U3525

U3525 ETL | Alldatasheet

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UNISONIC TECHNOLOGIES CO., LTD U3525 LINEAR INTEGRATED CIRCUIT www.unisonic.com.tw 1of 9 Copyright © 2005 Unisonic Technologies Co., Ltd QW-R103-032,A 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, providin g 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 cl ock pulse. The output stages are totem-pole designs capable of sourcing or sinking in excess of 200mA. „ 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 DIP -16 SOP -16 *Pb-free plating product number: U3525L „ ORDERING INFORMATION Order Number Normal Lead Free Plating Package Packing U3525-D16-T U3525L-D16-T DIP-16 Tube U3525-S16-R U3525L-S16-R SOP-16 Tape Reel U3525-S16-T U3525L-S16-T SOP-16 Tube U3525L-D16-T (1)Packing Type (2)Package Type (3)Lead Plating (1) R: Tape Reel, T: Tube (2) D16: DIP-16, S16: SOP-16 (3) L: Lead Free Plating , Blank: Pb/Sn

U3525 LINEAR INTEGRATED CIRCUIT UNISONIC TECHNOLOGIES CO., LTD 2 of 9 www.unisonic.com.tw Q W - R 1 0 3 - 0 3 2 , A „ PIN CONNECTIONS (top view) VREF +VI OUTPUT B VC GROUND OUTPUT A SHUT DOWN COMP9 161 8SOFT-START R T DISCHARGE CT OSC.OUTPUT SYNC N.I.INPUT INV.INPUT „ 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.

U3525 LINEAR INTEGRATED CIRCUIT UNISONIC TECHNOLOGIES CO., LTD 3 of 9 www.unisonic.com.tw Q W - R 1 0 3 - 0 3 2 , A „ BLOCK DIAGRAM 5kΩ 50μA 5kΩ PWM EA+ B A FLIP/ FLOP O SCILLATO R VREF

U3525 LINEAR INTEGRATED CIRCUIT UNISONIC TECHNOLOGIES CO., LTD 4 of 9 www.unisonic.com.tw Q W - R 1 0 3 - 0 3 2 , A „ ABSOLUATE MAXIUM RATINGS PARAMETER SYMBOL RATINGS UNIT Supply Voltage V iN 40 V Collector Supply Voltage V C 40 V Oscillator Charging Current I OSC 5 mA Output Current, Source or Sink Io 500 mA Reference Output Current I R 50 mA Current through CT Terminal Logic Inputs Analog Inputs I T - 0.3 ~ + 5.5 -0.3 ~ Vi mA V V Total Power Dissipation at Ta=70 °C P D 1000 mW Junction Temperature T J -55 ~ +125 ℃ Operating Ambient Temperature T ORP 0 ~ +70 ℃ Storage Temperature T STG -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 UNIT Input Voltage V IN 8 ~ 35 V Collector Supply Voltage V C 4.5 ~ 35 V Sink/Source Load Current (steady state) I STEAD 0 ~ 100 mA Sink/Source Load Current (peak) I PEAK 0 ~ 400 mA Reference Load Current I LOAD 0 ~ 20 mA Oscillator Frequency Range F O 100 ~ 400K Hz Oscillator Timing Resistor R O 2 ~ 150 K Ω Oscillator Timing Capacitor C O 0.001 ~ 0.1 µF Dead Time Resistor Range R T 0 ~ 500 Ω Note: Range over which the device is functional and parameter limits are guaranteed. „ ELECTRICAL CHARACTERISTICS(VIN= 25V, unless otherwise specified) PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT REFERENCE SECTION Output Voltage V REF TJ= 25℃ 5 5.1 5.2 V Total Output Variation (Note 1) Line, Load and Temperature 4.95 5.25 V Long Term Stability (Note 1) △VREF T J= 125℃, 1000 hrs 20 50 mV Line Regulation △VREF VIN= 8 ~ 35 V 10 20 mV Load Regulation △VREF IL = 0 ~ 20 mA 20 50 mV Temp. Stability (Note 1) △VREF/△T Over Operating Range 20 50 mV Output Noise Voltage (Note 1) 10 Hz ≤ f ≤ 10 kHz, TJ = 25℃ 40 200 µVrms Short Circuit Current VREF = 0, TJ = 25℃ 80 100 mA OSCILLATOR SECTION Clock Amplitude (Note 1, 2) 3 3.5 V Sync Threshold 1.2 2 2.8 V Sync Input Current Sync Voltage = 3.5 V 1 2.5 mA Current Mirror I RT = 2 mA 1.7 2 2.2 mA Maximum Frequency f MAX R T = 2 KΩ, CT = 470 pF 400 KHz Minimum Frequency f MIN R T = 200KΩ, CT = 0.1µF 120 Hz Clock Width (Note 1, 2) TJ = 25℃ 0.3 0.5 1 µs Initial Accuracy (Note 1, 2) TJ = 25℃ ±2 ±6 % Voltage Stability (Note 1, 2) V IN = 8 ~ 35 V ±1 ±2 % Temperature Stability (Note 1) △f/△T Over Operating Range ±3 ±6 %

U3525 LINEAR INTEGRATED CIRCUIT UNISONIC TECHNOLOGIES CO., LTD 5 of 9 www.unisonic.com.tw Q W - R 1 0 3 - 0 3 2 , A „ ELECTRICAL CHARACTERISTICS(Cont.) PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT ERROR AMPLIFIER SECTION (VCM = 5.1 V) Output Low Level 0.2 0.5 V Output High Level 3.8 5.6 V Input Offset Voltage V OS 2 10 mV Input Bias Current I b 1 10 µA Input Offset Current I os 1 µA Comm. Mode Reject. CMR V CM = 1.5 ~ 5.2 V 60 75 dB Supply Voltage Rejection PSR V IN = 8 ~ 35 V 50 60 dB DC Open Loop Gain R L ≥10 MΩ 60 75 dB DC Transconduct. (Note 1, 3) 30 KΩ ≤RL≤1 MΩ, TJ = 25℃ 1.1 1.5 ms Gain Bandwidth Product (Note 1) Gv = 0 dB, TJ = 25℃ 1 2 MHz PWM COMPARATOR Zero Duty-cycle 0.7 0.9 V Input Threshold (Note 2) Maximum Duty-cycle 3.3 3.6 V Input Bias Current (Note 1) 0.05 1 µA Minimum Duty-cycle 0 % Maximum Duty-cycle (Note 2) 45 49 % SHUTDOWN SECTION Soft Start Low Level V SD = 2.5 V 0.4 0.7 V Shutdown Threshold To outputs, VSS = 5.1 V, TJ = 25℃ 0.6 0.8 1 V Shutdown Input Current V SD = 2.5 V 0.4 1 mA Soft Start Current V SD = 0 V, VSS = 0 V 25 50 80 µA Shutdown Delay (Note 1) VSD = 2.5 V, TJ = 25℃ 0.2 0.5 µs OUTPUT DRIVERS (each output) (VC = 20 V) ISINK = 20 mA 0.2 0.4 V Output Low Level ISINK = 100 mA 1 2 V ISOURCE = 20 mA 18 19 V Output High Level ISOURCE = 100 mA 17 18 V Under-Voltage Lockout V COMP and VSS = High 6 7 8 V Collector Leakage I C V C = 35 V 200 µA Rise Time (Note 1) t R C L = 1 nF, TJ = 25 °C 100 600 ns Fall Time (Note 1) t F C L = 1 nF, TJ = 25 °C 50 300 ns TOTAL STANDBY CURRENT Supply Current I S V IN = 35 V 14 20 mA Note:1.The parameters are not 100% tested in production. 2.Tested at fosc=40 KHz (R T=3.6 KΩ, CT=10nF, RD=0 Ω). Approximate oscillator frequency is defined by : f = CT(0.7RT + 3RD) 3.DC transconductance (g M) relates to DC open-loop voltage gain (G V) according to the following equation: GV=gM RL where RL is the resistance from pin 9 to ground. The minimum g M specification is used to calculate minimum GV when the error amplifier output is loaded.

U3525 LINEAR INTEGRATED CIRCUIT UNISONIC TECHNOLOGIES CO., LTD 6 of 9 www.unisonic.com.tw Q W - R 1 0 3 - 0 3 2 , A „ TEST CIRCUIT 0.01μF 10kΩ COMP 1nF CT 0.1μF 9nF RAMP 1.5kΩ 10kΩPWM ADJ. 3kΩ 3.6kΩ RT 100Ω DEAD TIME SYNC CLOCK 0.1μF VREF 2kΩ 5μF SOFT START VREF SHUT DOWN GND OUT B 1KΩ 1KΩ OUTA 0.1μF 0.1μF VC +V1 V/I METER VOS = 1 (+) = 2 (-) = 3 2 1 UTC U3525

U3525 LINEAR INTEGRATED CIRCUIT UNISONIC TECHNOLOGIES CO., LTD 7 of 9 www.unisonic.com.tw Q W - R 1 0 3 - 0 3 2 , A „ APPLICATION INFORMATION AND CIRCUIT SHUTDOWN OPTIONS (see Block Diagram) Since both the compensation and soft-start terminals (P ins 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 curr ent 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 Q9Q8 400μA 25KΩ BLANKING TO OUTPUT TO PWM COMPARATOR RT 2kΩ 2kΩ Q10 Q11 5pF 23KΩ 1KΩ Q161KΩ Q15 Q14 DISCHARGE SYNC. GND Q12 Q13 3KΩ 250Ω CLOCK4 Q17 14KΩ 7.4KΩ 15VREF 5CT Q5Q1 Q2 Q4

U3525 LINEAR INTEGRATED CIRCUIT UNISONIC TECHNOLOGIES CO., LTD 8 of 9 www.unisonic.com.tw Q W - R 1 0 3 - 0 3 2 , A „ APPLICATION INFORMATION AND CIRCUIT(Cont.) OUTPUT CIRCUIT (1/2 CIRCUIT SHOWN) +VI 13 +VREF CLOCK Q12 2KΩ Q10 Q11 OUTPUT Q3Q3Q3 10KΩ10KΩ5KΩ F/F PWM 5KΩ +VC ERROR AMPLIFIER +VI 15 Q2Q1 200μA 5.8V 100Ω COMP. TO PWM COMPARATOR N. I. INPUT INV INPUT 1 100μA

U3525 LINEAR INTEGRATED CIRCUIT UNISONIC TECHNOLOGIES CO., LTD 9 of 9 www.unisonic.com.tw Q W - R 1 0 3 - 0 3 2 , A „ TYPICAL CHARACTERISTICS RT (KΩ) 1020 100 200500 1ms T (μs) 55 0 2 m s RD=0 CT=1nF C T=2nF C T=5nF C T=10nF C T=20nF CT=50nF C T=0.1μ F RT CT RD Oscillator Charge Time vs . RT and CT RD (Ω) 100 T (μs) 0.5 C T=1nF C T=2nF C T=10nF C T=20nF C T=10nF C T=0.1μ F Oscillator DisCharge Time vs . RD and CT 2 5 10 20 50 200 300 400 C T=5nF VCE (V) 0.01 IOUT (A) Output Saturation Characteristics 0.1 Tamb=25℃ SOURCE SAT,VC-VOH VIN=20V GV (dB) 100 f (Hz) Error Amplifier Voltage Gain and Phase vs. Frequency PHASE 1k 10k 100k 1M Values below 30kΩ will begin to limit the maximum duty cycle 30kΩ 100kΩ 300kΩ 1MΩ RL=∞ -360° -270° -180° Open Loop Phase VIN=20V SINK SAT, VOL UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) 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 systems where malfunction 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 information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.