Analog Devices Inc./Maxim Integrated MAX9248ECM+

Overview

MAX9248ECM+ from Maxim Integrated is a 27-bit DC-balanced LVDS deserializer IC that converts high-speed serial video/control data into 18-bit RGB video and 9-bit control parallel outputs. It operates at 5MHz–42MHz parallel clock frequency, features ±2% or ±4% programmable spread-spectrum output for EMI reduction, and supports AC-coupled isolation in automotive display links. It pairs with MAX9247 serializer for in-vehicle navigation and infotainment systems.

For engineers reviewing the MAX9248ECM+ datasheet, MAX9248ECM+ pinout, MAX9248ECM+ application, or MAX9248ECM+ equivalent, key selection criteria include spread-spectrum configuration (SS pin), latch-edge polarity (R/F), frequency range selection (RNG[1:0]), LVDS input biasing, and dual-supply operation (VCC = 3.3V core, VCCO = 1.8V–3.3V I/O).

Technical Context

The MAX9248ECM+ implements a dual-phase deserialization architecture: video data (RGB_OUT[17:0]) is latched during DE_OUT high, while control data (CNTL_OUT[8:0]) is latched during DE_OUT low - both synchronized to PCLK_OUT edge selected by R/F. Its proprietary DC-balanced encoding enables AC-coupling across long cables, eliminating ground-shift issues in automotive environments.

Internally, it integrates a PLL for clock recovery from the LVDS stream and a dedicated spread-spectrum PLL (SSPLL) that modulates PCLK_OUT and data outputs at 32kHz (scaled with REFCLK). Input-to-output delay varies between (4.5t_T + 8.0)ns and (36t_T + 16)ns due to SSPLL phase uncertainty, requiring timing margining in synchronous interfaces.

Key Specifications

Pinout & Package

MAX9248ECM+ uses a 48-pin LQFP package with segregated power domains: VCCLVDS (LVDS receiver supply), VCCPLL (PLL supply), VCC (core digital supply), and VCCO (I/O output supply). Ground pins are split into LVDSGND, PLLGND, GND, and VCCOGND to minimize noise coupling between analog, PLL, and digital sections.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX9250ECM+, MAX9248ECM+ provides superior EMI suppression but lacks output busing; compared with DS90UB928QSQ/NOPB, it offers tighter integration with MAX9247 serializer and simpler timing but no embedded control channel - making it optimal for cost-sensitive, fixed-function display links.

Availability

MAX9248ECM+ is available at Aetrix Electronics and suitable for automotive navigation displays, in-vehicle entertainment systems, and LCD instrument clusters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX9248ECM+ 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 automotive, industrial, and communications applications.

The MAX9248ECM+ belongs to Maxim's automotive-grade LVDS serializer/deserializer family, engineered specifically for noise-immune, long-cable digital video transport in harsh vehicle environments - emphasizing EMI resilience, ground isolation, and functional safety readiness.

FAQ

What is the primary function of the MAX9248ECM+ in an automotive video link?

The MAX9248ECM+ is a 27-bit LVDS deserializer that recovers parallel RGB video (18-bit) and control data (9-bit) from a high-speed serial stream. It enables noise-immune video transmission over shielded twisted-pair cables in automotive applications such as digital dashboards and rear-seat displays, leveraging DC-balanced encoding and spread-spectrum clocking to meet stringent EMI requirements.

How does the SS pin affect the operation of the MAX9248ECM+?

The SS pin on the MAX9248ECM+ selects the spread-spectrum modulation depth: high = ±4%, low = ±2%. This modulates PCLK_OUT and all data outputs around the reference clock frequency to reduce peak radiated emissions. Changing SS state triggers a 32,800×t_T delay before valid outputs resume - a critical timing consideration during dynamic EMI tuning.

Can the MAX9248ECM+ operate without an external reference clock?

No - the MAX9248ECM+ requires a valid REFCLK input (5MHz–42MHz, ±2% tolerance) to achieve initial PLL lock before acquiring the serial stream. REFCLK is used for coarse frequency alignment and remains active during loss-of-lock conditions. The device cannot synchronize to the LVDS input alone without this local reference.

What is the significance of the RNG[1:0] pins on the MAX9248ECM+?

RNG[1:0] on the MAX9248ECM+ configure the internal PLL bandwidth and output transition time to match the serializer's PCLK_IN frequency. Valid settings are 01 (5–10MHz), 10 (10–20MHz), and 11 (20–42MHz). Incorrect selection causes failed lock or excessive jitter - the datasheet explicitly prohibits RNG=00.

Does the MAX9248ECM+ support AC-coupling, and how is it implemented?

Yes - the MAX9248ECM+ supports AC-coupling via internal 42kΩ–78kΩ bias resistors to 1.2V on IN+/IN-, enabling galvanic isolation between transmitter and receiver. This blocks ground potential differences and low-frequency noise. For robustness, four capacitors (two at each end) are recommended in noisy automotive environments.