SLVS077F April   1977  – January 2021 SG2524 , SG3524

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configurations and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
  7. 7 12
    1. 7.1 Electrical Characteristics
    2. 7.2 Electrical Characteristics — Continued, Both Parts
    3. 7.3 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 17
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Blanking
      2. 9.3.2 Error Amplifier
      3. 9.3.3 Compensation
      4. 9.3.4 Output Circuitry
      5. 9.3.5 Current Limiting
    4. 9.4 Device Functional Modes
      1. 9.4.1 Synchronous Operation
      2. 9.4.2 Shutdown Circuitry
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Feedback Traces
      2. 10.1.2 Input/Output Capacitors
      3. 10.1.3 Compensation Components
      4. 10.1.4 Traces and Ground Planes
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    2. 11.2 Trademarks

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • NS|16
  • N|16
  • D|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.1 Overview

SGx524 is a fixed-frequency pulse-width-modulation (PWM) voltage-regulator control circuit. The regulator operates at a fixed frequency that is programmed by one timing resistor, RT, and one timing capacitor, CT. RT establishes a constant charging current for CT. This results in a linear voltage ramp at CT, which is fed to the comparator, providing linear control of the output pulse duration (width) by the error amplifier.

The SGx524 contains an onboard 5-V regulator that serves as a reference, as well as supplying the SGx524 internal regulator control circuitry. The internal reference voltage is divided externally by a resistor ladder network to provide a reference within the common-mode range of the error amplifier as shown in Figure 10-5, or an external reference can be used.

The output is sensed by a second resistor divider network and the error signal is amplified. This voltage is then compared to the linear voltage ramp at CT. The resulting modulated pulse out of the high-gain comparator then is steered to the appropriate output pass transistor (Q1 or Q2) by the pulse-steering flip-flop, which is synchronously toggled by the oscillator output. The oscillator output pulse also serves as a blanking pulse to ensure both outputs are never on simultaneously during the transition times. The duration of the blanking pulse is controlled by the value of CT.

The outputs may be applied in a push-pull configuration in which their frequency is one-half that of the base oscillator, or paralleled for single-ended applications in which the frequency is equal to that of the oscillator. The output of the error amplifier shares a common input to the comparator with the current-limiting and shut-down circuitry and can be overridden by signals from either of these inputs. This common point is pinned out externally via the COMP pin, which can be employed to either control the gain of the error amplifier or to compensate it. In addition, the COMP pin can be used to provide additional control to the regulator.