NTE7117 Integrated Circuit Switched–Mode Power Supply Controller Description: The NTE7117 is a control circuit in an 8–Lead DIP type package designed for use in switched–mode power supplies. It contains an internal temperature–compensated supply, PWM, sawtooth oscillator, over–current sense latch, and output stage. This device is intended for low cost SMPS applications where extensive housekeeping functions are not required. Features: D Pulse Width Modulator D Current Limiting (Cycle–by–Cycle) D Sawtooth Generator D Stabilized Power Supply D Double–Pulse Protection D Internal Temperature–Compensated Reference Applications: D Switch–Mode Power Supplies D DC Motor Controller Inverter D DC/DC Converter Absolute Maximum Ratings: Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18V Output Current, IOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40mA Output Duty Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98% Maximum Total Power Dissipation, PD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750mW Operating Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0° to +70°C DC Electrical Characteristics: (VCC = 12V, TA = +25°C unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit TA = +25°C 3.69 3.75 3.84 V TA = 0° to +70°C 3.66 – 3.87 V IL = 7mA 7.8 8.2 8.8 V Temperature Coefficient of VREF – ±100 – ppm/°C Temperature Coefficient of VZ – ±100 – ppm/°C TA = 0° to +70°C 50 – 100k Hz Initial Accuracy RT and CT Constant – 5 – % Duty Cycle Range fo = 20kHz 0 – 98 % Reference Section Internal Reference Voltage Internal Zener Reference VREF VZ Oscillator Section Frequency Range f DC Electrical Characteristics (Cont’d): (VCC = 12V, TA = +25°C unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit TA = +25°C – –2 –10 µA TA = 0° to +70°C – – –20 µA – 0.88 1.10 µs – 0.7 0.8 µs 0.4 0.5 0.6 V – 60 – dB 10k – – Ω Current Limiting Input Current IIN Single Pulse Inhibit Delay Pin6 = 250mV Inhibit Delay Time IOUT = 20mA for 20% Overdrive IOUT = 40mA Current Limit Trip Level Error Amplifier Open–Loop Gain Feedback Resistor Small–Signal Bandwidth BW – 3 – MHz Output Voltage Swing, High VOH 6.2 – – V Output Voltage Swing, Low VOL – – 0.7 V 20 – – mA IC = 20mA – – 0.4 V IC = 40mA – – 0.5 V TA = +25°C – – 10 mA TA = 0° to +70°C – – 13 mA IS = 10mA, Current–Fed 19 21 24 V ICC = 30mA, Current–Fed 20 – 30 V 8.0 9.0 10.5 V Output Stage Output Current IOUT TA = 0° to +70°C Saturation Voltage VCE TA = 0° to +70°C Supply Voltage/Current Supply Current ICC Supply Voltage VCC IZ = 0, Voltage–Fed Low Supply Protection Pin1 Threshold 8 5 .256 (6.52) Max Pin Connection Diagram 1 VCC 1 VZ 2 Feedback 3 Gain 4 4 8 GND 7 Output 6 Current Sense .393 (10.0) Max .300 (7.62) .150 (3.81) 5 RT, CT .100 (2.54) .070 (1.77) Min .300 (7.62)