LM22672/-Q1 42-V, 1-A SIMPLE SWITCHER® Step-Down Voltage Regulator with Features

1 Features

Wide Input Voltage Range: 4.5 V to 42 V
Internally Compensated Voltage Mode Control
Stable with Low ESR Ceramic Capacitors
200 mΩ N-Channel MOSFET
Output Voltage Options:
-ADJ (Outputs as Low as 1.285 V)
-5.0 (Output Fixed to 5 V)
±1.5% Feedback Reference Accuracy
500 kHz Default Switching Frequency
Adjustable Switching Frequency and Synchronization
–40°C to 125°C Junction Temperature Range
Precision Enable Input
Integrated Boot-Strap Diode
Adjustable Soft-Start
Fully WEBENCH® Enabled
LM22672-Q1 is an Automotive Grade Product
that is AEC-Q100 Grade 1 Qualified (–40°C to +125°C Junction Temperature)
SO PowerPAD (Exposed Pad)

2 Applications

Industrial Control
Telecom and Datacom Systems
Embedded Systems
Conversions from Standard 24 V, 12 V and 5 V Input Rails

Simplified Application Schematic

3 Description

The LM22672 switching regulator provides all of the functions necessary to implement an efficient high voltage step-down (buck) regulator using a minimum of external components. This easy to use regulator incorporates a 42 V N-channel MOSFET switch capable of providing up to 1 A of load current. Excellent line and load regulation along with high efficiency (> 90%) are featured. Voltage mode control offers short minimum on-time, allowing the widest ratio between input and output voltages. Internal loop compensation means that the user is free from the tedious task of calculating the loop compensation components. Fixed 5 V output and adjustable output voltage options are available.

The default switching frequency is set at 500 kHz allowing for small external components and good transient response. In addition, the frequency can be adjusted over a range of 200 kHz to 1 MHz with a single external resistor. The internal oscillator can be synchronized to a system clock or to the oscillator of another regulator. A precision enable input allows simplification of regulator control and system power sequencing. In shutdown mode the regulator draws only 25 µA (typ). An adjustable soft-start feature is provided through the selection of a single external capacitor. The LM22672 also has built in thermal shutdown, and current limiting to protect against accidental overloads.

The LM22672 is a member of Texas Instruments' SIMPLE SWITCHER® family. The SIMPLE SWITCHER^® concept provides for an easy to use complete design using a minimum number of external components and the TI WEBENCH^® design tool. TI's WEBENCH^® tool includes features such as external component calculation, electrical simulation, thermal simulation, and Build-It boards for easy design-in.

Device Information⁽¹⁾

PART NUMBER	PACKAGE	BODY SIZE (NOM)
LM22672, LM22672-Q1	HSOP (8)	4.89 mm x 3.90 mm

For all available packages, see the orderable addendum at the end of the data sheet.

4 Revision History

Changes from L Revision (April 2013) to M Revision

Added Pin Configuration and Functions section, Handling Rating table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section Go

Changes from K Revision (April 2013) to L Revision

Changed from National to TI format Go

5 Pin Configuration and Functions

8-Pin

HSOP Package

Top View

Pin Functions

PIN		TYPE	DESCRIPTION	APPLICATION INFORMATION
NAME	NO.	TYPE	DESCRIPTION	APPLICATION INFORMATION
BOOT	1	I	Bootstrap input	Provides the gate voltage for the high side NFET.
EN	5	I	Enable input	Used to control regulator start-up and shutdown. See Precision Enable and UVLO section of data sheet.
EP	EP	—	Exposed Pad	Connect to ground. Provides thermal connection to PCB. See Thermal Considerations.
FB	4	I	Feedback input	Feedback input to regulator.
GND	6	—	Ground input to regulator; system common	System ground pin.
RT/SYNC			Oscillator mode control input	Used to control oscillator mode of regulator. See Switching Frequency Adjustment and Synchronization section of data sheet.
SS	2	I	Soft-start input	Used to increase soft-start time. See Soft-Start section of data sheet.
SW	8	O	Switch output	Switching output of regulator.
VIN		I	Input voltage	Supply input to the regulator.

6 Specifications

6.1 Absolute Maximum Ratings⁽¹⁾⁽²⁾

over operating free-air temperature range (unless otherwise noted)

	MIN	MAX	UNIT
VIN to GND		43	V
EN Pin Voltage	–0.5	6	V
SS, RT/SYNC Pin Voltage	–0.5	7	V
SW to GND⁽³⁾	–5	V_IN	V
BOOT Pin Voltage		V_SW + 7	V
FB Pin Voltage	–0.5	7	V
Power Dissipation	Internally Limited
Junction Temperature		150	°C
For soldering specifications, refer to Application Report Absolute Maximum Ratings for Soldering (SNOA549).

6.2 Handling Ratings: LM22672

			MIN	MAX	UNIT
T_stg	Storage temperature range		–65	150	°C
V_(ESD)	Electrostatic discharge	Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins⁽¹⁾	–2	2	kV

(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.

6.3 Handling Ratings: LM22672-Q1

				MIN	MAX	UNIT
T_stg	Storage temperature range			–65	150	°C
V_(ESD)	Electrostatic discharge	Human body model (HBM), per AEC Q100-002⁽¹⁾		–2	2	kV

(1) AEC Q100-002 indicates HBM stressing is done in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

6.4 Recommended Operating Conditions

		MIN	MAX	UNIT
V_IN	Supply Voltage	4.5	42	V
	Junction Temperature Range	–40	125	°C

6.5 Thermal Information

THERMAL METRIC⁽¹⁾			LM22672, LM22672-Q1	UNIT
			HSOP
			8 PINS
R_θJA	Junction-to-ambient thermal resistance	MR Package, Junction to ambient thermal resistance⁽²⁾	60	°C/W

(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report (SPRA953).

(2) The value of Rθ_JA for the SO PowerPAD exposed pad (MR) package of 60°C/W is valid if package is mounted to 1 square inch of copper. The Rθ_JA value can range from 42 to 115°C/W depending on the amount of PCB copper dedicated to heat transfer.

6.6 Electrical Characteristics

Typical values represent the most likely parametric norm at T_A = T_J = 25°C, and are provided for reference purposes only. Unless otherwise specified: V_IN = 12 V.

PARAMETER		TEST CONDITIONS	MIN⁽⁵⁾	TYP⁽⁴⁾	MAX⁽⁵⁾	UNIT
LM22672-5.0
V_FB	Feedback Voltage	V_IN = 8 V to 42 V	4.925	5.0	5.075	V
V_FB	Feedback Voltage	V_IN = 8 V to 42 V, –40°C ≤ T_J ≤ 125°C	4.9		5.1	V
LM22672-ADJ
V_FB	Feedback Voltage	V_IN = 4.7 V to 42 V	1.266	1.285	1.304	V
V_FB	Feedback Voltage	V_IN = 4.7 V to 42 V, –40°C ≤ T_J ≤ 125°C	1.259		1.311	V
ALL OUTPUT VOLTAGE VERSIONS
I_Q	Quiescent Current	V_FB = 5 V		3.4		mA
I_Q	Quiescent Current	V_FB = 5 V, –40°C ≤ T_J ≤ 125°C			6	mA
I_STDBY	Standby Quiescent Current	EN Pin = 0 V		25	40	µA
I_CL	Current Limit		1.3	1.5	1.7	A
I_CL	Current Limit	–40°C ≤ T_J ≤ 125°C	1.2		1.8	A
I_L	Output Leakage Current	V_IN = 42 V, EN Pin = 0 V, V_SW = 0 V		0.2	2	µA
I_L	Output Leakage Current	V_SW = –1 V		0.1	3	µA
R_DS(ON)	Switch On-Resistance			0.2	0.24	Ω
R_DS(ON)	Switch On-Resistance	–40°C ≤ T_J ≤ 125°C			0.32	Ω
F_sw	Oscillator Frequency			500		kHz
F_sw	Oscillator Frequency	–40°C ≤ T_J ≤ 125°C	400		600	kHz
T_OFF	Minimum Off-time			200		ns
T_OFF	Minimum Off-time	–40°C ≤ T_J ≤ 125°C	100		300	ns
T_ON	Minimum On-time			100		ns
I_BIAS	Feedback Bias Current	V_FB = 1.3 V (ADJ Version Only)		230		nA
V_EN	Enable Threshold Voltage	Falling		1.6		V
V_EN	Enable Threshold Voltage	Falling, –40°C ≤ T_J ≤ 125°C	1.3		1.9	V
V_ENHYST	Enable Voltage Hysteresis			0.6		V
I_EN	Enable Input Current	EN Input = 0 V		6		µA
F_SYNC	Maximum Synchronization Frequency	V_SYNC = 3.5 V, 50% duty-cycle		1		MHz
V_SYNC	Synchronization Threshold Voltage			1.75		V
I_SS	Soft-Start Current			50		µA
I_SS	Soft-Start Current	–40°C ≤ T_J ≤ 125°C	30		70	µA
T_SD	Thermal Shutdown Threshold			150		°C

(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or other conditions beyond those indicated in the Recommended Operating Conditions is not implied. Recommended Operating Conditions indicate conditions at which the device is functional and should not be operated beyond such conditions. For ensured specifications and conditions, see the Electrical Characteristics table.

(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and specifications.

(3) The absolute maximum specification of the ‘SW to GND’ applies to dc voltage. An extended negative voltage limit of –10 V applies to a pulse of up to 50 ns.

(4) Typical values represent most likely parametric norms at the conditions specified and are not ensured.

(5) MIN and MAX limits are 100% production tested at 25°C. Limits over the operating temperature range are ensured through correlation using Statistical Quality Control (SQC) methods. Limits are used to calculate Average Outgoing Quality Level (AOQL).