Overview

Part: LM2596 from Texas Instruments

Type: 150-kHz 3-A Step-Down Voltage Regulator

Key Specs:

Output Load Current: 3 A
Input Voltage Range: Up to 40 V
Fixed Output Voltages: 3.3 V, 5 V, 12 V
Adjustable Output Voltage Range: 1.2 V to 37 V
Adjustable Output Voltage Accuracy: ±4% maximum over line and load conditions
Oscillator Frequency: 150 kHz
Standby Quiescent Current (IQ): Typically 80 µA

Features:

Adjustable output versions
Requires only four external components
Excellent line and load regulation specifications
Fixed-frequency internal oscillator
TTL shutdown capability
Low power standby mode
High efficiency
Uses readily available standard inductors
Thermal shutdown and current-limit protection
Internal frequency compensation

Applications:

Appliances
Grid infrastructure
EPOS
Home theater

Package:

NDH (TO-220, 5): 14.986 mm × 10.16 mm
KTT (TO-263, 5): 10.10 mm × 8.89 mm

Features

New product available:
- LMR51430 4.5 to 36-V, 3-A, 500-kHz and 1.1- MHz synchronous converter
For faster time to market:
- TLVM13630 3 to 36-V, 3-A, 200-kHz to 2.2-MHz power module
3.3-V, 5-V, 12-V, and adjustable output versions
Adjustable version output voltage range: 1.2-V to 37-V ±4% maximum over line and load conditions
Available in TO-220 and TO-263 packages
3-A output load current
Input voltage range up to 40 V
Requires only four external components
Excellent line and load regulation specifications
150-kHz fixed-frequency internal oscillator
TTL shutdown capability
Low power standby mode, IQ, typically 80 μA
High efficiency
Uses readily available standard inductors
Thermal shutdown and current-limit protection
Create a custom design using the LM2596 with the WEBENCH® Power Designer

Applications

Pin Configuration

Figure 6-1. 5-Pin TO-220 NDH Package Top View

Table 6-1. Pin Functions

| | PIN | |-----|----------|-----|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | NO. | NAME | I/O | DESCRIPTION | | 1 | VIN | I | This is the positive input supply for the IC switching regulator. A suitable input bypass
capacitor must be present at this pin to minimize voltage transients and to supply the
switching currents required by the regulator. | | 2 | Output | O | Internal switch. The voltage at this pin switches between approximately (+VIN − VSAT) and
approximately −0.5 V, with a duty cycle of VOUT / VIN. To minimize coupling to sensitive
circuitry, the PCB copper area connected to this pin must be kept to a minimum. | | 3 | Ground | — | Circuit ground | | 4 | Feedback | I | Senses the regulated output voltage to complete the feedback loop. | | 5 | ON/OFF | I | Allows the switching regulator circuit to be shut down using logic signals thus dropping
the total input supply current to approximately 80 µA. Pulling this pin below a threshold
voltage of approximately 1.3 V turns the regulator on, and pulling this pin above 1.3 V (up
to a maximum of 25 V) shuts the regulator down. If this shutdown feature is not required,
the ON/OFF pin can be wired to the ground pin or it can be left open. In either case, the
regulator will be in the ON condition. |

Electrical Characteristics

Specifications are for T_.I = 25°C (unless otherwise noted)

| _ | | | | MIN ⁽¹⁾ | (0) | (4) | |----------------------------------------------------------|---------------------------|-----------------------------------------------------|--------------------------------|--------------------|--------------------|--------------------|-------|--|--| | | PARAMETER TEST CONDITIONS | | | | TYP ⁽²⁾ | MAX ⁽¹⁾ | UNIT | | SYSTEM PARAMETERS (3) (see Figure 9-13 for test circuit) | | / | | 4.75 V ≤ V _IN ≤ 40 V, | T _J = 25°C | 3.168 | 3.3 | 3.432 | 3.432 | | V _OUT | Output voltage | $0.2 \text{ A} \le I_{\text{LOAD}} \le 3 \text{ A}$ | –40°C ≤ T _J ≤ 125°C | 3.135 | | 3.465 | V | | η | Efficiency | V _IN = 12 V, I _LOAD = 3 A | | 73% |

(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2596 is used as shown in Figure 9-13, system performance is shown in the test conditions column.

Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1) (2)

			MIN	MAX	UNIT
Maximum supply voltage (VIN)				45	V
SD/SS pin input voltage(3)				6	V
Delay pin voltage(3)				1.5	V
Flag pin voltage			–0.3	45	V
Feedback pin voltage				25	V
Output voltage to ground, steady-state				–1	V
Power dissipation				Internally limited
		Vapor phase (60 s)		215
Lead temperature	KTW package	Infrared (10 s)		245	°C
		NDZ package, soldering (10 s)
Maximum junction temperature				150	°C
Storage temperature, Tstg			–65	150	°C

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications.
(3) Voltage internally clamped. If clamp voltage is exceeded, limit current to a maximum of 1 mA.

7.2 ESD Ratings

			VALUE	UNIT
V(ESD)	Electrostatic discharge	Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)	±2000	V

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

7.3 Operating Conditions

	MIN	MAX	UNIT
Supply voltage	4.5	40	V
Temperature	–40	125	°C

Thermal Information

| | | | | LM2596 | |-----------|-----------------------------------------------|--------------|--------------|--------|------| | | THERMAL METRIC(1) | KTW (TO-263) | NDZ (TO-220) | UNIT | | | | 5 PINS | 5 PINS | | | | See(4) | — | 50 | | | | See(5) | 50 | — | | RθJA | Junction-to-ambient thermal resistance(2) (3) | See(6) | 30 | — | °C/W | | | | See(7) | 20 | — | | RθJC(top) | Junction-to-case (top) thermal resistance | | 2 | 2 | °C/W |

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.
(2) The package thermal impedance is calculated in accordance to JESD 51-7.
(3) Thermal Resistances were simulated on a 4-layer, JEDEC board.
(4) Junction to ambient thermal resistance (no external heat sink) for the package mounted TO-220 package mounted vertically, with the leads soldered to a printed circuit board with (1 oz.) copper area of approximately 1 in²
(5) Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 0.5 in² of 1-oz copper area.

(6) Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 2.5 in² of 1-oz copper area.
(7) Junction to ambient thermal resistance with the TO-263 package tab soldered to a double sided printed circuit board with 3 in² of 1-oz copper area on the LM2596S side of the board, and approximately 16 in² of copper on the other side of the PCB.

7.5 Electrical Characteristics – 3.3-V Version

Specifications are for T_.I = 25°C (unless otherwise noted)

| _ | | | | MIN ⁽¹⁾ | (0) | (4) | |----------------------------------------------------------|---------------------------|-----------------------------------------------------|--------------------------------|--------------------|--------------------|--------------------|-------|--|--| | | PARAMETER TEST CONDITIONS | | | | TYP ⁽²⁾ | MAX ⁽¹⁾ | UNIT | | SYSTEM PARAMETERS (3) (see Figure 9-13 for test circuit) | | / | | 4.75 V ≤ V _IN ≤ 40 V, | T _J = 25°C | 3.168 | 3.3 | 3.432 | 3.432 | | V _OUT | Output voltage | $0.2 \text{ A} \le I_{\text{LOAD}} \le 3 \text{ A}$ | –40°C ≤ T _J ≤ 125°C | 3.135 | | 3.465 | V | | η | Efficiency | V _IN = 12 V, I _LOAD = 3 A | | 73% |

(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2596 is used as shown in Figure 9-13, system performance is shown in the test conditions column.

7.6 Electrical Characteristics - 5-V Version

Specifications are for T_.I = 25°C (unless otherwise noted)

| | PARAMETER | TEST | MIN ⁽¹⁾ | TYP ⁽²⁾ | MAX ⁽¹⁾ | UNIT | |----------------------------------------------------------|------------|-----------------------------------------------------|---------------------------------------------|--------------------|--------------------|------|---|--|--| | SYSTEM PARAMETERS (3) (see Figure 9-13 for test circuit) | | V | | 7 V ≤ V _IN ≤ 40 V, | T _J = 25°C | 4.8 | 5 | 5.2 | | V _OUT | | $0.2 \text{ A} \le I_{\text{LOAD}} \le 3 \text{ A}$ | $-40$ °C $\leq$ T _J $\leq$ 125°C | 4.75 | | 5.25 | V | | η | Efficiency | V _IN = 12 V, I _LOAD = 3 A | | 80% |

(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2596 is used as shown in Figure 9-13, system performance is shown in the test conditions column.

7.7 Electrical Characteristics – 12-V Version

Specifications are for T₁ = 25°C (unless otherwise noted)

| epochications are for 11 20 0 (arrices outstance) | |----------------------------------------------------------|----------------|-----------------------------------------------------|--------------------------------|--------------------|--------------------|-------|---|--|--|--| | | PARAMETER | TEST CO | MIN ⁽¹⁾ | TYP ⁽²⁾ | MAX ⁽¹⁾ | UNIT | | SYSTEM PARAMETERS (3) (see Figure 9-13 for test circuit) | | V | Output voltage | 15 V ≤ V _IN ≤ 40 V, | T _J = 25°C | 11.52 | 12 | 12.48 | V | | V _OUT | Output voltage | $0.2 \text{ A} \le I_{\text{LOAD}} \le 3 \text{ A}$ | -40°C ≤ T _J ≤ 125°C | 11.4 | | 12.6 | V | | η | Efficiency | V _IN = 25 V, I _LOAD = 3 A | | 90% |

(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2596 is used as shown in Figure 9-13, system performance is shown in the test conditions column.

7.8 Electrical Characteristics – Adjustable Voltage Version

Specifications are for T₁ = 25°C (unless otherwise noted)

| | PARAMETER | TEST CON | IDITIONS | MIN ⁽¹⁾ | TYP ⁽²⁾ | MAX ⁽¹⁾ | UNIT | |----------------------------------------------------------|------------------|-----------------------------------------------------------------------------------------------------------|--------------------------------|--------------------|--------------------|--------------------|------|--| | SYSTEM PARAMETERS (3) (see Figure 9-13 for test circuit) | | | | $4.5 \text{ V} \le \text{V}{\text{IN}} \le 40 \text{ V}, 0.2 \text{ A} \le \text{I}{\text{LOAD}} \le 3$ | | 1.23 | | V _FB | Feedback voltage | V _OUT programmed for 3 V | T _J = 25°C | 1.193 | | 1.267 | V | | | | (see Figure 9-13 for test circuit) | –40°C ≤ T _J ≤ 125°C | 1.18 | | 1.28 | | η | Efficiency | V _IN = 12 V, V _OUT = 3 V, I _LOAD = 3 A | | 73% |

(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.

(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2596 is used as shown in Figure 9-13, system performance is shown in the test conditions column.

7.9 Electrical Characteristics – All Output Voltage Versions

Specifications are for $T_J = 25$ °C, $I_{LOAD} = 500$ mA, $V_{IN} = 12$ V for the 3.3-V, 5-V, and adjustable version, and $V_{IN} = 24$ V for the 12-V version (unless otherwise noted).

	PARAMETER	TEST CO	NDITIONS	MIN ⁽¹⁾	TYP ⁽²⁾	MAX ⁽¹⁾	UNIT
DEVIC	E PARAMETERS				'
	Feedback bias current	Adjustable version only,	T _J = 25°C		10	50	nA
I _b	reedback bias current	V _FB = 1.3 V	–40°C ≤ T _J ≤ 125°C			100	ПA
£	Oscillator frequency ⁽³⁾	T _J = 25°C	127	150	173	kHz
f _O	Oscillator frequency	–40°C ≤ T _J ≤ 125°C		110		173	KIZ
/	Saturation voltage ^{(4) (5)}	I - 2 A	T _J = 25°C		1.16	1.4	V
$V_{SAT}$	Saturation voltage(*)	I _OUT = 3 A	–40°C ≤ T _J ≤ 125°C			1.5	V
DC	Max duty cycle (ON) ⁽⁵⁾		•		100%
DC	Min duty cycle (OFF) ⁽⁶⁾				0%
	Current limit ^{(4) (5)}	Peak current	T _J = 25°C	3.6	4.5	6.9	Α
CL	Current mint	Peak current	–40°C ≤ T _J ≤ 125°C	3.4		7.5
	Output leakage current ⁽⁴⁾	Output = 0 V, V _IN = 40 V			50	μA
IL	(6)	Output = -1 V		2	30	mA
IQ	Operating quiescent current ⁽⁶⁾	See ⁽⁶⁾			5	10	mA
	Current standby	$\overline{ON}/OFF \text{ pin} = 5 \text{ V } (OFF)^{(7)}$	T _J = 25°C		80	200	μA
I _STBY	quiescent	ON/OFF PIN = 5 V (OFF)	–40°C ≤ T _J ≤ 125°C			250	μA
SHUTI	DOWN/SOFT-START CON	TROL (see Figure 9-13 for te	st circuit)
V _IH		Low (regulator ON)	T _J = 25°C		1.3		V
VІH	ON/OFF pin logic input	Low (regulator ON)	–40°C ≤ T _J ≤ 125°C			0.6	V
V	threshold voltage	High (regulator OFF)	T _J = 25°C		1.3		V
$V_{IL}$		riigii (regulator OFF)	–40°C ≤ T _J ≤ 125°C	2			V
I _H	ON/OFF pin input current	V _LOGIC = 2.5 V (regulator O	FF)		5	15	μA
Ι _L		V _LOGIC = 0.5 V (regulator O	N)		0.02	5	μΑ

⁽¹⁾ All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).

(7) $V_{IN} = 40 \text{ V}.$

⁽²⁾ Typical numbers are at 25 $^{\circ}\text{C}$ and represent the most likely norm.

⁽³⁾ The switching frequency is reduced when the second stage current limit is activated. The amount of reduction is determined by the severity of current overload.

⁽⁴⁾ No diode, inductor, or capacitor connected to output pin.

⁽⁵⁾ Feedback pin removed from output and connected to 0 V to force the output transistor switch ON.

⁽⁶⁾ Feedback pin removed from output and connected to 12 V for the 3.3-V, 5-V, and the adjustable versions, and 15 V for the 12-V version, to force the output transistor switch OFF.

7.10 Typical Characteristics

See Figure 9-13 for test circuit