ZXLB1600

ISSUE 3 - SEPTEMBER 2003

3

SEMICO NDUC TORS

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Output voltage control by dc voltage applied to ‘ADJ’ pin

1.23

V

40

ppm/ C

External overdrive voltage range

on ‘ADJ’ pin for output voltage

control

0.5

V

ADJ

(NOM)

V

-10

A

Default Output voltage

27

29

V

Output voltage control by PWM signal applied to ‘EN’ input

∆T/T

PWM duty cycle range at ‘EN’

input

10kHz

40

100

%

Internal low pass filter cut-off

frequency

4

kHz

Filter attenuation

f=30kHz

52.5

dB

Internal voltage setting resistors for output voltage

R1

Ref. Block diagram

317

k

R2

6.93

M

Enable input

Low level Input voltage

Device in shutdown

0.4

V

High level Input voltage

Device active

1.4

Vin

V

Low level input current

-100

nA

High level input current

100

nA

Enable active hold time

(6)

120

s

Low-battery detection circuit

Detection threshold

1.94

2.02

V

20

ppm/ C

Hysteresis

20

mV

Internal reference voltage

1.21

V

Maximum voltage on LBT pin

V

Low level output current

Output ‘on’

1

mA

Low level output voltage

0.4

V

High level output current

2

A

High level output voltage

Output ‘off’

29

V

Internal voltage setting resistors for low-battery detection circuit

R3

Ref. block diagram

1.56

M

R4

2.44

M

ELECTRICAL CHARACTERISTICS (Cont.)

Note:

5)

This is the minimum PWM frequency to maintain a continuous output. Lower frequencies can be used, but will result in gated operation of

the device i.e. device enters shutdown when EN is low (see Note 6).

6)

This is the time for which the device remains active after the EN pin has been driven low. This delay allows a continuous output to be

maintained during PWM mode operation at frequencies higher than 10kHz.