SNVS120G April   2000  – May 2019 LM2585

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      12-V Flyback Regulator Design Example
  4. 4 Revision History
  5. 5 Pin Configurations
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Ratings
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics: 3.3 V
    6. 6.6  Electrical Characteristics: 5 V
    7. 6.7  Electrical Characteristics: 12-V
    8. 6.8  Electrical Characteristics: Adjustable
    9. 6.9  Electrical Characteristics: All Versions
    10. 6.10 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Step-Up (Boost) Regulator Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Typical Boost Regulator Applications
      2. 8.2.2 Typical Flyback Regulator Applications
        1. 8.2.2.1 Transformer Selection (T)
        2. 8.2.2.2 Transformer Footprints
          1. 8.2.2.2.0.1 T6
          2. 8.2.2.2.0.2 T6
      3. 8.2.3 Design Requirements
      4. 8.2.4 Detailed Design Procedure
        1. 8.2.4.1 Custom Design With WEBENCH® Tools
        2. 8.2.4.2 Programming Output Voltage (Selecting R1 And R2)
        3. 8.2.4.3 Short Circuit Condition
        4. 8.2.4.4 Flyback Regulator Input Capacitors
        5. 8.2.4.5 Switch Voltage Limits
        6. 8.2.4.6 Output Voltage Limitations
        7. 8.2.4.7 Noisy Input Line Condition
        8. 8.2.4.8 Stability
      5. 8.2.5 Application Curve
    3. 8.3 Additional Application Examples
      1. 8.3.1 Test Circuits
  9. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Heat Sink/Thermal Considerations
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
      2. 10.1.2 Development Support
        1. 10.1.2.1 Custom Design With WEBENCH® Tools
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Community Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2.1 Transformer Selection (T)

Table 1 lists the standard transformers available for flyback regulator applications. Included in the table are the turns ratio(s) for each transformer, as well as the output voltages, input voltage ranges, and the maximum load currents for each circuit.

Table 1. Transformer Selection Table

Applications  Figure 22  Figure 23  Figure 24  Figure 25  Figure 26  Figure 27
Transformers T7 T7 T7 T6 T6 T5
VIN 4V–6V 4V–6V 8V–16V 4V–6V 18V–36V 18V–36V
VOUT1 3.3V 5V 12V 12V 12V 5V
IOUT1 (Max) 1.4A 1A 0.8A 0.15A 0.6A 1.8A
N1 1 1 1 1.2 1.2 0.5
VOUT2 −12V −12V 12V
IOUT2 (Max) 0.15A 0.6A 0.25A
N2 1.2 1.2 1.15
VOUT3 −12V
IOUT3 (Max) 0.25A
N3 1.15

Table 2. Transformer Manufacturer Guide

Transformer Type Manufacturers' Part Numbers
Coilcraft
(1) 		Coilcraft
(1)
Surface Mount		 Pulse
(2)
Surface Mount		 Pulse
(2) 		Renco
(3) 		Schott
(4)
T5 Q4338-B Q4437-B PE-68413 — RL-5532 67140890
T6 Q4339-B Q4438-B PE-68414 — RL-5533 67140900
T7 S6000-A S6057-A — PE-68482 RL-5751 26606
(1) Coilcraft Inc. Phone: (800) 322-2645 www.coilcraft.com
(2) Pulse Engineering Inc. Phone: (619) 674-8100 www.digikey.com
(3) Renco Electronics Inc. Phone: (800) 645-5828 www.cdiweb.com/renco
(4) Schott Corp. Phone: (612) 475-1173 www.schottcorp.com/