U UNISONIC TECHNOLOGIES CO., LTD REGULATING PWM IC DESCRIPTION The UTC U 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 00 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 00mA. SOP- DIP- *Pb-free plating product number: UL FEATURES * Input Voltage: 8~V * On-chip +.V reference is trimmed to ±% * 00HZ ~ 00KHZ 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 Order Number Normal Lead Free Plating Package Packing U-D-T UL-D-T DIP- Tube U-S-R UL-S-R SOP- Tape Reel U-S-T UL-S-T SOP- Tube UL-D-T ()Packing Type ()Package Type ()Lead Plating () R: Tape Reel, T: Tube () D: DIP-, S: SOP- () L: Lead Free Plating, Blank: Pb/Sn of 9 Copyright 00 Unisonic Technologies Co., Ltd QW-R0-0,A
U PIN CONNECTIONS (top view) INV.INPUT V REF N.I.INPUT +V I SYNC 4 OUTPUT B OSC.OUTPUT 4 V C C T GROUND R T OUTPUT A DISCHARGE 0 SHUT DOWN SOFT-START 8 9 COMP THERMAL DATA PARAMETER SYMBOL RATING UNIT DIP θ JA 80 C/W Thermal Resistance Junction-ambient SOP- θ JA 0 C/W Note:Thermal resistance junction-alumina with the device soldered on the middle of an alumina supporting substrate measuring 0 mm; 0. mm thickness with infinite heat sink. UNISONIC TECHNOLOGIES CO., LTD of 9 QW-R0-0,A
U BLOCK DIAGRAM OSCILLATOR A 9 PWM B 4 8 - + EA 0μA 0 kω kω VREF 4 FLIP/ FLOP UNISONIC TECHNOLOGIES CO., LTD of 9 QW-R0-0,A
U 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 ma Output Current, Source or Sink Io 00 ma Reference Output Current I R 0 ma Current through C T Terminal Logic Inputs Analog Inputs I T - 0. ~ +. -0. ~ Vi Total Power Dissipation at Ta=0 C P D 000 mw Junction Temperature T J - ~ + Operating Ambient Temperature T ORP 0 ~ +0 Storage Temperature T STG - ~ +0 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 ~ V Collector Supply Voltage V C 4. ~ V Sink/Source Load Current (steady state) I STEAD 0 ~ 00 ma Sink/Source Load Current (peak) I PEAK 0 ~ 400 ma Reference Load Current I LOAD 0 ~ 0 ma Oscillator Frequency Range F O 00 ~ 400K Hz Oscillator Timing Resistor R O ~ 0 KΩ Oscillator Timing Capacitor C O 0.00 ~ 0. µf Dead Time Resistor Range R T 0 ~ 00 Ω Note: Range over which the device is functional and parameter limits are guaranteed. ELECTRICAL CHARACTERISTICS(V IN = V, unless otherwise specified) PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT REFERENCE SECTION Output Voltage V REF T J =.. V Total Output Variation (Note ) Line, Load and Temperature 4.9. V Long Term Stability (Note ) V REF T J =, 000 hrs 0 0 mv Line Regulation V REF V IN = 8 ~ V 0 0 mv Load Regulation V REF I L = 0 ~ 0 ma 0 0 mv Temp. Stability (Note ) V REF / T Over Operating Range 0 0 mv Output Noise Voltage (Note ) 0 Hz f 0 khz, T J = 40 00 µvrms Short Circuit Current V REF = 0, T J = 80 00 ma OSCILLATOR SECTION Clock Amplitude (Note, ). V Sync Threshold..8 V Sync Input Current Sync Voltage =. V. ma Current Mirror I RT = ma.. ma Maximum Frequency f MAX R T = KΩ, C T = 40 pf 400 KHz Minimum Frequency f MIN R T = 00KΩ, C T = 0.µF 0 Hz Clock Width (Note, ) T J = 0. 0. µs Initial Accuracy (Note, ) T J = ± ± % Voltage Stability (Note, ) V IN = 8 ~ V ± ± % Temperature Stability (Note ) f/ T Over Operating Range ± ± % ma V V UNISONIC TECHNOLOGIES CO., LTD 4 of 9 QW-R0-0,A
U ELECTRICAL CHARACTERISTICS(Cont.) PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT ERROR AMPLIFIER SECTION (V CM =. V) Output Low Level 0. 0. V Output High Level.8. V Input Offset Voltage V OS 0 mv Input Bias Current I b 0 µa Input Offset Current I os µa Comm. Mode Reject. CMR V CM =. ~. V 0 db Supply Voltage Rejection PSR V IN = 8 ~ V 0 0 db DC Open Loop Gain R L 0 MΩ 0 db DC Transconduct. (Note, ) 0 KΩ R L MΩ, T J =.. ms Gain Bandwidth Product (Note ) Gv = 0 db, T J = MHz PWM COMPARATOR Input Threshold (Note ) Zero Duty-cycle 0. 0.9 V Maximum Duty-cycle.. V Input Bias Current (Note ) 0.0 µa Minimum Duty-cycle 0 % Maximum Duty-cycle (Note ) 4 49 % SHUTDOWN SECTION Soft Start Low Level V SD =. V 0.4 0. V Shutdown Threshold To outputs, V SS =. V, T J = 0. 0.8 V Shutdown Input Current V SD =. V 0.4 ma Soft Start Current V SD = 0 V, V SS = 0 V 0 80 µa Shutdown Delay (Note ) V SD =. V, T J = 0. 0. µs OUTPUT DRIVERS (each output) (V C = 0 V) Output Low Level I SINK = 0 ma 0. 0.4 V I SINK = 00 ma V Output High Level I SOURCE = 0 ma 8 9 V I SOURCE = 00 ma 8 V Under-Voltage Lockout V COMP and V SS = High 8 V Collector Leakage I C V C = V 00 µa Rise Time (Note ) t R C L = nf, T J = C 00 00 ns Fall Time (Note ) t F C L = nf, T J = C 0 00 ns TOTAL STANDBY CURRENT Supply Current I S V IN = V 4 0 ma Note:.The parameters are not 00% tested in production..tested at fosc=40 KHz (R T =. KΩ, C T =0nF, R D =0 Ω). Approximate oscillator frequency is defined by : f = C T (0.R T + R D ).DC transconductance (g M ) relates to DC open-loop voltage gain (G V ) according to the following equation: G V =g M R L where R L is the resistance from pin 9 to ground. The minimum g M specification is used to calculate minimum G V when the error amplifier output is loaded. UNISONIC TECHNOLOGIES CO., LTD of 9 QW-R0-0,A
U TEST CIRCUIT V REF +V 0.μF 0.μF CLOCK 4 V C kω SYNC 0.μF OUTA PWM ADJ. 0kΩ.kΩ R T KΩ W KΩ 9nF RAMP DEAD TIME 00Ω UTC U 4 W OUT B.kΩ 0.μF CT COMP nf 0kΩ 0.0μF 9 8 μf GND SOFT START V OS = (+) = (-) = V/I METER 0 kω SHUT DOWN V REF UNISONIC TECHNOLOGIES CO., LTD of 9 QW-R0-0,A
U 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 00µA 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 0 which has been improved to enhance the available shutdown options. Activating this circuit by applying a positive signal on Pin 0 performs two functions: the PWM latch is immediately set providing the fastest turn-off signal to the outputs; and a 0µA 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 0 high for a longer duration, however, will ultimately discharge this external capacitor, recycling slow turn-on upon release. Pin 0 should not be left floating as noise pickup could conceivably interrupt normal operation. OSCILLATOR SCHEMATIC V REF Q Q Q4 Q.4KΩ R T Q Q Q C T Q8 Q9 TO PWM COMPARATOR SYNC. kω 4KΩ DISCHARGE Q 400μA kω Q0 Q KΩ Q4 Q pf KΩ BLANKING TO OUTPUT GND KΩ Q Q Q KΩ KΩ 4 0Ω CLOCK UNISONIC TECHNOLOGIES CO., LTD of 9 QW-R0-0,A
U APPLICATION INFORMATION AND CIRCUIT(Cont.) OUTPUT CIRCUIT (/ CIRCUIT SHOWN) +VI +V C Q4 Q Q Q Q0 Q +V REF Q8 KΩ 4 OUTPUT Q Q Q Q9 Q KΩ KΩ 0KΩ 0KΩ CLOCK F/F PWM ERROR AMPLIFIER +VI Q Q4 9 COMP. Q 00Ω INV INPUT Q Q N. I. INPUT TO PWM COMPARATOR 00μA 00μA.8V UNISONIC TECHNOLOGIES CO., LTD 8 of 9 QW-R0-0,A
U TYPICAL CHARACTERISTICS Oscillator Charge Time vs. R T and C T Oscillator DisCharge Time vs. R D and C T 400 RT (KΩ) 0 0 0 C T =nf C T =nf C T =nf C T =0nF C T =0nF C T =0nF C T =0.μF R T R D =0 R D CT 00 000 0000ms ms RD (Ω) 00 00 00 0 0. C T =nf C T =nf C T =nf C T =0nF C T =0nF C T =0nF 0 0 0 CT=0.μF T (μs) T (μs) Output Saturation Characteristics Error Amplifier Voltage Gain and Phase vs. Frequency 80 RL= V CE (V) VIN=0V Tamb= 0 0.0 SOURCE SAT,V C-V OH SINK SAT, V OL 0. G V (db) MΩ 0 00kΩ 00kΩ 40 0kΩ 0 0 Values below 0kΩ will begin to limit the maximum duty cycle 00 PHASE VIN=0V k 0k 00k M -80-0 -0 Open Loop Phase I OUT (A) f (Hz) 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. UNISONIC TECHNOLOGIES CO., LTD 9 of 9 QW-R0-0,A