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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 - UC3845B

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.

Symbols

Symbols

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Footprints

3D model

3D models

Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
UC3845BD1
Active
SO-8 Industrial Ecopack2
UC3845BD1013TR
Active
SO-8 Industrial Ecopack2
UC3845BN
Active
DIP-8 Industrial Ecopack2

UC3845BD1

Package:

SO-8

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-8

Grade

Industrial

RoHS Compliance Grade

Ecopack2

UC3845BD1013TR

Package:

SO-8

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-8

Grade

Industrial

RoHS Compliance Grade

Ecopack2

UC3845BN

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

Part Number
Order from Distributors
Order from ST
Marketing Status
ECCN (US)
ECCN (EU)
Packing Type
Package
Temperature (°C) Country of Origin
Budgetary Price (US$)*/Qty
min
max
UC3845BN Available at 7 distributors

Distributor availability ofUC3845BN

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 4000 1 Buy from Distributor
RS COMPONENTS EUROPE 30 1 Buy from Distributor
FUTURE WORLDWIDE 3400 1 Buy from Distributor
Newark Element14 AMERICA 254 0 Buy from Distributor
MOUSER WORLDWIDE 4210 1 Buy from Distributor
Farnell Element14 EUROPE 888 1 Buy from Distributor
ANGLIA Live EUROPE 2950 50 Buy from Distributor

Distributor reported inventory date: 2021-10-19

Distributor Name

DIGIKEY

Stock

4000

Min.Order

1

Region

WORLDWIDE Buy from Distributor

RS COMPONENTS

Stock

30

Min.Order

1

FUTURE

Stock

3400

Min.Order

1

Region

WORLDWIDE Buy from Distributor

Newark Element14

Stock

254

Min.Order

0

Region

AMERICA Buy from Distributor

MOUSER

Stock

4210

Min.Order

1

Region

WORLDWIDE Buy from Distributor

Farnell Element14

Stock

888

Min.Order

1

ANGLIA Live

Stock

2950

Min.Order

50

Distributor reported inventory date: 2021-10-19

Buy Direct
Active
EAR99 NEC Tube DIP-8 - - CHINA 0.3353 / 1k
UC3845BD1 Available at 3 distributors

Distributor availability ofUC3845BD1

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2000 1 Buy from Distributor
RS COMPONENTS EUROPE 80 1 Buy from Distributor
Newark Element14 AMERICA 163 0 Buy from Distributor

Distributor reported inventory date: 2021-10-19

Distributor Name

DIGIKEY

Stock

2000

Min.Order

1

Region

WORLDWIDE Buy from Distributor

RS COMPONENTS

Stock

80

Min.Order

1

Newark Element14

Stock

163

Min.Order

0

Region

AMERICA Buy from Distributor

Distributor reported inventory date: 2021-10-19

Active
EAR99 NEC Tube SO-8 - - MOROCCO 0.3353 / 1k
UC3845BD1013TR No availability of distributors reported, please contact our sales office
Active
EAR99 NEC Tape And Reel SO-8 - - MOROCCO 0.3353 / 1k

UC3845BN

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

0.3353 / 1k

Distributor availability ofUC3845BN

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 4000 1 Buy from Distributor
RS COMPONENTS EUROPE 30 1 Buy from Distributor
FUTURE WORLDWIDE 3400 1 Buy from Distributor
Newark Element14 AMERICA 254 0 Buy from Distributor
MOUSER WORLDWIDE 4210 1 Buy from Distributor
Farnell Element14 EUROPE 888 1 Buy from Distributor
ANGLIA Live EUROPE 2950 50 Buy from Distributor

Distributor reported inventory date: 2021-10-19

Distributor Name

DIGIKEY

Stock

4000

Min.Order

1

Region

WORLDWIDE Buy from Distributor

RS COMPONENTS

Stock

30

Min.Order

1

FUTURE

Stock

3400

Min.Order

1

Region

WORLDWIDE Buy from Distributor

Newark Element14

Stock

254

Min.Order

0

Region

AMERICA Buy from Distributor

MOUSER

Stock

4210

Min.Order

1

Region

WORLDWIDE Buy from Distributor

Farnell Element14

Stock

888

Min.Order

1

ANGLIA Live

Stock

2950

Min.Order

50

Distributor reported inventory date: 2021-10-19

ECCN (EU)

NEC

Packing Type

Tube

Package

DIP-8

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

0.3353 / 1k

Country of Origin

CHINA

UC3845BD1

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

0.3353 / 1k

Distributor availability ofUC3845BD1

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2000 1 Buy from Distributor
RS COMPONENTS EUROPE 80 1 Buy from Distributor
Newark Element14 AMERICA 163 0 Buy from Distributor

Distributor reported inventory date: 2021-10-19

Distributor Name

DIGIKEY

Stock

2000

Min.Order

1

Region

WORLDWIDE Buy from Distributor

RS COMPONENTS

Stock

80

Min.Order

1

Newark Element14

Stock

163

Min.Order

0

Region

AMERICA Buy from Distributor

Distributor reported inventory date: 2021-10-19

ECCN (EU)

NEC

Packing Type

Tube

Package

SO-8

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

0.3353 / 1k

Country of Origin

MOROCCO

UC3845BD1013TR

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

0.3353 / 1k

ECCN (EU)

NEC

Packing Type

Tape And Reel

Package

SO-8

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

0.3353 / 1k

Country of Origin

MOROCCO

(*) 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