General Description
The Fairchild Semiconductor 100319QI is a member of the 100K ECL (Emitter-Coupled Logic) family, specifically a dual differential 4-input multiplexer. It is designed for high-speed digital applications and is optimized for systems requiring low propagation delays and high data throughput. This device offers differential ECL-compatible inputs and outputs, making it ideal for high-speed logic systems and communication interfaces.

Functional Description
The 100319QI integrates two identical 4:1 multiplexers. Each multiplexer selects one of four differential data inputs (D0–D3) under the control of two select inputs (S0 and S1). The selected input pair is passed through to the differential output pair. This structure enables the selection and routing of high-speed digital signals with minimal jitter and high signal integrity.

Key Features

* Dual 4-input differential multiplexers
* ECL-compatible logic levels (MECL 10K/100K standard)
* Differential inputs and outputs for noise immunity and signal integrity
* High-speed operation with low propagation delay
* 100K logic family compatibility

Electrical Characteristics (Typical @ 25°C, V_EE = -4.5V)

* Propagation Delay (tpd): 1.0 ns (typ), 1.5 ns (max)
* Maximum Toggle Frequency: >500 MHz
* Input Voltage Levels:

* VIH (min): -1165 mV
* VIL (max): -1475 mV
* Output Voltage Levels:

* VOH: -880 mV (typ)
* VOL: -1610 mV (typ)
* Power Dissipation: Approx. 440 mW (per device)
* Noise Margin: Typically 150 mV
* Input Current: ±300 µA (max)

Supply and Power

* Power Supply: V_CC = 0V, V_EE = -4.5V (typ)
* Power Supply Range: V_EE from -4.2V to -5.5V
* Total Device Dissipation: Less than 500 mW (standard operation)

Package and Mounting

* Package Type: Ceramic Leadless Chip Carrier (CLCC)
* Package Code: QI (32-lead square ceramic chip carrier)
* Mounting: Surface-mount technology (SMT)
* Pin Count: 32
* Dimensions: Standard 32-pin CLCC footprint

Temperature and Environmental Ratings

* Operating Temperature Range: 0°C to +85°C
* Storage Temperature Range: –65°C to +150°C
* ESD Protection: Built-in input protection diodes

Applications

* High-speed digital multiplexing and signal routing
* Clock and data path selection in high-speed computing systems
* Telecommunication systems requiring low-skew signal switching
* Data acquisition systems
* Digital test equipment and automatic test systems (ATE)
* Logic level translation and interfacing in mixed-voltage systems

Design Considerations

* ECL logic requires proper termination and controlled impedance traces for high-frequency signals
* Differential architecture requires matched-length routing to maintain signal integrity
* Power supply filtering and bypassing are critical for minimizing jitter and crosstalk
* CLCC package may require thermal management in high-speed or high-density applications

Conclusion
The Fairchild 100319QI is a robust and reliable choice for engineers designing high-speed digital systems with differential signaling. With its dual 4:1 multiplexer architecture and compliance with the 100K ECL logic family, it provides excellent speed, noise immunity, and compatibility for demanding communication and logic applications.