Product overview

Description

The UC284xB family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include a trimmed oscillator for precise DUTY CYCLE CONTROL under voltage lockout featuring start-up current less than 0.5mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N-Channel MOSFETs, is low in the off-state.

Differences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges. The UC2842B and UC2844B have UVLO thresholds of 16V (on) and 10V (off), ideally suited off-line applications The corresponding thresholds for the UC2843B and UC2845B are 8.5V and 7.9V. The UC2842B and UC2843B can operate to duty cycles approaching 100%. A range of the zero to < 50 % is obtained by the UC2844B and UC2845B by the addition of an internal toggle flip flop which blanks the output off every other clock cycle.

  • All features

    • LOW START-UP AND OPERATING CURRENT
    • UNDERVOLTAGE LOCKOUT WITH HYSTERESIS
    • INTERNALLY TRIMMED REFERENCE WITH UNDERVOLTAGE LOCKOUT
    • CURRENT LIMITING
    • TRIMMED OSCILLATOR FOR PRECISE FREQUENCY CONTROL
    • CURRENT MODE OPERATION TO 500kHz
    • OSCILLATOR FREQUENCY GUARANTEED AT 250kHz
    • LATCHING PWM FOR CYCLE-BY-CYCLE
    • HIGH CURRENT TOTEM POLE OUTPUT
    • AUTOMATIC FEED FORWARD COMPENSATION

Circuit Diagram

EDA Symbols, Footprints and 3D Models

STMicroelectronics - UC3844B

Speed up your design by downloading all the EDA symbols, footprints and 3D models for your application. You have access to a large number of CAD formats to fit with your design toolchain.

Please select one model supplier :

Symbols

Symbols

Footprints

Footprints

3D model

3D models

Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
UC3844BD1
Active
SO-8 Industrial Ecopack2
UC3844BD1013TR
Active
SO-8 Industrial Ecopack2
UC3844BN
Active
DIP-8 Industrial Ecopack2

UC3844BD1

Package:

SO-8

Material Declaration**:

Marketing Status

Active

Package

SO-8

Grade

Industrial

RoHS Compliance Grade

Ecopack2

UC3844BD1013TR

Package:

SO-8

Material Declaration**:

Marketing Status

Active

Package

SO-8

Grade

Industrial

RoHS Compliance Grade

Ecopack2

UC3844BN

Package:

DIP-8

Material Declaration**:

PDF XML

Marketing Status

Active

Package

DIP-8

Grade

Industrial

RoHS Compliance Grade

Ecopack2

(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.

Sample & Buy

Swipe or click the button to explore more details Don't show this again
Part Number
Marketing Status
Budgetary Price (US$)*/Qty
Order from ST
Order from distributors
Package
Packing Type
RoHS
Country of Origin
ECCN (US)
ECCN (EU)
UC3844BD1
Available at distributors

Distributor availability of UC3844BD1

Distributor Name
Region Stock Min. Order Third party link

Distributor reported inventory date:

No availability of distributors reported, please contact our sales office
UC3844BD1013TR
Available at distributors

Distributor availability of UC3844BD1013TR

Distributor Name
Region Stock Min. Order Third party link

Distributor reported inventory date:

No availability of distributors reported, please contact our sales office
UC3844BN
Available at distributors

Distributor availability of UC3844BN

Distributor Name
Region Stock Min. Order Third party link

Distributor reported inventory date:

No availability of distributors reported, please contact our sales office

UC3844BD1 Active

Budgetary Price (US$)*/Qty:
-
Package:
Packing Type:
RoHS:
Country of Origin:
ECCN (US):
ECCN (EU):

Part Number:

UC3844BD1

Distributor Name

Distributor reported inventory date:

UC3844BD1013TR Active

Budgetary Price (US$)*/Qty:
-
Package:
Packing Type:
RoHS:
Country of Origin:
ECCN (US):
ECCN (EU):

Part Number:

UC3844BD1013TR

Distributor Name

Distributor reported inventory date:

UC3844BN Active

Budgetary Price (US$)*/Qty:
-
Package:
Packing Type:
RoHS:
Country of Origin:
ECCN (US):
ECCN (EU):

Part Number:

UC3844BN

Distributor Name

Distributor reported inventory date:

Swipe or click the button to explore more details Don't show this again

(*) Suggested Resale Price (USD) per defined quantity for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors