MIC38HC42/3/4/5 Micrel MIC38HC42/3/4/5 BiCMOS 1A Current-Mode PWM Controllers General Description Features The MIC38HC4x family are fixed frequency current-mode PWM controllers with 1A drive current capability. Micrel’s BiCMOS devices are pin-compatible with 384x bipolar devices. Their high output drive, with fast rise and fall times, combined with low startup current make it an ideal PWM controller where high efficiency is required. Undervoltage lockout circuitry allows the ’42 and ’44 versions to start up at 14.5V and operate down to 9V, and the ’43 and ’45 versions start at 8.4V with operation down to 7.6V. All versions operate up to 20V. When compared to bipolar UC384x devices operating from a 15V supply, start-up current has been reduced to 50µA typical and operating current has been reduced to 4.0 mA typical. Decreased output rise and fall times drive larger MOSFETs, and rail-to-rail output capability increases efficiency, especially at lower supply voltages. The MIC38HC4x also features a trimmed oscillator discharge current and bandgap reference. MIC38HC4x-1 is available in 14-pin plastic DIP and SOIC packages. 8-pin devices feature small size, while 14-pin devices separate the analog and power connections for improved performance and power dissipation. • Fast 20ns output rise and 15ns output fall times • –40°C to +85°C temperature range exceeds UC284x specifications • High-performance, low-power BiCMOS Process • Ultralow start-up current (50µA typical) • Low operating current (4mA typical) • High output drive (1A peak current, HC version) • CMOS outputs with rail-to-rail swing • Current-mode operation up to 500kHz • Trimmed 5V bandgap reference • Pin-for-pin compatible with UC3842/3843/3844/3845(A) • Trimmed oscillator discharge current • UVLO with hysteresis • Low cross-conduction currents Applications • • • • • • • Current-mode, off-line, switched-mode power supplies Current-mode, dc-to-dc converters. Step-down “buck” regulators Step-up “boost” regulators Flyback, isolated regulators Forward converters Synchronous FET converters Functional Diagram * VDD 7 (12) 35V 5V Reference VREF 8 (14) UVLO (VD) (11) † Oscillator RT/CT OUT 4 (7) 6 (10) FB T Q S R Q 2R 2 (3) 2.5V R ‡ (PGND) (8) * COMP 1 (1) GND*(AGND) 5 (9) ISNS 3 (5) ( ) pins are on MIC38HC4x-1 (14-lead) versions only * MIC38HC4x (8-lead) versions only † MIC38HC42, MIC38HC43 (96% max. duty cycle) versions only ‡ MIC38HC44, MIC38HC45 (50% max. duty cycle) versions only Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com August 2000 1 MIC38HC42/3/4/5 MIC38HC42/3/4/5 Micrel Ordering Information Part Number Temperature Range Package MIC38HC42BN –40°C to +85°C 8-pin Plastic DIP MIC38HC43BN –40°C to +85°C 8-pin Plastic DIP MIC38HC44BN –40°C to +85°C 8-pin Plastic DIP MIC38HC45BN –40°C to +85°C 8-pin Plastic DIP MIC38HC42-1BN –40°C to +85°C 14-pin Plastic DIP MIC38HC43-1BN –40°C to +85°C 14-pin Plastic DIP MIC38HC44-1BN –40°C to +85°C 14-pin Plastic DIP MIC38HC45-1BN –40°C to +85°C 14-pin Plastic DIP MIC38HC42BM –40°C to +85°C 8-pin SOIC MIC38HC43BM –40°C to +85°C 8-pin SOIC MIC38HC44BM –40°C to +85°C 8-pin SOIC MIC38HC45BM –40°C to +85°C 8-pin SOIC MIC38HC42-1BM –40°C to +85°C 14-pin SOIC MIC38HC43-1BM –40°C to +85°C 14-pin SOIC MIC38HC44-1BM –40°C to +85°C 14-pin SOIC MIC38HC45-1BM –40°C to +85°C 14-pin SOIC Selection Guide UVLO Thresholds MIC38HC42/3/4/5 Duty Cycle Startup 8.4V Minimum Operating 7.6V Startup 14.5V Minimum Operating 9V 0% to 96% MIC38HC43 MIC38HC42 0% to 50% MIC38HC45 MIC38HC44 2 August 2000 MIC38HC42/3/4/5 Micrel Pin Configuration MIC38HC4x-1 COMP 1 MIC38HC4x 14 VREF NC 2 13 NC FB 3 12 VDD NC 4 11 VD COMP 1 8 VREF FB 2 7 VDD NC 6 9 AGND ISNS 3 6 OUT RT/CT 7 8 PGND RT/CT 4 5 GND ISNS 5 8-Pin DIP (N) 8-Lead SOIC (M) 10 OUT 14-Pin DIP (-1BN) 14-Lead SOIC (-1BM) Pin Description Pin Number N, M, MM Pin Number -1BN, -1BM Pin Name 1 1 COMP 2 NC Not internally connected. 3 FB Feedback (Input): Error amplifier input. Feedback is 2.5V at desired output voltage. 4 NC Not internally connected. 5 ISNS 6 NC 7 RT/CT 2 3 4 5 6 7 8 August 2000 GND Pin Function Compensation: Connect external compensation network to modify the error amplifier output. Current Sense (Input): Current sense comparator input. Connect to current sensing resistor or current transformer. Not internally connected. Timing Resistor/Timing Capacitor: Connect external RC network to select switching frequency. Ground: Combined analog and power ground. 8 PGND Power Ground: N-channel driver transistor ground. 9 AGND Analog Ground: Controller circuitry ground. 10 OUT 11 VD Power Supply (Input): P-channel driver transistor supply input. Return to power ground (PGND). 12 VDD Analog Supply (Input): Controller circuitry supply input. Return to analog ground (AGND). 13 NC 14 VREF Power Output: Totem-pole output. Not internally connected. 5V Reference (Output): Connect external RC network. 3 MIC38HC42/3/4/5 MIC38HC42/3/4/5 Micrel Absolute Maximum Ratings Zener Current (VDD) ................................................... 30mA Operation at ≥18V may require special precautions (Note 6). Supply Voltage (VDD), Note 6 ....................................... 20V Switch Supply Voltage (VD) .......................................... 20V Current Sense Voltage (VISNS) ..................... –0.3V to 5.5V Feedback Voltage (VFB) ................................ –0.3V to 5.5V Output Current, 38HC42/3/4/5 (IOUT) .............................. 1A Operating Junction Temperature (TJ) ....................... 150°C Package Thermal Resistance 8-Pin Plastic DIP (θJA) ....................................... 125°C/W 8-Pin MM8™ (θJA) ............................................. 250°C/W 8-Pin SOIC (θJA) ...............................................170°C/W 14-Pin Plastic DIP (θJA) ....................................... 90°C/W 14-Pin SOIC (θJA) ............................................. 145°C/W Storage Temperature (TA) ....................... –65°C to +150°C Electrical Characteristics VDD = 15V, Note 4; RT = 9.09kΩ; CT = 3.3nF; –40°C ≤ TA ≤ 85°C; unless noted Parameter Test Conditions Min Typ Max Units Output Voltage TA = 25°C, IO = 1mA 4.90 5.00 5.10 V Line Regulation 12V ≤ VDD ≤ 18V, IO = 5µA, Note 6 2 20 mV Load Regulation 1 ≤ IO ≤ 20mA 1 25 mV Temp. Stability Note 1 Total Output Variation Line, Load, Temp., Note 1 Output Noise Voltage 10Hz ≤ f ≤ 10kHz, TA = 25°C, Note 1 50 Long Term Stability TA = 125°C, 1000 hrs., Note 1 5 25 mV –30 –80 –180 mA 49 52 55 kHz 1.0 % Reference Section 0.2 4.82 Output Short Circuit mV/°C 5.18 V µV Oscillator Section Initial Accuracy TA = 25°C, Note 5 Voltage Stability 12 ≤ VDD ≤ 18V, Note 6 0.2 Temp. Stability TMIN ≤ TA ≤ TMAX, Note 1 0.04 Clock Ramp Reset Current TA = 25°C, VRT/CT = 2V TA = TMIN to TMAX Amplitude VRT/CT peak to peak 7.7 7.2 8.4 8.4 %/°C 9.0 9.5 1.9 mA mA Vp-p Error Amp Section Input Voltage VCOMP = 2.5V Input Bias Current VFB = 5.0V AVOL 2 ≤ VO ≤ 4V 65 90 dB Unity Gain Bandwidth Note 1 0.7 1.0 MHz PSRR 12 ≤ VDD ≤ 18V 60 Output Sink Current VFB = 2.7V, VCOMP = 1.1V 2 14 mA Output Source Current VFB = 2.3V, VCOMP = 5V –0.5 –1 mA VOUT High VFB = 2.3V, RL = 15k to ground 5 6.8 V VOUT Low VFB = 2.7V, RL = 15k to VREF MIC38HC42/3/4/5 2.42 2.50 2.58 V –0.1 –2 µA dB 0.1 4 1.1 V August 2000 MIC38HC42/3/4/5 Parameter Micrel Test Conditions Min Typ Max Units Gain Notes 2, 3 2.85 3.0 3.15 V/V MaximumThreshold VCOMP = 5V, Note 2 0.9 1 1.1 V PSRR 12 ≤ VDD ≤ 18V, Note 2 Current Sense 70 dB Input Bias Current –0.1 –2 µA Delay to Output 120 250 ns Output Ω Ω RDS(ON) ‘HC’ High RDS(ON) ‘HC’ Low ISOURCE = 200mA ISINK = 200mA 10 5.5 Rise Time TA = 25°C, CL = 1nF 20 50 ns Fall Time TA = 25°C, CL = 1nF 15 40 ns Undervoltage Lockout Start Threshold Minimum Operating Voltage MIC38HC42/4 13.5 14.5 15.5 V MIC38HC43/5 7.8 8.4 9.0 V MIC38HC42/4 8 9 10 V MIC38HC43/5 7.0 7.6 8.2 V MIC38HC42/3 94 96 % MIC38HC44/5 46 50 % Pulse Width Modulator Maximum Duty Cycle Minimum Duty Cycle 0 % 50 200 µA 4.0 6.0 mA Total Standby Current Start-Up Current VDD = 13V, 38HC42/44 VDD = 7.5V, 38HC43/45 Operating Supply Current VFB = VISNS = 0V Zener Voltage (VDD) IDD = 25mA, Note 6 30 37 V Note 1: These parameters, although guaranteed, are not 100% tested in production. Note 2: Parameter measured at trip point of latch with VEA = 0. Note 3: Gain defined as: A = ∆ VPIN1 ; 0 ≤ VTH (ISNS ) ≤ 0.8V VTH (ISNS ) Note 4: Adjust VDD above the start threshold before setting at 15V. Note 5: Output frequency equals oscillator frequency for the MIC38HC42 and MIC38HC43. Output frequency for the MIC38HC44, and MIC38HC45 equals one half the oscillator frequency. Note 6: On 8-pin version, 20V is maximum input on pin 7, as this is also the supply pin for the output stage. On 14-pin version, 40V is maximum for pin 12 and 20V maximum for pin 11. August 2000 5 MIC38HC42/3/4/5 MIC38HC42/3/4/5 Micrel MIC38C/HC42/43 Output Dead Time vs. Oscillator Frequency 100 200pF 470pF 1nF 1.8nF 10 4.7nF 10nF OUTPUT DEAD TIME (%) RT RESISTANCE (kΩ) 100 VDD = 15V 1.2 1.0 125°C 0.8 0.6 25°C 0.4 -50°C 0 2 4 6 8 ERROR AMPLIFIER OUTPUT (V) MIC38HC42/3/4/5 10 200pF 10nF 470pF 1nF 1 1x104 VREF SHORT CURCUIT CURRENT (mA) CURRENT SENSE AMP THRESHOLD (V) Current Sense Amplifier vs. Error Amplifier Output 0.0 4.7nF 18nF 1 1x105 1x106 1x104 OSCILLATOR FREQUENCY (Hz) 0.2 VDD = 15V 1x105 FREQUENCY (Hz) 1x106 Oscillator Discharge Current vs. Temperature 9.0 8.8 8.6 8.4 8.2 8.0 7.8 7.6 7.2 7.0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) MIC38C4x Output Waveform 120 25 100 80 60 40 20 VDD = 15V VOSC = 2V 7.4 Short-Circuit Reference Current vs. Temperature VDD = 15V 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 6 OUTPUT VOLTAGE (V) Oscillator Frequency Configuration OSC. DISCHARGE CURRENT (mA) Typical Characteristics 20 15 10 5 0 -5 -10 -15 0.0 VD = 15V CL = 1nF 0.2 0.4 0.6 TIME (µs) 0.8 1.0 August 2000 MIC38HC42/3/4/5 Micrel Package Information PIN 1 DIMENSIONS: INCH (MM) 0.380 (9.65) 0.370 (9.40) 0.255 (6.48) 0.245 (6.22) 0.135 (3.43) 0.125 (3.18) 0.300 (7.62) 0.013 (0.330) 0.010 (0.254) 0.018 (0.57) 0.380 (9.65) 0.320 (8.13) 0.130 (3.30) 0.100 (2.54) 0.0375 (0.952) 8-Pin Plastic DIP (N) .770 (19.558) MAX PIN 1 .235 (5.969) .215 (5.461) .060 (1.524) .045 (1.143) .310 (7.874) .280 (7.112) .160 MAX (4.064) .080 (1.524) .015 (0.381) .015 (0.381) .008 (0.2032) .160 (4.064) .100 (2.540) .110 (2.794) .090 (2.296) .023 (.5842) .015 (.3810) .060 (1.524) .045 (1.143) .400 (10.180) .330 (8.362) 14-Pin Plastic DIP (N) August 2000 7 MIC38HC42/3/4/5 MIC38HC42/3/4/5 Micrel 0.026 (0.65) MAX) PIN 1 0.157 (3.99) 0.150 (3.81) DIMENSIONS: INCHES (MM) 0.020 (0.51) 0.013 (0.33) 0.050 (1.27) TYP 0.064 (1.63) 0.045 (1.14) 45° 0.0098 (0.249) 0.0040 (0.102) 0°–8° 0.197 (5.0) 0.189 (4.8) SEATING PLANE 0.010 (0.25) 0.007 (0.18) 0.050 (1.27) 0.016 (0.40) 0.244 (6.20) 0.228 (5.79) 8-Pin SOIC (M) PIN 1 DIMENSIONS: INCHES (MM) 0.154 (3.90) 0.026 (0.65) MAX) 0.193 (4.90) 0.050 (1.27) 0.016 (0.40) TYP TYP 45° 0.006 (0.15) 0.057 (1.45) 0.049 (1.25) 0.344 (8.75) 0.337 (8.55) 3°–6° 0.244 (6.20) 0.228 (5.80) SEATING PLANE 14-Pin SOIC (M) MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2000 Micrel Incorporated MIC38HC42/3/4/5 8 August 2000