LT1614_15 Datasheet, PDF (1/16 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
APPLICATIO S
s _{MR Head Bias}
s _{LCD Bias}
s _{GaAs FET Bias}
s _{Positive-to-Negative Conversion}
LT1614
Inverting 600kHz
Switching Regulator
DESCRIPTIO
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 APPLICATIO
V_IN
5V
+
L1
22µH
C1
33µF
100k
V_IN
SW
SHDN
LT1614
V_C
NFB
GND
1nF
C3
1µF
69.8k
24.9k
L2
22µH
D1
V_OUT
– 5V
200mA
C2
33µF
C1, C2: AVX TAJB336M010
C3: TAIYO YUDEN EMK316BJ105MF
D1: MBR0520
L1, L2: MURATA LQH3C220
Figure 1. 5V to – 5V/200mA Converter
1614 TA01
5V to – 5V Converter Efficiency
90
80
70
60
50
40
3
10
30
100
300
LOAD CURRENT (mA)
1614 TA02
1