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| Order this document A78S40/D A78S40 Universal Switching Regulator Subsystem The A78S40 is a switching regulator subsystem, consisting of a temperature compensated voltage reference, controlled-duty cycle oscillator with an active current limit circuit, comparator, high-current and high-voltage output switch, capable of 1.5 A and 40 V, pinned-out power diode and an uncommitted operational amplifier, which can be powered up or down independent of the IC supply. The switching output can drive external NPN or PNP transistors when voltages greater the 40 V, or currents in excess of 1.5 A, are required. Some of the features are wide-supply voltage range, low standby current, high efficiency and low drift. The A78S40 is available in commercial (0 to + 70C), and automotive (-40 to + 85C) temperature ranges. Some of the applications include use in step-up, step-down, and inverting regulators, with extremely good results obtained in battery- operated systems. * Output Adjustable from 1.25 V to 40 V UNIVERSAL SWITCHING REGULATOR SUBSYSTEM SEMICONDUCTOR TECHNICAL DATA * * * * * Peak Output Current of 1.5 A Without External Transistor 80 dB Line and Load Regulation Operation from 2.5 V to 40 V Supply Low Standby Current Drain High Gain, High Output Current, Uncommitted Op Amp P SUFFIX PLASTIC PACKAGE CASE 648 PIN CONNECTIONS Simplified Block Diagram Noninv. Input 9 Inv. Input 10 Timing Capacitor 12 Ipk Sense 14 Driver Collector 15 Switch Collector 16 Diode Cathode 1 Diode Anode 2 Switch Emitter 3 Op Amp Output 4 VCC Op Amp 5 Op Amp Noninv. 6 Inv. Input 7 Reference 8 (Top View) 16 Switch Collector 15 Driver Collector 14 Ipk Sense 13 VCC 12 Timing Capacitor 11 Ground Comparator 10 Inv. Input 9 Comparator Noninv. Input Gnd 11 VCC 13 CT Ipk Oscilator - Comp. + 1.25V Reference - Op Amp + 7 Inv Input 6 Noninv Input 5 VCC Op Amp 4 Output S Q R 170 D1 ORDERING INFORMATION 8 Ref Output 3 Switch Emitter 2 Diode Anode 1 Diode Cathode Device A78S40PC A78S40PV Temperature Range TA = 0 to +70C TA = - 40 to +85C Package Plastic Plastic (Bottom View) (c) Motorola, Inc. 1996 Rev 1 MOTOROLA ANALOG IC DEVICE DATA 1 A78S40 MAXIMUM RATINGS Rating Power Supply Voltage Op Amp Power Supply Voltage Common Mode Input Range (Comparator and Op Amp) Differential Input Voltage (Note 2) Output Short Circuit Duration (Op Amp) Reference Output Current Voltage from Switch Collectors to Gnd Voltage from Switch Emitters to Gnd Voltage from Switch Collectors to Emitter Voltage from Power Diode to Gnd Reverse-Power Diode Voltage Current through Power Switch Current through Power Diode Power Dissipation and Thermal Characteristics: Plastic Package (TA = + 25C) Derate above + 25C (Note 1) Storage Temperature Range Operating Temperature Range A78S40V A78S40C VDR ISW ID PD 1/RJA Tstg TA -40 to +85 0 to +70 Iref Symbol VCC VCC (Op Amp) VICR VID Value 40 40 -0.3 to VCC 30 Continuous 10 40 40 40 40 40 1.5 1.5 1500 14 -65 to + 150 Unit V V V V - mA V V V V V A A mW mW/C C C NOTES: 1. Tlow = -40 for A78S40PV Thigh = +85 for A78S40PV = 0 for A78S40PC = +70 for A78S40PC 2. For supply voltages less than 30 V the maximum differential input voltage (Error Amp and Op Amp) is equal to the supply voltage. ELECTRICAL CHARACTERISTICS (VCC = VCC (Op Amp) 5.0 V, TA = Tlow to Thigh, unless otherwise noted.) Characteristic GENERAL Supply Voltage Supply Current (Op Amp VCC, disconnected) (VCC = 5.0 V) (VCC = 40 V) Supply Current (Op Amp VCC, connected) (VCC = 5.0 V) (VCC = 40 V) REFERENCE Reference Voltage (Iref = 1.0 mA) Reference Voltage Line Regulation (3.0 V VCC 40 V, Iref = 1.0 mA, TA = 25C) Reference Voltage Load Regulation (1.0 mA Iref 10 mA, TA = 25C) Vref Regline Regload 1.180 - - 1.245 0.04 0.2 1.310 0.2 0.5 V mV/V mV/mA VCC ICC - - ICC - - - - 4.0 5.5 1.8 2.3 3.5 5.0 mA 2.5 - 40 V mA Symbol Min Typ Max Unit 2 MOTOROLA ANALOG IC DEVICE DATA A78S40 ELECTRICAL CHARACTERISTICS (VCC = VCC (Op Amp) 5.0 V, TA = Tlow to Thigh, unless otherwise noted.) Characteristic OSCILLATOR Charging Current (TA = 25C) (VCC = 5.0 V) (VCC = 40 V) Discharging Current (TA = 25C) (VCC = 5.0 V) (VCC = 40 V) Oscillator Voltage Swing (TA = 25C) (VCC = 5.0 V) Ratio of Charge/Discharge Time CURRENT LIMIT Current-Limit Sense Voltage (TA = 25C) (VCC - Vlpk Sense) OUTPUT SWITCH Output Saturation Voltage 1 (ISW = 1.0 A, Pin 15 tied to Pin 16) Output Saturation Voltage 2 (ISW = 1.0 A, I15 = 50 mA) Output Transistor Current Gain (TA = 25C) (IC = 1.0 A, VCE = 5.0 V) Output Leakage Current (TA = 25C) (VCE = 40 V) POWER DIODE Forward Voltage Drop (ID = 1.0 A) Diode Leakage Current (TA = 25C) (VDR = 40 V) COMPARATOR Input Offset Voltage (VCM = Vref) Input Bias Current (VCM = Vref) Input Offset Current (VCM = Vref) Common Mode Voltage Range (TA = 25C) Power-Supply Rejection Ratio (TA = 25C) (3.0 VCC 40 V) OUTPUT OPERATION AMPLIFIER Input Offset Voltage (VCM = 2.5 V) Input Bias Current (VCM = 2.5 V) Input Offset Current (VCM = 2.5 V) Voltage Gain + (TA = 25C) (RL = 2.0 k to Gnd, 1.0 V VO 2.5 V) Voltage Gain - (TA = 25C) (RL = 2.0 k to VCC (Op Amp), 1.0 V VO 2.5 V) Common Mode Voltage Range (TA = 25C) Common Mode Rejection Ratio (TA = 25C) (VCM = 0 V to 3.0 V) Power-Supply Rejection Ratio (TA = 25C) (3.0 V VCC (Op Amp) 40 V) Output Source Current (TA = 25C) Output Sink Current (TA = 25C) Slew Rate (TA = 25C) Output Low Voltage (TA = 25C, IL = -5.0 mA) Output High Voltage (TA = 25C, IL = 50 mA) VIO IIB IIO AVOL+ AVOL- VICR CMRR PSRR ISource ISink SR VOL VOH - - - 25 25 0 76 76 75 10 - - VCC(Op Amp) - 3.0 4.0 30 5.0 250 250 - 100 100 150 35 0.6 - - 15 200 75 - - VCC - 2.0 - - - - - 1.0 - mV nA nA V/mV V/mV V dB dB mA mA V/s V V VIO IIB IIO VICR PSRR - - - 0 70 1.5 35 5.0 - 96 15 200 75 VCC - 2.0 - mV nA nA V dB VD IDR - - 1.25 10 1.5 - V nA Vsat1 Vsat2 hFE IC(off) - - - - 0.93 0.5 70 10 1.3 0.7 - - V V - nA VCLS 250 - 350 mV Ichg 20 20 Idis 150 150 Vosc tchg/tdis - - - - 0.5 6.0 250 350 - - V - - - 50 70 A A Symbol Min Typ Max Unit MOTOROLA ANALOG IC DEVICE DATA 3 A78S40 Figure 1. Output Switch On/Off Time versus Oscillator Timing Capacitor 1000 VCC = 5.0 V Ipk(sense) = VCC Pin 10 = Gnd Pin 9 = Vref ton toff 10 3.2 I CC , SUPPLY CURRENT (mA) t on-off , OUTPUT SWITCH ON-OFF TIME ( s) Figure 2. Standby Supply Current versus Supply Voltage CT = 0.001 F Ipk(sense) = VCC Pin 3 = Gnd 2.4 100 1.6 0.8 1.0 0.1 1.0 10 100 0 0 5.0 10 15 20 25 30 35 40 CT, OSCILLATOR TIMING CAPACITOR (nF) VCC, SUPPLY VOLTAGE (V) Figure 3. Emitter-Follower Configuration Output Switch Saturation Voltage versus Emitter Current V CE(sat) , SATURATION VOLTAGE (V) VCC = 5.0 V Pins 14, 15, 16 = VCC Pins 10, 12 = Gnd Pin 9 = Vref V CE(sat) , SATURATION VOLTAGE (V) 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 IE, EMITTER CURRENT (A) 1.2 1.0 0.8 0.6 Figure 4. Common-Emitter Configuration Output Switch Saturation Voltage versus Collector Current VCC = 5.0 V Pin 14 = VCC Pins 3, 10, 12 = Gnd Pin 9 = Vref Darlington Connection Forced Beta = 20 0.4 0.2 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 IC, COLLECTOR CURRENT (A) 4 MOTOROLA ANALOG IC DEVICE DATA A78S40 Figure 5. Step-Down Converter Vin 25V 100 CT 9 10 11 12 470 pF 13 VCC 14 15 16 + RSC 0.33 CT Ipk Oscilator S Q - + 1.25V Reference Comp. R 170 - Op Amp + D1 8 R2 3.6k R1 1.2k 7 6 5 4 3 2 1 1N5822 L 220H + Vout 5.0V/500mA CO * * Use external rectifier to increase circuit efficiency 470 Figure 6. Step-Up Converter L Vin 12V 100 CT 9 10 11 12 1500 pF 13 VCC 14 + RSC 0.22 170H 180 15 16 CT Ipk Oscilator S Q - + 1.25V Reference Comp. R 170 - Op Amp + D1 8 7 6 5 4 3 2 1 1N5822 * R2 47k R1 22k * Use external rectifier to increase circuit efficiency 150 + Vout 28V/175mA CO MOTOROLA ANALOG IC DEVICE DATA 5 A78S40 Figure 7. Inverting Converter Vin 15V 100 CT 9 10 11 12 1800 pF 13 VCC 14 15 16 D45H8 + RSC 0.30 100 270 50H 1N5822 Vout -15V/500mA CO L 100 + CT Ipk Oscilator S Q - + 1.25V Reference Comp. R 170 - Op Amp + D1 R1 1.5k R2 18k 8 7 6 5 4 3 2 1 Design Formula Table Calculation ton toff (ton + toff) max CT Ipk(switch) RSC Step-Down Vout + VF Vin(min) - Vsat - Vout I fmin 4 x 10 5 ton 2 Iout(max) 0.33 Ipk(switch) Vin(min) - Vsat - Vout ton(max) Ipk(switch) Ipk(switch) (ton + toff) 8 Vripple(pp) Step-Up Vout - VF Vin(min) Vin(min) Vsat I fmin 4 x 10 5 ton 2 Iout(max) ton - toff toff Inverting Vout + VF Vin(min) - Vsat I fmin 4 x 10 5 ton 2 Iout(max) ton + toff toff 0.33 Ipk(switch) Vin(min) - Vsat Ipk(switch) Iout ton Vripple ton(max) 0.33 Ipk(switch) Vin(min) - Vsat Ipk(switch) Iout ton Vripple ton(max) L(min) CO Vsat = Saturation voltage of the output switch. VF = Forward voltage drop of the ringback rectifier. The following power supply characteristics must be chosen: Vin - Nominal input voltage. If this voltage is not constant, then use Vin(max) for step-down and Vin(min) for step-up and inverting convertor. R2 1.25 R2 for step-down and step-up: Vout for inverting. 1 R1 R1 Iout - Desired output current. fmin - Minimum desired output switching frequency at the selected values for Vin and IO. Vripple(pp) - Desired peak-to-peak output ripple voltage. In practice, the calculated value will need to be increased due to the capacitor's equivalent series - resistance and board layout. The ripple voltage should be kept to a low value since it will directly effect the line and load regulation. Vout - Desired output voltage: Vout = 1.25 ) + See Application Note AN920 for further information 6 MOTOROLA ANALOG IC DEVICE DATA A78S40 OUTLINE DIMENSIONS P SUFFIX PLASTIC PACKAGE CASE 648-08 ISSUE R 9 -A- 16 B 1 8 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. 3. DIMENSION L TO CENTER OF LEADS WHEN FORMED PARALLEL. 4. DIMENSION B DOES NOT INCLUDE MOLD FLASH. 5. ROUNDED CORNERS OPTIONAL. DIM A B C D F G H J K L M S INCHES MIN MAX 0.740 0.770 0.250 0.270 0.145 0.175 0.015 0.021 0.040 0.70 0.100 BSC 0.050 BSC 0.008 0.015 0.110 0.130 0.295 0.305 0_ 10 _ 0.020 0.040 MILLIMETERS MIN MAX 18.80 19.55 6.35 6.85 3.69 4.44 0.39 0.53 1.02 1.77 2.54 BSC 1.27 BSC 0.21 0.38 2.80 3.30 7.50 7.74 0_ 10 _ 0.51 1.01 F S C L -T- H G D 16 PL SEATING PLANE K J TA M M 0.25 (0.010) M MOTOROLA ANALOG IC DEVICE DATA 7 A78S40 Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. "Typical" parameters which may be provided in Motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including "Typicals" must be validated for each customer application by customer's technical experts. Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer. How to reach us: USA / EUROPE / Locations Not Listed: Motorola Literature Distribution; P.O. Box 20912; Phoenix, Arizona 85036. 1-800-441-2447 or 602-303-5454 MFAX: RMFAX0@email.sps.mot.com - TOUCHTONE 602-244-6609 INTERNET: http://Design-NET.com JAPAN: Nippon Motorola Ltd.; Tatsumi-SPD-JLDC, 6F Seibu-Butsuryu-Center, 3-14-2 Tatsumi Koto-Ku, Tokyo 135, Japan. 03-81-3521-8315 ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park, 51 Ting Kok Road, Tai Po, N.T., Hong Kong. 852-26629298 8 *UA78S40/D* MOTOROLA ANALOG IC DEVICE DATA A78S40/D |
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