Overview
The CD74HC85EE4 is a high-speed CMOS logic 4-bit magnitude comparator produced by Texas Instruments. This device utilizes silicon-gate CMOS technology to achieve operating speeds similar to LSTTL (Low-power Schottky Transistor-Transistor Logic) while maintaining the low power consumption characteristic of standard CMOS integrated circuits. The CD74HC85EE4 compares two binary, BCD, or other monotonic codes and presents the three possible magnitude results at the outputs (A > B, A < B, and A = B). The 4-bit input words are weighted, with A3 and B3 being the most significant bits. This component is available in a 16-pin PDIP (Plastic Dual In-Line Package) and is part of the HC (High-Speed CMOS) family, known for its high noise immunity and significant power reduction compared to LSTTL logic ICs.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC (Supply Voltage Range) | 2 | 6 | V | |
| VCC (Supply Voltage Range) for HCT types | 4.5 | 5.5 | V | |
| VI, VO (Input or Output Voltage) | 0 | VCC | V | |
| TA (Temperature Range) | -55 | 125 | ℃ | |
| tPLH, tPHL (Propagation Delay, An, Bn to (A > B) OUT, (A < B) OUT) | 140 | 175 | 210 | ns |
| tPLH, tPHL (Propagation Delay, An, Bn to (A = B) OUT) | 175 | 240 | 265 | ns |
| VIL (Low Level Input Voltage) for HCT types | 0.8 | V | ||
| VIH (High Level Input Voltage) for HCT types | 2 | V | ||
| ICC (Supply Current) | 80 | μA | ||
| ΔICC (Additional Supply Current per Input Pin) | 100 | μA |
Key Features
- Buffered inputs and outputs
- Typical propagation delay: 13 ns (data to output at VCC = 5 V, CL = 15 pF, TA = 25℃)
- Serial or parallel expansion without external gating
- Fanout (over temperature range): Standard outputs support 10 LSTTL loads, bus driver outputs support 15 LSTTL loads
- Wide operating temperature range: -55℃ to 125℃
- Balanced propagation delay and transition times
- Significant power reduction compared to LSTTL logic ICs
- HC types: 2 V to 6 V operation, high noise immunity (NIL = 30%, NIH = 30% of VCC at VCC = 5 V)
- HCT types: 4.5 V to 5.5 V operation, direct LSTTL input logic compatibility, CMOS input compatibility
Applications
The CD74HC85EE4 is suitable for various digital logic and comparison applications, including:
- Binary, BCD, or other monotonic code comparisons
- High-speed digital circuits requiring low power consumption
- Systems needing high noise immunity and balanced propagation delays
- Applications across a wide temperature range (-55℃ to 125℃)
- Serial and parallel data processing systems
Q & A
- What is the typical propagation delay of the CD74HC85EE4?
The typical propagation delay is 13 ns at VCC = 5 V, CL = 15 pF, and TA = 25℃.
- What is the operating voltage range for the HC types of this component?
The operating voltage range for HC types is 2 V to 6 V.
- What is the operating voltage range for the HCT types of this component?
The operating voltage range for HCT types is 4.5 V to 5.5 V.
- What is the temperature range for the CD74HC85EE4?
The temperature range is -55℃ to 125℃.
- Can the CD74HC85EE4 be expanded in serial or parallel fashion without external gating?
- What is the fanout capability of the CD74HC85EE4?
The standard outputs can drive up to 10 LSTTL loads, and the bus driver outputs can drive up to 15 LSTTL loads.
- What is the supply current for the CD74HC85EE4?
The supply current is up to 80 μA.
- Does the CD74HC85EE4 have high noise immunity?
- Is the CD74HC85EE4 compatible with LSTTL input logic?
- What package types are available for the CD74HC85EE4?
The CD74HC85EE4 is available in a 16-pin PDIP (Plastic Dual In-Line Package).
