AIC AIC1578CS, AIC1578 Datasheet

AIC1578

µ

High-Efficiency, Step-Down DC/DC Converter

FEATURES



• 4V to 20V Input Voltage Operation.

• High Efficiency (up to 95%).

• Low Quiescent Current at 90µA.

• Pulse-Skipping and Pulse-Frequency Modulation.

• Inputs-Uncommitted Current Sense Comparator.

• Duty Cycle Adjustable.

• 90KHz to 280KHz Oscillator Frequency.

• Power-Saving Shutdown Mode (8µA Typical).

• Push-Pull Driver Output.

APPLICATIONS



• Notebook 5V/3.3V Main Power

• Step-Down DC/DC Converter Module.

• Constant Current Source for Battery Chargers.

TYPICAL APPLICATION CIRCUIT



V

IN

IRF9Z34

+

C1

Q1

F

µ

C2

F

0.1

100

*Sumida MPP CORE

R2

1M

Contro l

* L1

33µH
D1
1N5820

R

VIN

DUTY

DUTY

1M

SHDN

FB

**Charge current=57mV/RS

C3

220µF

AIC1578

+

CS+

CS -

DRI

GND

**RS

+

C4

10µF

DESCRIPTION



The AIC1578 is a high performance step-down
DC/DC converter, designed to drive an external
P-channel MOSFET to generate programmable
output voltages. Two main schemes of Pulse­Skipping and Pulse-Frequency Modulation are
employed to maintain low quiescent current and
high conversion efficiency under wide ranges of
input voltage and loading condition. The
AIC1578 delivers 10mA to 2A of output current
with 87%~93% efficiency at V

=9V, V

IN

OUT

=5V
condition. A current sense comparator with both
inverting and non-inverting input uncommitted is
included to provide the crucial function of either
current limit protection or constant output current
control. When the AIC1578 is used in a high-side
current sensing step-down constant current
source, the efficiency is typically greater than
90%. Duty cycle can be adjusted to greater than
90% by connecting a resistor from DUTY pin to
V

. Quiescent current is about 90µA and can be

IN

reduced to 8µA in shutdown mode. Switching
frequency being in around 90KHz to 280KHz

D2

1N5820

Battery

range, small size switching components are ideal
for battery powered portable equipment.

Constant Current Source for Battery Charger

ORDERING INFORMATION



AIC1578 XX

PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE

TEMPERATURE RANGE
C: 0°C~+70°C

ORDER NUMBER

AIC1578CN
(PLASTIC DIP)

AIC1578CS
(PLASTIC SO)

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

DS-1578-02 Dec 27, 00 TEL: [phone] FAX: [phone]

PIN CONFIGURATION

TOP VIEW

VIN

1

DUTY

2

3

SHDN

4

FB

CS+

8

7

CS-

6

DRI

GND

5

1

ABSOLUTE MAXIMUM RATINGS



VIN Supply Voltage .....…………............................................................................. 20V

DUTY Voltage .........................................……………................................................ 20V

Voltage ......................................………….................................................... 15V

SHDN

AIC1578

Operating Temperature Range ..

Storage Temperature Range

TEST CIRCUIT



Refer to Fig. 1 circuit of Application Examples.

ELECTRICAL CHARACTERISTICS



specified.)

PARAMETERS CONDITIONS MIN. TYP. MAX. UNIT

Operation Voltage 4 20 V

Quiescent Current VFB = 1.5V 90 160 µA

Shutdown Mode Current V

Internal Reference Voltage 1.16 1.22 1.28 V

..............…………......................................... 0°C~70°C

......................…………................................. -65°C~ 150°C

(VIN= 13V, Ta=25°°°°C, unless otherwise

= 0V 8 20 µA

SHDN

Driver Sinking "ON Resistance" 16 Ω

Driver Sourcing "ON Resistance" 11 Ω

Current Limit Sense Threshold

Shutdown Threshold 0.8 1.5 2.4 V

Pin Leakage Current V

SHDN

Duty Cycle V

Oscillator Frequency V

V

= 13V 50 70 90 mV

CS+

< 15V 1 µA

SHDN

DUTY

DUTY

= V

= V

IN

IN

71 %

225 KHz

2

TYPICAL PERFORMANCE CHARACTERISTICS

)



AIC1578

90

Frequency & Duty Cycle vs V

IN

Ta = 27°C

85

80

Duty

Frequency

75

70

Duty (%)

65

60

55

4 6 8 101214161820

VIN ( V)

Frequency vs Temperature

290

VIN=20V

240

35

30

25

20

15

Frequency (KHz)

10

50

0

90

85

80

75

70

Duty Cycle (%)

65

60

0 20406080

10

Duty Cycle vsTemperature

VIN=5V

VIN=13V

VIN=20V

Temperature (°C)

Duty Cycle vs R

DUTY

VIN=5V

90

190

Frequency (KHz)

140

90

0 10203040506070

VIN=13V

VIN=5V

Temperature (°C)

20

15

Shutdown Current vs V

IN

Ta=25°C

Ta=0°C

10

Shutdown Current (µA)

5

0

Ta=70°C

VIN (V)

80

Duty Cycle (%)

70

60

01234

VIN=20V

R

R

refer to Typ. App.

DUTY

(M

DUTY

Quiescent Current vs V

11

A)

µ

100

90

Ta= 0°C

VIN=10V

VIN=15V

Ω

IN

Ta= 25°C

80

Quiescent Current (

70

2046 81012141618

60

468101214161820

Ta= 70°C

VIN (V)

3