SNVS847F June 2012 – November 2017 LM34926
PRODUCTION DATA.
- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Control Overview
- 7.3.2 VCC Regulator
- 7.3.3 Regulation Comparator
- 7.3.4 Overvoltage Comparator
- 7.3.5 On-Time Generator
- 7.3.6 Current Limit
- 7.3.7 N-Channel Buck Switch and Driver
- 7.3.8 Synchronous Rectifier
- 7.3.9 Undervoltage Detector
- 7.3.10 Thermal Protection
- 7.3.11 Ripple Configuration
- 7.3.12 Soft Start
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Custom Design With WEBENCH® Tools
- 8.2.2.2 Transformer Turns Ratio
- 8.2.2.3 Total IOUT
- 8.2.2.4 RFB1, RFB2
- 8.2.2.5 Frequency Selection
- 8.2.2.6 Transformer Selection
- 8.2.2.7 Primary Output Capacitor
- 8.2.2.8 Secondary Output Capacitor
- 8.2.2.9 Type III Feedback Ripple Circuit
- 8.2.2.10 Secondary Diode
- 8.2.2.11 VCC and Bootstrap Capacitor
- 8.2.2.12 Input Capacitor
- 8.2.2.13 UVLO Resistors
- 8.2.2.14 VCC Diode
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
- DDA|8
Orderable Information
1 Features
- Wide 7.5-V to 100-V Input Range
- Integrated 300-mA High-Side
and Low-Side Switches - No Schottky Required
- Constant On-Time Control
- No Loop Compensation Required
- Ultra-Fast Transient Response
- Nearly Constant Operating Frequency
- Intelligent Peak Current Limit
- Adjustable Output Voltage From 1.225 V
- Precision 2% Feedback Reference
- Frequency Adjustable to 1 MHz
- Adjustable Undervoltage Lockout (UVLO)
- Remote Shutdown
- Thermal Shutdown
- Packages:
- WSON-8
- SO PowerPAD™-8 Packages
- Create a Custom Design Using the LM34926 With the WEBENCH® Power Designer
2 Applications
- Isolated Telecom Bias Supply
- Isolated Automotive and Industrial Electronics
3 Description
The LM34926 regulator features all of the functions needed to implement a low-cost, efficient, isolated bias regulator. This high-voltage regulator contains two 100-V N-channel MOSFET switches — a high-side buck switch and a low-side synchronous switch. The constant on-time (COT) control scheme employed in the LM34926 requires no loop compensation and provides excellent transient response. The regulator operates with an on-time control that is inversely proportional to the input voltage. This feature allows the operating frequency to remain relatively constant. An intelligent peak current limit is implemented with integrated sense circuit. Other features include a programmable input undervoltage comparator to inhibit operation during low-voltage conditions. Protection features include thermal shutdown and VCC Undervoltage Lockout (UVLO). The LM34926 device is offered in WSON-8 and SO PowerPAD-8 plastic packages.
Device Information(1)
| PART NUMBER | PACKAGE | BODY SIZE (NOM) |
|---|---|---|
| LM34926 | HSOP (8) | 4.89 mm × 3.90 mm |
| WSON (8) | 4.00 mm × 4.00 mm |
- For all available packages, see the orderable addendum at the end of the data sheet.
Typical Application
