Overview

Part: TPS56A37 from Texas Instruments

Type: Synchronous Buck Converter

Key Specs:

Input voltage range: 4.5V to 28V
Output voltage range: 0.6V to 13V
Continuous output current: 10A
Reference voltage: 0.6V ±1% at 25°C
Quiescent current: 45uA

Features

4.5V to 28V input voltage range
0.6V to 13V output voltage range
Supports 10A continuous output current
Integrated 19.4mΩ and 8.5mΩ MOSFETs
0.6V ±1% reference voltage at 25°C
45uA low quiescent current
D-CAP3™ control mode for fast transient response
Eco-mode (auto-skip mode) for high light-load efficiency
Fixed 500kHz switching frequency
Cycle by cycle over current limit
Adjustable soft-start time with default 1.8ms
Built-in output discharge function
Power-good indicator to monitor output voltage
Supports up to 98% duty operation
Non-latched protections for UV, OV, OT, and UVLO
–40°C to +150°C operating junction temperature
Small 10-pin 3.0mm × 3.0mm HotRod™ QFN package
Pin-to-pin compatible with 6A TPS56637 and 8A TPS56837

Applications

Pin Configuration

Table 4-1. Pin Functions

PIN		TYPE(1)	DESCRIPTION
NAME	NO.
EN	1	I	Enable input control. Driving EN high or leaving this pin floating enables the converter. A resistor divider between this pin, VIN and AGND can be used to implement an external UVLO.
FB	2	I	Output feedback. Connect FB to the output voltage with a feedback resistor divider.
AGND	3	G	Ground of internal analog circuitry. Connect AGND to PGND plane at a single point.
PG	4	O	Open drain power-good indicator, this pin is asserted low if output voltage is out of PG threshold due to overvoltage, undervoltage, thermal shutdown, EN shutdown, or during soft start.
SS	5	O	Soft-start time selection pin. Connecting an external capacitor to AGND to set the soft-start time and if no external capacitor is connected, the soft-start time is 1.8ms by default.
SW	6	O	Switching node terminal. Connect the output inductor to this pin with wide and short tracks.
BOOT	7	I	Supply input for the gate drive voltage of the high-side MOSFET. Connect a 0.1µF bootstrap capacitor between BOOT and SW.
VIN	8	P	Input voltage supply pin. Drain terminal of high-side MOSFET. Connect the input decoupling capacitors between VIN and PGND.
PGND	9	G	Power GND terminal. Source terminal of low-side MOSFET.
MODE	10	I	Connect this pin with a 52.3K resistor to AGND.

Electrical Characteristics

The electrical ratings specified in this section apply to all specifications in this document unless otherwise noted. These specifications are interpreted as conditions that do not degrade the parametric or functional specifications of the device for the life of the product containing it. Typical values correspond to T^J = 25°C, VIN = 24V. Minimum and maximum limits are based on T^J = –40°C to +150°C, VIN = 4.5V to 28V (unless otherwise noted).

	PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNIT
SUPPLY CURRENT
IQ	Quiescent current, Operating (1)	TJ = 25°C, VEN = 5V, VFB = 0.65V, non-switching		45		μA
ISHDNN	Shutdown supply current	TJ = 25°C, VEN = 0V		3		μA
UVLO
		Wake up VIN voltage	4.0	4.2	4.4	V
	VIN undervoltage lockout	Shutdown VIN voltage	3.5	3.65	3.8	V
		Hysteresis VIN voltage		550		mV
ENABLE(EN PIN)
IEN_PULLUP	EN pullup current	VEN = 1.1V		1		μA
IEN_HYS	Hysteresis current	VEN = 1.3V		3		μA
VEN_ON		EN rising		1.18	1.26	V
VEN_OFF	Enable threshold	EN falling	1	1.07		V
FEEDBACK VOLTAGE
VFB	Feedback voltage	VOUT = 5V, continuous mode operation, TJ = 25°C	0.594	0.6	0.606	V
		VOUT = 5V, continuous mode operation, TJ = –40°C to 150°C	0.591	0.6	0.609	V
MOSFET
Rdson_HS	High-side MOSFET on-resistance	TJ = 25°C, VBST – VSW = 5V		19.4		mΩ
Rdson_LS	Low-side MOSFET on-resistance	TJ = 25°C		8.5		mΩ
CURRENT LIMIT
ILS_OCL	Low-side MOSFET valley current limit		10	12	13.8	A
IHS_OCL	High-side MOSFET peak current limit		12.75	15	17.25	A

Absolute Maximum Ratings

Over the recommended operating junction temperature range of –40°C to +150°C (unless otherwise noted)(1)

		MIN	MAX	UNIT
	VIN	–0.3	32	V
	BOOT	–0.3	SW + 6	V
Input voltage	BOOT-SW	–0.3	6	V
	EN, FB, MODE	–0.3	6	V
	PGND, AGND	–0.3	0.3	V
Output voltage	SW	–2	32	V
	SW (<10ns transient)	–5	35	V
	PG, SS	–0.3	6	V
	Operating junction temperature, TJ	–40	150	°C
	Storage temperature, Tstg	–65	150	°C

(1) Operation outside the Absolute Maximum Ratings may cause permanent device damage. Absolute Maximum Ratings do not imply functional operation of the device at these or any other conditions beyond those listed under Recommended Operating Conditions. If used outside the Recommended Operating Conditions but within the Absolute Maximum Ratings, the device may not be fully functional, and this may affect device reliability, functionality, performance, and shorten the device lifetime.

Recommended Operating Conditions

Over the recommended operating junction temperature range of –40°C to 150°C (unless otherwise noted).(1)

		MIN	MAX	UNIT
Input voltage	VIN	4.5	28	V
	BOOT	–0.1	SW + 5.5	V
	BOOT-SW	–0.1	5.5	V
	EN, FB, SS, MODE	–0.1	5.5	V
	PGND, AGND	–0.1	0.1	V
Output voltage	SW	–1	28	V
	PG	–0.1	5.5	V
Operating junction temperature, TJ		–40	150	°C

Thermal Information

		TPS56A37
	THERMAL METRIC(1)	QFN HotRod 10 PINS	UNIT
RθJA	Junction-to-ambient thermal resistance (JEDEC)(2)	68.1	°C/W
Eff RθJA	Effective junction-to-ambient thermal resistance (4-layer TI EVM)	30	°C/W
RθJC(top)	Junction-to-case (top) thermal resistance	40.4	°C/W
RθJB	Junction-to-board thermal resistance	17.6	°C/W
ΨJT	Junction-to-top characterization parameter	1.4	°C/W
ΨJB	Junction-to-board characterization parameter	17.2	°C/W

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

(2) This junction-to-ambient thermal resistance (JEDEC) is based on JEDEC standard EVM without GND thermal vias.

5.5 Electrical Characteristics