LT1076-5
5V Step-Down
Switching Regulator
FEATURES
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DESCRIPTIO
Fixed 5V Output
2A On-Board Switch
100kHz Switching Frequency
2% Output Voltage Tolerance Over Temperature
Greatly Improved Dynamic Behavior
Available in Low Cost 5- and 7-Lead Packages
Only 9.5mA Quiescent Current
Operates Up to 60V Input
APPLICATIO S
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5V Output Buck Converter
Tapped Inductor Buck Converter with 4A Output
at 5V
Positive-to-Negative Converter
The LT1076-5 is a 2A fixed 5V output monolithic bipolar
switching regulator which requires only a few external parts
for normal operation. The power switch, all oscillator and
control circuitry, all current limit components, and an output
monitor are included on the chip. The topology is a classic
positive 鈥渂uck鈥?configuration but several design innova-
tions allow this device to be used as a positive-to-negative
converter, a negative boost converter, and as a flyback
converter. The switch output is specified to swing 40V below
ground, allowing the LT1076-5 to drive a tapped inductor
in the buck mode with output currents up to 4A.
The LT1076-5 uses a true analog multiplier in the feedback
loop. This makes the device respond nearly instantaneously
to input voltage fluctuations and makes loop gain indepen-
dent of input voltage. As a result, dynamic behavior of the
regulator is significantly improved over previous designs.
On-chip pulse by pulse current limiting makes the LT1076-5
nearly bust-proof for output overloads or shorts. The input
voltage range as a buck converter is 8V to 60V, but a self-
boot feature allows input voltages as low as 5V in the
inverting and boost configurations.
The LT1076-5 is available in a low cost 5- and 7-lead TO-220
packages with frequency pre-set at 100kHz and current
limit at 2.6A. See Application Note 44 for design details.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Basic Positive Buck Converter
100碌H**
鈥?/div>
8V TO 40V
V
IN
LT1076-5
SENSE
GND
V
C
R3
1.5k
C2
0.033碌F
V
SW
MBR340*
+
C3
200碌F
+
C1
500碌F
25V
LT1076-5 TA01
U
5V
鈮?.8A
* MBR330P MAY BE USED
FOR V
IN
鈮?/div>
25V
** COILTRONICS #100-1-52
HURRICANE #HL-AG210LL
鈥?/div>
U
U
VALUE MAY BE REDUCED TO 50碌H
FOR OUTPUT LOADS BELOW 1.5A
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