UC3844B
Full part number: UC3844BD1013TR
Key datasheet specifications and the closest alternatives, ranked by parametric similarity and grounded in the manufacturer datasheet.
This datasheet covers the UC3842B through UC3845B family of high-performance current-mode PWM controllers. The document details their use in off-line and DC-to-DC fixed-frequency control schemes with minimal external components. Key parameters include a guaranteed 250 kHz oscillator frequency extendable to 500 kHz, an internally trimmed 5V reference, and start-up current under 0.5 mA. These chips feature automatic feed-forward compensation, latching PWM for cycle-by-cycle current limiting, and a totem-pole output stage capable of sourcing or sinking up to 1A peak current to drive N-channel MOSFETs.
Datasheet parameters
| Parameter | Min | Typ | Max | Conditions |
|---|---|---|---|---|
| quiescent current | — | 12 mA | 17 mA | VPIN2 = VPIN3 = 0V |
| output voltage | 4.9 V | 5 V | 5.1 V | Tj = 25°C Io = 1mA |
| output current | 2 mA | 12 mA | — | VPIN2 = 2.7V VPIN1 = 1.1V |
| supply voltage range | 8.5 V | 10 V | 11.5 V | X842B/4B |
| switching frequency | 52 kHz | — | 250 kHz | |
| gain bandwidth | 700 kHz | 1 MHz | — | TJ = 25°C |
| operating temperature | -40 °C | — | 85 °C | |
| power dissipation | — | — | 1.25 W | |
| standby current | — | 300 µA | 500 µA | Vi = 6.5V for UCX843B/45B |
| psrr | 70 dB | — | — | 12V ≤ Vi≤ 25V |
| dropout voltage | — | 1.6 V | — | |
| rise time | — | 50 ns | 150 ns | Tj = 25°C CL = 1nF (2) |
| fall time | — | 50 ns | 150 ns | Tj = 25°C CL = 1nF (2) |
| output noise voltage | — | 50 µV | — | 10Hz ≤ f ≤ 10KHz Tj = 25°C (note 2) |
| zener voltage | 30 V | 36 V | — | Ii = 25mA |
| output count | — | 2 | — |
Closest matches to UC3844B
Frequently asked questions
What is the dropout voltage?
The dropout voltage is 1.6 V.
What is the fall time of the UC3844BD1013TR?
The fall time is 50 ns at Tj = 25°C with CL = 1nF (2).
What is the gain bandwidth of the UC3844BD1013TR?
The gain bandwidth is 1 MHz at TJ = 25°C.
What is the maximum operating temperature for the UC3844BD1013TR?
The operating temperature is 85 °C.
What is the output count for the UC3844BD1013TR?
The output count is 2.
What is the output current when VPIN2 = 2.7V and VPIN1 = 1.1V?
The output current is 12 mA.
What is the output noise voltage specification for the UC3844BD1013TR?
The output noise voltage is 50 µV at 10Hz ≤ f ≤ 10KHz Tj = 25°C (note 2).
What is the output voltage at Tj = 25°C Io = 1mA?
The output voltage is 5 V at Tj = 25°C Io = 1mA.