i SGS:THOMSON VF MICROELECTRONICS $G2524 $G3524 REGULATING PULSE WIDTH MODULATORS a COMPLETE PWM POWER CONTROL GIR- CUITRY a UNCOMMITTED OUTPUTS FOR SINGLE- ENDED OR PUSH PULL APPLICATIONS a LOW STANDBY CURRENT &mA TYPICAL a OPERATION UP TO 300KHz a 1% MAXIMUM TEMPERATURE VARIATION OF REFERENCE VOLTAGE DESCRIPTION The $G2524, and SG3524 incorporate on a sin- gle monolithic chip all the function required for the construction of regulating power suppies inverters or switching regulators. They can also be used as the control element for high power-output applica- tions. The SG3524 family was designed for switching regulators of either polarity, trans- former-coupled dc-to-dc converters, transformer- less voltage doublers and polarity converter appli- cations employing fixed-frequency, pulse-width medulation techniques. The dual alternating out- puts allows either single-ended or push-pull appli- DIP16 S016 ORDERING NUMBERS: SG2524N (DIP 16) SG3524N (DIP16) SG2524P (SO16) SG3524P (SO16) cations. Each device includes an on-ship refer- ence, error amplifier, programmable oscillator, pulse-steering flip flop, two uncommitted output transistors, a high-gain comparator, and current- limiting and shut-down circuitry. BLOCK DIAGRAM Vi VREF osc.ouUT cA RT EA CT CB COMPENSATION EB INV. INPUT +SENSE N.1I.INPUT ~ SENSE SHUTDOWN GND N9PSE3524~-81 December 1995 1/9$G2524 - $G3524 ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit Vin Supply Voltage 40 Vv Ic Collector Output Current 100 mA IR Reference Output Current 50 mA Ir Current Through Cry Terminal -5 mA Prot Total Power Dissipation at Tame = 70C 1000 mw Taig Storage Temperature Range 65 to 150 C Too Operating Ambient Temperature Range: SG2524 25 to 85 C $G3524 Oto 70 C PIN CONNECTION (Top view) INV. INPUT 1 16[] +5V Vrer NON INV, INPUT []2 sf] +; OSC.i SYNC. (| 3 14 "| EMITTER B c.ute)sense fc 13 j COLLECTOR B C.L{-) SENSE { 4 12 COLLECTOR a Ry (ls 11 EMITTER A Cy 7 ol SHUTOOWN GROUND {je 3 |] COMPENSATION $-6393/1 THERMAL DATA Symbol Parameter DIP16 $016 Unit Rin j-amb Thermal Resistance Junction-ambient Max. 80 = CAN Rip (alumina Thermal Resistance Junction-alumina (*) Max. - 50 C/W (*) Thermal resistance junction-alumina with the davice soldered on the micdle of an alumina supporting substrate measuring 15 x 20mm; 0.65mm thickness with infinite heatsink. 2/9 hy SGS-THOMSON MICAGELECTREMICS$G2524 - $G3524 ELECTRICAL CHARACTERISTICS (unless otherwise stated, these specitications apply for Tj = -25 to +85C for the $G2524, and 0 to 70C for the SG3524, Vin =20V, andt = 20KHz). Symbol Parameter Test Condition SG2524 SG3524 Unit Min. | Typ. | Max. | Min. | Typ. | Max. REFERENCE SECTION VReEF Output Voltage 4.8 5 5.2 46 5 5.4 V AVRer Line Regulation Vin= 8to 40V 10 20 10 30 mV AVrRer Load Regulation IL =0 to 20mA 20 50 20 50 mV Ripple Rejection f = 120Hz, Tj = 25C 66 66 dB Short Circuit Current Veer = 0, Tj) = 25C 100 100 mA Limit AVrer/AT | Temperature Stability Over Operating 0.3 1 0.3 1 % Temperature range AVREF Long Term Stability Tj = 125C, t= 1000Hrs 20 20 mV OSCILLATOR SECTION fax Maximum Frequency Gr =0.001nF, Rr = 2KO 300 300 KHz Initial Accuracy Rr and Cr Constant 5 5 % Voltage Stability Vin = 8to 40V, Tj = 25C 1 % ATAT. Temperature Stability Over Operating 2 2 % Temperature Range Output Amplitude Pin 3, T, = 25C 3.5 3.5 Vv Output Pulse Width Cr =0.01pF, Tj = 25C 0.5 0.5 pis ERROR AMPLIFIER SECTION Vos Input Offset Voltage Vom= 2.5V 0.5 5 2 10 mv lb Input Bias Current 2 10 2 10 LA Gy Open Loop Voltage Gain 72 80 60 80 dB CMV Common Mode Voltage | Tj = 25C 1.8 3.4 | 18 3.4 Vv CMR Common Mode Rejection} Tj = 25C 70 70 dB B Small Signal Bandwidth | Ay = OdB, T, = 25C 3 3 MHz Vo Output Voltage Ti = 28C 0.5 3.8 0.5 3.8 Vv COMPARATOR SECTION Duty-cycle % Each Output On 0 45 0 45 % Vir Input Threshold Zero Duty-cycle 1 1 Maximum Duty-cycle 3.5 3.5 V lo Input Bias Current 1 1 LA CURRENT LIMITING SECTION Sense Voltage Pin 8 = 2V with Error 190 |] 200 | 210 | 180 |} 200 | 220 mV Amp. Set for Max. Out. Tj = 25C Sense Voltage T.C. 0.2 0.2 mvPC CMV Common Mode Voltage 1 1 1 1 OUTPUT SECTION(each output) Collector-emitter Voltage 40 40 Vv Collector Leackage Curr. | Voce = 40V 0.1 50 0.1 50 LA Saturation Voltage Ic = 50mA 1 2 1 2 Vv Emitter Output Voltage Vin = 20V 17 18 17 18 Vv t Rise Time Ro = 2K2, Tj = 25C 0.2 0.2 Ls ti Fall Time Ro = 2KQ, T= 25C 0.1 0.1 ps lq (*) Total Standby Current Vin = 40V 8 10 8 10 mA (*) Excluding oscillator charging current, error and current limitdividers, and with outputs open. 3/9 97 BScncomones$G2524 - $G3524 Figure 1: Open-loop Voltage Amplification of Error Amplifier vs. Frequency G- 3191 By Cap} ; e204 60 20 Re is impedance from pin 9 to ground. Walues below 30K will begin to limit the maximum duty ~ cycle. 190 1s 10K 100K Ut Hs} Figure 3: Qutput Dead Time vs. Timing Capacitance Value. ta ( Yin = 4 1 Os 7 F Note. Dead time =blanking puise width plus output delay | + a4 | | | Of 0.0QT 0.0 o.01 O.U4 CT (pF) Figure 5: Open Loop Test Circuit. Figure 2: Oscillator Frequency vs. Timing Componenis. G&- sya 1. 2 4 20 Ryka Figure 4: Output Saturation Voltage vs. load Current. G- 514074 Yee (veh Q 20 40 60 80 Ig{ma} INFUT OF WELT INEUT COMP DOWN 1 WW CURRENT INY. SHUT LIMIT &~6199 4/9 Ly SGS-THOMSON MICROELECTROMICS$G2524 - $G3524 PRINCIPLES OF OPERATION The 5G2524/3524 is a fixed frequency pulse- with-moedulation voltage regulator control circuit. The regulator operates at a frequency that is pro- grammed by one timing resistor (Rt) and one tim- ing capacitor (Cr). Rr established a constant charging current for Gr. This results in a linear voltage ramp at Gr, which is fed to the compara- tor providing linear control of the output pulse width by the error amplifier. the SG2524/3524 contains, an on-board 5V regulator that serves as a reference as well as powering the 5G2524/3524s internal control circuitry and is also useful in supplying external support tunctions. This reference voltage is lowered externally by a resistor divider to provide a reference within the common mode range the error amplifier or an ex- ternal reference may be used. The power supply output is sensed by a second resistor divider net- work to generale a feedback signal to error ampli- tier. The amplifier output voltage is then com- pared to the linear voltage ramp at Gr. The resulting modulated pulse out of the high-gain comparator is then steered to the appropriate out- put pass transistors (Qa or Gp) by the pulse- steering flip-flop, which is synchronously toggled by the oscillator output. The oscillator output pulse also serves as a blanking pulse to assure both output are never on simultaneously during the transition times. The width of the blanking pulse is controlled by the value of Gr. The outputs may be applied in a push-pull configuration in which their frequency is halt that of the base oscil- lator, or paralleled for single-ended applications in which the frequency is equal to that of the oscilla- tor. The output of the error amplifier shares a common input to the comparator with the current limiting at shutdown circuitry and can be overrid- den by signals from either of these inputs. This common point is also available externally and may be employed to control the gain of, or to compensate, the error amplifier, or to provide ac- ditional control to the regulator. RECOMMENDED OPERATING CONDITIONS Supply voltage Vin 8 to 40V Reference Output Current 0 to 20mA Current trough Gr Terminal - 0.03 to -2mA Timing Resistor, Rr 1.8 to 100KQ Timing Capacitor, Cr 0.001 to 0.1pF TYPICAL APPLICATIONS DATA OSCILLATOR The oscillator controls the frequency of the Sy SGS-THOMSON 5G2524 and is programmed by Rr and Cr ac- cording to the approximate formula: 1.18 -RG where: Rr is in KQ Cr is in HF Tisin KHz Pratical values of Cr fall between 0.001 and 0.1uF. Pratical values of Rr fall between 1.8 and 100K. This results in a frequency range typically from 120Hz to to 500KHz. BLANKING The output pulse of oscillator is used as a blank- ing pulse at the output. This pulse width is con- trolled by the value of Cr.If small values of Cry are required for frequency control, the oscillator out- put pulse width may still be increased by applying a shunt capacitance of up to 100pF from pin 3 to ground. If still greater dead-time is required, it should be accomplished by limiting the maximum duty cycle by clamping the output of the error am- plitier. This can easily be done with the circuit be- low: Figure 6. REF ANGIG Comp (3+ SK SL Gnd (8) %-6400 SYNCRONOUS OPERATION When an external clock is desired, a clock pulse of approximately 3V can be applied directly to the oscillator output terminal. The impedance to ground at this point is approximately 2KQ. In this configuration Rt Cr must be selected for a clock period slightly greater than that the external clack. If two more SG2524 regulators are tobe operated synchronously, all oscillator output terminals should be tied together, all Cr terminals con- nected to a single timing capacitor, and timing re- sistor connected te a single Rr terminal. The other Rr terminals can be left open or shorted to Vrer. Minimum lead lengths should be used be- tween the Cr terminals. 5/9 MICRHOELECTROMICS$G2524 - $G3524 Figure 7: Flyback Converter Circuit. Vin = Sv oO L 25 5 wo UF KM |KO SK 15 4 , 1 q 2 s4n Lis 2K 6 e+} 6 q gpeore 7 3 r10 8 = S-G4Nre4 Figure 8: PUSH-PULL Transtormer-coupled circuit. KO tw 2N5184 6/9 Ky7 SGS;THOMSON$G2524 - $G3524 DIP16 PACKAGE MECHANICAL DATA DIM. mm inch MIN. TYP. MAX. MIN. TYP. MAX. al 0.51 6.020 B O77 1.65 0.030 0.065 b 0.5 0.020 b1 0.25 0.010 D 20 0.787 E 8.5 0.335 e 2.54 0.100 e3 17.78 0,700 F 7.1 0.280 | 5.1 0.201 L 3.3 0.130 Zz 1.27 0.050 | a a | | = > i+ 4 bt y a lob 3 Le! E ~" e3 : a D ~~ boop oooog | 6 9 7 LL 1 8 a 7/9 97 BScncomones$G2524 - $G3524 5016 NARROW PACKAGE MECHANICAL DATA mm DIM. A al a2 b bi Cc cl at bil. e| =| 5 I 3 E : > 1M oooooononm 6 9 1 DUOUUCOUUCO 8/9 L397 Sponscmoncs$G2524 - $G3524 Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any intringement of patents or other rights of third parties which may result from its use. No licanse is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specitications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical componentsin life support devices or systems without express written approval of SGS-THOMSON Microelectronics. 1996 SGS-THOMSON Microelectronics All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thaliand - United Kingdom - U.S.A. o/9 97 BScncomones