NTE7098 & NTE7099 Integrated Circuit Current Mode Pulse Width Modulator (PWM) Control Circuit Description: The NTE7098 and NTE7099 are integrated circuits in 8–Lead DIP type packages that incorporate a new precision temperature–controlled oscillator to minimize variations in frequency. An internal toggle flip–flop, which blanks the output off every other clock cycle, limits the duty–cycle range to less than 50%. An under–voltage lockout ensures that VREF is stabilized before the output stage is enabled. Other features include low start–up current, pulse–by–current limiting, and high–current totem pole output for driving capacitive loads, such as the gate of a power MOSFET. The output is low in the off state, consistent with N–channel devices. Features: D Optimized for Off–Line Control D Temperature Compensated Oscillator D 50% Maximum Duty–Cycle Clamp D Vref Stabilized before Output Stage is Enabled D Low Start–Up Current D Pulse–by Pulse Current Limiting D Improved U/V Lockout D Double Pulse Suppression D 1% Trimmed Bandgap Reference D High Current Totem Pole Output Absolute Maximum Ratings: Supply Voltage (ICC < 30mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Self Limiting Supply Voltage (Low Impedence Source) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30V Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1A Output Energy (Capacitive Load) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5µJ Analog Inputs (VFB, VSENSE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to VCC Error Amp Output Sink Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA Elecrtrical Characteristics: (0° ≤ TA ≤ +70°C, VCC = 15V, RT = 10K, CT = 3.3nF for sawtooth mode, Note 1 unless otherwise specified) Parameter Test Conditions Min Typ Max Unit 4.9 5.0 5.1 V Reference Section Output Voltage TJ = +25°C, IREF = 1mA Line Regulation 12V ≤ VIN ≤ 25V – 6 20 mV Load Regulation 1mA ≤ IREF ≤ 20mA – 6 25 mV Temperature Stability Note 2 Total Output Variation Line, Load, Temperature, Note 2 Output Noise Voltage 10Hz ≤ f ≤ 10kHz, TJ = +25°C, Note 2 Long Term Stability TA = +125°C, 1000Hrs., Note 2 – Output Short Circuit TA = +25°C –30 Initial Accuracy Sawtooth Mode, TJ = +25°C 47 Voltage Stability 12V ≤ VCC ≤ 25V – Temperature Stability Sawtooth Mode, 0° ≤ TA ≤ +70°C, Note 2 Amplitude VPIN4 peak to peak – 0.2 0.4 mV/°C 4.82 – 5.18 V – 50 – µV 5 25 mV –100 –180 mA 52 57 kHz 0.2 1.0 % – 5 – % – 1.7 – V 2.42 2.50 2.58 V – –0.3 –2.0 µA Oscillator Section Error Amp Section Input Voltage VCOMP = 2.5V Input Bias Current VFB = 0V AVOL 2V ≤ VO ≤ 4V 65 90 – dB Unity Gain Bandwidth Note 2 0.7 1.0 – MHz PSRR 12V ≤ VCC ≤ 25V 60 70 – dB Output Sink Current VFB = 2.7V, VCOMP = 1.1V 2 6 – mA Output Source Current VFB = 2.3V, VCOMP = 5V –0.5 –0.8 – mA VOUT High VFB = 2.3V, RL = 15K to GND 5 6 – V VOUT Low VFB = 2.7V, RL = 15K to Pin8 – 0.7 1.1 V Current Sense Section Gain Note 3, Note 4 2.85 3.00 3.15 V/V Maximum Input Signal VCOMP = 5V, Note 3 0.9 1.0 1.1 V PSRR 12V ≤ VCC ≤ 25V, Note 3 – 70 – dB Input Bias Current VSENSE = 0V – –2 –10 µA Delay to Output TJ = +25°C, Note 2 – 150 300 ns ISINK = 20mA – 0.1 0.4 V Output Section Output Low Level ISINK = 200mA Output High Level – 1.5 2.2 V ISOURCE = 20mA 13.0 13.5 – V ISOURCE = 200mA 12.0 13.5 – V Rise Time TJ = +25°C,CL = 1nF, Note 2 – 50 150 ns Fall Time TJ = +25°C,CL = 1nF, Note 2 – 50 150 ns – 0.5 1.0 mA Total Standby Current Start–Up Current Operating Supply Current VFB = VSENSE = 0V, RT = 10K, CT = 3.3nF – 11 17 mA VCC Zener Voltage ICC = 25mA – 34 – V Maximum Duty Cycle 46 48 50 % Minimum Duty Cycle – – 0 % PWM Section Parameter Test Conditions Min Typ Max Unit 14.5 16.0 17.5 V 7.8 8.4 9.0 V 8.5 10.0 11.5 V 7.0 7.6 8.2 V Under–Voltage Lockout Section Start Threshold NTE7098 NTE7099 Minimum Operating Voltage NTE7098 After Turn On NTE7099 Note Note Note Note 1. 2. 3. 4. Adjust VCC above the start threshold before setting at 15V. These parameters, although guaranteed, are not 100% tested in production. Parameter measured at trip point of latch with VFB = 0. Gain defined as: ∆VCOMP ; 0 ≤ VPIN3 ≤ 0.8V A= ∆VSENSE Pin Connection Diagram COMP 1 8 VREF VFB 2 7 VCC ISENSE 3 6 OUTPUT RTCT 4 5 GND 8 5 .260 (6.6) 1 4 .390 (9.9) Max .300 (7.62) .155 (3.93) .100 (2.54) .145 (3.68) .300 (7.62)