MC34060A

The control signals are external inputs that can be fed into the deadtime control, the error amplifier inputs, or the
feedback input. The deadtime control comparator has an effective 120 mV input offset which limits the minimum output dead time to approximately the first 4% of the sawtoothcycle time. This would result in a maximum duty cycle of 96%. Additional dead time may be imposed on the output by setting the dead timecontrol input to a fixed voltage, ranging between 0 V to 3.3 V.

The pulse width modulator comparator provides a means for the error amplifiers to adjust the output pulse width from
the maximum percent ontime, established by the dead time control input, down to zero, as the voltage at the feedback pin varies from 0.5 V to 3.5 V. Both error amplifiers have a common mode input range from 0.3 V to (V_CC 2.0 V), and may be used to sense power supply output voltage and current. The erroramplifier outputs are active high and are ORed together at the noninverting input of the pulsewidth modulator comparator. With this configuration, the amplifier that demands minimum output on time, dominates control of the loop.

The MC34060A has an internal 5.0 V reference capable of sourcing up to 10 mA of load currents for external bias circuits. The reference has an internal accuracy of ±5% with a typical thermal drift of less than 50 mV over an operating temperature range of 0° to +70.

The MC34060A is a low cost fixed frequency, pulse width modulation control circuit designed primarily for singleended SWITCHMODE power supply control.

The MC34060A is specified over the commercial operating temperature range of 0° to +70 , and the MC33060A is specified over an automotive temperature range of 40° to +85 .