Analog Devices Inc./Maxim Integrated MAX9422EHJ

Overview

MAX9422EHJ from Maxim Integrated is a quad differential LVECL-to-LVPECL translator in 32-pin TQFP (5mm × 5mm), designed for high-speed clock and data distribution. It features 100Ω differential input impedance, open-emitter LVPECL outputs, 336ps typical propagation delay (asynchronous mode), 17ps typical channel-to-channel skew, and operates from -40°C to +85°C with VEE = -2.0V to -3.6V and VCC = 2.375V to 3.6V. Used in DSLAM backplane clock distribution and base station timing subsystems.

For engineers reviewing the MAX9422EHJ datasheet, MAX9422EHJ pinout, MAX9422EHJ application, or MAX9422EHJ equivalent, this page delivers verified electrical parameters, synchronous/asynchronous operation modes, input termination architecture, thermal performance data, and real-world design constraints for high-frequency signal integrity-critical systems.

Technical Context

The MAX9422EHJ implements four independent LVECL-to-LVPECL translation channels with selectable synchronous (clocked) or asynchronous (transparent) operation via differential SEL inputs. Its internal 100Ω differential input termination eliminates external resistors, while open-emitter outputs require external 50Ω termination to VCC − 2.0V for proper LVPECL level compliance.

It supports dual supply rails: negative VEE (−2.0V to −3.6V) for LVECL-compatible input biasing and positive VCC (2.375V to 3.6V) for LVPECL output referencing. Propagation delay variation is tightly controlled at 0.2–1.0 ps/°C, and deterministic jitter remains ≤45 ps(P-P) at 3.0 Gbps input rates.

Key Specifications

Pinout & Package

MAX9422EHJ uses a 32-pin 5mm × 5mm TQFP package with exposed paddle connected to VEE internally. Pin functions are fully differential: each signal (IN₀–IN₃, OUT₀–OUT₃, CLK, SEL, EN) has complementary noninverting/inverting terminals. Power pins include four VCC (pins 11, 17, 24, 30), four GND (pins 14, 20, 21, 27), and two VEE (pins 1, 8).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad LVECL-to-LVPECL translation applications.

Compared with MAX9423EHJ, MAX9422EHJ trades integrated output termination for design flexibility in termination topology; versus MC100EP139DTG, it adds mode-selectable synchronous operation at the cost of slightly higher propagation delay and dual-supply requirement-critical for telecom clock tree reconfiguration.

Availability

MAX9422EHJ is available at Aetrix Electronics and suitable for DSLAM backplane clock distribution, base station timing subsystems, and central office interconnect applications requiring stable component supply across extended product lifecycles.

Supply support for MAX9422EHJ 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 industrial, communications, and computing markets.

The MAX9420–MAX9423 family targets high-frequency clock/data translation in telecom infrastructure, offering selectable operation modes, integrated terminations, and sub-350ps delay in compact packages.

FAQ

What is the correct termination configuration for MAX9422EHJ's open-emitter LVPECL outputs?

MAX9422EHJ requires external 50Ω termination from each output (e.g., OUT₀ and OUT₀) to VCC − 2.0V to establish valid LVPECL logic levels. Identical termination on both sides of each differential pair is mandatory to minimize output skew. The MAX9422EHJ datasheet specifies this as the standard configuration for achieving 600–660mV differential output amplitude and proper common-mode voltage (VCC − 1.5V to VCC − 1.1V).

How does the SEL input affect timing behavior in MAX9422EHJ?

In MAX9422EHJ, a differential high on SEL (SEL = high, SEL = low) enables asynchronous mode: inputs pass directly to outputs with 336ps typical delay. A differential low (SEL = low, SEL = high) enables synchronous mode: all four channels sample inputs on the rising edge of CLK, adding ~506ps typical CLK-to-OUT delay. This dual-mode capability is built into the MAX9422EHJ silicon and requires no external configuration registers.

Does MAX9422EHJ support DC coupling of LVECL inputs?

Yes, MAX9422EHJ supports DC-coupled LVECL inputs because its 100Ω differential input termination is internally connected between INₓ and INₓ, with no AC-blocking capacitors required. The input common-mode range (VEE to VEE + 1.4V) and differential voltage range (±3V max) are explicitly specified in the MAX9422EHJ datasheet for direct connection to LVECL drivers operating at VEE = −3.3V.

What is the maximum guaranteed data rate for MAX9422EHJ in asynchronous mode?

The MAX9422EHJ is guaranteed to operate up to 2GHz in asynchronous mode (SEL = high), with VOH − VOL ≥ 400mV, as confirmed in the AC Electrical Characteristics table. This rating is validated using 23−1 PRBS patterns and 125ps (20%–80%) input transition times under standard conditions (VEE = −3.3V, VCC = 3.3V, TA = +25°C). Performance degrades above 2GHz due to reduced output amplitude.

Can unused inputs on MAX9422EHJ be left floating?

No, unused inputs on MAX9422EHJ must not be left floating. The MAX9422EHJ datasheet mandates biasing unused differential inputs (e.g., IN₂, IN₂) with 1kΩ resistors to VCC or VEE to prevent noise-induced toggling. Figure 5 shows recommended bias networks: 1kΩ from INₓ to VCC and 1kΩ from INₓ to VEE for stable quiescent state-this is a hard design requirement for reliable MAX9422EHJ operation.