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TC18C43 TC28C43 TC38C43 BiCMOS CURRENT MODE PWM CONTROLLERS
FEATURES
s s s s s s s s s s s s s s Low Power BiCMOS Design Tough CMOSTM Construction Low Supply Current ............. 1.0mA Typ @ 100kHz Wide Supply Voltage Operation .............. 8V to 15V Latch-Up Immunity ................... 500mA on Outputs Input Will Withstand Negative Inputs to – 5 Volts High Output Drive .................................... 0.7A Peak (1.2A on 14-Pin and 16-Pin Versions) 2 kV ESD Protection Current Mode Control Fast Rise/Fall Time (Max) ........... 60nsec @ 1000pF High Frequency Operation ..........................500kHz Clock Ramp Reset Current ................. 2.5mA ±10% Low Propagation Delay Current Amp to Output ............................................ 140nsec Typ. Pin Compatible with UC3843
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GENERAL DESCRIPTION
The TC38C43 is a current mode BiCMOS PWM control IC. With a low 1.0 mA supply current along with high drive current (0.7A peak) it provides a low cost solution for a PWM that operates to 500 kHz and directly drives MOSFETs up to HEX 3 size. Performance of the oscillator and current sense amplifier have been greatly improved over previous bipolar versions. Voltage and temperature stability have been improved by a factor of 3. Noise immunity (PSRR) has also been improved. The TC38C43 is pin compatible with the earlier bipolar version so that designers can easily update older designs. Improvements have been added, though. For example, clock ramp reset current is specified at 2.5mA (±10%) for accurate dead time control. A few component values must be changed (RT & CT) to use the TC38C43 in existing bipolar designs. The 14-pin DIP and 16-pin SOIC versions have separate and internally isolated grounds, and are rated for higher output current (1.2A). These separate grounds allow for ‘bootstrap’ operation of the PWM to further improve efficiency. FUNCTIONAL BLOCK DIAGRAM
2 3 4 5 6 7
PIN NUMBERS FOR 14-PIN DIP
ORDERING INFORMATION
Part No. TC18C43MJA TC18C43MJD TC28C43EOE TC28C43EPA TC28C43EPD TC38C43COE TC38C43CPA TC38C43CPD Package 8-Pin CerDIP 14-Pin CerDIP Temperature – 55°C to +125°C – 55°C to +125°C
16-Pin SOIC (Wide) – 40°C to +85°C 8-Pin Plastic DIP – 40°C to +85°C 14-Pin Plastic DIP – 40°C to +85°C 16-Pin SOIC (Wide) 8-Pin Plastic DIP 14-Pin Plastic DIP 0°C to +70°C 0°C to +70°C 0°C to +70°C
VIN 12 VREF 2.5V 1.4V
VREF 14
RT/CT 7 OSC CLK 11 10 VDD OUTPUT POWER GROUND
PIN CONFIGURATIONS 8-Pin Plastic DIP
CMPTR VFB ISENSE RT / CT 1 2 3 4 8 VREF VIN OUTPUT GND 7 6 5
16-Pin SOIC (Wide)
NC NC CMPTR VFB ISENSE RT / CT 1 2 3 4 5 6 7 8 16 15 14 13 NC VREF VIN VDD OUTPUT GND POWER GND NC
UNDER VOLTAGE SECTION ANALOG GND 9
UV GOOD
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TC18CMJA TC28CEPA TC38CCPA
0.4V SENSE 5 – +
PWM COMPARATOR + S Q – CLK R
TC28CCOE TC38CEOE
12 11 10 9
14-Pin Plastic DIP
CMPTR NC VFB NC ISENSE NC RT / CT 1 2 3 4 5 6 7 14 VREF 13 NC 12 VIN
NC NC
ERROR AMP 2.5V VFB COMP 1 R 3 + – 2R
LIMIT BUFFER + – 1.4V
TC18CMJD TC28CEPD TC38CCPD
11 VDD 10 OUTPUT 9 8 .