SYNCHRONOUS PWM CONTROLLER WITH

DUAL LOW DROPOUT REGULATOR

CONTROLLERS

© 2000 SEMTECH CORP.

PRELIMINARY - October 16, 2000

SC1109

3

TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com

ELECTRICAL CHARACTERISTICS (Cont.)

Unless specified: VOSENSE = V

PARAMETER

SYM

CONDITIONS

MIN

TYP

MAX

UNITS

Internal Drivers

Peak DH Source Current

Isource

DH

BST-DH = 4.5V

500

mA

Peak DH Sink Current

Isink

DH

DH-GND = 3.1V

DH-GND = 1.5V

500

100

mA

mA

Peak DL Source Current

Isource

DL

VCC-DL = 4.5V

500

mA

Peak DL Sink Current

Isink

DL

DL-GND = 3.1V

DL-GND = 1.5V

500

100

mA

mA

Dead time

T

DEAD

40

100

ns

Linear Sections

Standby Voltage

V

STBY

4.4

5

5.25

V

Standby Quiescent current

I

STDBYQ

VSTBY = 5V, SS/EN = 0V

5

mA

Tracking Difference

(4)

Delta

TRACK

200

mV

Output Voltage LDO1

V

LDO1

I

1.782 1.818 1.854

V

Output Voltage LDO2

V

LDO2

I

2.475 2.525 2.575

V

Load Regulation

LOAD

REG

I

0.3

%

Line Regulation

LINE

REG

3.3V Vin = 3.13V to 3.47V, I

o

0.3

%

LDOS(1,2) Output Impedance

Z

OUT

V

1

1.5

k

Ω

LDOS(1,2) Input Impedance

Z

IN

10

k

Ω

Gain (A

(3)

GAIN

LDO

LDOS (1,2) to GATE (1,2)

50

dB

LDO1 Gate Voltage

Vgate

LDO1

V

8

V

LDO2 Gate Voltage

Vgate

LDO2

V

7

V

Notes:

(1) All electrical characteristics are for the application circuit on page 6.

(2) Soft start function is performed after Vcc is above the UVLO and SS/EN is above 600mV. The Soft start

capacitor is then charged at a 10uA constant current until SS/EN is charged to above 1V.

(3) Guaranteed by design

(4) Tracking Difference is defined as the delta between 3.3V Vin and the LDO1, LDO2 output voltages during the

linear ramp up until regulation is achieved.