5962-8768101EA vs UC3825AN vs UC3825N Comparison

DESCRIPTION The UC1825 family of PWM control ICs is optimized for high fre quency switched mode power supply applications. Particular care was given to minimizing propagation delays through the comparators and logic circuitry while maximizing bandwidth and slew rate of the error amplifier. This controller is designed for use in either current-mode or voltage mode systems with the capability for input voltage feed-forward.

The UC3825AN is a high speed Pulse Width Modulation (PWM) Controller, an improved versions of the standard UC3825 family. Performance enhancements have been made to several of the circuit blocks. Error amplifier gain bandwidth product is 12MHz, while input offset voltage is 2mV. Current limit threshold is assured to a tolerance of 5%. Oscillator discharge current is specified at 10mA for accurate dead time control. Frequency accuracy is improved to 6%. Startup supply current, typically 100µA, is ideal for off-line applications. The output drivers are redesigned to actively sink current during UVLO at no expense to the startup current specification. In addition each output is capable of 2A peak currents during transitions. Functional improvements have also been implemented in this family. The UC3825 shutdown comparator is now a high-speed overcurrent comparator with a threshold of 1.2V.

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Compatible with voltage-mode or current-mode control methods

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50ns Propagation delay to output

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High-current dual totem pole outputs (2A peak)

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Trimmed oscillator discharge current

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Pulse-by-pulse current limiting comparator

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Latched overcurrent comparator with full cycle restart

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Green product and no Sb/Br

The UC3825N is a High Speed Pulse Width Modulation (PWM) Controller designed for high frequency switched mode power supply applications. Particular care was given to minimizing propagation delays through the comparators and logic circuitry while maximizing bandwidth and slew rate of the error amplifier. This controller is designed for use in either current-mode or voltage mode systems with the capability for input voltage feed-forward. Protection circuitry includes a current limit comparator with a 1V threshold, a TTL compatible shutdown port and a soft start pin which will double as a maximum duty cycle clamp. The logic is fully latched to provide jitter free operation and prohibit multiple pulses at an output. An under-voltage lockout section with 800mV of hysteresis assures low start up current. During under-voltage lockout, the outputs are high impedance.

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Green product and no Sb/Br

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Compatible with voltage or current mode topologies

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High current dual totem pole outputs

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Wide bandwidth error amplifier

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Fully latched logic with double pulse suppression

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Pulse-by-pulse current limiting

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Soft start/max duty cycle control

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Under-voltage lockout with hysteresis