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L4971
1.5A STEP DOWN SWITCHING REGULATOR
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FEATURES
Figure 1. Package
UP TO 1.5A STEP DOWN CONVERTER
OPERATING INPUT VOLTAGE FROM 8V TO
55V
PRECISE 3.3V (±1%) INTERNAL
REFERENCE VOLTAGE
OUTPUT VOLTAGE ADJUSTABLE FROM
3.3V TO 50V
SWITCHING FREQUENCY ADJUSTABLE UP
TO 300KHz
VOLTAGE FEEDFORWARD
ZERO LOAD CURRENT OPERATION
INTERNAL CURRENT LIMITING (PULSEBYPULSE AND HICCUP MODE)
INHIBIT FOR ZERO CURRENT
CONSUMPTION
PROTECTION AGAINST FEEDBACK
DISCONNECTION
THERMAL SHUTDOWN
SOFT START FUNCTION
DIP8
SO16W
Table 1. Order Codes
Part Number
Package
L4971
DIP8
L4971D
SO16W
L4971D013TR
SO16 in Tape & Reel
A switching frequency up to 300KHz is achievable
(the maximum power dissipation of the packages
must be observed).
A wide input voltage range between 8V to 55V and
output voltages regulated from 3.3V to 50V cover
the majority of today’s applications.
Features of this new generations of DC-DC converter include pulse-by-pulse current limit, hiccup
mode for short circuit protection, voltage feedforward regulation, soft-start, protection against feedback loop disconnection, inhibit for zero current
consumption and thermal shutdown.
The device is available in plastic dual in line, DIP8
for standard assembly, and SO16W for SMD assembly.
DESCRIPTION
The L4971 is a step down monolithic power
switching regulator delivering 1.5A at a voltage between 3.3V and 50V (selected by a simple external
divider). Realized in BCD mixed technology, the
device uses an internal power D-MOS transistor
(with a typical Rdson of 0.25Ω) to obtain very high
efficency and high switching speed.
Figure 1. Block Diagram
Vi=8V to 55V
5
8
R1
20K
L4971
3
C1
220µF
63V
C7
220nF
C2
2.7nF
C5
100nF
2
4
1
7
R2
9.1K
C4
22nF
L1
126µH
(77120)
6
C6
100nF
D1
STPS
3L60U
VO=3.3V/1.5A