LT1070_1 Datasheet, PDF (1/12 Pages) Linear Technology – 5A and 2.5A High Efficiency Switching Regulators

FEATURES
s _{Wide Input Voltage Range: 3V to 60V}
s _{Low Quiescent Current: 6mA}
s _{Internal 5A Switch (2.5A for LT1071)}
s _{Very Few External Parts Required}
s _{Self Protected Against Overloads}
s _{Operates in Nearly All Switching Topologies}
s _{Shutdown Mode Draws Only 50µA Supply Current}
s _{Flyback Regulated Mode Has Fully Floating Outputs}
s _{Comes in Standard 5-Pin TO-220 Package}
s _{Can be Externally Synchronized (Consult Factory)}
U
APPLICATIO S
s _{Logic Supply 5V at 10A}
s _{5V Logic to ±15V Op Amp Supply}
s _{Off-Line Converter Up to 200W}
s _{Battery Upconverter}
s _{Power Inverter (+ to –) or (– to +)}
s _{Fully Floating Multiple Outputs}
s _{For Lower Current Applications, See the LT1072}
USER NOTE:
This data sheet is only intended to provide specifications, graphs and a general functional
description of the LT1070/LT1071. Application circuits are included to show the capability of the
LT1070/LT1071. A complete design manual (AN19) should be obtained to assist in developing new
designs. This manual contains a comprehensive discussion of both the LT1070 and the external
components used with it, as well as complete formulas for calculating the values of these
components. The manual can also be used for the LT1071 by factoring in the lower switch current
rating. A second Application Note, AN25, which details off-line applications is available.
LT1070/LT1071
5A and 2.5A High Efficiency
Switching Regulators
DESCRIPTIO
The LT^®1070/LT1071 are monolithic high power switch-
ing regulators. They can be operated in all standard switch-
ing configurations including buck, boost, flyback, for-
ward, inverting and “Cuk”. A high current, high efficiency
switch is included on the die along with all oscillator,
control and protection circuitry. Integration of all func-
tions allows the LT1070/LT1071 to be built in a standard
5-pin T0-220 power package. This makes it extremely
easy to use and provides “bust proof” operation similar to
that obtained with 3-pin linear regulators.
The LT1070/LT1071 operate with supply voltages from 3V
to 60V, and draw only 6mA quiescent current. They can
deliver load power up to 100W with no external power
devices. By utilizing current mode switching techniques,
they provide excellent AC and DC load and line regulation.
The LT1070/LT1071 have many unique features not found
even on the vastly more difficult to use low power control
chips presently available. They use adaptive antisat switch
drive to allow very wide ranging load currents with no loss
in efficiency. An externally activated shutdown mode
reduces total supply current to 50µA typical for standby
operation. Totally isolated and regulated outputs can be
generated by using the optional “flyback regulation mode”
built into the LT1070/LT1071, without the need for
optocouplers or extra transformer windings.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Boost Converter (5V to 12V)
L2
10µH
5V L1**
150µH
OUTPUT
FILTER
C3
100µF
+
C3*
100µF
V_{IN VSW}
LT1070
GND V_C ^FB
D1
+
R3
1k
C1
1µF
*REQUIRED IF INPUT LEADS ≥ 2"
**PULSE ENGINEERING 92113
C2
1000µF
12V
1A
R1
10.7k
1%
R2
1.24k
1%
1070/71 TA01
Maximum Output Power*
100
80
BOOST
60
BUCK/BOOST
V_O = 30V
FLYBACK
40
ISOLATED
20
BUCK/BOOST
V_O = 5V
0
0
10
20
30
40
50
INPUT VOLTAGE (V)
1070/71 TA02
*ROUGH GUIDE ONLY. BUCK MODE P_OUT = 5A • V_OUT.
SPECIAL TOPOLOGIES DELIVER MORE POWER
**DIVIDE VERTICAL POWER SCALE BY 2 FOR LT1071
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