ON Semiconductor Three-Terminal Adjustable Output Negative Voltage Regulator The LM337 is an adjustable 3–terminal negative voltage regulator capable of supplying in excess of 1.5 A over an output voltage range of –1.2 V to –37 V. This voltage regulator is exceptionally easy to use and requires only two external resistors to set the output voltage. Further, it employs internal current limiting, thermal shutdown and safe area compensation, making it essentially blow–out proof. The LM337 serves a wide variety of applications including local, on card regulation. This device can also be used to make a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM337 can be used as a precision current regulator. • Output Current in Excess of 1.5 A • Output Adjustable between –1.2 V and –37 V • Internal Thermal Overload Protection • Internal Short Circuit Current Limiting Constant with Temperature • Output Transistor Safe–Area Compensation • Floating Operation for High Voltage Applications • Eliminates Stocking many Fixed Voltages • Available in Surface Mount D2PAK and Standard 3–Lead Transistor Package LM337 THREE–TERMINAL ADJUSTABLE NEGATIVE VOLTAGE REGULATOR SEMICONDUCTOR TECHNICAL DATA T SUFFIX PLASTIC PACKAGE CASE 221A Heatsink surface connected to Pin 2. 1 2 3 Pin 1. Adjust 2. Vin 3. Vout Standard Application D2T SUFFIX PLASTIC PACKAGE CASE 936 (D2PAK) IPROG Cin* 1.0 µF R2 + CO** 1.0 µF R1 120 Vin LM337 2 3 + Heatsink surface (shown as terminal 4 in case outline drawing) is connected to Pin 2. IAdj -Vin 1 Vout -Vout ORDERING INFORMATION *Cin is required if regulator is located more than 4 inches from power supply filter. *A 1.0 µF solid tantalum or 10 µF aluminum electrolytic is recommended. **CO is necessary for stability. A 1.0 µF solid tantalum or 10 µF aluminum electrolytic **is recommended. March, 2001 – Rev. 2 LM337BT LM337T 1 Operating Temperature Range LM337BD2T LM337D2T R V out 1.25V 1 2 R1 Semiconductor Components Industries, LLC, 2001 Device Package Surface Mount TJ = –40° to +125°C TJ = 0° to +125°C Insertion Mount Surface Mount Insertion Mount Publication Order Number: LM337/D LM337 MAXIMUM RATINGS Rating Symbol Value Unit VI–VO 40 Vdc PD θJA θJC Internally Limited 65 5.0 W °C/W °C/W PD θJA θJC Internally Limited 70 5.0 W °C/W °C/W Operating Junction Temperature Range TJ –40 to +125 °C Storage Temperature Range Tstg –65 to +150 °C Input–Output Voltage Differential Power Dissipation Case 221A TA = +25°C Thermal Resistance, Junction–to–Ambient Thermal Resistance, Junction–to–Case Case 936 (D2PAK) TA = +25°C Thermal Resistance, Junction–to–Ambient Thermal Resistance, Junction–to–Case ELECTRICAL CHARACTERISTICS (|VI–VO| = 5.0 V; IO = 0.5 A for T package; TJ = Tlow to Thigh [Note 1]; Imax and Pmax [Note 2].) Characteristics Figure Symbol Min Typ Max Unit – 0.01 0.04 %/V – – 15 0.3 50 1.0 mV % VO Regtherm – 0.003 0.04 % VO/W Line Regulation (Note 3), TA = +25°C, 3.0 V ≤ |VI–VO| ≤ 40 V 1 Regline Load Regulation (Note 3), TA = +25°C, 10 mA ≤ IO ≤ Imax |VO| ≤ 5.0 V |VO| ≥ 5.0 V 2 Regload Thermal Regulation, TA = +25°C (Note 6), 10 ms Pulse 3 IAdj – 65 100 µA Adjustment Pin Current Change, 2.5 V ≤ |VI–VO| ≤ 40 V, 10 mA ≤ IL ≤ Imax, PD ≤ Pmax, TA = +25°C 1, 2 ∆IAdj – 2.0 5.0 µA Reference Voltage, TA = +25°C, 3.0 V ≤ |VI–VO| ≤ 40 V, 10 mA ≤ IO ≤ Imax, PD ≤ Pmax, TJ = Tlow to Thigh 3 Vref –1.213 –1.20 –1.250 –1.25 –1.287 –1.30 V Line Regulation (Note 3), 3.0 V ≤ |VI–VO| ≤ 40 V 1 Regline – 0.02 0.07 %/V Load Regulation (Note 3), 10 mA ≤ IO ≤ Imax |VO| ≤ 5.0 V |VO| ≥ 5.0 V 2 Regload – – 20 0.3 70 1.5 mV % VO Temperature Stability (Tlow ≤ TJ ≤ Thigh) 3 TS – 0.6 – % VO Minimum Load Current to Maintain Regulation (|VI–VO| ≤ 10 V) (|VI–VO| ≤ 40 V) 3 ILmin – – 1.5 2.5 6.0 10 Maximum Output Current |VI–VO| ≤ 15 V, PD ≤ Pmax, T Package |VI–VO| ≤ 40 V, PD ≤ Pmax, TJ = +25°C, T Package 3 – – 1.5 0.15 2.2 0.4 – 0.003 – – 66 60 77 – – S – 0.3 1.0 %/1.0 k Hrs. RθJC – 4.0 – °C/W Adjustment Pin Current RMS Noise, % of VO, TA = +25°C, 10 Hz ≤ f ≤ 10 kHz Imax N Ripple Rejection, VO = –10 V, f = 120 Hz (Note 4) Without CAdj CAdj = 10 µF 4 Long–Term Stability, TJ = Thigh (Note 5), TA = +25°C for Endpoint Measurements 3 Thermal Resistance Junction–to–Case, T Package mA A RR % VO dB NOTES: 1. Tlow to Thigh = 0° to +125°C, for LM337T, D2T. Tlow to Thigh = –40° to +125°C, for LM337BT, BD2T. 2. Imax = 1.5 A, Pmax = 20 W 3. Load and line regulation are specified at constant junction temperature. Change in VO because of heating effects is covered under the Thermal Regulation specification. Pulse testing with a low duty cycle is used. 4. CAdj, when used, is connected between the adjustment pin and ground. 5. Since Long Term Stability cannot be measured on each device before shipment, this specification is an engineering estimate of average stability from lot to lot. 6. Power dissipation within an IC voltage regulator produces a temperature gradient on the die, affecting individual IC components on the die. These effects can be minimized by proper integrated circuit design and layout techniques. Thermal Regulation is the effect of these temperature gradients on the output voltage and is expressed in percentage of output change per watt of power change in a specified time. http://onsemi.com 2 LM337 Representative Schematic Diagram Adjust 60 100 2.0k 2.5k 810 21k Vout 10k 800 15pF 25pF 220 5.0k 75 0 60k 100k 2.0k 15pF 800 18k 4.0k 6.0k 100 1.0k 2.2k 3.0k 9.6k 270 240 5.0pF 100pF 20k 18k 30k 2.0 pF 250 5.0k 8.0k 0.2 100k 600 2.9k 4.0k 15 2.4k 500 15 500 155 0.05 Vin This device contains 39 active transistors. 1% R2 Cin 1.0 µF CO IAdj Vin LM337 1.0 µF 120 1% R1 Adjust *Pulse testing required. 1% Duty Cycle is suggested. + Vout VIH VIL * VEE RL VOH VOL LineRegulation(%V) |V V | OL OH x100 |V | OH Figure 1. Line Regulation and ∆IAdj/Line Test Circuit http://onsemi.com 3 LM337 R2 Cin *Pulse testing required. 1% Duty Cycle is suggested. 1% CO + 1.0 µF IAdj R1 1.0 µF 120 * Adjust -VI Vin Vout LM337 RL (max Load) IL Load Regulation (mV) = VO (min Load) - VO (max Load) -VO (min Load) -VO (max Load) Load Regulation (% VO) = VO (min Load) - VO (max Load) VO (min Load) x 100 Figure 2. Load Regulation and ∆IAdj/Load Test Circuit 1% R2 Cin VI CO 1.0 µF Vref R1 Adjust Vin R2 = VO RL IAdj To Calculate R2: + 1.0 µF VO Vref This assumes IAdj is negligible. LM337 Vout 120 IL R1 -1 * Pulse testing required. * 1% Duty Cycle is suggested. Figure 3. Standard Test Circuit R2 Cin CAdj 1% 10µF CO 1.0 µF Adjust Vin + LM337 120 R1 D1* + 1.0 µF RL 1N4002 Vout Vout = -1.25 V 14.3 V 4.3 V VO * D1 Discharges CAdj if output is shorted to Ground. f = 120 Hz Figure 4. Ripple Rejection Test Circuit http://onsemi.com 4 0.2 4.0 0 IL = 0.5 A -0.2 I out , OUTPUT CURRENT (A) ∆V out , OUTPUT VOLTAGE CHANGE (%) LM337 -0.4 -0.6 -0.8 Vin = -15 V Vout = -10 V -1.0 IL = 1.5 A -1.2 -1.4 -50 -25 0 25 50 75 100 125 TJ, JUNCTION TEMPERATURE (°C) 3.0 2.0 TJ = 25°C 1.0 0 150 0 10 20 30 Vin-Vout , INPUT-OUTPUT VOLTAGE DIFFERENTIAL (Vdc) Figure 5. Load Regulation Figure 6. Current Limit 3.0 V in - Vout , INPUT-OUTPUT VOLTAGE DIFFERENTIAL (Vdc) IAdj, ADJUSTMENT CURRENT (µA) 80 75 70 65 60 55 50 45 40 -50 -25 0 25 50 75 100 125 TJ, JUNCTION TEMPERATURE (°C) Vout = -5.0 V ∆VO = 100 mV 2.5 IL = 1.5 A 2.0 1.0 A 500 mA 1.5 200 mA 20 mA 1.0 150 -50 Figure 7. Adjustment Pin Current -25 0 25 50 75 100 125 TJ, JUNCTION TEMPERATURE (°C) 150 Figure 8. Dropout Voltage I B , QUIESCENT CURRENT (mA) V ref , REFERENCE VOLTAGE (V) 1.27 1.26 1.25 1.24 1.23 40 -50 -25 0 25 50 75 100 125 TJ, JUNCTION TEMPERATURE (°C) 1.8 1.6 1.4 1.2 1.0 0.6 0.4 0.2 0 150 TJ = 25°C 0.8 Figure 9. Temperature Stability 0 10 20 30 40 Vin-Vout , INPUT-OUTPUT VOLTAGE DIFFERENTIAL (Vdc) Figure 10. Minimum Operating Current http://onsemi.com 5 LM337 100 CAdj = 10 µF 80 60 RR, RIPPLE REJECTION (dB) RR, RIPPLE REJECTION (dB) 100 Without CAdj 40 Vin - Vout = 5.0 V IL = 500 mA f = 120 Hz TJ = 25°C 20 0 0 -5.0 -10 -15 -20 -25 Vout, OUTPUT VOLTAGE (V) -30 -35 40 0 0.01 10 Figure 12. Ripple Rejection versus Output Current CAdj =10 µF 60 Z O , OUTPUT IMPEDANCE () Ω Vin = -15 V Vout = -10 V IL = 500 mA TJ = 25°C Without CAdj 20 100 1.0 k 10 k 100 k 1.0 M Vin = -15 V Vout = -10 V IL = 500 mA CL = 1.0 µF TJ = 25°C 100 10-1 Without CAdj CAdj = 10 µF 10-2 10-3 10 10 M f, FREQUENCY (Hz) 1.0 k 10 k f, FREQUENCY (Hz) Figure 13. Ripple Rejection versus Frequency Figure 14. Output Impedance ∆V out , OUTPUT VOLTAGE DEVIATION (V) RR, RIPPLE REJECTION (dB) 0.8 0.6 0.4 0.2 0 Without CAdj CAdj = 10 µF -0.2 -0.4 I L , LOAD CURRENT (A) ∆V in, INPUT ∆V out , OUTPUT VOLTAGE CHANGE (V) VOLTAGE DEVIATION (V) 0.1 1.0 IO, OUTPUT CURRENT (A) 101 80 Vout = -10 V IL = 50 mA TJ = 25°C CL = 1.0 µF 0 -0.5 -1.0 Vin = -15 V Vout = -10 V f = 120 Hz TJ = 25°C 20 -40 100 0 10 Without CAdj 60 Figure 11. Ripple Rejection versus Output Voltage 40 CAdj = 10 µF 80 0 10 20 30 40 100 100 k 0.6 0.4 Without CAdj 0.2 0 -0.2 CAdj = 10 µF -0.4 -0.6 Vin = -15 V Vout = -10 V IL = 50 mA TJ = 25°C CL = 1.0 µF 0 -0.5 -1.0 -1.5 0 10 20 30 t, TIME (µs) t, TIME (µs) Figure 15. Line Transient Response Figure 16. Load Transient Response http://onsemi.com 6 1.0 M 40 LM337 APPLICATIONS INFORMATION Basic Circuit Operation The LM337 is a 3–terminal floating regulator. In operation, the LM337 develops and maintains a nominal –1.25 V reference (Vref) between its output and adjustment terminals. This reference voltage is converted to a programming current (IPROG) by R1 (see Figure 17), and this constant current flows through R2 from ground. The regulated output voltage is given by: near the load ground to provide remote ground sensing and improve load regulation. External Capacitors A 1.0 µF tantalum input bypass capacitor (Cin) is recommended to reduce the sensitivity to input line impedance. The adjustment terminal may be bypassed to ground to improve ripple rejection. This capacitor (CAdj) prevents ripple from being amplified as the output voltage is increased. A 10 µF capacitor should improve ripple rejection about 15 dB at 120 Hz in a 10 V application. An output capacitance (CO) in the form of a 1.0 µF tantalum or 10 µF aluminum electrolytic capacitor is required for stability. R V out V 1 2 I R 2 ref Adj R1 Since the current into the adjustment terminal (IAdj) represents an error term in the equation, the LM337 was designed to control IAdj to less than 100 µA and keep it constant. To do this, all quiescent operating current is returned to the output terminal. This imposes the requirement for a minimum load current. If the load current is less than this minimum, the output voltage will rise. Since the LM337 is a floating regulator, it is only the voltage differential across the circuit which is important to performance, and operation at high voltages with respect to ground is possible. Protection Diodes When external capacitors are used with any IC regulator it is sometimes necessary to add protection diodes to prevent the capacitors from discharging through low current points into the regulator. Figure 18 shows the LM337 with the recommended protection diodes for output voltages in excess of –25 V or high capacitance values (CO > 25 µF, CAdj > 10 µF). Diode D1 prevents CO from discharging thru the IC during an input short circuit. Diode D2 protects against capacitor CAdj discharging through the IC during an output short circuit. The combination of diodes D1 and D2 prevents CAdj from the discharging through the IC during an input short circuit. + Vout R2 IPROG IAdj Vin LM337 CO R1 Vref - Vout Vout R2 Vref = -1.25 V Typical Cin Figure 17. Basic Circuit Configuration Load Regulation JUNCTIONTOAIR (° C/W) Vin LM337 3.0 2.0 oz. Copper L Minimum Size Pad 50 ÎÎÎÎ ÎÎÎÎ ÎÎÎÎ 2.5 2.0 L 40 1.5 RθJA 0 5.0 CO D2 1N4002 + - Vout Figure 18. Voltage Regulator with Protection Diodes Free Air Mounted Vertically 60 Vout + Vout + D1 1N4002 PD(max) for TA = +50°C 70 30 R1 3.5 80 R θ JA, THERMAL RESISTANCE Adjust -Vin The LM337 is capable of providing extremely good load regulation, but a few precautions are needed to obtain maximum performance. For best performance, the programming resistor (R1) should be connected as close to the regulator as possible to minimize line drops which effectively appear in series with the reference, thereby degrading regulation. The ground end of R2 can be returned CAdj + 10 15 20 L, LENGTH OF COPPER (mm) 25 30 1.0 Figure 19. D2PAK Thermal Resistance and Maximum Power Dissipation versus P.C.B. Copper Length http://onsemi.com 7 PD, MAXIMUM POWER DISSIPATION (W) Adjust + LM337 PACKAGE DIMENSIONS T SUFFIX PLASTIC PACKAGE CASE 221A–09 ISSUE AA SEATING PLANE –T– B C F T S 4 DIM A B C D F G H J K L N Q R S T U V Z A Q 1 2 3 U H K Z L R V NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. 3. DIMENSION Z DEFINES A ZONE WHERE ALL BODY AND LEAD IRREGULARITIES ARE ALLOWED. J G D N http://onsemi.com 8 INCHES MIN MAX 0.570 0.620 0.380 0.405 0.160 0.190 0.025 0.035 0.142 0.147 0.095 0.105 0.110 0.155 0.018 0.025 0.500 0.562 0.045 0.060 0.190 0.210 0.100 0.120 0.080 0.110 0.045 0.055 0.235 0.255 0.000 0.050 0.045 ----0.080 MILLIMETERS MIN MAX 14.48 15.75 9.66 10.28 4.07 4.82 0.64 0.88 3.61 3.73 2.42 2.66 2.80 3.93 0.46 0.64 12.70 14.27 1.15 1.52 4.83 5.33 2.54 3.04 2.04 2.79 1.15 1.39 5.97 6.47 0.00 1.27 1.15 ----2.04 LM337 PACKAGE DIMENSIONS D2T SUFFIX PLASTIC PACKAGE CASE 936–03 (D2PAK) ISSUE B OPTIONAL CHAMFER A E TERMINAL 4 –T – U S K V B H F 1 2 3 M L P J N D 0.010 (0.254) M R T G C http://onsemi.com 9 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. 3. TAB CONTOUR OPTIONAL WITHIN DIMENSIONS A AND K. 4. DIMENSIONS U AND V ESTABLISH A MINIMUM MOUNTING SURFACE FOR TERMINAL 4. 5. DIMENSIONS A AND B DO NOT INCLUDE MOLD FLASH OR GATE PROTRUSIONS. MOLD FLASH AND GATE PROTRUSIONS NOT TO EXCEED 0.025 (0.635) MAXIMUM. DIM A B C D E F G H J K L M N P R S U V INCHES MIN MAX 0.386 0.403 0.356 0.368 0.170 0.180 0.026 0.036 0.045 0.055 0.051 REF 0.100 BSC 0.539 0.579 0.125 MAX 0.050 REF 0.000 0.010 0.088 0.102 0.018 0.026 0.058 0.078 5 REF 0.116 REF 0.200 MIN 0.250 MIN MILLIMETERS MIN MAX 9.804 10.236 9.042 9.347 4.318 4.572 0.660 0.914 1.143 1.397 1.295 REF 2.540 BSC 13.691 14.707 3.175 MAX 1.270 REF 0.000 0.254 2.235 2.591 0.457 0.660 1.473 1.981 5 REF 2.946 REF 5.080 MIN 6.350 MIN LM337 Notes http://onsemi.com 10 LM337 Notes http://onsemi.com 11 LM337 ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. 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