LT1614
Inverting 600kHz
Switching Regulator
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DESCRIPTIO
FEATURES
The LT®1614 is a fixed frequency, inverting mode switch-
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
tolessthan10µA.NoloadquiescentcurrentoftheLT1614
is 1mA and the internal NPN power switch handles a
500mA current with a voltage drop of just 295mV.
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Better Regulation Than a Charge Pump
0.1Ω Effective Output Impedance
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–5V at 200mA from a 5V Input
600kHz Fixed Frequency Operation
Operates with VIN as Low as 1V
1mA Quiescent Current
Low Shutdown Current: 10µA
Low-Battery Detector
Low VCESAT Switch: 295mV at 500mA
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APPLICATIO S
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.
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MR Head Bias
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LCD Bias
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GaAs FET Bias
Positive-to-Negative Conversion
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The LT1614 is available in 8-lead MSOP or SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATIO
C3
1µF
L1
22µH
L2
22µH
5V to –5V Converter Efficiency
V
IN
90
5V
V
OUT
V
SW
IN
–5V
80
70
60
50
40
+
SHDN
LT1614
C1
200mA
69.8k
24.9k
33µF
C2
33µF
D1
V
C
NFB
+
GND
100k
1nF
1614 TA01
C1, C2: AVX TAJB336M010
C3: TAIYO YUDEN EMK316BJ105MF
D1: MBR0520
L1, L2: MURATA LQH3C220
3
10
30
100
300
Figure 1. 5V to –5V/200mA Converter
LOAD CURRENT (mA)
1614 TA02
1