参数资料
型号: L4978D013TR
厂商: STMICROELECTRONICS
元件分类: 稳压器
英文描述: 3.5 A SWITCHING REGULATOR, 300 kHz SWITCHING FREQ-MAX, PDSO16
封装: SO-16
文件页数: 1/13页
文件大小: 581K
代理商: L4978D013TR
1/13
L4978
May 2005
1
Features
UP TO 2A 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 (PULSE-
BYPULSE AND HICCUP MODE)
INHIBIT FOR ZERO CURRENT
CONSUMPTION
PROTECTION AGAINST FEEDBACK
DISCONNECTION
THERMAL SHUTDOWN
SOFT START FUNCTION
2
DESCRIPTION
The L4978 is a step down monolithic power
switching regulator delivering 2A at a voltage be-
tween 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 0.25) to obtain very high
efficency and high switching speed.
A switching frequency up to 300KHz is achievable
(the maximum power dissipation of the packages
must be observed). A wide input voltage range be-
tween 8V to 55V and output voltages regulated
from 3.3V to 50V cover the majority of today’s ap-
plications. 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, DIP-
8 for standard assembly, and SO16W for SMD as-
sembly.
2A STEP DOWN SWITCHING REGULATOR
Figure 2. Typical Application Circuit
D98IN837A
5
2
8
4
1
L4978
C1
220
F
63V
C8
330
F
VO=3.3V/2A
Vi=8V to 55V
R1
20K
C2
2.7nF
R2
9.1K
C4
22nF
3
7
L1
126
H
(77120)
6
D1
ST
PS3L60U
C5
100nF
C7
220nF
C6
100nF
Rev. 9
Figure 1. Packages
Table 1. Order Codes
Part Number
Package
L4978
DIP-8
L4978D
SO16
L4978D013TR
SO16 in Tape & Reel
DIP-8
SO16W
相关PDF资料
PDF描述
L4978 3.5 A SWITCHING REGULATOR, 300 kHz SWITCHING FREQ-MAX, PDIP8
L497B SPECIALTY ANALOG CIRCUIT, PDIP16
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