1

LT1614

Inverting 600kHz

Switching Regulator

July 1998

FEATURES

The LT

ing reglator that operates from an input voltage as low as

1V. Utilizing a low noise topology, the LT1614 can gener-

ate a negative output down to – 24V from a 1V to 5V input.

Fixed frequency switching ensures a clean output free

from low frequency noise. The device contains a low-

battery detector with a 200mV reference and shuts down

to less than 10

µA.NoloadquiescentcurrentoftheLT1614

is 1mA and the internal NPN power switch handles a

500mA current with a voltage drop of just 295mV.

High frequency switching enables the use of small induc-

tors and capacitors. Ceramic capacitors can be used in

many applications, eliminating the need for bulky tanta-

lum types.

The LT1614 is available in 8-lead MSOP or SO packages.

s

Better Regulation Than a Charge Pump

s

0.1

s

– 5V at 200mA from a 5V Input

s

600kHz Fixed Frequency Operation

s

s

1mA Quiescent Current

s

Low Shutdown Current: 10

µA

s

Low-Battery Detector

s

Final Electrical Specifications

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

, LTC and LT are registered trademarks of Linear Technology Corporation.

s

MR Head Bias

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LCD Bias

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GaAs FET Bias

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Positive-to-Negative Conversion

5V to – 5V Converter Efficiency

5V to – 5V Converter

SW

LT1614

L1

22

µH

5V

D1

NFB

SHDN

69.8k

24.9k

100k

1nF

– 5V

200mA

C1, C2: AVX TAJB336M010

C3: AVX 1206CY106

D1: MBR0520

L1, L2: MURATA LQH3C220

1614 TA01

C1

33

µF

C2

33

µF

GND

L2

22

µH

C3

1

µF

+

LOAD CURRENT (mA)

310

30

60

70

80

90

100

300

1614 TA02

50

40