LT1614 Datasheet, PDF (1/8 Pages) Linear Technology – Inverting 600kHz Switching Regulator

FEATURES
s _{Better Regulation Than a Charge Pump}
s _{0.1Ω Effective Output Impedance}
s _{– 5V at 200mA from a 5V Input}
s _{600kHz Fixed Frequency Operation}
s _{Operates with VIN as Low as 1V}
s _{1mA Quiescent Current}
s _{Low Shutdown Current: 10µA}
s _{Low-Battery Detector}
s _{Low VCESAT Switch: 295mV at 500mA}
U
APPLICATIONS
s _{MR Head Bias}
s _{LCD Bias}
s _{GaAs FET Bias}
s _{Positive-to-Negative Conversion}
Final Electrical Specifications
LT1614
Inverting 600kHz
Switching Regulator
July 1998
DESCRIPTION
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
to less than 10µA. No load quiescent current of the LT1614
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
5V to – 5V Converter
V_IN
5V
+
L1
22µH
C1
33µF
100k
V_IN
SW
SHDN
LT1614
V_C
NFB
GND
C3
1µF
69.8k
24.9k
1nF
L2
22µH
D1
C1, C2: AVX TAJB336M010
C3: AVX 1206CY106
D1: MBR0520
L1, L2: MURATA LQH3C220
V_OUT
– 5V
200mA
C2
33µF
1614 TA01
5V to – 5V Converter Efficiency
90
80
70
60
50
40
3
10
30
100
300
LOAD CURRENT (mA)
1614 TA02
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.
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