28G – Linear PAM4 VCSEL Driver

The HXT14400 is a quad-channel, low power, linear PAM4 VCSEL driver for SR optical applications that supports signaling rates up to 28GBaud or 56Gbps PAM4. In conjunction with an individual DFB laser diode, the device handles the complete digital-to-optical conversion, including CML input with equalization, laser driver, drive control, and supervision. The HXT14400 also integrates a number of functions required for Automatic Power Control (APC), as well as internal and module temperature measurements and reporting. Using the included RSSI input, the module receive optical power can also be measured and reported. Designed for direct DC-coupled die in TOSA applications with a small number of additional components for cost-effective and compact assemblies. Available in die form.


  • 227mW per channel PDISS if configured for:
    • IMOD = 5mAPP
    • IBIAS = 5mA
  • Supports up to: IMOD = 12mAPP & IBIAS = 12mA with VCC = 3.3V
  • Integrated 12-bit ADC with 6 channel analog multiplexor front-end
  • Programmable 8-bit Laser Modulation and Bias current control
  • Integrated Bias Monitor, Transmit and Receive Power monitor capability
  • Automatic Power Control (APC)
  • Programmable Input LOS and Squelch function with disable, Transmit Disable, and Transmit Fault indication
  • Programmable Input CTLE Equalization
  • Integrated Temperature Sensor and input for external module temperature sensor
  • Interrupts with User selectable Mask control
  • Input Polarity Inversion
  • Laser Disable for IMOD and IBIAS
  • Integrated OTP for calibration
  • 2-wire interface control

Product Options

Orderable Part ID Part Status Pkg. Code Pkg. Type Temp. Grade Carrier Type Buy Sample
HXT14400-DNT Not Recommended for New Designs DICEW WAFER C Box Availability

Technical Documentation

Title Other Languages Type Format File Size Date
Datasheets & Errata
HXT14400 Datasheet Datasheet - Advance PDF 1.38 MB Dec 18, 2017
HXT14400 Short Form Datasheet Short Form Datasheet PDF 113 KB Dec 13, 2017