UC3846 STMicroelectronics Integrated Circuit (Dual-In-Line Packages) In Stock
The STMicroelectronics UC3846 is a current-mode PWM switching controller capable of driving outputs up to 0.5 A at switching frequencies up to 500 kHz, housed in a DIP package. It integrates cycle-by-cycle current limiting and slope compensation, making it a robust solution for push-pull, half-bridge, and full-bridge SMPS topologies.
- Manufacturer
- STMicroelectronics
- Package
- Dual-In-Line Packages
- Pin Count
- 16
- Lifecycle
- OBSOLETE
- Datasheet
- UC3846 Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- Up to 500 kHz maximum switching frequency enables compact transformer and filter designs in high-frequency SMPS
- 0.5 A peak output drive current directly drives power MOSFET gates in push-pull and bridge converter stages
- Current-mode control with slope compensation provides inherent cycle-by-cycle over-current protection and excellent line regulation
- Dual complementary PWM outputs for push-pull and bridge converter topologies without external logic
- Integrated soft-start and shutdown control reduce component count in the controller stage of industrial power supplies
Applications
The UC3846 is used in push-pull, half-bridge, and full-bridge DC-DC converter designs for industrial power supplies, UPS systems, and telecommunications power modules operating at switching frequencies up to 500 kHz. Its current-mode control architecture provides cycle-by-cycle over-current limiting, which is critical for protecting the power stage during output short-circuit conditions in 48 V to 400 V input bus converters. The DIP package and dual complementary PWM output structure make the UC3846 a straightforward drop-in controller for existing transformer-coupled converter designs requiring high-frequency operation.
Specifications
| YTEOL | 0 |
| Package | Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| HTS Code | 8542.39.00.01 |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for UC3846:
Switching Controller, Current-mode, 0.5A, 500kHz Switching Freq-Max, BICMOS, PDIP16
Frequently Asked Questions
What switching frequency range does the UC3846 support, and how does this compare to lower-frequency PWM controllers?
The UC3846 supports switching frequencies up to 500 kHz, compared to the 200 kHz limit of older controllers such as the UC3842. Operating at 500 kHz allows transformer core size to be reduced by roughly 60% compared to a 100 kHz design for the same power level, directly reducing the overall power supply volume and weight in DC-DC converters used in telecom and industrial equipment.
Which converter topologies are best served by the UC3846's dual complementary PWM outputs?
The UC3846 is optimized for push-pull, half-bridge, and full-bridge transformer-coupled DC-DC converter topologies, where two alternating gate drive signals are required to drive pairs of power MOSFETs or bipolar transistors. Each output can sink and source up to 0.5 A of peak current, sufficient to directly drive low-gate-charge MOSFETs rated for 200 V to 400 V in a 500 W push-pull converter without additional gate driver ICs.
How does current-mode control in the UC3846 protect the power stage during a load short circuit?
In current-mode control, the UC3846 monitors the switch current every switching cycle and immediately truncates the PWM pulse width when the sensed current exceeds the programmed peak limit. This cycle-by-cycle response limits the peak energy delivered to the transformer and power switch to a single switching period (as short as 2 µs at 500 kHz), preventing thermal runaway of the output rectifiers and primary switches during a short-circuit event faster than any fault detection loop could respond.
For a designer transitioning from the UC2846 to the UC3846, what is the key difference between these two parts?
The UC3846 is the commercial temperature grade version operating from 0°C to 70°C, while the UC2846 is rated for the industrial temperature range of -40°C to +85°C. Both share the same 0.5 A peak output current, 500 kHz maximum frequency, and current-mode PWM architecture with dual complementary outputs. A designer moving from an industrial to a commercial-grade design can substitute the UC3846 directly with no circuit changes, reducing component cost while maintaining identical electrical performance.
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About STMicroelectronics
STMicroelectronics is a global semiconductor leader serving customers across the spectrum of electronics applications. ST's products are found in a wide range of applications including automotive, industrial, personal electronics, and communications.
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