SNOAA82 November   2021 TLV3601 , TLV3601-Q1 , TLV3603 , TLV3603-Q1

 

  1.   Design Process
    1.     Design Steps
    2.     Transient Simulation Results
  2.   Design References
  3.   Design Featured Comparator
  4.   Design Alternate Comparator

Design Process

Design Goals

System Supply Input

Type

 Output Pulse

Width 50% to 50% to Drive LED

 FET

Switch Type
5 V

LVDS

 3 ns ±10%

Low-Side

Design Description

LVDS GaN Driver Transmitter Circuit

For this application, it is crucial to produce as narrow of a pulse as possible when driving a laser diode. For this design, the output of the GaN FET produces a 3-ns wide pulse that can be used to control a low-resistance, 1-Ω load. It is common to use low-voltage differential signal (LVDS) on a long cable or long trace to reduce EMI. The inputs to the GaN FET driver interface circuit must also accept LVDS inputs. To provide speed and accept LVDS input signals, the TLV3601 high-speed comparator is used. The TLV3601 is used to convert an LVDS signal to a single-ended output to drive the input of a GaN FET driver. The EPC2019 GaN FET and the LMG1020 GaN FET driver are also used. The design requirements are reflected in the Design Goals table.

Design Notes

  1. Select a high-speed comparator that can be driven differentially by an LVDS signal
  2. The low-resistance, 1-Ω load is used in simulation in place of an LED
  3. Both the TLV3601 and the LMG1020 devices are powered from a 5-V supply (VSUPPLY)