Analog Devices Inc./Maxim Integrated MAX9679ETG+

Overview

MAX9679ETG+ from Maxim Integrated is a 12-channel, 10-bit programmable gamma and VCOM reference voltage generator for TFT LCD panels. It integrates 12 gamma DACs (GMA1–GMA12), one VCOM DAC, a programmable 20V full-scale reference (VPREF), high-current output buffers, and multiple-time programmable (MTP) memory - enabling precise grayscale calibration and VCOM adjustment in automotive and industrial displays.

For engineers reviewing the MAX9679ETG+ datasheet, MAX9679ETG+ pinout, MAX9679ETG+ application, or MAX9679ETG+ equivalent, key selection considerations include its dual-bank gamma/VCOM switching via BKSEL, ±0.1% VPREF accuracy, 200mA gamma output drive, 600mA VCOM sink/source capability, and I²C Fast-Mode Plus (1MHz) interface compatibility with TCON controllers.

Technical Context

The MAX9679ETG+ implements two independent volatile gamma/VCOM banks (Bank 1/Bank 2), selected in real time by the BKSEL logic input - enabling seamless frame-rate switching between gamma curves without I²C transaction latency. Each gamma channel uses a dedicated 10-bit DAC buffered by a high-current amplifier capable of 200mA transient sourcing/sinking.

VCOM output employs a rail-to-rail operational amplifier powered by AVDD_AMP, delivering 600mA peak current with 0.5mV/mA load regulation and 60MHz bandwidth. The integrated 10-bit programmable reference (VPREF) sets DAC full-scale at 20V ±0.1%, derived from an internal linear regulator for high PSRR (>60dB up to 10MHz).

Key Specifications

Pinout & Package

MAX9679ETG+ is housed in a 24-pin TQFN-EP (4mm × 4mm, 0.5mm pitch) with exposed pad (EP) internally connected to AGND. Thermal resistance: θ_JA = 39°C/W, θ_JC = 6°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar gamma/VCOM reference generator applications.

Compared with MAX9678ETG+, MAX9679ETG+ adds two gamma channels and supports larger, higher-resolution panels; compared with MAX9650ETA+, it integrates full gamma/VCOM generation and control - eliminating external DACs, references, and coordination logic required by discrete solutions.

Availability

MAX9679ETG+ is available at Aetrix Electronics and suitable for automotive instrument clusters, industrial HMIs, medical diagnostic monitors, and avionics display systems requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MAX9679ETG+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and medical applications.

The MAX9679 belongs to Maxim's TFT LCD power and timing IC portfolio, engineered specifically to consolidate gamma correction, VCOM generation, and reference voltage functions into a single package - reducing system complexity and improving grayscale consistency in high-reliability displays.

FAQ

What is the full-scale voltage accuracy of the programmable reference (VPREF) in MAX9679ETG+?

The MAX9679ETG+ features a programmable reference voltage (VPREF) with ±0.1% full-scale accuracy - specified as 19.96V to 20.00V at +25°C. This high-precision reference sets the DAC output range for all 12 gamma channels and the VCOM output, eliminating the need for external reference ICs and enabling system-level gamma calibration traceability. The reference is generated by an internal linear regulator for superior PSRR.

How does the BKSEL pin function in MAX9679ETG+ and what is its switching speed?

The BKSEL pin on MAX9679ETG+ selects between two independent volatile gamma/VCOM register banks (Bank 1 and Bank 2) in hardware, enabling real-time switching without I²C transactions. When BKSEL transitions, gamma outputs settle within 200ns (GMA1) and VCOM settles within 400ns - critical for flicker-free transitions between display modes (e.g., day/night). This deterministic, low-latency switching is distinct from software-controlled alternatives requiring full register reloads.

What are the maximum continuous output currents for gamma and VCOM channels in MAX9679ETG+?

Each gamma output (GMA1–GMA12) in MAX9679ETG+ supports 200mA peak transient current to handle fast polarity reversals and line transitions, while delivering 4mA DC current within 200mV of the rails. The VCOM output sustains 600mA continuous sink/source current - sufficient to drive large-area TFT-LCD backplanes directly. Both outputs feature built-in current limiting and thermal shutdown protection at +165°C.

Does MAX9679ETG+ include nonvolatile memory, and how many write cycles does it support?

Yes, MAX9679ETG+ integrates multiple-time programmable (MTP) nonvolatile memory that retains gamma, VCOM, and VPREF codes across power cycles. It supports up to 100 write cycles - sufficient for factory calibration, field re-tuning, and firmware updates. Upon power-up, MTP contents automatically load into volatile I²C registers within 400ns, ensuring consistent behavior without host intervention.

What power supply domains does MAX9679ETG+ use, and why are they separated?

MAX9679ETG+ uses three independent analog supplies: AVDD1 (for GMA1–GMA6), AVDD2 (for GMA7–GMA12), and AVDD_AMP (for VCOM amplifier). This separation reduces thermal coupling between gamma banks and enables flexible power sequencing - e.g., AVDD2 can be set to 12V instead of AVDD1's 18V to lower chip temperature. All supplies tolerate 6V–20V, with undervoltage lockout at 2.1V–2.6V on DVDD.