UC3851N

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Texas Instruments

PROGRAMMABLE OFF-LINE PWM CONTROLLER

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DocumentsProgrammable, Off-Line, PWM Controller datasheet Datasheet

UC3851N

Active

Texas Instruments

PROGRAMMABLE OFF-LINE PWM CONTROLLER

Deep-Dive with AI

DocumentsProgrammable, Off-Line, PWM Controller datasheet Datasheet

Specifications Pricing Series Description Documents

Technical Specifications

Parameters and characteristics for this part

Specification	UC3851N

Control Features	Soft Start, Frequency Control
Duty Cycle	50 %
Fault Protection	Over Voltage, Current Limiting
Internal Switch(s)	False
Mounting Type	Through Hole
Operating Temperature [Max]	70 °C
Operating Temperature [Min]	0 °C
Package / Case	18-DIP
Package / Case [x]	0.3 in
Package / Case [x]	7.62 mm
Supplier Device Package	18-PDIP
Topology	Flyback, Boost, Forward, Buck
Voltage - Start Up	8 V
Voltage - Supply (Vcc/Vdd) [Max]	32 V
Voltage - Supply (Vcc/Vdd) [Min]	7.8 V

UC3851 Series

Programmable off-line PWM controller

Part	Duty Cycle	Supplier Device Package	Mounting Type	Operating Temperature [Max]	Operating Temperature [Min]	Control Features	Internal Switch(s)	Package / Case	Package / Case [x]	Package / Case [x]	Voltage - Supply (Vcc/Vdd) [Max]	Voltage - Supply (Vcc/Vdd) [Min]	Fault Protection	Topology	Voltage - Start Up	Package / Case [y]	Package / Case [y]
Texas Instruments UC3851N	50 %	18-PDIP	Through Hole	70 °C	0 °C	Frequency Control Soft Start		18-DIP	0.3 in	7.62 mm	32 V	7.8 V	Current Limiting Over Voltage	Boost Buck Flyback Forward	8 V
Texas Instruments UC3851DWTR	50 %	18-SOIC	Surface Mount	70 °C	0 °C	Frequency Control Soft Start		18-SOIC			32 V	7.8 V	Current Limiting Over Voltage	Boost Buck Flyback Forward	8 V	0.295 in	7.5 mm

Pricing

Prices provided here are for design reference only. For realtime values and availability, please visit the distributors directly

Distributor	Package	Quantity	$

Digikey	Tube	60	$ 19.85
Texas Instruments	TUBE	1	$ 21.96
		100	$ 19.18
		250	$ 14.79
		1000	$ 13.23

Description

General part information

UC3851 Series

The UC1851 family of PWM controllers are optimized for off-line primary side control. These devices include a high current totem pole output stage and a toggle flip-flop for absolute 50% duty cycle limiting. In all other respects this line of controllers is pin for pin compatible with the UC1841 series. Inclusion of all major housekeeping functions in these high performance controllers makes them ideal for use in cost sensitive applications.

Important features of these controllers include low current start-up, linear feed-forward for constant volt-second operation, and compatibility with both voltage or current mode control. In addition, these devices include a programmable start threshold, as well as programmable over-voltage, under-voltage, and over current fault thresholds. The fault latch on these devices can be configured for automatic restart, or latched off response to a fault.

These devices are packaged in 18-pin plastic or ceramic dual-in-line packages, or for surface mount applications, a 20 Pin PLCC. The UC1851 is characterized for -55°C to +125°C operation while the UC2851 and UC3851 are designed for -40°C to +85°C and 0°C to +70°C, respectively.