Document
A4402
www.DataSheet4U.com
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
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.
Applications:
▪ Photo and inkjet printers ▪ Industrial controls ▪ Distributed power systems ▪ Network applications
Package: 16-pin TSSOP with exposed thermal pad (suffix LP)
Not to scale
Typical Application
TON VIN1 CTSET TSET 0.15 μF CPOR POR 0.33 μF 0.1 μF 10 μF Switching Regulator Output VSW 5V Rton 750 kΩ VBAT
BOOT
0.01 μF LX ISEN RSENSE GND GND R1 31.6 kΩ R2 9.76 kΩ L1 33 μH 4.7 μF
A 4402
VO2 20 kΩ NPOR ENB WDI 4.7 kΩ GND
FB1
VIN2 VO2 R3 10 kΩ FB2 R4 5.62 kΩ Linear Regulator Output VLIN 3.3 V 300 mA 1 μF
4402-DS, Rev. 1
www.DataSheet4U.com
A4402
Constant On-Time Buck Converter with Integrated Linear Regulator
Packing
4000 pieces per 13-in. reel
Selection Guide
Part Number
A4402ELPTR-T
Package
16-pin TSSOP with exposed thermal pad
Absolute Maximum Ratings
Characteristic VIN1 Pin VIN2 Pin LX Pin ISEN Pin ENB Pin VO2 Pin WDI Pin TON Pin FB1 and FB2 Pins NPOR Ambient Operating Temperature Junction Temperature Storage Temperature Range Symbol VIN1 VIN2 VLX VISEN VENB VO2 VWDI VTON VFBx VNPOR TA Tj(max) Tstg Range E Notes Rating –0.3 to 50 –0.3 to 7 –1 to 50 –0.5 to 1 –0.3 to 7 –0.3 to 7 –0.3 to 6 –0.3 to 7 –0.3 to 7 –0.3 to 6.5 –40 to 85 150 –40 to 150 Units V V V V V V V V V V °C °C °C
Thermal Characteristics
Characteristic
Package Thermal Resistance
Symbol
RθJA
Test Conditions*
On 4-layer PCB based on JEDEC standard
Value Units
34 ºC/W
*Additional thermal information available on the Allegro website.
Terminal List Table
Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 – Name TON GND FB2 VIN2 VO2 WDI TSET NPOR FB1 POR ISEN BOOT LX GND VIN1 ENB PAD Function On time setting terminal Ground Feedback for VLIN Input vol.