Analog Devices Inc./Maxim Integrated MAX14778ETP+

Overview

The MAX14778ETP+ from Maxim Integrated is a dual ±25V above- and below-the-rails 4:1 analog multiplexer IC designed for high-voltage signal routing in mixed-protocol interfaces. It supports RS-485 (20Mbps), USB 1.1 (12Mbps), and audio/data signals with 1.5Ω max on-resistance, ±300mA bidirectional current handling, and operates from a single 3.0V to 5.5V supply across -40°C to +85°C.

For engineers reviewing the MAX14778ETP+ datasheet, MAX14778ETP+ pinout, MAX14778ETP+ application, or MAX14778ETP+ equivalent, key selection criteria include ±25V rail-to-rail analog range, independent dual-mux control, break-before-make timing (840µs), ESD-hardened A_/B_ pins (±6kV HBM), and TQFN-20 (5mm × 5mm) package compatibility with industrial connector-sharing designs.

Technical Context

The MAX14778ETP+ integrates three charge pumps (5V regulated, +35V, and -27V) to enable ±25V analog signal switching from a single low-voltage supply; bias generation is dynamically optimized when VDD exceeds 4.64V, reducing supply current by disabling the internal 5V pump. Its dual independent 4:1 muxes feature separate ENA/ENB enables and SA0/SA1/SB0/SB1 select logic, supporting asynchronous channel selection.

Each mux path delivers 75MHz large-signal bandwidth, -80dB off-isolation at 100kHz, and -103dB crosstalk, enabling clean multiplexing of full-speed USB 1.1 and RS-485 signals without inter-channel interference. The device maintains 3mΩ typical R_ON flatness over -25V to +25V common-mode range, ensuring minimal THD+N (0.003%) and signal distortion across its full voltage swing.

Key Specifications

Pinout & Package

MAX14778ETP+ is housed in a 20-pin, 5mm × 5mm TQFN-EP package with exposed pad connected to VN. The package supports thermal dissipation of 2666.7mW at +70°C (θ_JA = 30°C/W, θ_JC = 2°C/W) and is rated for industrial temperature operation (-40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog multiplexer applications.

Compared with MAX14777ETP+, the MAX14778ETP+ adds a second independent mux for concurrent signal routing, while TMUX6219RTER trades voltage range and integration for lower quiescent current and smaller footprint - making it unsuitable for direct replacement in full ±25V industrial applications.

Availability

MAX14778ETP+ is available at Aetrix Electronics and suitable for POS peripherals, handheld industrial devices, gaming machines, and communication systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX14778ETP+ 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, communications, and computing markets.

The MAX14778ETP+ belongs to Maxim's high-voltage analog switch product line, engineered specifically for connector consolidation in multi-protocol embedded systems where ±25V signal integrity, ESD robustness, and single-supply operation are mandatory.

FAQ

What is the maximum continuous current rating for each channel of the MAX14778ETP+?

The MAX14778ETP+ supports ±300mA continuous bidirectional current through any selected A_ or B_ channel when connected to its respective common terminal (ACOM or BCOM). This rating applies across the full -40°C to +85°C operating range and is validated under worst-case conditions including ±25V common-mode voltage and 1.5Ω max on-resistance. Exceeding ±300mA may trigger thermal shutdown at 145°C junction temperature.

Does the MAX14778ETP+ require external capacitors, and if so, what values and locations?

Yes, the MAX14778ETP+ requires three external capacitors: a 1µF ceramic capacitor from VDD to GND (pin 13), and two 100nF 50V ceramic capacitors - one from VP to GND (pin 2) and one from VN to GND (pin 4). These are mandatory for stable charge-pump operation, full ±6kV HBM ESD protection on A_/B_ pins, and prevention of transient latch-up during signal transitions. Placement must be within 5mm of respective pins per Maxim's layout guidelines.

Can the MAX14778ETP+ operate with only VDD applied, or do VP and VN need active biasing?

The MAX14778ETP+ can operate with only VDD applied (3.0V–5.5V); VP and VN are internally generated by on-chip charge pumps and do not require external voltage sources. However, the 100nF bypass capacitors on VP and VN are mandatory - without them, the device fails to achieve specified ±25V analog range, exhibits degraded ESD immunity, and risks instability during fast dv/dt events. VP and VN are output-only nodes, not inputs.

What is the logic voltage compatibility of the MAX14778ETP+ control inputs (ENA, ENB, SA0, etc.)?

The MAX14778ETP+ control inputs (ENA, ENB, SA0, SA1, SB0, SB1) are fully compatible with standard CMOS logic levels across the entire VDD range (3.0V–5.5V). VIH minimum is 1.7V at VDD = 3.0V and rises to 2.2V at VDD = 5.5V; VIL maximum is 0.7V at VDD = 3.0V and 0.8V at VDD = 5.5V. No level-shifting is needed when driven directly from 3.3V or 5V microcontrollers, FPGAs, or CPLDs.

How does the MAX14778ETP+ handle unpowered operation, and what are the safe input voltage limits when VDD = 0V?

When VDD = 0V, the MAX14778ETP+ tolerates analog input voltages from -25V to +25V on A_, B_, ACOM, and BCOM pins. DC leakage remains below 1µA typical, though technology spread allows up to ~1mA in some units. VP and VN capacitors will charge via internal diodes during voltage application, requiring dv/dt limiting to ≤3V/µs after capacitor saturation to avoid exceeding the ±500mA absolute maximum current rating and damaging internal structures.