A4402 Constant On-Time Buck Converter With Integrated Linear Regulator FEATURES AND BENEFITS DESCRIPTION The A4402 is a dual-output regulator, combining in a single 2 MHz switching frequency package a constant on-time buck regulator and a linear regulator Adjustable soft start timer (LDO)each with adjustable output voltages. It is ideal for Watchdog input applications that require two regulated voltages, such as in Power-on reset output microcontroller- or DSP-based applications requiring core Adjustable buck and linear regulators and I/O voltage rails. Enable input 6 to 50 V supply voltage range The buck regulator output supplies the adjustable linear Overcurrent protection regulator to reduce power dissipation and increase overall Undervoltage lockout (UVLO) efficiency. The switching regulator is capable of operating Thermal shutdown protection above 2 MHz, allowing the use of small low value inductors and capacitors while avoiding sensitive EMI frequency bands APPLICATIONS: such as AM radio in automotive applications. Automotive (K version) Commercial (E version) Protection features include undervoltage lockout and thermal Power steering control units Photo and inkjet printers shutdown. In case of a shorted load, each regulator features Transmission control units Industrial controls overcurrent protection. Lighting control units Distributed power systems Infotainment Networking applications The device has an integrated power-on reset with adjustable Cluster Point-of-sale delay to monitor LDO output voltage and provide a signal that Centerstack Security systems can be used to reset a DSP or microcontroller. It also includes Other body control a watchdog circuit. 16-pin eTSSOP PACKAGE: The A4402 is provided in a 16-pin eTSSOP, with exposed with exposed thermal pad pad for enhanced thermal dissipation. It is lead (Pb) free, with (suffix LP) 100% matte tin leadframe plating. Not to scale Typical Application V BAT R ton 750 k TON VIN1 C TSET Efficiency vs. Output Current 0.1 F 10 F TSET BOOT 90 0.15 F 0.01 F Switching Regulator Output 5 V SW LX C 5 V 85 POR L1 33 H POR ISEN 3.3 0.33 F 80 A4402 R SENSE 4.7 F GND R1 GND 75 V (V) k OUT 31.6 V O2 FB1 R2 70 20 k 9.76 k 65 NPOR VIN2 Linear Regulator Output V VO2 LIN ENB 60 3.3 V 250 mA 0 200 400 600 800 1000 1200 WDI R3 1 F 10 k 4.7 k I (mA) OUT FB2 GND R4 5.62 k Data is for reference only. Efficiency data from circuit shown in left panel. 4402-DS, Rev. 13 January 14, 2019 MCO-0000345 Efficiency %Constant On-Time Buck Converter A4402 With Integrated Linear Regulator SELECTION GUIDE Ambient Operating Part Number Packing Package Temperature, T A A4402ELPTR-T 40C to 85C 4000 pieces per 13-inch reel 16-pin eTSSOP with exposed thermal pad A4402KLPTR-T 40C to 150C ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Notes Rating Unit VIN1 Pin V 0.3 to 50 V IN1 VIN2 Pin V 0.3 to 7 V IN2 LX Pin V 1 to 50 V LX ISEN Pin V 0.5 to 1 V ISEN ENB Pin V 0.3 to 7 V ENB VO2 Pin V 0.3 to 7 V O2 WDI Pin V 0.3 to 6 V WDI TON Pin V 0.3 to 7 V TON FB1 and FB2 Pins V 0.3 to 7 V FBx NPOR V 0.3 to 6.5 V NPOR TSET Pin V 0.3 to 7 V TSET POR Pin V 0.3 to 6 V POR BOOT Pin V V to V + 7 V BOOT LX IN1 Range E 40 to 85 C Ambient Operating Temperature T A Range K 40 to 150 C Junction Temperature T 150 C J(max) Storage Temperature Range T 40 to 150 C stg THERMAL CHARACTERISTICS Characteristic Symbol Test Conditions* Value Unit Package Thermal Resistance R On 4-layer PCB based on JEDEC standard JESD51-7 34 C/W JA *Additional thermal information available on the Allegro website. 2 Allegro MicroSystems, LLC 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com