Low Power Current Mode Push-Pull PWM
• 130µA Typical Starting
• 1mA Typical Run Current
• Operation to 1MHz
• Internal Soft Start
• On Chip Error Amplifier With
2MHz Gain Bandwidth Product
• On Chip VDD Clamping
• Dual Output Drive Stages In
• Output Drive Stages Capable
Of 500mA Peak Source
Current, 1A Peak Sink Current
The UCC3808 is a family of BiCMOS push-pull, high-speed, low power, pulse
width modulators. The UCC3808 contains all of the control and drive circuitry re-
quired for off-line or DC-to-DC fixed frequency current-mode switching power
supplies with minimal external parts count.
The UCC3808 dual output drive stages are arranged in a push-pull configura-
tion. Both outputs switch at half the oscillator frequency using a toggle flip-flop.
The dead time between the two outputs is typically 60ns to 200ns depending on
the values of the timing capacitor and resistors, thus limits each output stage
duty cycle to less than 50%.
The UCC3808 family offers a variety of package options temperature range op-
tions, and choice of undervoltage lockout levels. The family has UVLO thresh-
olds and hysteresis options for off-line and battery powered systems.
Thresholds are shown in the table below.
Turn on Threshold
Turn off Threshold