Order this document by LM350/D The LM350 is an adjustable three-terminal positive voltage regulator capable of supplying in excess of 3.0 A over an output voltage range of 1.2 V to 33 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 LM350 serves a wide variety of applications including local, on card regulation. This device also makes an especially simple adjustable switching regulator, a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM350 can be used as a precision current regulator. * Guaranteed 3.0 A Output Current * * * * * * * * * THREE-TERMINAL ADJUSTABLE POSITIVE VOLTAGE REGULATOR SEMICONDUCTOR TECHNICAL DATA T SUFFIX PLASTIC PACKAGE CASE 221A Output Adjustable between 1.2 V and 33 V Pin 1. Adjust 2. Vout 3. Vin Load Regulation Typically 0.1% Line Regulation Typically 0.005%/V Internal Thermal Overload Protection 1 2 Internal Short Circuit Current Limiting Constant with Temperature 3 Output Transistor Safe Area Compensation Heatsink surface is connected to Pin 2. Floating Operation for High Voltage Applications Standard 3-lead Transistor Package Eliminates Stocking Many Fixed Voltages Simplified Application Vin LM350 vout R1 240 IAdj Adjust Cin* 0.1F + C ** O 1F R2 ORDERING INFORMATION Device * = Cin is required if regulator is located an appreciable distance from power supply filter. ** = CO is not needed for stability, however, it does improve transient response. Vout + 1.25 V 1 ) RR21 ) IAdj R2 Since IAdj is controlled to less than 100 A, the error associated with this term is negligible in most applications. LM350T LM350BT# Operating Temperature Range TJ = 0 to +125C Plastic Power TJ = -40 to +125C Plastic Power # Automotive temperature range selections are available with special test conditions and additional tests. Contact your local Motorola sales office for information. Motorola, Inc. 1996 MOTOROLA ANALOG IC DEVICE DATA Package Rev 0 1 LM350 MAXIMUM RATINGS Rating Symbol Value Unit VI-VO 35 Vdc Power Dissipation PD Internally Limited W Operating Junction Temperature Range TJ - 40 to +125 C Tstg - 65 to +150 C Tsolder 300 C Input-Output Voltage Differential Storage Temperature Range Soldering Lead Temperature (10 seconds) ELECTRICAL CHARACTERISTICS (VI-VO = 5.0 V; IL = 1.5 A; TJ = Tlow to Thigh; Pmax [Note 1], unless otherwise noted.) Figure Symbol Min Typ Max Unit Line Regulation (Note 2) TA = 25C, 3.0 V VI-VO 35 V 1 Regline - 0.0005 0.03 %/V Load Regulation (Note 2) TA = 25C, 10 mA Il 3.0 A VO 5.0 V VO 5.0 V 2 Regload - - 5.0 0.1 25 0.5 mV % VO Regtherm - 0.002 - % VO/W 3 IAdj - 50 100 A Adjustment Pin Current Change 3.0 V VI-VO 35 V 10 mA IL 3.0 A, PD Pmax 1,2 IAdj - 0.2 5.0 A Reference Voltage 3.0 V VI-VO 35 V 10 mA IO 3.0 A, PD Pmax 3 Vref 1.20 1.25 1.30 V Line Regulation (Note 2) 3.0 V VI-VO 35 V 1 Regline - 0.02 0.07 %/V Load Regulation (Note 2) 10 mA IL 3.0 A 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 - 1.0 - % VO Minimum Load Current to Maintain Regulation (VI-VO = 35 V) 3 ILmin - 3.5 10 mA Maximum Output Current VI-VO 10 V, PD Pmax VI-VO = 30 V, PD Pmax, TA = 25C 3 Imax 3.0 0.25 4.5 1.0 - - - 0.003 - - 66 65 80 - - - 0.3 1.0 - - 2.3 - - 1.5 Characteristics Thermal Regulation, Pulse = 20 ms, (TA = +25C) Adjustment Pin Current RMS Noise, % of VO TA= 25C, 10 Hz f 10 kHz N Ripple Rejection, VO = 10 V, f = 120 Hz (Note 3) Without CAdj CAdj = 10 F 4 Long Term Stability, TJ = Thigh (Note 4) TA= 25C for Endpoint Measurements 3 Thermal Resistance, Junction-to-Case Peak (Note 5) Average (Note 6) A RR S RJC % VO dB %/1.0 k Hrs. C/W NOTES: 1. Tlow to Thigh = 0 to +125C; Pmax = 25 W for LM350T; Tlow to Thigh = - 40 to +125C; Pmax = 25 W for LM350BT 2. Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used. 3. CAdj, when used, is connected between the adjustment pin and ground. 4. 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. 5. Thermal Resistance evaluated measuring the hottest temperature on the die using an infrared scanner. This method of evaluation yields very accurate thermal resistance values which are conservative when compared to the other measurement techniques. 6. The average die temperature is used to derive the value of thermal resistance junction to case (average). 2 MOTOROLA ANALOG IC DEVICE DATA LM350 Representative Schematic Diagram Vin 310 310 230 5.6K 120 6.3V 160 6.8K 510 12K 5.0pF 12.4K 135 125K 6.7K 170 13K 200 6.3V 6.3V 30 pF 5.1K 110 190 5.8K 3.6K 30 pF 2.4K 105 12.5K 4 0.45 Vout Adjust Figure 1. Line Regulation and IAdj/Line Test Circuit VCC Line Regulation (%/V) = * VOH - VOL x 100 VOL VIH VIL Vin LM350 Adjust Cin 0.1F * Pulse Testing Required: 1% Duty Cycle is suggested. MOTOROLA ANALOG IC DEVICE DATA IAdj Vout VOH VOL IL R1 240 1% RL + CO 1F R2 1% 3 LM350 Figure 2. Load Regulation and IAdj/Load Test Circuit VO (min Load) - VO (max Load) X 100 VO (min Load) Load Regulation (mV) = VO (min Load) -VO (max Load) Load Regulation (% VO) = Vin Vin Vout LM350 Adjust VO (min Load) VO (max Load) IL R1 RL (max Load) 240 1% RL (min Load) * + Cin 0.1F CO IAdj 1.0F R2 1% * Pulse Testing Required: 1% Duty Cycle is suggested. Figure 3. Standard Test Circuit Vout Vin IL LM350 Adjust 240 1% R1 VI IAdj Vref RL + 0.1F Cin 1.0F CO VO ISET R2 1% To Calculate R2: Vout = ISET R2 + 1.250 V Assume ISET = 5.25 mA Pulse Testing Required: 1% Duty Cycle is suggested. Figure 4. Ripple Rejection Test Circuit 24V Vout Vin 14V LM350 f = 120 Hz Adjust Cin Vout = 10 V IL R1 240 1% 0.1F D1 * 1N4002 CO R2 1.65K 1% ** CAdj RL + 1.0F VO + 10F * D1 Discharges CAdj if Output is Shorted to Ground. **CAdj provides an AC ground to the adjust pin. 4 MOTOROLA ANALOG IC DEVICE DATA LM350 Figure 6. Current Limit 7 0.4 I out , OUTPUT CURRENT (A) Vout , OUTPUT VOLTAGE CHANGE (%) Figure 5. Load Regulation 0.2 0 IL = 0.5 A -0.2 IL = 1.5 A -0.4 -0.6 Vin = 15 V Vout = 10 V -0.8 TJ = 55C 5 TJ = 25C 3 TJ = 150C 1 -1.0 -75 -50 -25 0 25 50 75 100 125 0 150 0 10 TJ, JUNCTION TEMPERATURE (C) 20 Figure 7. Adjustment Pin Current V in -Vout , INPUT-OUTPUT VOLTAGE DIFFERENTIAL (Vdc) IAdj, ADJUSTMENT PIN CURRENT ( A) 70 65 60 55 50 45 40 -50 -25 0 25 50 75 100 125 V0 = 100 mV IL = 3.0 A 2.5 IL = 2.0 A 2.0 IL = 500 mA 1.5 1.0 -75 150 IL = 20 mA -50 -25 TJ, JUNCTION TEMPERATURE (C) 0 25 50 75 100 IL = 200 mA 125 150 TJ, JUNCTION TEMPERATURE (C) Figure 9. Temperature Stability Figure 10. Minimum Operating Current 1.260 5.0 IB , QUIESCENT CURRENT (mA) Vref, REFERENCE VOLTAGE (V) 40 Figure 8. Dropout Voltage 3.0 35 -75 30 Vin-Vout, INPUT VOLTAGE DIFFERENTIAL (Vdc) 1.250 1.240 1.230 4.5 TJ = -55C 4.0 TJ = 25C 3.5 3.0 TJ = 150C 2.5 2.0 1.5 1.0 0.5 1.220 -75 -50 -25 0 25 50 75 100 TJ, JUNCTION TEMPERATURE (C) MOTOROLA ANALOG IC DEVICE DATA 125 150 0 0 10 20 30 40 Vin-Vout, INPUT-OUTPUT VOLTAGE DIFFERENTIAL (Vdc) 5 LM350 Figure 11. Ripple Rejection versus Output Voltage Figure 12. Ripple Rejection versus Output Current 100 140 RR, RIPPLE REJECTION (dB) RR, RIPPLE REJECTION (dB) CAdj = 10 F 80 Without CAdj 60 40 Vin - Vout = 5 V IL = 500 mA f = 120 Hz TJ = 25C 20 0 0 5 10 120 100 60 40 20 15 20 25 30 Vout, OUTPUT VOLTAGE (V) CAdj = 10 F 80 Without CAdj Vin - Vout = 5 V IL = 500 mA f = 120 Hz TJ = 25C 0 0.01 35 0.1 1 Iout, OUTPUT CURRENT (A) Figure 13. Ripple Rejection versus Frequency Figure 14. Output Impedance 101 Z O , OUTPUT IMPEDANCE ( ) 60 40 CAdj = 10 F Without CAdj 20 100 1.0 k 10 k 100 k 1.0 M f, FREQUENCY (Hz) Vin = 15 V Vout = 10 V IL = 500 mA TJ = 25C 100 10-1 Without CAdj 10-2 CAdj = 10 F 10-3 10 10 M 100 Figure 15. Line Transient Response 1.5 1.0 CL = 1.0 F; CAdj = 10 F 0.5 0 -0.5 Vout = 10 V IL = 50 mA TJ = 25C -1.0 -1.5 CL = 0; Without CAdj 1.0 0 10 20 t, TIME (s) 30 100 k 1.0 M 3 2 1 CL = 1.0 F; CAdj = 10 F 0 -2 CL = 0; Without CAdj -3 1.5 IL 0.5 40 Vin = 15 V Vout = 10 V INL = 50 mA TJ = 25C -1 1.0 Vin 0.5 0 1.0 k 10 k f, FREQUENCY (Hz) Figure 16. Load Transient Response Vout , OUTPUT VOLTAGE DEVIATION (V) Vout , OUTPUT VOLTAGE DEVIATION (V) Vin , INPUT VOLTAGE CHANGE (V) 6 IL = 500 mA Vin = 15 V Vout = 10 V TJ = 25C 80 I L , LOAD CURRENT (A) RR, RIPPLE REJECTION (dB) 100 0 10 10 0 0 10 20 t, TIME (s) 30 40 MOTOROLA ANALOG IC DEVICE DATA LM350 APPLICATIONS INFORMATION Basic Circuit Operation The LM350 is a three-terminal floating regulator. In operation, the LM350 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 to ground. The regulated output voltage is given by: R2 Vout = Vref (1 + ) + IAdj R2 R1 Since the current from the terminal (IAdj) represents an error term in the equation, the LM350 was designed to control IAdj to less than 100 A 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 LM350 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. Figure 17. Basic Circuit Configuration Vin LM350 Vout External Capacitors A 0.1 F disc or 1 F 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 F capacitor should improve ripple rejection about 15 dB at 120 Hz in a 10 V application. Although the LM350 is stable with no output capacitance, like any feedback circuit, certain values of external capacitance can cause excessive ringing. An output capacitance (CO) in the form of a 1 F tantalum or 25 F aluminum electrolytic capacitor on the output swamps this effect and insures stability. 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 LM350 with the recommended protection diodes for output voltages in excess of 25 V or high capacitance values (CO > 25 F, CAdj > 10 F). 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 discharging through the IC during an input short circuit. + R1 Vref Adjust Figure 18. Voltage Regulator with Protection Diodes IPROG Vout IAdj D1 R2 1N4002 Vref = 1.25 V Typical Vin Vout LM350 + Load Regulation The LM350 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 near the load ground to provide remote ground sensing and improve load regulation. MOTOROLA ANALOG IC DEVICE DATA Cin R1 Adjust D2 CO 1N4002 R2 CAdj 7 LM350 Figure 19. "Laboratory" Power Supply with Adjustable Current Limit and Output Voltage D6 1N4002 Vin 32V Vout1 RSC LM350 (1) Vin1 Vin2 IO Vout 2 LM350 (2) VO 240 0.1F D1 1N4001 Adjust 1 1K Current Limit Adjust 1N4001 D2 Adjust 2 5.0K 10F 1N4001 D3 D4 -10V Diodes D1 and D2 and transistor Q2 are added to allow adjustment of output voltage to 0 V. Figure 20. Adjustable Current Limiter Vout 1N4001 Q2 2N5640 Figure 21. 5.0 V Electronic Shutdown Regulator D1 Iout 620 Vin 1N4002 Vin Adjust 100 Vout LM350 D1 1N4001 R2 * To provide current limiting of IO to the system ground, the source of the FET must be tied to a negative voltage below -1.25 V. R2 Vout R1 Output Range: 0 VO 25 V 0 IO 1.5 A -10V D6 protects both LM350's during an input short circuit. LM350 + 1.0F 120 D2 1N4001 Adjust MPS2222 720 1.0k 2N5640 Vref IDSS Vref R1 = IOmax + IDSS VO < V(BR)DSS + 1.25 V + VSS ILmin - IDSS < IO < 3.0 A As shown O < IO < 1.0 A D1 protects the device during an input short circuit. Figure 23. Current Regulator Vin Vout LM350 Vout Iout R1 LM350 240 Adjust R2 TTL Control Minimum Vout = 1.25 V VSS* Figure 22. Slow Turn-On Regulator Vin 1.0F Tantalum + Voltage Adjust Q1 2N3822 +25V + D5 IN4001 1N4001 MPS2907 IAdj Adjust 50k + 10F Iout + ^ ) Vref R1 IAdj 1.25 V R1 10 mA Iout 3.0 A 8 MOTOROLA ANALOG IC DEVICE DATA LM350 OUTLINE DIMENSIONS T SUFFIX PLASTIC PACKAGE CASE 221A-06 ISSUE Y -T- B C F T S SEATING PLANE 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. 4 A Q 1 2 3 U H K Z L R V J G D N MOTOROLA ANALOG IC DEVICE DATA DIM A B C D F G H J K L N Q R S T U V Z 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 9 LM350 NOTES 10 MOTOROLA ANALOG IC DEVICE DATA LM350 NOTES MOTOROLA ANALOG IC DEVICE DATA 11 LM350 Motorola reserves the right to make changes without further notice to any products herein. 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