onsemi High Performance Current Mode Controllers UC3842B, UC3843B, UC2842B, UC2843B Datasheet

Category: Electronics, ON Semiconductor LLC, Other Semiconductors

Summary of onsemi Current Mode Controllers

onsemi introduces the UC3842B, UC3843B, UC2842B, and UC2843B series, which are high-performance, fixed frequency current mode controllers tailored for Off-Line and DC-DC converter applications. These devices are designed to provide a cost-effective solution with minimal external components needed.

Key Features:

The integrated circuits include several features:

Trimmed Oscillator: Ensures precise duty cycle control, with a guaranteed oscillator frequency at 250 kHz.
Current Mode Operation: Allows functioning up to 500 kHz alongside automatic feed-forward compensation.
Latching PWM: This enables cycle-by-cycle current limiting.
Internally Trimmed Reference: Comes with an undervoltage lockout feature.
High Current Totem Pole Output: Ideal for driving power MOSFETs.
Undervoltage Lockout (UVLO): Includes hysteresis, improving the reliability and performance of the system.
Low Startup and Operating Current: Enhances efficiency.
Pb-Free and Halide-Free Device: Signifying compliance with environmental standards.

Additionally, the ICs are equipped with several protective features:

Input and reference undervoltage lockouts each with hysteresis.
Cycle-by-cycle current limiting.
Programmable output deadtime.
A latch for single pulse metering.

Variants and Packaging:

The different variants of the series are differentiated by their undervoltage lockout thresholds, the UCX842B being ideal for off-line converters with UVLO thresholds of 16 V (on) and 10 V (off). The UCX843B, on the other hand, is suited for lower voltage applications with UVLO thresholds of 8.5 V (on) and 7.6 V (off).

The controllers are offered in multiple package options:

8-pin dual-in-line plastic package (PDIP-8).
8-pin and 14-pin plastic surface mount packages (SOIC-8 and SOIC-14 respectively); the SOIC-14 features separate power and ground pins for the output stage.

The document also includes the pin connection diagrams corresponding to each package type, outlining the specific roles of each pin, and the simplified block diagram provides a high-level view of the internal components of the controllers.

Further details on ordering information and device marking are available on pages 17 and 19 respectively of the full datasheet.