UNISONIC TECHNOLOGIES CO., LTD U3525 LINEAR INTEGRATED CIRCUIT REGULATING PWM IC DESCRIPTION The UTC U3525 is a pulse width modulator IC and designed for switching power supplies application to improve performance and reduce external parts usage. A shutdown terminal controls both the soft-start circuitry and the output stages, providing instantaneous turn off through the PWM latch with pulsed shutdown, as well as soft-start recycle with longer shutdown commands. The output stage features NOR logic, giving a LOW output for an OFF state. An under-voltage lockout circuitry, which keeps the outputs off and the soft-start capacitor discharged for sub-normal input voltages, includes approximately 500 mV of hysteresis for jitter free operation. The PWM circuits also feature a latch following the comparator. When a PWM pulses has been terminated, the outputs will remain off for the duration of the period. The latch is reset with each clock pulse. The output stages are totem-pole designs capable of sourcing or sinking in excess of 200mA. SOP-16 DIP- 16 *Pb-free plating product number: U3525L FEATURES * Input Voltage: 8~35V * On-chip +5.1V reference is trimmed to ±1% * 100HZ ~ 500KHZ oscillator range * Separate oscillator sync terminal * Adjustable dead time control * Internal soft-start * Pulse-by-pulse shutdown * Input under-voltage lockout with hysteresis * Latching PWM to prevent multiple pulses * Dual source/sink output drivers ORDERING INFORMATION Normal U3525-D16-T U3525-S16-R U3525-S16-T Order Number Lead Free Plating U3525L-D16-T U3525L-S16-R U3525L-S16-T Package Packing DIP-16 SOP-16 SOP-16 Tube Tape Reel Tube U3525L-D16-T (1)Packing Type (2)Package Type (3)Lead Plating www.unisonic.com.tw Copyright © 2005 Unisonic Technologies Co., Ltd (1) R: Tape Reel, T: Tube (2) D16: DIP-16, S16: SOP-16 (3) L: Lead Free Plating, Blank: Pb/Sn 1of 9 QW-R103-032,A U3525 LINEAR INTEGRATED CIRCUIT PIN CONNECTIONS (top view) INV.INPUT 1 16 VREF N.I.INPUT 2 15 +VI SYNC 3 14 OUTPUT B OSC.OUTPUT 4 13 VC CT 5 12 GROUND RT 6 11 OUTPUT A DISCHARGE 7 10 SHUT DOWN SOFT-START 8 9 COMP THERMAL DATA PARAMETER SYMBOL RATING UNIT DIP16 θJA 80 °C/W Thermal Resistance Junction-ambient SOP-16 θJA 50 °C/W Note:Thermal resistance junction-alumina with the device soldered on the middle of an alumina supporting substrate measuring 15×20 mm; 0.65 mm thickness with infinite heat sink. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 9 QW-R103-032,A U3525 LINEAR INTEGRATED CIRCUIT BLOCK DIAGRAM 3 OSCI LLATOR 13 6 7 A 11 B 14 5 9 PWM 8 1 - 2 + EA 50μA 12 10 5kΩ 5kΩ 15 VREF 16 4 FLIP/ FLOP UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 3 of 9 QW-R103-032,A U3525 LINEAR INTEGRATED CIRCUIT ABSOLUATE MAXIUM RATINGS PARAMETER SYMBOL RATINGS UNIT Supply Voltage ViN 40 V Collector Supply Voltage VC 40 V Oscillator Charging Current IOSC 5 mA Output Current, Source or Sink Io 500 mA Reference Output Current IR 50 mA mA Current through CT Terminal 5 V Logic Inputs IT - 0.3 ~ + 5.5 V Analog Inputs -0.3 ~ Vi Total Power Dissipation at Ta=70 °C PD 1000 mW Junction Temperature TJ -55 ~ +125 ℃ Operating Ambient Temperature TORP 0 ~ +70 ℃ Storage Temperature TSTG -65 ~ +150 ℃ Note Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. RECOMMENDED OPERATING CONDITIONS (Note) PARAMETER SYMBOL RATINGS Input Voltage VIN 8 ~ 35 Collector Supply Voltage VC 4.5 ~ 35 Sink/Source Load Current (steady state) ISTEAD 0 ~ 100 Sink/Source Load Current (peak) IPEAK 0 ~ 400 Reference Load Current ILOAD 0 ~ 20 Oscillator Frequency Range FO 100 ~ 400K Oscillator Timing Resistor RO 2 ~ 150 Oscillator Timing Capacitor CO 0.001 ~ 0.1 Dead Time Resistor Range RT 0 ~ 500 Note: Range over which the device is functional and parameter limits are guaranteed. UNIT V V mA mA mA Hz KΩ µF Ω ELECTRICAL CHARACTERISTICS(VIN= 25V, unless otherwise specified) PARAMETER REFERENCE SECTION Output Voltage Total Output Variation (Note 1) Long Term Stability (Note 1) Line Regulation Load Regulation Temp. Stability (Note 1) Output Noise Voltage (Note 1) Short Circuit Current OSCILLATOR SECTION Clock Amplitude (Note 1, 2) Sync Threshold Sync Input Current Current Mirror Maximum Frequency Minimum Frequency Clock Width (Note 1, 2) Initial Accuracy (Note 1, 2) Voltage Stability (Note 1, 2) Temperature Stability (Note 1) SYMBOL TEST CONDITIONS TJ= 25℃ Line, Load and Temperature △VREF TJ= 125℃, 1000 hrs △VREF VIN= 8 ~ 35 V △VREF IL = 0 ~ 20 mA △VREF/△T Over Operating Range 10 Hz ≤ f ≤ 10 kHz, TJ = 25℃ VREF = 0, TJ = 25℃ VREF TYP MAX 5 4.95 5.1 20 10 20 20 40 80 5.2 V 5.25 V 50 mV 20 mV 50 mV 50 mV 200 µVrms 100 mA 3.5 2 1 2 2.8 2.5 2.2 0.5 ±2 ±1 ±3 120 1 ±6 ±2 ±6 3 1.2 fMAX fMIN △f/△T Sync Voltage = 3.5 V IRT = 2 mA RT = 2 KΩ, CT = 470 pF RT = 200KΩ, CT = 0.1µF TJ = 25℃ TJ = 25℃ VIN = 8 ~ 35 V Over Operating Range UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw MIN 1.7 400 0.3 UNIT V V mA mA KHz Hz µs % % % 4 of 9 QW-R103-032,A U3525 LINEAR INTEGRATED CIRCUIT ELECTRICAL CHARACTERISTICS(Cont.) PARAMETER SYMBOL ERROR AMPLIFIER SECTION (VCM = 5.1 V) Output Low Level Output High Level Input Offset Voltage VOS Input Bias Current Ib Input Offset Current Ios Comm. Mode Reject. CMR Supply Voltage Rejection PSR DC Open Loop Gain DC Transconduct. (Note 1, 3) Gain Bandwidth Product (Note 1) PWM COMPARATOR Input Threshold (Note 2) Input Bias Current (Note 1) Minimum Duty-cycle Maximum Duty-cycle (Note 2) SHUTDOWN SECTION Soft Start Low Level Shutdown Threshold Shutdown Input Current Soft Start Current Shutdown Delay (Note 1) OUTPUT DRIVERS (each output) (VC = 20 V) Output Low Level Output High Level TEST CONDITIONS MIN 3.8 TYP 0.2 5.6 2 1 VCM = 1.5 ~ 5.2 V VIN = 8 ~ 35 V RL ≥10 MΩ 30 KΩ ≤RL≤1 MΩ, TJ = 25℃ Gv = 0 dB, TJ = 25℃ 60 50 60 1.1 1 75 60 75 1.5 2 Zero Duty-cycle Maximum Duty-cycle 0.7 0.9 3.3 0.05 45 VSD = 2.5 V To outputs, VSS = 5.1 V, TJ = 25℃ VSD = 2.5 V VSD = 0 V, VSS = 0 V VSD = 2.5 V, TJ = 25℃ ISINK = 20 mA ISINK = 100 mA ISOURCE = 20 mA ISOURCE = 100 mA VCOMP and VSS = High VC = 35 V CL = 1 nF, TJ = 25 °C CL = 1 nF, TJ = 25 °C 0.6 25 18 17 6 MAX UNIT 0.5 10 10 1 V V mV µA µA dB dB dB ms MHz 3.6 1 0 V V µA % % 0.4 0.8 0.4 50 0.2 0.7 1 1 80 0.5 V V mA µA µs 0.2 1 19 18 7 0.4 2 V V V V V µA ns ns 49 Under-Voltage Lockout 8 Collector Leakage IC 200 Rise Time (Note 1) tR 100 600 Fall Time (Note 1) tF 50 300 TOTAL STANDBY CURRENT Supply Current IS VIN = 35 V 14 20 mA Note:1.The parameters are not 100% tested in production. 2.Tested at fosc=40 KHz (RT=3.6 KΩ, CT=10nF, RD=0 Ω). Approximate oscillator frequency is defined by : 1 f= C T(0.7R T + 3R D) 3.DC transconductance (gM) relates to DC open-loop voltage gain (GV) according to the following equation: GV=gM RL where RL is the resistance from pin 9 to ground. The minimum gM specification is used to calculate minimum GV when the error amplifier output is loaded. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 9 QW-R103-032,A U3525 LINEAR INTEGRATED CIRCUIT TEST CIRCUIT VREF +V1 16 15 0.1μF 0.1μF VC 13 4 CLOCK 0.1μF OUTA 3kΩ 11 3 SYNC 1KΩ RT PWM ADJ. 3.6kΩ 10kΩ 1W 1KΩ 6 DEAD TIME 7 9nF RAMP 100Ω UTC U3525 1W 14 OUT B 5 1.5kΩ CT GND 12 COMP 1nF 10kΩ 0.1μF 9 2 3 V/I METER VOS = 1 (+) = 2 (-) = 3 1 2 3 1 2 0.01μF 3 21 3 UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 1 2 SOFT START 8 5μF VREF 10 2kΩ SHUT DOWN 6 of 9 QW-R103-032,A U3525 LINEAR INTEGRATED CIRCUIT APPLICATION INFORMATION AND CIRCUIT SHUTDOWN OPTIONS (see Block Diagram) Since both the compensation and soft-start terminals (Pins 9 and 8) have current source pull-ups, either can readily accept a pull-down signal which only has to sink a maximum of 100µA to turn off the outputs. This is subject to the added requirement of discharging whatever external capacitance may be attached to these pins. An alternate approach is the use of the shutdown circuitry of Pin 10 which has been improved to enhance the available shutdown options. Activating this circuit by applying a positive signal on Pin 10 performs two functions: the PWM latch is immediately set providing the fastest turn-off signal to the outputs; and a 150µA current sink begins to discharge the external soft-start capacitor. If the shutdown command is short, the PWM signal is terminated without significant discharge of the soft-start capacitor, thus, allowing, for example, a convenient implementation of pulse-by-pulse current limiting. Holding Pin 10 high for a longer duration, however, will ultimately discharge this external capacitor, recycling slow turn-on upon release. Pin 10 should not be left floating as noise pickup could conceivably interrupt normal operation. OSCILLATOR SCHEMATIC VREF 15 Q1 RT 6 Q2 Q3 CT 5 7.4KΩ Q5 Q4 Q6 Q7 Q8 TO PWM COMPARATOR Q9 2kΩ SYNC. DISCHARGE 14KΩ 7 3 Q17 400μA 2kΩ 25KΩ Q10 Q11 Q14 1KΩ GND UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw Q12 BLANKING TO OUTPUT 5pF Q13 Q15 23KΩ 1KΩ Q16 3KΩ 250Ω 4 CLOCK 7 of 9 QW-R103-032,A U3525 LINEAR INTEGRATED CIRCUIT APPLICATION INFORMATION AND CIRCUIT(Cont.) OUTPUT CIRCUIT (1/2 CIRCUIT SHOWN) 13 +VC +VI Q5 Q7 Q10 Q6 Q4 Q11 11 5KΩ +VREF OUTPUT 14 Q8 Q12 Q9 Q3 5KΩ CLOCK Q3 Q3 10KΩ 10KΩ F/F 2KΩ PWM ERROR AMPLIFIER +VI 15 Q3 Q4 9 Q5 INV INPUT 1 N. I. INPUT 2 Q1 COMP. 100Ω Q2 TO PWM COMPARATOR 200μA 100μA UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5.8V 8 of 9 QW-R103-032,A U3525 LINEAR INTEGRATED CIRCUIT TYPICAL CHARACTERISTICS Oscillator Charge Time vs. RT and CT Oscillator DisCharge Time vs. R D and CT CT=1 nF CT=2 nF CT = 5nF CT = 1 0n F CT = 20 n F CT = 1 0n F CT = 0.1 μF 400 20 10 5 2 RT 300 RD (Ω) CT = CT = 1nF 2 C n C T =5n F C T =10n F T= 20 F C n T= 50 F CT nF =0 .1 μ F RT (KΩ) 50 RD=0 6 5 200 100 RD7 CT 0 1 2 5 10 20 50 100 2005001ms2ms 0.5 1 2 5 10 20 50 T (μs) T (μs) Output Saturation Characteristics Error Amplifier Voltage Gain and Phase vs. Frequency 80 R L=∞ VIN=20V Tamb=25℃ 2 SOURCE SAT,VC-VOH 1 V IN=20V 40 30kΩ Values below 30kΩ 20 will begin to limit the maximum duty cycle 0 PHASE SINK SAT, VOL 0 0.01 0.1 IOUT (A) Open Loop Phase G V (dB) VCE (V) 3 1MΩ 60 300kΩ 100kΩ 100 1k 10k 100k 1M -180° -270° -360° f (Hz) UTC assumes no responsibility for equipm ent failures that result from using products at values that exceed, even mom entarily, rated values (such as m aximum ratings, operating condition ranges, or other param eters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or system s where m alfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The inform ation presented in this docum ent does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 9 of 9 QW-R103-032,A