a4403geu-t Allegro MicroSystems, Inc., a4403geu-t Datasheet - Page 3

• Manufacturer Part Number: a4403geu-t
• Description: Valley Current Mode Control Buck Converter
• Manufacturer: Allegro MicroSystems, Inc.

A4403
Switch
Closed = On
TON
VIN
NC
SS
R1
68 kΩ
Pin-out Diagram
V
IN
1
2
3
4
9 to 44.1 V
(Top View)
PAD
R2
Not
Fitted
TON
Switching Frequency = 1 MHz
All capacitors are X5R or X7R ceramic
Resistors R3 and R4 should be surface mount, low inductance type, rated at 250 mW at 70°C
C6 is an optional speed-up capacitor, to improve the transient response
DIS
C1
2.2 μF
VIN UVLO
Linear OK
TSD
12
10
11
9
LX
BOOT
DIS
SGND
Circuit
Timer
Timer
Sleep
Off
On
Fault
VIN
Regulator
Linear
Terminal List Table
2, 7, 13, 14, 15, 16
Control
Comparator
Logic
Regulator
Soft-Start
Number
+
–
Functional Block Diagram
10
12
11
1
3
4
5
6
8
9
–
SS
C5
47 nF
Valley Current Mode Control Buck Converter
Overvoltage
Comparator
Amplifier
Driver
–
+
–
+
BOOT
SGND
BOOT
Blank
Name
GND
ISEN
TON
PAD
Reg Ref
+80 mV
Reg Ref
VIN
DIS
NC
SS
FB
LX
NC
Top-off
Charge
Pump
Input supply
No connection; tie to GND
Terminal for on-time setting with external resistor
Terminal for soft-start setting with external capacitor
Feedback terminal
Ground terminal
Current sense input
Current sense ground reference
Disable logic input; active high
Bootstrap supply node
Switch node
Exposed thermal pad; connect to ground plane
(GND) by through-hole vias
GND
C2
22 nF
V
IN
SGND
FB
ISEN
LX
R3
100 mΩ
D1
Function
L1
4.7 μH
100 mΩ
R4
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
C3
10 μF
C6
10 nF
10 μF
C4
2.37 kΩ
R5
R6
750 Ω
V
3.3 V
3 A
OUT
3