The UCCx8C5x series of control integrated circuits provide the features necessary to implement AC-DC or DC‑to-DC fixed-frequency current-mode control schemes with a minimum number of external components. Protection circuitry includes undervoltage lockout (UVLO) and current limiting. Internally implemented circuits include a start-up current of less than 75 µA, a precision reference trimmed for accuracy at the error amplifier input, logic to ensure latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and an output stage designed to source or sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in the OFF state. The oscillator contains a trimmed discharge current that enables accurate programming of the maximum duty cycle and dead time limit, making this device suitable for high-speed applications.

Major differences between members of this series are the UVLO thresholds, acceptable ambient temperature range, maximum duty cycle and frequency. Typical UVLO thresholds of 14.5 V (ON) and 9 V (OFF) on the UCCx8C52 and UCCx8C54 devices make them ideally suited to off-line AC-DC applications. The corresponding typical thresholds for the UCCx8C53 and UCCx8C55 devices are 8.4 V (ON) and 7.6 V (OFF), making them ideal for use with regulated input voltages used in DC-DC applications. The UCCx8C50 and UCCx8C51 feature a start-up threshold of 7 V and a turnoff threshold of 6.6 V (OFF), which makes them suitable for battery-powered applications. The UCC28C56H/L, UCC28C57H/L, UCC28C58 and UCC28C59 can operate with higher UVLO thresholds to reliably drive SiC MOSFETs in high-voltage applications. The UCC28C56H and UCC28C57H operate with start threshold of 18.8 V (ON) and stop threshold of 15.5 V (OFF). The UCC28C56L and UCC28C57L operate with start threshold of 18.8V (ON) and stop threshold of 14.5 V (OFF). The UCC28C58 and UCC28C59 operate with start threshold of 16 V (ON) and stop threshold of 12.5 V (OFF). The UCCx8C50, UCCx8C52, UCCx8C53, UCC28C56H/L and UCC28C58 devices can operate with duty cycles approaching 100%. The UCCx8C51, UCCx8C54, UCCx8C55, UCC28C57H/L and UCC28C59 devices can operate from 0% to 50% duty cycle, by the addition of an internal toggle flip-flop, which blanks the output off every other clock cycle. The UCC28C5x series is specified for operation from –40°C to 125°C, and the UCC38C5x series is specified for operation from 0°C to 85°C. The switching frequency (fSW) of the UCCx8C50, UCCx8C52, UCCx8C53, UCC28C56H/L and UCC28C58 gate drive is equal to f_OSC; the switching frequency of the UCCx8C51, UCCx8C54, UCCx8C55, UCC28C57H/L and UCC28C59 is equal to half of the f_OSC.

The UCC28C5x and UCC38C5x series devices are drop-in replacement for BiCMOS UCCx8C4x family and pin-to-pin compatibile with the bipolar UC284x, UC384x, UC284xA, and UC384xA families. The new series offers improved performance when compared to older bipolar devices and other competitive BiCMOS devices with similar functionality. These improvements generally consist of tighter specification limits that are a subset of the older product ratings. In new designs, these improvements can reduce the component count or enhance circuit performance when compared to theolder generation devices.