Home Power management AC/DC & isolated DC/DC switching regulators PWM controllers

TL3845B

ACTIVE

30-V, 0.2A high Performance 500KHz current mode PWM with 8.4V/7.6V UVLO, 50% duty cycle, 0C to 70C

Product details

Topology Boost, Flyback Control mode Current Duty cycle (max) (%) 50 Switching frequency (max) (kHz) 300 Features Adjustable switching frequency, Error amplifier, Multi-topology UVLO thresholds on/off (V) 8.4/7.6 Operating temperature range (°C) 0 to 70 Rating Catalog Gate drive (typ) (A) 1
Topology Boost, Flyback Control mode Current Duty cycle (max) (%) 50 Switching frequency (max) (kHz) 300 Features Adjustable switching frequency, Error amplifier, Multi-topology UVLO thresholds on/off (V) 8.4/7.6 Operating temperature range (°C) 0 to 70 Rating Catalog Gate drive (typ) (A) 1
PDIP (P) 8 92.5083 mm² 9.81 x 9.43 SOIC (D) 14 51.9 mm² 8.65 x 6 SOIC (D) 8 29.4 mm² 4.9 x 6
  • Low Start-Up Current (<0.5 mA)
  • Trimmed Oscillator Discharge Current
  • Current Mode Operation to 500 kHz
  • 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
  • Double-Pulse Suppression

  • Low Start-Up Current (<0.5 mA)
  • Trimmed Oscillator Discharge Current
  • Current Mode Operation to 500 kHz
  • 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
  • Double-Pulse Suppression

The TL284xB and TL384xB series of control integrated circuits provide the features that are necessary to implement off-line or dc-to-dc fixed-frequency current-mode control schemes, with a minimum number of external components. Internally implemented circuits include an undervoltage lockout (UVLO) and a precision reference that is trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator that 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 when it is in the off state.

The TL284xB and TL384xB series are pin compatible with the standard TL284x and TL384x with the following improvements. The start-up current is specified to be 0.5 mA (max), while the oscillator discharge current is trimmed to 8.3 mA (typ). In addition, during undervoltage lockout conditions, the output has a maximum saturation voltage of 1.2 V while sinking 10 mA (VCC = 5 V).

Major differences between members of these series are the UVLO thresholds and maximum duty-cycle ranges. Typical UVLO thresholds of 16 V (on) and 10 V (off) on the TLx842B and TLx844B devices make them ideally suited to off-line applications. The corresponding typical thresholds for the TLx843B and TLx845B devices are 8.4 V (on) and 7.6 V (off). The TLx842B and TLx843B devices can operate to duty cycles approaching 100%. A duty-cycle range of 0% to 50% is obtained by the TLx844B and TLx845B by the addition of an internal toggle flip-flop, which blanks the output off every other clock cycle.The TL284xB-series devices are characterized for operation from -40°C to 85°C. The TL384xB-series devices are characterized for operation from 0°C to 70°C.

The TL284xB and TL384xB series of control integrated circuits provide the features that are necessary to implement off-line or dc-to-dc fixed-frequency current-mode control schemes, with a minimum number of external components. Internally implemented circuits include an undervoltage lockout (UVLO) and a precision reference that is trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator that 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 when it is in the off state.

The TL284xB and TL384xB series are pin compatible with the standard TL284x and TL384x with the following improvements. The start-up current is specified to be 0.5 mA (max), while the oscillator discharge current is trimmed to 8.3 mA (typ). In addition, during undervoltage lockout conditions, the output has a maximum saturation voltage of 1.2 V while sinking 10 mA (VCC = 5 V).

Major differences between members of these series are the UVLO thresholds and maximum duty-cycle ranges. Typical UVLO thresholds of 16 V (on) and 10 V (off) on the TLx842B and TLx844B devices make them ideally suited to off-line applications. The corresponding typical thresholds for the TLx843B and TLx845B devices are 8.4 V (on) and 7.6 V (off). The TLx842B and TLx843B devices can operate to duty cycles approaching 100%. A duty-cycle range of 0% to 50% is obtained by the TLx844B and TLx845B by the addition of an internal toggle flip-flop, which blanks the output off every other clock cycle.The TL284xB-series devices are characterized for operation from -40°C to 85°C. The TL384xB-series devices are characterized for operation from 0°C to 70°C.

Download View video with transcript Video

Similar products you might be interested in

open-in-new Compare alternates
Drop-in replacement with upgraded functionality to the compared device
UC3845A ACTIVE 30V,1A, 500KHz current mode PWM controller with 8.4V/7.6V UVLO 50% duty cycle, 0°C to 70°C Pin-to-pin equivalent alternate product
Similar functionality to the compared device
TL2845B ACTIVE 30-V, 0.2A high Performance 500KHz current mode PWM with 8.4V/7.6V UVLO, 50% duty cycle, -40C to 85C Wider temperature range

Technical documentation

star =Top documentation for this product selected by TI
No results found. Please clear your search and try again.
View all 2
Type Title Date
* Data sheet High Performance Current-Mode PWM Controllers datasheet (Rev. B) 02 Jul 2007
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Package Pins Download
PDIP (P) 8 View options
SOIC (D) 14 View options
SOIC (D) 8 View options

Ordering & quality

Information included:
  • RoHS
  • REACH
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

Recommended products may have parameters, evaluation modules or reference designs related to this TI product.

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​

Videos