4078

4078 - 8-Input NOR/OR Gate Technical Summary

Overview

The 4078 is a high-performance CMOS 8-input NOR/OR gate integrated circuit designed for medium-speed digital logic applications. This device is part of the 4000B series CMOS logic family and is available in two temperature range variants: the HCC4078B for extended temperature range operation and the HCF4078B for intermediate temperature range applications. The 4078 provides a versatile logic solution with its 8-input NOR gate complemented by an OR output, making it suitable for complex logic operations requiring high fan-in capabilities.

Manufactured using silicon gate CMOS technology, the 4078 offers the low power consumption typical of CMOS devices while providing improved speed over basic 4000-series parts. The device is characterized for operation at multiple supply voltages, making it adaptable to various system requirements.

Key Features

• Medium-speed operation with typical propagation delay of 75ns at VDD = 10V
• Wide supply voltage range: 3V to 20V (HCC device)
• Low power consumption with quiescent current specified up to 20V
• Parametric ratings available for 5V, 10V, and 15V operation
• Exceptionally low input current: 100nA maximum at 18V and 25°C (HCC device)
• 100% tested for quiescent current compliance
• Complies with JEDEC Tentative Standard No. 13A for "B" series CMOS devices
• Buffered inputs and outputs for improved noise immunity
• Standardized symmetrical output characteristics

Applications

The 4078 finds use in a wide range of digital logic applications including:

• High fan-in logic systems
• Arithmetic logic units (ALUs)
• Data processing systems
• Industrial control systems
• Automotive electronics
• Instrumentation and measurement equipment
• Communication systems
• Security systems
• Waveform generation
• Multi-input gating applications

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (VDD): -0.5V to +22V
• Input Voltage (VIN): -0.5V to VDD + 0.5V
• DC Input Current (IIN): ±10mA
• Operating Temperature Range:
  • HCC4078B: -55°C to +125°C
  • HCF4078B: -40°C to +85°C
• Storage Temperature Range: -65°C to +150°C

DC Characteristics (VDD = 5V, 10V, 15V, TA = 25°C)

• High Level Output Voltage (VOH): 4.95V (min) at VDD = 5V
• Low Level Output Voltage (VOL): 0.05V (max) at VDD = 5V
• Input Leakage Current (IIN): ±100nA (max) at VDD = 18V
• Quiescent Device Current (IDD): 1μA (max) at VDD = 20V

AC Characteristics (TA = 25°C)

• Propagation Delay Time (tPHL, tPLH):
  • 75ns (typ) at VDD = 10V, CL = 50pF
  • 150ns (max) at VDD = 5V, CL = 50pF
• Transition Time (tTLH, tTHL): 75ns (typ) at VDD = 10V, CL = 50pF
• Input Capacitance (CIN): 7.5pF (typ)

Functional Description

The 4078 is an 8-input NOR gate with an additional OR output. The device features buffered inputs and outputs to provide standard logic levels and improved noise immunity. The NOR output provides the logical NOR of all eight inputs, while the OR output provides the complement of the NOR function (effectively an OR of all inputs).

When any input is high, the NOR output will be low and the OR output will be high. When all inputs are low, the NOR output will be high and the OR output will be low. This dual-output configuration provides flexibility in system design, allowing the device to serve multiple logic functions within a circuit.

Package Information

The 4078 is available in multiple package options to suit different application requirements:

Standard Package Options

• 14-lead PDIP (Plastic Dual In-line Package)
  • Body Dimensions: 19.3mm x 6.35mm
  • Lead Pitch: 2.54mm
• 14-lead SOIC (Small Outline Integrated Circuit)
  • Body Dimensions: 8.65mm x 3.9mm
  • Lead Pitch: 1.27mm
• 14-lead TSSOP (Thin Shrink Small Outline Package)
  • Body Dimensions: 5mm x 4.4mm
  • Lead Pitch: 0.65mm

Pin Configuration

• Pin 1: Input A
• Pin 2: Input B
• Pin 3: Input C
• Pin 4: Input D
• Pin 5: Input E
• Pin 6: Input F
• Pin 7: VSS (Ground)
• Pin 8: OR Output
• Pin 9: NOR Output
• Pin 10: Input G
• Pin 11: Input H
• Pin 12: NC (No Connection)
• Pin 13: NC (No Connection)
• Pin 14: VDD (Positive Supply)

Design Considerations

When implementing the 4078 in circuit designs, several factors should be considered:

Power Supply Decoupling

Proper power supply decoupling is essential for reliable operation. A 0.1μF ceramic capacitor should be placed as close as possible between VDD and VSS pins to minimize noise and voltage fluctuations.

Unused Inputs

All unused inputs must be tied to either VDD or VSS to prevent floating input conditions that could lead to excessive power consumption or erratic operation. In most applications, tying unused inputs to VSS is preferred.

Output Loading

The output drive capability is limited to approximately 1mA at 5V supply. For driving higher current loads or large capacitive loads, an appropriate buffer or driver should be used.

Transition Times

The relatively slow transition times (compared to modern high-speed logic families) make the 4078 susceptible to transmission line effects in high-speed applications. Proper termination techniques should be employed for trace lengths exceeding a few centimeters.

Reliability and Quality

The 4078 is manufactured under strict quality control procedures and meets or exceeds all relevant industry standards. Key reliability features include:

• ESD protection on all inputs and outputs
• Latch-up immunity exceeds 100mA
• 100% automated testing of DC parameters
• Burn-in available for high-reliability applications
• Moisture Sensitivity Level (MSL) rating of 1 for most packages

Environmental Compliance

The 4078 is available in lead-free and RoHS compliant versions, meeting current environmental regulations for hazardous substances. The device is also halogen-free in its standard versions.

Ordering Information

The device is available with several ordering options:

• Temperature range suffix:
  • HCC: -55°C to +125°C
  • HCF: -40°C to +85