inexpensive N-channel

power switches.

AP2003 features include temperature compensated

voltage reference, an internal 200KHz virtual

frequency oscillator, under-voltage lockout

protection, soft-start, and shutdown function.

 Pin Assignment

SOP-8L

(Top View)

VCC

GND

AP2003

DRVH

DRVL

BSTH

SENSE

SS/SHDN COMP

 Ordering Information

AP2003 X X X

Package Packing

S: SOP-8L Blank : Tube

A : Taping

Lead Free

Blank : Normal

L : Lead Free Package

 Pin Descriptions

Name Description

VCC Chip supply voltage

DRVH High side driver output

DRVL Low side driver output

BSTH Bootstrap, high side driver

SENSE Voltage sense input

COMP Compensation pin

SS/ SHDN Soft start, a capacitor to ground sets

the slow start time

GND Ground

AP2003

Synchronous PWM Controller (Preliminary)

Anachip Corp.

www.anachip.com.tw Rev. 0.1 Feb.10, 2004

2/6

 Block Diagram

DRVH

DRVL

VCC

GND

SS/SHDN

SENSE

BSTH

DRVH

DRVL

One-ShotOscillator

PWM

Foult

0.6V

0.5V

Vcc

10uA

2uA

Error Amp

Under

Voltage

Vbg

0.8V

COMP

Cross

Current

Control

 Absolute Maximum Ratings

Symbol Parameter Max. Unit

VIN VCC to GND -1 to 14 V

ΘJC Thermal Resistance Junction to Case 60 oC/W

ΘJA Thermal Resistance Junction to Ambient 160 oC/W

TOP Operating Temperature Range -40 to +85 oC

TST Storage Temperature Range -65 to +150 oC

TLEAD Lead Temperature (Soldering) 10 Sec. 300 oC

AP2003

Synchronous PWM Controller (Preliminary)

Anachip Corp.

www.anachip.com.tw Rev. 0.1 Feb.10, 2004

3/6

 Electrical Characteristics

Unless specified: VCC = 12V; GND = 0V; FB = VO; VBSTH-GND = 12V; TJ = 25oC

Symbol Parameter Conditions Min. Typ. Max. Unit

Power Supply

VCC Supply Voltage VCC 4.2 16 V

ICC Supply Current 6 10 mA

∆VLINE Line Regulation VO = 2.5V 0.5 %

Error Amplifier

AOL Gain (AOL) 50 dB

IB Input Bias 5 8 uA

Oscillator

FOSC Oscillator Frequency 180 200 220 KHz

DCMAX Oscillator Max Duty Cycle 90 95 %

Mofset Drivers

IDRVH DRVH Source/Sink VBSTH – VDRVH =4.5V

VDRVH – VPHASE = 2V 1 A

IDRVL DRVL Source/Sink VBSTH – VDRVL = 4.5V

VDRVL – VGND = 2V 1 A

Protection

TDEAD Dead Time 45 100 nS

Reference

Reference Voltage 0.792 0.8 0.808 V

VREF Accuracy 0oC to 70oC -1 + 1 %

Soft Start

ISSC Charge Current VSS = 1.5V 8.0 10 12 uA

ISSD Discharge Current VSS = 1.5V 1.3 2 2.7 uA

Under voltage lockout (UVLO)

VUT Upper threshold voltage

(VCC) 4.2 V

VLWT Lower threshold voltage

(VCC) 4.1 V

VHT Hysteresis (VCC)

IO(REF) = 0.1mA

TA = 25ºC

200 mV

Note 1. Specification refers to Typical Application Circuit.

Note 2. This device is ESD sensitive. Use of standard ESD handling precautions is required.

AP2003

Synchronous PWM Controller (Preliminary)

Anachip Corp.

www.anachip.com.tw Rev. 0.1 Feb.10, 2004

4/6

 Typical Application Circuit

(1)

Option

VCC

COMPSS/SHDN

SENSE

DRVH BSTH

GND DRVL

STP40NE

4uH

180/4V

C10

180/4V

C11

180/4V

C12

180/4V

C13

180/4V Vout=2.0V*

Vin

680/6.3V

127

191*

Note:

* Vout=0.8 x (1+R8/R7)

+12V

AP2003

10u

0.1u

R6 Option

R5 Option

(2)

Option

VCC

COMPSS/SHDN

SENSE

DRVH BSTH

GND DRVL

STP40NE

4uH

180/4V

C10

180/4V

C11

180/4V

C12

180/4V

C13

180/4V Vout=2.0V*

Vin

680/6.3V

127

191*

Note:

* Vout=0.8 x (1+R8/R7)

AP2003

10u

0.1u

R5 Option

5V input with Bootstrapped BSTH

R6 Option

AP2003

Synchronous PWM Controller (Preliminary)

Anachip Corp.

www.anachip.com.tw Rev. 0.1 Feb.10, 2004

5/6

 Function Description

Synchronous Buck Converter

Primary VCORE power is provided by a synchronous,

voltage-mode pulse width modulated (PWM)

controller. This section has all the features required

to build a high efficiency synchronous buck

converter, shutdown function.

The output voltage of the synchronous converter is

set and controlled by the output of the error

amplifier. The external resistive divider reference

voltage is derived from an internal trimmed

band-gap voltage reference. The inverting input of

the error amplifier receives its voltage from the

SENSE pin.

The internal oscillator uses an on-chip capacitor

and trimmed precision current sources to set the

oscillation frequency to 200KHz. The triangular

output of the oscillator sets the reference voltage at

the inverting input of the comparator. When the

oscillator output voltage drops below the error

amplifier output voltage, the comparator output

goes high. This pulls DRVL low, turning off the

low-side FET, and DRVH is pulled high, turning on

the high-side FET (once the cross-current control

allows it). When the oscillator voltage rises back

above the error amplifier output voltage, the

comparator output goes low. This pulls DRVH low,

turning off the high-side FET, and DRVL is pulled

high, turning on the low-side FET (once the

cross-current control allows it).

As SENSE increases, the output voltage of the

error amplifier decreases. This causes a reduction

in the on-time of the high-side MOSFET connected

to DRVH, hence lowering the output voltage.

Under Voltage Lockout

The under voltage lockout circuit of the AP2003

assures that the high-side MOSFET driver outputs

remain in the off state whenever the supply voltage

drops below set parameters. Lockout occurs if VCC

falls below 4.1V. Normal operation resumes once

VCC rises above 4.2V.

Soft Start

Initially, SS/ SHDN sources 10uA of current to

charge an external capacitor. The outputs of the

error amplifiers are clamped to a voltage

proportional to the voltage on SS/ SHDN . This

limits the on-time of the high-side MOSFETs, thus

leading to a controlled ramp-up of the output

voltages.

Hiccup Mode

During power up, the SS/ SHDN pin is internally

pulled low until VCC reaches the under-voltage

lockout level of 4.2V. Once VCC has reached 4.2V,

the SS/ SHDN pin is released and begins to source

10uA of current to the external soft-start capacitor.

As the soft-start voltage rises, the output of the

internal error amplifier is clamped to this voltage.

When the error signal reaches the level of the

internal triangular oscillator, which swings from 1V

to 2V at a fixed frequency of 200KHz, switching

occurs. As the error signal crosses over the

oscillator signal, the duty cycle of the PWM signal

continues to increase until the output comes into

regulation.

The soft-start voltage will begin to decrease as the

2uA of current discharge the external capacitor.

When the soft-start voltage reaches 0.8V, the

SS/ SHDN pin will begin to source 10uA and begin

to charge the external capacitor causing the

soft-start voltage to rise again. Again, when the

soft-start voltage reaches the level of the internal

oscillator, switching will occur.

In conclusion, above is shown a typical “12V

Application Circuit” which has a BSTH voltage

derived by bootstrapping input voltage to the

PHASE node through diode D2. This circuit is very

useful in cases where only single input power of

5V(or 12V) is available.

In order to prevent substrate glitching, a

small-signal diode should be placed in close

proximity to the chip with cathode connected to

PHASE and anode connected to GND.

AP2003

Synchronous PWM Controller (Preliminary)

Anachip Corp.

www.anachip.com.tw Rev. 0.1 Feb.10, 2004

6/6

 Marking Information

(Top View)

SOP-8L

AP2003

YY WW X X

Logo

Part No.

ID code: internal

Year: "01" =2001

"02" =2002

Xth week: 01~52

Blank: normal

L: Lead Free Package

 Package Information

Package Type: SOP-8L

VIEW "A"

7(4X) 0.015x45 7(4X)

Dimensions In Millimeters Dimensions In Inches

Symbol Min. Nom. Max. Min. Nom. Max.

A 1.40 1.60 1.75 0.055 0.063 0.069

A1 0.10 - 0.25 0.040 - 0.100

A2 1.30 1.45 1.50 0.051 0.057 0.059

B 0.33 0.41 0.51 0.013 0.016 0.020

C 0.19 0.20 0.25 0.0075 0.008 0.010

D 4.80 5.05 5.30 0.189 0.199 0.209

E 3.70 3.90 4.10 0.146 0.154 0.161

e - 1.27 - - 0.050 -

H 5.79 5.99 6.20 0.228 0.236 0.244

L 0.38 0.71 1.27 0.015 0.028 0.050

y - - 0.10 - - 0.004

θ 0O - 8O 0

O - 8O