BLOCK DIAGRAMUC1526AUC2526AUC3526ARegulating Pulse Width ModulatorFEATURES• Reduced Supply Current• Oscillator Frequency to 600kHz• Precision Band-Gap Reference• 7 to 35V Operation• Dual 200mA Source/Sink Outputs• Minimum Output Cross-Conduction• Double-Pulse Suppression Logic• Under-Voltage Lockout• Programmable Soft-Start• Thermal Shutdown• TTL/CMOS Compatible Logic Ports• 5 Volt Operation (VIN = VC = VREF = 5.0V)DESCRIPTIONThe UC1526A Series are improved-performance pulse-width modu-lator circuits intended for direct replacement of equivalent non- “A”versions in all applications. Higher frequency operation has beenenhanced by several significant improvements including: a more ac-curate oscillator with less minimum dead time, reduced circuit de-lays (particularly in current limiting), and an improved output stagewith negligible cross-conduction current. Additional improvementsinclude the incorporation of a precision, band-gap reference gener-ator, reduced overall supply current, and the addition of thermalshutdown protection.Along with these improvements, the UC1526A Series retains theprotective features of under-voltage lockout, soft-start, digital cur-rent limiting, double pulse suppression logic, and adjustabledeadtime. For ease of interfacing, all digital control ports are TTLcompatible with active low logic.Five volt (5V) operation is possible for “logic level” applications byconnecting VIN, VC and VREF to a precision 5V input supply. Consultfactory for additional information.6/93RECOMMENDED OPERATING CONDITIONS (Note 3)Input Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V to +35VCollector Supply Voltage . . . . . . . . . . . . . . . . . . +4.5V to +35VSink/Source Load Current (each output) . . . . . . . . 0 to 100mAReference Load Current . . . . . . . . . . . . . . . . . . . . . . 0 to 20mAOscillator Frequency Range. . . . . . . . . . . . . . . . 1Hz to 600kHzOscillator Timing Resistor. . . . . . . . . . . . . . . . . . . 2kΩ to 150kΩOscillator Timing Capacitor. . . . . . . . . . . . . . . . . 400pF to 20µFAvailable Deadtime Range at 40kHz . . . . . . . . . . . . 1% to 50%Operating Ambient Temperature Range UC1526A. . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to +125°C UC2526A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25°C to +85°C UC3526A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°CABSOLUTE MAXIMUM RATINGS (Note 1, 2)Input Voltage (+VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40VCollector Supply Voltage (+VC) . . . . . . . . . . . . . . . . . . . . . +40VLogic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +5.5VAnalog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +VINSource/Sink Load Current (each output) . . . . . . . . . . . . 200mAReference Load Current. . . . . . . . . . . . . . . . . . . . . . . . . . 50mALogic Sink Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15mAPower Dissipation at TA = +25°C (Note 2) . . . . . . . . . 1000mWPower Dissipation at TC = +25°C (Note 2). . . . . . . . . . 3000mWOperating Junction Temperature . . . . . . . . . . . . . . . . . . +150°CStorage Temperature Range . . . . . . . . . . . . . . -65°C to +150°CLead Temperature (soldering, 10 seconds). . . . . . . . . . +300°CCONNECTION DIAGRAMSPACKAGE PIN FUNCTIONFUNCTION PINN/C 1+ERROR 2-ERROR 3COMP. 4CSS 5RESET 6- CURRENT SENSE 7+ CURRENT SENSE 8SHUTDOWN 9RTIMING 10CT 11RD 12SYNC 13OUTPUT A 14VC 15N/C 16GROUND 17OUTPUT B 18+VIN 19VREF 20PLCC-20, LCC-20 (TOP VIEW) Q and L PackagesDIL-18, SOIC-18 (TOP VIEW)J or N Package, DW PackageNote 1: Values beyond which damage may occur.Note 2: Consult packaging Section of Databook for thermal limitations and considerations of package.Note 3: Range over which the device is functional and parameter limits are guaranteed.UC1526AUC2526AUC3526A2PARAMETER TEST CONDITIONSUC1526A / UC2526A UC3526AUNITSMIN TYP MAX MIN TYP MAXReference Section (Note 4)Output Voltage TJ = +25°C 4.95 5.00 5.05 4.90 5.00 5.10 VLine Regulation +VIN = 7 to 35V 2 10 2 15 mVLoad Regulation IL = 0 to 20mA 5 20 5 20 mVTemperature Stability Over Operating TJ (Note 5) 15 50 15 50 mVTotal Output VoltageRangeOver Recommended OperatingConditions4.90 5.00 5.10 4.85 5.00 5.15 VShort Circuit Current VREF = 0V 25 50 100 25 50 100 mAUnder-Voltage LockoutRESET Output Voltage VREF = 3.8V 0.2 0.4 0.2 0.4 VVREF = 4.7V 2.4 4.7 2.4 4.8 VOscillator Section (Note 6)Initial Accuracy TJ = +25°C ±3 ±8 ±3 ±8%Voltage Stability +VIN = 7 to 35V 0.5 1 0.5 1 %Temperature Stability Over Operating TJ (Note 5) 26 13%Minimum Frequency RT = 150kΩ, CT = 20µF (Note 5) 1 1 HzMaximum Frequency RT = 2kΩ, CT = 470pF 550 650 kHzSawtooth Peak Voltage +VIN = 35V 3.0 3.5 3.0 3.5 VSawtooth Valley Voltage +VIN =7V 0.5 1.0 0.5 1.0 VSYNC Pulse Width TJ = 25°C, RL = 2.7kΩ to VREF1.1 1.1 µsError Amplifier Section (Note 7)Input Offset Voltage RS ≤ 2kΩ 25 210mVInput Bias Current -350 -1000 -350 -2000 nAInput Offset Current 35 100 35 200 nADC Open Loop Gain RL ≥ 10MΩ 64 72 60 72 dBHIGH Output Voltage VPIN 1 - VPIN 2 ≥ 150mV, ISOURCE = 100µA 3.6 4.2 3.6 4.2 VLOW Output Voltage VPIN 2 - VPIN 1 ≥ 150mV, ISINK = 100µA 0.2 0.4 0.2 0.4 VCommon Mode Rejection RS ≤ 2kΩ 70 94 70 94 dBSupply Voltage Rejection +VIN = 12 to 18V 66 80 66 80 dBPWM Comparator (Note 6)Minimum Duty Cycle VCOMPENSATION = +0.4V 0 0 %Maximum Duty Cycle VCOMPENSATION = +3.6V 45 49 45 49 %Digital Ports (SYNC, SHUTDOWN, and RESET)HIGH Output Voltage ISOURCE = 40µA 2.4 4.0 2.4 4.0 VLOW Output Voltage ISINK = 3.6mA 0.2 0.4 0.2 0.4 VHIGH Input Current VIH = +2.4V -125 -200 -125 -200 µALOW Input Current VIL = +0.4V -225 -360 -225 -360 µAShutdown Delay From Pin 8, TJ = 25°C 160 160 nsCurrent Limit Comparator (Note 8)Sense Voltage RS ≤ 50Ω 90 100 110 80 100 120 mVInput …