UC2845B
Key datasheet specifications and the closest alternatives, ranked by parametric similarity and grounded in the manufacturer datasheet.
This ST datasheet covers the UC284xB and UC384xB family of high-performance current mode PWM controllers. Designed for off-line or DC-to-DC fixed frequency control, it features a trimmed oscillator guaranteed at 250kHz with operation up to 500kHz. Key parameters include a 1.8V to 36V supply range, 1A peak output current, and an internally trimmed 5V reference with under-voltage lockout. The device offers automatic feed-forward compensation and latching PWM for cycle-by-cycle current limiting.
Datasheet parameters
| Parameter | Min | Typ | Max | Conditions |
|---|---|---|---|---|
| quiescent current | — | 12 mA | 17 mA | VPIN2 = VPIN3 = 0V |
| output voltage | 4.95 V | 5 V | 5.05 V | Tj = 25°C Io = 1mA |
| output current | 2 mA | 12 mA | — | VPIN2 = 2.7V VPIN1 = 1.1V |
| supply voltage range | 2.45 V | 2.5 V | 2.55 V | VPIN1 = 2.5V |
| switching frequency | 52 kHz | — | 250 kHz | |
| gain bandwidth | 700 kHz | 1 MHz | — | TJ = 25°C |
| operating temperature | -40 °C | — | 150 °C | |
| power dissipation | — | — | 1.25 W | |
| standby current | — | 300 µA | 500 µA | Vi = 6.5V for UCX843B/45B |
| psrr | 60 dB | 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 | — | 1 | — |
Closest matches to UC2845B
Frequently asked questions
What is the dropout voltage of the UC2845B?
The dropout voltage is 1.6 V.
What is the fall time of the UC2845B at Tj = 25°C with CL = 1nF (2)?
The fall time is 50 ns.
What is the gain bandwidth of the UC2845B at TJ = 25°C?
The gain bandwidth is 1 MHz at TJ = 25°C.
What is the maximum operating temperature for the UC2845B?
The operating temperature is 150 °C.
What is the output count for the UC2845B?
The output count is 1.
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 for the UC2845B?
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.