LT1370 Datasheet, PDF (1/16 Pages) Linear Technology – 500kHz High Efficiency 6A Switching Regulator

LT1370
500kHz High Efficiency
6A Switching Regulator
FEATURES
s _{Faster Switching with Increased Efficiency}
s _{Uses Small Inductors: 4.7µH}
s _{All Surface Mount Components}
s _{Low Minimum Supply Voltage: 2.7V}
s _{Quiescent Current: 4.5mA Typ}
s _{Current Limited Power Switch: 6A}
s _{Regulates Positive or Negative Outputs}
s _{Shutdown Supply Current: 12µA Typ}
s _{Easy External Synchronization}
s _{Switch Resistance: 0.065Ω Typ}
U
APPLICATIONS
s _{Boost Regulators}
s _{Laptop Computer Supplies}
s _{Multiple Output Flyback Supplies}
s _{Inverting Supplies}
DESCRIPTION
The LT^®1370 is a monolithic high frequency current mode
switching regulator. It can be operated in all standard
switching configurations including boost, buck, flyback,
forward, inverting and “Cuk.” A 6A high efficiency switch
is included on the die, along with all oscillator, control and
protection circuitry.
The LT1370 typically consumes only 4.5mA quiescent
current and has higher efficiency than previous parts.
High frequency switching allows for very small inductors
to be used.
New design techniques increase flexibility and maintain
ease of use. Switching is easily synchronized to an exter-
nal logic level source. A logic low on the Shutdown pin
reduces supply current to 12µA. Unique error amplifier
circuitry can regulate positive or negative output voltage
while maintaining simple frequency compensation tech-
niques. Nonlinear error amplifier transconductance
reduces output overshoot on start-up or overload recov-
ery. Oscillator frequency shifting protects external com-
ponents during overload conditions.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
ON
OFF
+ C1**
22µF
25V
5V to 12V Boost Converter
5V
L1*
D1
MBRD835L
V_OUT†
12V
V_IN
S/S
V_SW
LT1370
FB
GND
V_C
C2
0.047µF
R3
2k
R1
53.6k
1%
+
R2
6.19k
1%
C3
0.0047µF
C4**
22µF
25V
×2
*COILTRONICS
UP2-4R7 (4.7µH)
UP4-100 (10µH)
**AVX TPSD226M025R0200
†_{MAX IOUT}
L1 I_OUT
4.7µH 1.8A
10µH 2A
LT1370 • TA01
12V Output Efficiency
92
V_IN = 5V
L = 10µH
90
88
86
84
82
80
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
LOAD CURRENT (A)
LT1370 • TA02
1