A4402 Datasheet, PDF (1/15 Pages) Allegro MicroSystems – Constant On-Time Buck Converter with Integrated Linear Regulator

A4402
Constant On-Time Buck Converter
with Integrated Linear Regulator
Features and Benefits
▪ 2 MHz switching frequency
▪ Adjustable soft start timer
▪ Watchdog input
▪ Power-on reset output
▪ Adjustable 2% buck regulator
▪ Adjustable 2% linear regulator
▪ Enable input
▪ 6 to 50 V supply voltage range
▪ Overcurrent protection
▪ Undervoltage lockout (UVLO)
▪ Thermal shutdown protection
Applications:
▪ Photo and inkjet printers
▪ Industrial controls
▪ Distributed power systems
▪ Network applications
Package: 16-pin TSSOP with exposed
thermal pad (suffix LP)
Description
The A4402 is a power management IC that combines a 2%
constant on-time buck regulator and a 2% linear regulator.
Ideal for applications that require two regulated voltages. The
buck regulator output supplies the adjustable linear regulator
to reduce power dissipation and increase overall efficiency.
The switching regulator is capable of operating above 2 MHz.A
greater than 2 MHz switching frequency enables the customer
to select low value inductors and capacitors while avoiding
EMI.
Protection features include undervoltage lockout and thermal
shutdown. In case of a shorted load, each regulator features
overcurrent protection. The A4402 also features a power-on
reset with adjustable delay for the microprocessor output.
The A4402 is provided in a 16-pin, ≤1.20 mm nominal
overall height TSSOP, with exposed pad for enhanced thermal
dissipation. It is lead (Pb) free, with 100% matte tin leadframe
plating.
Not to scale
V_O2
20 kΩ
4.7 kΩ
C_TSET
TSET
0.15 μF
C_POR
POR
0.33 μF
NPOR
ENB
WDI
Typical Application
TON
A 4402
GND
VIN1
BOOT
LX
ISEN
GND
GND
FB1
VIN2
VO2
FB2
R_ton
750 kΩ
V_BAT
0.1 μF
10 μF
0.01 μF
L1
33 μH
R_SENSE
R1
31.6 kΩ
4.7 μF
Switching Regulator Output
V_SW
5V
R2
9.76 kΩ
R3
10 kΩ
Linear Regulator Output
V_LIN
3.3 V
300 mA
1 μF
R4
5.62 kΩ
4402-DS, Rev. 1