A8697 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – Wide Input Voltage 4.0 A Step Down Regulator

A8697
Wide Input Voltage 4.0 A Step Down Regulator
Features and Benefits
▪ 8 to 25 V input range
▪ Integrated DMOS switch
▪ Adjustable fixed off-time
▪ Adjustable output
Package: 8-Lead SOIC with exposed
thermal pad (suffix LJ)
Description
The A8697 is a constant off-time current mode step-down
regulator with a wide input voltage range. Regulation voltage is
set by external resistors, to output voltages as low as 0.8 V.
The A8697 includes an integrated power DMOS switch to
reduce the total solution footprint. It also features internal
compensation, allowing users to design stable regulators with
minimal design efforts.
The off-time can be set with an external resistor, allowing
flexibility in inductor selection. Additionally, the A8697 has
a logic level enable pin which can shut the device down and
put it into a low quiescent current mode for power sensitive
applications.
The A8697 is supplied in a low-profile 8-lead SOIC with
exposed pad (package LJ). Applications include:
▪ Applications with 8 to 25 V input
▪ Consumer electronics, networking equipment
▪ 12 V lighter-powered applications (portable DVD, etc.)
▪ Point of Sale (POS) applications
Approximate Scale 1:1
Typical Application
CBOOT
0.01 μF
V_IN
+12 V
+ CIN
47 μF
25 V
BOOT
VIN
ENB
LX
A8697
TSET
RTSET
51.1 k7
GND
VBIAS
FB
Ratings:
L: CDRH104R-3R8
COUT: EEUFM1V151
CIN: EEVFC1H470P
L
3.8 μH
D1
R1
2 k7
R2
6.14 k7
Circuit for 12 V step down to 1.06 V at 4 A
V_OUT
1.06 V/ 4.0 A
+
COUT
150 μF
56 mΩ
Efficiency versus Load Current
90
80
VOUT = 2.5 V
70
VOUT = 1.8 V
60
VOUT = 1.06 V
50
40
30
20
10
0
0
1
2
3
4
Load Current (A)
Efficiency curve for circuit at left
A8697-DS, Rev. 2