NSC LM137HMDS, LM137HMDA, LM137H, LM137KMDA, LM137KGMD8 Datasheet

May 1999

LM137/LM337

3-Terminal Adjustable Negative Regulators

General Description

The LM137/LM337 are adjustable 3-terminal negative voltage regulators capable of supplying in excess of −1.5A over an output voltage range of −1.2V to −37V. These regulators are exceptionally easy to apply, requiring only 2 external resistors to set the output voltage and 1 output capacitor for frequency compensation. The circuit design has been optimized for excellent regulation and low thermal transients. Further, the LM137 series features internal current limiting, thermal shutdown and safe-area compensation, making them virtually blowout-proof against overloads.

The LM137/LM337 serve a wide variety of applications including local on-card regulation, programmable-output voltage regulation or precision current regulation. The LM137/ LM337 are ideal complements to the LM117/LM317 adjustable positive regulators.

Features

nOutput voltage adjustable from −1.2V to −37V

n1.5A output current guaranteed, −55ÊC to +150ÊC

nLine regulation typically 0.01%/V

nLoad regulation typically 0.3%

nExcellent thermal regulation, 0.002%/W

n77 dB ripple rejection

nExcellent rejection of thermal transients

n50 ppm/ÊC temperature coefficient

nTemperature-independent current limit

nInternal thermal overload protection

nP+ Product Enhancement tested

nStandard 3-lead transistor package

nOutput is short circuit protected

LM137 Series Packages and Power

Capability

		Rated	Design
Device	Package	Power	Load
		Dissipation	Current
LM137/337	TO-3 (K)	20W	1.5A
	TO-39 (H)	2W	0.5A
LM337	TO-220 (T)	15W	1.5A
LM337	SOT-223	2W	1A
	(MP)

Typical Applications	Comparison between SOT-223 and
Adjustable Negative Voltage Regulator	D-Pak (TO-252) Packages

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Scale 1:1

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Full output current not available at high input-output voltages

²C1 = 1 µF solid tantalum or 10 µF aluminum electrolytic required for stability

*C2 = 1 µF solid tantalum is required only if regulator is more than 4" from power-supply filter capacitor

Output capacitors in the range of 1 µF to 1000 µF of aluminum or tantalum electrolytic are commonly used to provide improved output impedance and rejection of transients

Regulators Negative Adjustable Terminal-3 LM137/LM337

© 1999 National Semiconductor Corporation

DS009067

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Absolute Maximum Ratings (Notes 1, 4)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

Power Dissipation	Internally Limited
Input-Output Voltage Differential	40V
Operating Junction Temperature Range
LM137	−55ÊC to +150ÊC

LM337	0ÊC to +125ÊC
Storage Temperature	−65ÊC to +150ÊC
Lead Temperature (Soldering, 10 sec.)	300ÊC
Plastic Package (Soldering, 4 sec.)	260ÊC
ESD Rating	2k Volts

Electrical Characteristics

(Note 1)

Parameter	Conditions		LM137			LM337		Units
		Min	Typ	Max	Min	Typ	Max
Line Regulation	Tj = 25ÊC, 3V ≤ |VIN − V OUT| ≤ 40V		0.01	0.02		0.01	0.04	%/V
	(Note 2) IL = 10 mA
Load Regulation	Tj = 25ÊC, 10 mA ≤ IOUT ≤ IMAX		0.3	0.5		0.3	1.0	%
Thermal Regulation	Tj = 25ÊC, 10 ms Pulse		0.002	0.02		0.003	0.04	%/W
Adjustment Pin Current			65	100		65	100	µA
Adjustment Pin Current Charge	10 mA ≤ IL ≤ IMAX		2	5		2	5	µA
	3.0V ≤ |VIN − V OUT| ≤ 40V,
	TA = 25ÊC
Reference Voltage	Tj = 25ÊC (Note 3)	−1.225	−1.250	−1.275	−1.213 −1.250 −1.287			V
	3V ≤ |VIN − V OUT| ≤ 40V, (Note 3)	−1.200	−1.250	−1.300	−1.200	−1.250 −1.300		V
	10 mA ≤ IOUT ≤ IMAX, P ≤ PMAX
Line Regulation	3V ≤ |VIN − V OUT| ≤ 40V, (Note 2)		0.02	0.05		0.02	0.07	%/V
Load Regulation	10 mA ≤ IOUT ≤ IMAX, (Note 2)		0.3	1		0.3	1.5	%
Temperature Stability	TMIN ≤ Tj ≤ TMAX		0.6			0.6		%
Minimum Load Current	|VIN − V OUT| ≤ 40V		2.5	5		2.5	10	mA
	|VIN − V OUT| ≤ 10V		1.2	3		1.5	6	mA
Current Limit	|VIN − V OUT| ≤ 15V
	K, MP and T Package	1.5	2.2	3.5	1.5	2.2	3.7	A
	H Package	0.5	0.8	1.8	0.5	0.8	1.9	A
	|VIN − V OUT| = 40V, Tj = 25ÊC
	K, MP and T Package	0.24	0.4		0.15	0.4		A
	H Package	0.15	0.17		0.10	0.17		A
RMS Output Noise, % of VOUT	Tj = 25ÊC, 10 Hz ≤ f ≤ 10 kHz		0.003			0.003		%
Ripple Rejection Ratio	VOUT = −10V, f = 120 Hz		60			60		dB
	CADJ = 10 µF	66	77		66	77		dB
Long-Term Stability	Tj = 125ÊC, 1000 Hours		0.3	1		0.3	1	%
Thermal Resistance, Junction to	H Package		12	15		12	15	ÊC/W
Case	K Package		2.3	3		2.3	3	ÊC/W
	T Package					4		ÊC/W
Thermal Resistance, Junction to	H Package		140			140		ÊC/W
Ambient (No Heat Sink)	K Package		35			35		ÊC/W
	T Package					50		ÊC/W
	MP Package					170		ÊC/W

Note 1: Unless otherwise specified, these specifications apply −55ÊC ≤ Tj ≤ +150ÊC for the LM137, 0ÊC ≤ Tj ≤ +125ÊC for the LM337; VIN − V OUT = 5V; and IOUT = 0.1A for the TO-39 package and IOUT = 0.5A for the TO-3, SOT-223 and TO-220 packages. Although power dissipation is internally limited, these specifications

are applicable for power dissipations of 2W for the TO-39 and SOT-223 (see Application Hints), and 20W for the TO-3, and TO-220. IMAX is 1.5A for the TO-3, SOT-223 and TO-220 packages, and 0.2A for the TO-39 package.

Note 2: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are covered under the specification for thermal regulation. Load regulation is measured on the output pin at a point 1¤8" below the base of the TO-3 and TO-39 packages.

Note 3: Selected devices with tightened tolerance reference voltage available.

Note 4: Refer to RETS137H drawing for LM137H or RETS137K drawing for LM137K military specifications.

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Schematic Diagram

Thermal Regulation

When power is dissipated in an IC, a temperature gradient occurs across the IC chip affecting the individual IC circuit components. With an IC regulator, this gradient can be especially severe since power dissipation is large. Thermal regulation is the effect of these temperature gradients on output voltage (in percentage output change) per Watt of power change in a specified time. Thermal regulation error is independent of electrical regulation or temperature coefficient, and occurs within 5 ms to 50 ms after a change in power dissipation. Thermal regulation depends on IC layout as well as electrical design. The thermal regulation of a voltage regulator is defined as the percentage change of VOUT, per Watt, within the first 10 ms after a step of power is applied. The LM137's specification is 0.02%/W, max.

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LM137, VOUT = −10V

VIN − V OUT = −40V

IIL = 0A → 0.25A → 0A

Vertical sensitivity, 5 mV/div

FIGURE 1.

In Figure 1, a typical LM137's output drifts only 3 mV (or 0.03% of VOUT = −10V) when a 10W pulse is applied for 10 ms. This performance is thus well inside the specification limit of 0.02%/W x 10W = 0.2% max. When the 10W pulse is ended, the thermal regulation again shows a 3 mV step at the LM137 chip cools off. Note that the load regulation error of about 8 mV (0.08%) is additional to the thermal regulation error. In Figure 2, when the 10W pulse is applied for 100 ms, the output drifts only slightly beyond the drift in the first 10 ms, and the thermal error stays well within 0.1% (10 mV).

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Thermal Regulation (Continued)

TO-220

Plastic Package

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LM137, VOUT = −10V

VIN − V OUT = −40V

IL = 0A → 0.25A → 0A

Horizontal sensitivity, 20 ms/div

FIGURE 2.

Connection Diagrams

TO-3

Metal Can Package

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Case is Input

Bottom View

Order Number LM137K/883

LM137KPQML and LM137KPQMLV(Note 5)

See NS Package Number K02C

Order Number LM337K STEEL

See NS Package Number K02A

TO-39

Metal Can Package

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Case Is Input

Note 5: See STD Mil DWG 5962P99517 for Radiation Tolerant Devices

Bottom View

Order Number LM137H, LM137H/883 or LM337H LM137HPQML and LM137HPQMLV(Note 5)

See NS Package Number H03A

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Front View

Order Number LM337T

See NS Package Number T03B

3-Lead SOT-223

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Front View

Order Number LM337IMP

Package Marked N02ASee NS Package Number MA04A

Application Hints

When a value for θ(H−A) is found using the equation shown, a heatsink must be selected that has a value that is less than

or equal to this number.

HEATSINKING SOT-223 PACKAGE PARTS

The SOT-223 (ªMPº) packages use a copper plane on the PCB and the PCB itself as a heatsink. To optimize the heat sinking ability of the plane and PCB, solder the tab of the package to the plane.

Figures 3, 4 show the information for the SOT-223 package.

Figure 4 assumes a θ(J−A) of 75ÊC/W for 1 ounce copper and 51ÊC/W for 2 ounce copper and a maximum junction tem-

perature of 125ÊC.

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