ZXLD1321

Issue 1 - January 2008

6

www.zetex.com

© Zetex Semiconductors plc 2008

DC-DC converter output parameters

Switching NPN transistor

NOTES:

(c) Measured under pulse conditions.

(d) This current is measured via the collectors and emitters of the switch with these connected to ground (0V)

(e) Measured under pulse conditions. Peak Current = Ic

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Toff(100)

Discharge pulse width

100% output current

0.7

1.2

1.7

µs

Toff(10)

Discharge pulse width

10% output current

4

8

12

µs

Maximum operating

frequency

600

KHz

Switching frequency in start-

up mode

VIN=1.2V

50

KHz

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Average continuous switch

current(c)

2A

Maximum base current into

switch transistor from internal

drive circuit(d)

2V<VIN<18V

BIAS pin at 0V

30

50

70

mA

Base current into switch

transistor using external

to ground

10

mA

Collector-Emitter breakdown

voltage

20

V

Collector-Emitter saturation

voltage

50

120

mV

mV

Static forward current transfer

ratio

209

116

Output capacitance

64

pF

t(on)

Turn-on time

30

ns

t(off)

Turn-off time

28

ns