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UC3844B: High Performance Current Mode PWM Controller

Datasheet: High Performance Current Mode Controller
Rev. 11 (393.0kB)
Product Overview
»View Reliability Data
»View Material Composition
» Product Change Notification
The UC3844B, UC3845B series are high performance fixed frequency current mode controllers. They are specifically designed for Off-Line and dc-to-dc converter applications offering the designer a cost-effective solution with minimal external components. These integrated circuits feature an oscillator, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET.

Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle-by-cycle current limiting, a latch for single pulse metering, and a flip-flop which blanks the output off every other oscillator cycle, allowing output deadtimes to be programmed from 50% to 70%.

These devices are available in an 8-pin dual-in-line and surface mount (SO-8) plastic package as well as the 14-pin plastic surface mount (SO-14). The SO-14 package has separate power and ground pins for the totem pole output stage.

The UCX844B has UVLO thresholds of 16 V (on) and 10 V (off), ideally suited for off-line converters. The UCX845B is tailored for lower voltage applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off).
Features
 
  • Trimmed Oscillator for Precise Frequency Control
  • Oscillator Frequency Guaranteed at 250 kHz
  • Current Mode Operation to 500 kHz Output Switching Frequency
  • Output Deadtime Adjustable from 50% to 70%
  • Automatic Feed Forward Compensation
  • Latching PWM for Cycle-By-Cycle Current Limiting
  • Internally Trimmed Reference with Undervoltage Lockout
  • High Current Totem Pole Output
  • Undervoltage Lockout with Hysteresis
  • Low Startup and Operating Current
  • Pb-Free Packages are Available
Technical Documentation & Design Resources
Data Sheets (1) Package Drawings (3)
Availability & Samples
Specifications
Product
Status
Compliance
Description
Package
MSL
Container
Budgetary Price/Unit
Type
Case Outline
Type
Temperature
Type
Qty.
UC3844BD1G Active
Pb-free
Halide free
UC3844B SOIC-8 751-07 1 260 Tube 98 $0.2595
UC3844BD1R2G Active
Pb-free
Halide free
UC3844B SOIC-8 751-07 1 260 Tape and Reel 2500 $0.1772
UC3844BDG Active
Pb-free
Halide free
UC3844B SOIC-14 751A-03 1 260 Tube 55 $0.2673
UC3844BDR2G Active
Pb-free
Halide free
UC3844B SOIC-14 751A-03 1 260 Tape and Reel 2500 $0.1772
UC3844BNG Active
Pb-free
Halide free
UC3844B PDIP-8 626-05 NA Tube 50 $0.26
UC3844BVD1G Active
Pb-free
Halide free
UC3844B SOIC-8 751-07 1 260 Tube 98 Contact Sales Office
UC3844BVD1R2G Active
Pb-free
Halide free
UC3844B SOIC-8 751-07 1 260 Tape and Reel 2500 $0.1855
UC3844BVDG Active
Pb-free
Halide free
UC3844B SOIC-14 751A-03 1 260 Tube 55 $0.2631
UC3844BVDR2G Active
Pb-free
Halide free
UC3844B SOIC-14 751A-03 1 260 Tape and Reel 2500 $0.3129
UC3844BVNG Active
Pb-free
Halide free
UC3844B PDIP-8 626-05 NA Tube 50 $0.3383
Market Leadtime (weeks) : 2 to 4
ON Semiconductor   (2020-09-02 00:00) : 294
Market Leadtime (weeks) : 17 to 20
FutureElectronics   (2020-08-19 00:00) : >1K
PandS   (2020-09-14 00:00) : >10K
Market Leadtime (weeks) : 2 to 4
PandS   (2020-09-14 00:00) : <100
ON Semiconductor   (2020-09-02 00:00) : 6,325
Market Leadtime (weeks) : Contact Factory
PandS   (2020-09-14 00:00) : >1K
Market Leadtime (weeks) : 17 to 20
PandS   (2020-09-14 00:00) : <100
FutureElectronics   (2020-08-19 00:00) : >1K
Market Leadtime (weeks) : 2 to 4
Market Leadtime (weeks) : 8 to 12
PandS   (2020-09-14 00:00) : >1K
Market Leadtime (weeks) : 2 to 4
ON Semiconductor   (2020-09-02 00:00) : 8,030
Market Leadtime (weeks) : 2 to 4
Avnet   (2020-08-19 00:00) : >1K
ON Semiconductor   (2020-09-02 00:00) : 5,000
Market Leadtime (weeks) : 2 to 4
Avnet   (2020-08-19 00:00) : <1K
ON Semiconductor   (2020-09-02 00:00) : 23,550
FutureElectronics   (2020-08-19 00:00) : <1K

Product
Description
Pricing ($/Unit)
Compliance
Status
Topology
Control Mode
fsw Typ (kHz)
Stand-by Mode
UVLO (V)
Short Circuit Protection
Latch
Soft Start
VCC Max (V)
Drive Cap. (mA)
Package Type
UC3844BD1G  
 $0.2595 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
No
25
200 / 200
SOIC-8
UC3844BD1R2G  
 $0.1772 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
No
25
200 / 200
SOIC-8
UC3844BDG  
 $0.2673 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
No
25
200 / 200
SOIC-14
UC3844BDR2G  
 $0.1772 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
No
25
200 / 200
SOIC-14
UC3844BNG  
 $0.26 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
No
25
200 / 200
PDIP-8
UC3844BVD1G  
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
Yes
25
200 / 200
SOIC-8
UC3844BVD1R2G  
 $0.1855 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
Yes
25
200 / 200
SOIC-8
UC3844BVDG  
 $0.2631 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
Yes
25
200 / 200
SOIC-14
UC3844BVDR2G  
 $0.3129 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
Yes
25
200 / 200
SOIC-14
UC3844BVNG  
 $0.3383 
Pb
H
 Active   
Flyback
Forward
Step-Down
Step-Up
Current Mode
52
No
Yes
Yes
No
Yes
25
200 / 200
PDIP-8
Case Outlines
751-07    751A-03    626-05   
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