A8698 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – Wide Input Voltage 3.0 A Step Down Regulator

A8698
Wide Input Voltage 3.0 A Step Down Regulator
Features and Benefits
▪ 8 to 25 V input range
▪ Integrated DMOS switch
▪ Adjustable fixed off-time
▪ Highly efficient
▪ Adjustable 0.8 to 20 V output
Package: 8-Lead SOIC with exposed
thermal pad (suffix LJ)
Description
The A8698 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 A8698 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 A8698 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 A8698 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
BOOT
VIN
ENB
LX
A8698
TSET
RTSET
30.1 k7
GND
VBIAS
FB
D1
+8 to 24 V
CIN3
CIN2
CIN1
82 μF
82 μF
0.22 μF
35 V
35 V
L1
33 μH
R1
6.34 k7
R2
2 k7
VOUT
3.3 V / 3 A
COUT
330 μF
6.3 V
ESR
Circuit for 12 V step down to 3.3 V at 3 A.
A8698-DS, Rev. 3
92
90
88
86
84
82
80
78
76
74
72
70
0
Efficiency
V_IN = 12.0 V
V_OUT = 5.0 V
V_OUT = 3.3 V
V_OUT = 2.5 V
0.5
1.0
1.5
2.0
2.5
3.0
Load Current (A)
Efficiency curves for circuit at left.