onsemi MC100E122FNR2

Overview

MC100E122FNR2 from ON Semiconductor is a 9-bit non-inverting ECL buffer IC designed for high-speed clock and data distribution in PECL or NECL mode. It operates across VCC = 4.2–5.7 V (PECL) or VEE = −4.2 to −5.7 V (NECL), delivers ≤500 ps propagation delay, supports 800 MHz maximum toggle frequency, and features internal 50 kΩ input pulldown resistors for unused inputs - used in telecom line cards and high-speed test equipment.

For engineers reviewing the MC100E122FNR2 datasheet, pinout, applications, or equivalent options, this page provides verified package mapping (PLCC-28), confirmed DC/AC specs across temperature, real-world termination guidance (50 Ω to VCC − 2.0 V), and validated alternatives for ECL fanout expansion.

Technical Context

The MC100E122FNR2 implements nine independent ECL buffer stages with matched propagation paths, enabling sub-75 ps within-device skew (D→Q). Its dual-supply architecture supports both PECL (VCC = 4.2–5.7 V, VEE = 0 V) and NECL (VCC = 0 V, VEE = −4.2 to −5.7 V) configurations without external level shifting.

All nine inputs (D0–D8) and outputs (Q0–Q8) are fully differential ECL-compatible, with VOH/VOL specified at ±100 mV over temperature when terminated into 50 Ω to VCC − 2.0 V. Input thresholds track supply rails (VIH/VIL vary 1:1 with VCC), and IIL remains ≤0.5 µA across operating range.

Key Specifications

Pinout & Package

MC100E122FNR2 is housed in a 28-lead Plastic Leaded Chip Carrier (PLCC-28), case 776, with lead pitch 1.27 mm and body size 11.43 mm × 11.43 mm × 3.56 mm (R/U/H dimensions).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ECL buffer applications.

Compared with MC100E122FNR2, MC100E116FNR2 reduces channel count and removes input pulldowns, while SN65EPT23DR introduces LVDS interface logic - neither matches the 9-channel, self-biasing, pure-ECL fanout capability of MC100E122FNR2.

Availability

MC100E122FNR2 is available at Aetrix Electronics and suitable for telecom infrastructure, high-speed test instrumentation, radar beamforming, and industrial data acquisition requiring stable component supply and long-term obsolescence management.

Supply support for MC100E122FNR2 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

ON Semiconductor (now part of onsemi) is a global semiconductor supplier specializing in power management, analog, sensor, and logic solutions for automotive, industrial, and communications markets.

The MC100E122FNR2 belongs to the ECLinPS™ 100E family - engineered for high-speed, low-skew clock and data distribution in telecom and test equipment where sub-nanosecond timing integrity is mandatory.

FAQ

What is the recommended termination for MC100E122FNR2 outputs?

Each MC100E122FNR2 output must be terminated with a 50 Ω resistor to VCC − 2.0 V, as specified in Figure 3 and Application Note AND8020/D. This termination establishes correct ECL logic thresholds (VOH ≈ VCC − 0.9 V, VOL ≈ VCC − 1.7 V) and prevents reflections on high-speed traces. Failure to apply this exact termination results in invalid output voltage levels and timing violations.

Does MC100E122FNR2 support both PECL and NECL operation?

Yes, MC100E122FNR2 supports dual-mode operation: PECL mode with VCC = 4.2–5.7 V and VEE = 0 V, or NECL mode with VCC = 0 V and VEE = −4.2 to −5.7 V. The device's internal circuitry adapts automatically - no configuration pins or external components are needed to switch modes. Both modes deliver identical AC performance including ≤500 ps propagation delay and ≤75 ps skew.

What is the purpose of the internal 50 kΩ pulldown resistors on MC100E122FNR2 inputs?

The internal 50 kΩ pulldown resistors on D0–D8 of MC100E122FNR2 ensure unused inputs default to a defined LOW state (≈ VEE), preventing floating nodes that could cause excessive current draw or oscillation. This eliminates the need for external biasing components in partial-use configurations - a key reliability and BOM-cost advantage over earlier ECL families like 10E.

Can MC100E122FNR2 be used in industrial temperature range applications?

No - MC100E122FNR2 is rated for 0°C to +85°C only, as confirmed in Table 2 (TA Operating Temperature Range). It is not qualified for extended industrial (−40°C to +85°C) or automotive temperature ranges. For designs requiring operation below 0°C, derating analysis or alternative devices such as the MC100EP122 (−40°C to +85°C) must be evaluated.

How does MC100E122FNR2 differ from MC10E122FNR2?

MC100E122FNR2 includes on-die temperature compensation for improved VOH/VOL stability over temperature, whereas MC10E122FNR2 lacks this feature. Additionally, MC100E122FNR2 specifies tighter IIL limits (0.2–0.5 µA vs. 0.2–0.3 µA) and higher IEE upper limit (57 mA vs. 49 mA) at 85°C, reflecting its enhanced drive capability and thermal robustness for sustained high-speed operation.