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. 77 dB ripple rejection Excellent rejection of thermal transients 50 ppm/˚C temperature coefficient Temperature-independent current limit Internal thermal overload protection P+ Product Enhancement tested Standard 3-lead transistor package Output is short circuit protected LM137 Series Packages and Power Capability Rated Device Output voltage adjustable from −1.2V to −37V 1.5A output current guaranteed, −55˚C to +150˚C Line regulation typically 0.01%/V Load regulation typically 0.3% Excellent thermal regulation, 0.002%/W Typical Applications Package Design Power Load Dissipation Current TO-3 (K) 20W 1.5A TO-39 (H) 2W 0.5A LM337 TO-220 (T) 15W 1.5A LM337 SOT-223 (MP) 2W 1A LM137/337 Features n n n n n n n n n n n n n Comparison between SOT-223 and D-Pak (TO-252) Packages Adjustable Negative Voltage Regulator DS009067-31 Scale 1:1 DS009067-1 Full output current not available at high input-output voltages †C1 = 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 © 2001 National Semiconductor Corporation DS009067 www.national.com LM137/LM337 3-Terminal Adjustable Negative Regulators May 1999 LM137/LM337 Absolute Maximum Ratings (Notes 1, 4) LM337 Storage Temperature Lead Temperature (Soldering, 10 sec.) Plastic Package (Soldering, 4 sec.) ESD Rating If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Power Dissipation Input-Output Voltage Differential Operating Junction Temperature Range LM137 Internally Limited 40V 0˚C to +125˚C −65˚C to +150˚C 300˚C 260˚C 2k Volts −55˚C to +150˚C Electrical Characteristics (Note 1) Parameter Conditions LM137 Min Line Regulation Tj = 25˚C, 3V ≤ |VIN − VOUT| ≤ 40V LM337 Typ Max 0.01 0.02 Min Units Typ Max 0.01 0.04 %/V (Note 2) IL = 10 mA Load Regulation Tj = 25˚C, 10 mA ≤ IOUT ≤ IMAX Thermal Regulation Tj = 25˚C, 10 ms Pulse Adjustment Pin Current Adjustment Pin Current Charge 10 mA ≤ IL ≤ IMAX 0.3 0.5 0.3 1.0 % 0.002 0.02 0.003 0.04 %/W 65 100 65 100 µA 2 5 2 5 µA 3.0V ≤ |VIN − VOUT| ≤ 40V, TA = 25˚C Reference Voltage Tj = 25˚C (Note 3) −1.225 −1.250 −1.275 −1.213 −1.250 −1.287 V 3V ≤ |VIN − VOUT| ≤ 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 − VOUT| ≤ 40V, (Note 2) 0.02 0.05 1 0.02 0.07 %/V 0.3 1.5 % Load Regulation 10 mA ≤ IOUT ≤ IMAX, (Note 2) 0.3 Temperature Stability TMIN ≤ Tj ≤ TMAX 0.6 Minimum Load Current |VIN − VOUT| ≤ 40V 2.5 5 2.5 10 mA |VIN − VOUT| ≤ 10V 1.2 3 1.5 6 mA Current Limit 0.6 % |VIN − VOUT| ≤ 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 − VOUT| = 40V, Tj = 25˚C 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 = 25˚C, 10 Hz ≤ f ≤ 10 kHz Ripple Rejection Ratio VOUT = −10V, f = 120 Hz CADJ = 10 µF Long-Term Stability Tj = 125˚C, 1000 Hours Thermal Resistance, Junction to Case 66 0.003 0.003 % 60 60 dB 77 1 H Package 12 K Package 2.3 T Package Thermal Resistance, Junction to Ambient (No Heat Sink) 66 0.3 77 dB 0.3 1 % 15 12 15 ˚C/W 3 2.3 3 ˚C/W 4 ˚C/W H Package 140 140 ˚C/W K Package 35 35 ˚C/W 50 170 ˚C/W ˚C/W T Package MP Package Note 1: Unless otherwise specified, these specifications apply −55˚C ≤ Tj ≤ +150˚C for the LM137, 0˚C ≤ Tj ≤ +125˚C for the LM337; VIN − VOUT = 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. www.national.com 2 LM137/LM337 Schematic Diagram DS009067-2 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. DS009067-3 LM137, VOUT = −10V VIN − VOUT = −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). 3 www.national.com LM137/LM337 Thermal Regulation (Continued) TO-220 Plastic Package DS009067-4 LM137, VOUT = −10V VIN − VOUT = −40V IL = 0A → 0.25A → 0A Horizontal sensitivity, 20 ms/div FIGURE 2. Connection Diagrams DS009067-7 TO-3 Metal Can Package Front View Order Number LM337T See NS Package Number T03B 3-Lead SOT-223 DS009067-34 DS009067-5 Front View Order Number LM337IMP Package Marked N02ASee NS Package Number MA04A 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 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 (“MP”) 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. TO-39 Metal Can Package Figures 3, 4 show the information for the SOT-223 package. Figure 4 assumes a θ(J−A) of 75˚C/W for 1 ounce copper and 51˚C/W for 2 ounce copper and a maximum junction temperature of 125˚C. DS009067-6 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 www.national.com 4 LM137/LM337 Application Hints Typical Applications (Continued) Adjustable Lab Voltage Regulator DS009067-32 FIGURE 3. θ(J−A) vs Copper (2 ounce) Area for the SOT-223 Package DS009067-9 Full output current not available at high input-output voltages *The 10 µF capacitors are optional to improve ripple rejection Current Regulator DS009067-33 DS009067-11 FIGURE 4. Maximum Power Dissipation vs TAMB for the SOT-223 Package Please see AN1028 for power enhancement techniques to be used with the SOT-223 package. Negative Regulator with Protection Diodes DS009067-13 *When CL is larger than 20 µF, D1 protects the LM137 in case the input supply is shorted **When C2 is larger than 10 µF and −VOUT is larger than −25V, D2 protects the LM137 in case the output is shorted 5 www.national.com LM137/LM337 Typical Applications (Continued) High Stability −10V Regulator −5.2V Regulator with Electronic Shutdown* DS009067-14 DS009067-10 *Minimum output . −1.3V when control input is low Adjustable Current Regulator DS009067-12 www.national.com 6 (K Steel and T Packages) Current Limit Load Regulation Adjustment Current DS009067-16 Dropout Voltage DS009067-19 Minimum Operating Current DS009067-20 Ripple Rejection DS009067-21 Ripple Rejection DS009067-22 Output Impedance DS009067-18 DS009067-17 Temperature Stability Ripple Rejection LM137/LM337 Typical Performance Characteristics DS009067-23 Line Transient Response Load Transient Response DS009067-26 DS009067-25 7 DS009067-24 DS009067-27 www.national.com LM137/LM337 Physical Dimensions inches (millimeters) unless otherwise noted Metal Can Package (H) Order Number LM137H, LM137H/883 or LM337H NS Package Number H03A www.national.com 8 LM137/LM337 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Metal Can Package (K) Order Number LM337K STEEL NS Package Number K02A Mil-Aero Metal Can Package (K) Order Number LM137K/883 NS Package Number K02C 9 www.national.com LM137/LM337 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 3-Lead SOT-223 Package Order Number LM337IMP NS Package Number M04A www.national.com 10 LM137/LM337 3-Terminal Adjustable Negative Regulators Physical Dimensions inches (millimeters) unless otherwise noted (Continued) TO-220 Plastic Package (T) Order Number LM337T NS Package Number T03B LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. 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