Analog Devices Inc./Maxim Integrated MAX4990ETD+T

Overview

MAX4990ETD+T from Maxim Integrated is a high-voltage DC-AC converter IC designed specifically to drive electroluminescent (EL) lamps, featuring ±15kV ESD protection on VA/VB outputs, 250V_P-P peak-to-peak output voltage, and a wide +2.4V to +5.5V input supply range - enabling direct operation from single-cell Li+ batteries in portable backlighting applications.

For engineers reviewing the MAX4990ETD+T datasheet, MAX4990ETD+T pinout, MAX4990ETD+T application, or MAX4990ETD+T equivalent, this page delivers verified technical context on EL lamp dimming control (DIM), slew-rate programming (SLEW), dual-frequency configuration (SW/EL inputs), thermal shutdown (+158°C), and low-power shutdown (100nA).

Technical Context

The MAX4990ETD+T integrates an inductor-based boost converter (switching frequency set via SW pin and external CSW capacitor or PWM signal) followed by a high-voltage full-bridge output stage (EL switching frequency set via EL pin and CEL capacitor or clock input). Its proprietary acoustic noise-reduction circuit uses SLEW-pin resistor biasing to control VA/VB slew rate (e.g., 30V/100µs at RSLEW = 375kΩ), directly reducing audible EL panel noise.

Dimming is implemented through the DIM pin, supporting three modes: DC analog voltage (0.35V–1.3V), PWM (200kHz–1MHz), or resistor-to-GND - with optional CDIM capacitor enabling soft fade-on/fade-off transitions. Shutdown is controlled jointly by EN and DIM logic thresholds (EN > +1.2V & DIM > +0.35V to enable; EN < +0.2V & DIM < +0.15V to disable), delivering 100nA max shutdown current.

Key Specifications

Pinout & Package

MAX4990ETD+T is housed in a 14-pin, 3mm × 3mm TDFN-EP package with exposed thermal pad (EP) that must be connected to GND for optimal thermal performance and EMI control.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar electroluminescent lamp driver applications.

Compared with MAX14521EASA+ and LT3573EDDB#TRPBF, the MAX4990ETD+T uniquely integrates full-bridge AC generation, ±15kV ESD-hardened outputs, programmable slew rate, and dual-frequency tuning - making it the only single-chip solution for high-brightness, low-noise, automotive-grade EL lighting.

Availability

MAX4990ETD+T is available at Aetrix Electronics and suitable for keypad backlighting, MP3 player displays, LCD backlights, automotive instrument clusters, and PDA/smartphone UI illumination requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for MAX4990ETD+T 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, automotive, and portable applications.

The MAX4990ETD+T belongs to Maxim's high-voltage EL driver product line, engineered specifically for noise-sensitive, battery-operated electroluminescent lighting where integrated ESD protection, compact packaging, and multi-mode dimming are critical.

FAQ

What is the maximum EL lamp output voltage of the MAX4990ETD+T?

The MAX4990ETD+T delivers up to 250V_P-P across VA and VB outputs when DIM is set to +1.3V (DC) or 100% PWM duty cycle, with VDD = +3V. This peak-to-peak voltage is confirmed in the Electrical Characteristics table (page 2 of datasheet) and enables maximum brightness for demanding EL panels. Operation above 250V_P-P is not guaranteed and may reduce reliability.

How does the SLEW pin control audible noise in the MAX4990ETD+T?

The SLEW pin on the MAX4990ETD+T accepts an external resistor (RSLEW) to GND, setting a reference current (IB = 1V/RSLEW) that directly controls the slew rate of VA and VB outputs. At RSLEW = 375kΩ, the typical slew rate is 30V/100µs - slow enough to suppress mechanical resonance in EL panels while maintaining usable brightness. Values from 100kΩ to 2.2MΩ are supported.

Can the MAX4990ETD+T be used with a PWM signal on the DIM pin?

Yes - the MAX4990ETD+T fully supports PWM dimming on the DIM pin across 200kHz to 1MHz. Internally, the PWM is converted to an equivalent DC voltage (0–1.22V range), which linearly scales the VA–VB peak-to-peak output. A 50% duty cycle at 500kHz yields ~125V_P-P output (VDD = +3V), matching the response to a +0.65V DC input.

What happens if the SW pin is held high on the MAX4990ETD+T?

Holding the SW pin high on the MAX4990ETD+T shorts the internal LX switch to GND continuously, causing excessive power dissipation in the die. The device detects this condition as thermal overload and enters thermal shutdown at +158°C. It remains latched off until junction temperature falls to +150°C. Do not hold SW high - use GND or PWM/clock signals only.

Is the exposed pad (EP) on the MAX4990ETD+T required to be connected to GND?

Yes - the exposed pad (EP) on the MAX4990ETD+T must be soldered to a GND plane. It serves as the primary thermal conduction path (θ_JA = 41°C/W) and improves ESD robustness. Leaving EP unconnected degrades thermal performance and increases risk of ESD-induced failure on VA/VB pins. Maxim's recommended layout shows EP tied directly to GND with multiple vias.