AIC AIC1574 Datasheet

AIC1574

5-bit DAC, Synchronous PWM Power Regulator

with Triple Linear Controllers

Analog Integrations Corporation 4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC

www.analog.com.tw

DS-1574-00 May 22, 01 TEL: [phone] FAX: [phone]

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FEATURES

l Compatible with HIP6021.
l Provides 4 Regulated Voltages for Microprocessor

Core, AGP Bus, Memory and GTL Bus Power.

l TTL Compatible 5-bit Digital-to-Analog Core Output

Voltage Selection. Range from 1.3V to 3.5V.

0.1V Steps from 2.1V to 3.5V.

0.05V Steps from 1.3V to 2.05V.

l ±1.0% Output Voltage for VCORE, ±3.0% Accu-

racy for Linear Controller Outputs.

l Simple Voltage-Mode PWM Control and Built in

Internal Compensation Network s.

l N-Channel MOSFET Driver for PWM Buck Con-

verter.

l Linear Controller Drives Compatible with both N–

Chanel MOSFET and NPN Bipolar Series Pass
Transistor.

l Operates from +3.3V, +5V and +12V Inputs.
l Fast Transient Response.
l Full 0% to 100% Duty Ratios.
l Adjustable Current Limit without External Sense

Resistor.

l Microprocessor Core Voltage Protection against

Upper MOSFET shorted to +5V.

l Power Good Output Voltage Monitor.
l Over-Voltage and Over-Current Fault Monitors.
l 200KHz Free-Running Oscillator Programmable up

to 700KHz.

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APPLICATIONS

l Full Motherboard Power Regulation for Computers.

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DESCRIPTION

The AIC1574 combines a synchronous voltage mode
controller with three linear controller as well as the
monitoring and protection functions in this chip. The
PWM controller regulates the microprocessor core
voltage with a synchronous rectified buck converter.
The three linear controllers regulate power for the

1.5V or 3.3V AGP bus power, the 1.5V GTL bus and
the 1.8V power for the chip set core voltage and/or
cache memory circuits.

An integrated 5 bit D/A converter that adjusts the
core PWM output voltage from 2.1V to 3.5V in 0.1V
increments and from 1.3V to 2.05V in 0.05V incre­ments. The linear controller for AGP bus power is
selectable by TTL-compatible SELECT pin status for

1.5V or 3.3V with ±3% accuracy. The other two
linear controller provide 1.5V±3% and 1.8V±3% or
adjustable output voltage by means of external di­vided resistor based on FIX pin status.

This chip monitors all the output voltages. Power
Good signal is issued when the core voltage is
within ±10% of the DAC setting and the other levels
are above their under-voltage levels. Over-voltage
protection for the core output uses the lower N­channel MOSFET to prevent output voltage above
116% of the DAC setting.

The PWM over-current function monitors the output
current by using the voltage drop across the upper
MOSFET’s R

DS(ON)

, eliminating the need for a cur-

rent sensing resistor.

AIC1574

2

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TYPICAL APPLICATION

+

+

+

VAUX

DRIVE2

VSEN2

SELECT

DRIVE3

VSEN3

SD

DRIVE4

VESN4

FIX 2

9111016COUT2

Q3

+3.3VIN

3.3V or 1.5V

VOUT2

+12VIN

10

2.2µF

COUT4

1.8V

Q5

Q4

COUT3

14

VOUT4

15

VOUT3

19

18

1.5V

1

GND

2823VCC177

6

5
4
3

8

13

12

20212224252627

+

+

UGATE1

PHASE1

LGATE1

PGND

VSEN1

FB

NC

VID0
VID1
VID2
VID3

VID4

PGOOD

FAULT/RT

SS

COUT1

Css

OCSET1

L1

GND

+5VIN

D5820

1µH

L1

Q2

Q1

VOUT1

AIC1574

3

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ORDERING INFORMATION

ORDER NUMBER

PIN CONFIGURATION

AIC1574 -CX

AIC157 4CS
(SO2 8)

PACKAGING TYPE
S: SMALL OUTLINE

134257689

10

VID

1

FIX

VID4VID3DRIVE2

VID2VSEN2

VID0

SD

PGOOD

11

12

SS

SELECT

PHASE1

VCC

UGATE1

OCSET

LGATE1

PGND

2019

VSEN1

VSEN3

FBNC28262725242321221817GND

DRIVE3

13

1

4

VSEN4

FAULT/RT

1

6

15

DRIVE4

VAUX

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ABSOLUTE MAXIMUM RATINGS

Supply Voltage, VCC ...............…………….....…………...……...…..……..................... +15V

PGOOD, FAULT and GATE Voltage ...………….....………..….... GND -0.3V to VCC +0.3V

Input, Output , or I/O Voltage ......…...……………………..……............ GND -0.3V to 7V

Recommended Operating Conditions

Supply Voltage; VCC……...............…………..................... +12V±10%

Ambient temperature Range ……..………………................. 0°C~70°C

Junction Temperature Range ……......… ..…….................. 0°C~125°C

Thermal Information

Thermal Resistance, θ

JA

SOIC package ……………………………..……..…….............. 70°C/W

SOIC package (with 3in2 of copper) …...……….........…......... 50°C/W

Maximum Junction Temperature (Plastic Package) …………………..……...... 150°C

Maximum Storage Temperature Range …………………………….... -65°C ~ 150°C

Maximum Lead Temperature (Soldering 10 sec) …………………………..…... 300°C

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TEST CIRCUIT

Refer to APPLICATION CIRCUIT.

AIC1574

4

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ELECTRICAL CHARACTERISTICS (Vcc=12V, TJ=25°C, Unless otherwise specified)

PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

VCC SUPPLY CURRENT

Supply Current

UGATE, LGATE, GATE3 and
VOUT2 open

I

CC

3 mA

POWER ON RESET

Rising VCC Threshold VOCSET=4.5V V

CCTHR

10.4 V

Falling VCC Threshold VOCSET=4.5V V

CCTHF

8.2 V

Rising VAUX Threshold VAUX

THR

2.5 V

VAUX Threshold Hy steresis VAUX

HYS

500 mV

Rising VOCSET1 Threshold V

OCSETH

1.26 V
OSCILLATOR
Free Running Frequency RT=Open F 170 200 230 KHz
Total Variation 6kΩ<RT to GND<200k Ω -15 +15 %
Ramp. Amplitude RT=open ∆V

OSC

1.5 VP-P
REFERENCE AND DAC
DAC (VID0~VID4) Input Low
Voltage

V

IDL

0.8 V
DAC (VID0~VID4) Input High

Voltage

V

IDH

2.0 V

DACOUT Voltage Accuracy V

DAC

=1.8V~3.5V -1.0 +1.0 %

Bandgap Reference Voltage V

REF

1.265 V
Bandgap Reference Toler­ance

-2.5 +2.5 %

LINEAR REGULATOR (OUT2, OUT3, OUT4)
Regulation 3 %
VSEN2 Regulation Voltage Select<0.8V V

REG2

1.5 V
VSEN2 Regulation Voltage Select>2.0V V

REG2

3.3 V
VSEN3 Regulation Voltage V

REG3

1.5 V
VSEN3 Regulation Voltage V

REG4

1.8 V
Under-Voltage Level
( V

SEN/VREG

)

V

SEN

Rising V

SENUV

75 %

Under-Voltage Hysteresis
(V

SEN/VREG

)

V

SEN

Falling 5 %

Output Drive Current (All
Linears )

V

AUX-VDRIVE

> 0.6V 20 30 mA

AIC1574

5

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ELECTRICAL CHARACTERISTICS (Continued)

PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

SYNCHRONOUS PWM CONTROLLER AMPLIFIER
DC Gain (G.B.D.) 80 dB
Gain-Bandwidth Product (G.B.D.) G

BWP

13 MHz

Slew Rate (G.B.D.) note 1. S

R

6 V/µs

PWM CONTROLLER GATE DRIVER
Upper Drive Source VCC=12V, V

UGATE

= 6V I

UGH

0.9 A
Upper Drive Sink V

UGATE

=1V R

UGL

2.8 3.5 Ω
Lower Drive Source VCC=12V, V

LGATE

=6V I

LGH

1 A

Lower Drive Sink V

LGATE

=1V R

LGL

2.2 3.0 Ω
PROTECTION

VSEN1 Over-Voltage
( V

SEN1/DACOUT

)

V

SEN1

Rising OVP 116 120 %

FAULT Sourcing Current V

CC-VFAULT/RT

=2.0V I

OVP

20 mA

OCSET Current Source V

OCSET

=4.5VDC I

O

CSET

170 200 230 µA

Soft-Start Current I

SS

25 µA

POWER GOOD
V

SEN1

Upper Threshold

( V

SEN1

/DA

COUT

)

V

SEN1

Rising 108 111 %

V

SEN1

Under-Voltage

( VSEN1/DACOUT )

V

SEN

Falling 92 95 %

V

SEN1

Hysteresis

(VSEN1/DACOUT)

Upper and Lower Threshold 2 %

P

GOOD

Voltage Low I

PGOOD

=-4mA V

PGOOD

0.4 0.8 V

Note 1. Without internal compensation network, the gain bandwidth product is 13MHz. Being associated with in­ternal compensation networks, the Bode Plot is shown in Fig. 3, “Internal Compensation Gain of PWM Error Am­plifier”.

AIC1574

6

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TYPICAL PERFORMANCE CHARACTERISTICS

PGOOD

V

OUT4

V

OUT3

SS

V

OUT2

V

OUT1

Fig. 1 Soft Start Interval with 4 Outputs and P

GOOD

SS

VDAC=3.5V

VDAC=2V

VDAC=1.3V

Fig. 2 Soft Start Initiates PWM Output

1k 10k 100k 1M

-5

0

5

10

15

20

25

30

90°C

Internal Compensation Gain of PWM Error Amplifier

Gain (dB)

Fig. 3 Frequency (Hz)

-40°C

22°C

10k 100k 1M

1k

10k

100k

1M

10M

R

T

Pull Up to 12V

Resistance (Ω)

Fig. 4 Switching Frequency (Hz)

R

T

Pull Down to GND

RT Resistance vs. Frequency

200k 300k 400k 500k 600k 700k 800k 900k 1M

0

20

40

60

80

100

120

C=680pF

C=1.5nF

C=3.3nF

C=4.7nF

VCC=12V
C

UG1=CLG1

=C

Supply Current vs. Frequency

ICC (mA)

Fig. 5 Switching Frequency (Hz)

SS

Inductor
Current 5A/div

Over Load
Applied

Fault

Over Current ON Inductor

Fig. 6