Analog Devices Inc./Maxim Integrated MAX9238EUM+

Overview

MAX9238EUM+ from Maxim Integrated is a hot-swappable, 21-bit, DC-balanced LVDS deserializer that converts three LVDS serial data streams and one parallel-rate LVDS clock into 21 single-ended LVCMOS/LVTTL outputs. It operates from 16MHz to 66MHz, features falling-edge output strobe, supports 1.8V–5V output logic levels via separate VCCO supply, and enables AC-coupled links for extended common-mode voltage tolerance in automotive display interconnects.

For engineers reviewing the MAX9238EUM+ datasheet, MAX9238EUM+ pinout, MAX9238EUM+ application, or MAX9238EUM+ equivalent, key selection criteria include its 66MHz upper frequency limit, ISO 10605 ±25kV air-gap ESD rating on LVDS inputs, 48-pin TSSOP package with N.C. at Pin 6, and compatibility with MAX9215/MAX9213 serializers in DC-balanced mode only.

Technical Context

The MAX9238EUM+ implements a dedicated PLL with no external components required, locking within 32,800 RxCLK IN periods. Its DC-balanced decoding-based on 7-bit data + 2 control bits per word-limits digital sum variation (DSV) to ≤10 for data channels and ≤5 for clock, enabling reliable AC-coupling with series capacitors.

It decodes serialized video/data from companion Maxim serializers (e.g., MAX9215), using differential input thresholds of ±50mV and supporting input common-mode range up to 2.4V. The falling-edge RxCLK OUT strobe synchronizes 21 parallel outputs, with setup/hold timing referenced to 0.30× and 0.45× RCOP respectively.

Key Specifications

Pinout & Package

MAX9238EUM+ is housed in a lead(Pb)-free, RoHS-compliant 48-pin TSSOP package (body size 7.0mm × 4.4mm, 0.5mm pitch). Pin 6 is No Connect (N.C.), distinguishing it from legacy MAX9222. All power domains-digital (VCC), output (VCCO), PLL (PLL VCC), and LVDS (LVDS VCC)-require local 0.1µF + 0.001µF ceramic bypassing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LVDS deserializer applications.

Compared with MAX9222EUM+, MAX9238EUM+ guarantees hot-swap and DC-balance-only operation-critical for automotive safety-critical displays-while DS90CR288AMTDX offers higher bandwidth but demands more complex layout and external component validation.

Availability

MAX9238EUM+ is available at Aetrix Electronics and suitable for automotive navigation systems, digital copiers, and laser printer engine control requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MAX9238EUM+ 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 high-speed interface ICs for automotive, industrial, and communications markets.

The MAX9234/MAX9236/MAX9238 family targets high-reliability serial video and data links in electrically noisy, space-constrained environments-specifically engineered for AC-coupled, hot-pluggable display interconnects in vehicles and office equipment.

FAQ

What is the maximum operating frequency of the MAX9238EUM+?

The MAX9238EUM+ operates from 16MHz to 66MHz. This upper limit defines its capability to deserialize high-resolution video streams-for example, supporting WXGA (1280×720) at 60Hz with embedded sync. At 66MHz, worst-case supply current reaches 177mA (VCC = VCCO = 3.6V), requiring careful thermal design. The MAX9238EUM+ does not support frequencies below 16MHz, unlike the MAX9234/MAX9236 variants.

Does the MAX9238EUM+ support AC-coupling, and what design considerations apply?

Yes, the MAX9238EUM+ supports AC-coupling via built-in DC balance (DSV ≤10), allowing series capacitors to isolate ground potential differences. Designers must use high-frequency ceramic capacitors (e.g., 0.077µF for 2% droop at 8MHz, scaled per Equation 1) and ensure proper biasing: unused LVDS inputs require 10kΩ pullup/pulldown resistors, while the clock input needs ±15mV differential bias via matched 10kΩ resistors to prevent noise-induced false triggering.

How does the PWRDWN pin function on the MAX9238EUM+?

The PWRDWN pin on the MAX9238EUM+ is a 5V-tolerant LVTTL/LVCMOS input, internally pulled down to GND. Driving it low places all 21 RxOUT and RxCLK OUT pins in high-impedance state, stops the PLL, and reduces supply current to ≤50µA. This enables output busing-two MAX9238EUM+ devices can share a common data bus, with PWRDWN sequencing (≥100ns delay between disable/enable) preventing contention.

What is the purpose of the N.C. pin (Pin 6) on the MAX9238EUM+?

Pin 6 on the MAX9238EUM+ is designated No Connect (N.C.)-it is unconnected internally and must remain floating or grounded (not driven). This distinguishes the MAX9238EUM+ from the pin-compatible MAX9222EUM+, where Pin 6 serves as the DCB (DC Balance) configuration input. Leaving Pin 6 unconnected ensures the MAX9238EUM+ operates exclusively in DC-balanced mode, as specified in its functional description.

Which serializer ICs are compatible with the MAX9238EUM+?

The MAX9238EUM+ is designed to decode data from Maxim's MAX9209, MAX9211, MAX9213, and MAX9215 serializers-each implementing the same 7+2-bit DC-balanced encoding scheme. These serializers provide complementary LVDS outputs and support matching frequency ranges (e.g., MAX9215 covers 16–66MHz), ensuring full interoperability. Interoperability is validated only with these specific Maxim parts; third-party serializers are not guaranteed compatible due to encoding and timing dependencies.