Overview
The CD74HC165M is an 8-bit parallel or serial-in shift register produced by Texas Instruments. It is part of the HC and HCT series of high-speed CMOS logic integrated circuits. This device is designed to handle both parallel and serial data input and output, making it versatile for various digital logic applications. When the parallel load (SH/LD) input is LOW, the register loads parallel data from inputs A to H asynchronously. When the SH/LD is HIGH, data enters the register serially at the SER input and shifts one place to the right with each positive-going clock transition. This feature enables parallel-to-serial converter expansion by connecting the QH output to the SER input of the succeeding device.
Key Specifications
| Parameter | Condition | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| VCC Supply Voltage | HC Types | 2 | - | 6 | V |
| VCC Supply Voltage | HCT Types | 4.5 | - | 5.5 | V |
| Input Voltage (VI) | - | 0 | - | VCC | V |
| High Level Input Voltage (VIH) | VCC = 2 V | 1.5 | - | 1.5 | V |
| Low Level Input Voltage (VIL) | VCC = 2 V | 0.5 | - | 0.5 | V |
| High Level Output Voltage (VOH) | IOH = -20 μA, VCC = 4.5 V | 4.4 | - | 4.4 | V |
| Low Level Output Voltage (VOL) | IOL = 20 μA, VCC = 4.5 V | 0.1 | - | 0.1 | V |
| Propagation Delay (tpd) | CLK to QH, VCC = 4.5 V | 13 | - | 33 | ns |
| Maximum Clock Pulse Frequency (fMAX) | VCC = 4.5 V | 27 | - | - | MHz |
| Operating Temperature Range | - | -55 | - | 125 | ℃ |
| Junction Temperature | - | - | - | 150 | ℃ |
Key Features
- Buffered inputs
- Asynchronous parallel load
- Complementary serial outputs (QH and Q̄H)
- Fanout capability: 10 LSTTL loads for standard outputs, 15 LSTTL loads for bus driver outputs
- 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
- HCT types: 4.5 V to 5.5 V operation, direct LSTTL input logic compatibility
Applications
- Parallel-to-serial data conversion
- Serial data transmission and reception
- Shift register applications in digital logic circuits
- Use in microprocessor and microcontroller systems for data serialization
- Applications requiring high-speed CMOS logic with low power consumption
Q & A
- What is the CD74HC165M used for?
The CD74HC165M is an 8-bit parallel or serial-in shift register used for parallel-to-serial data conversion and other digital logic applications.
- What are the operating voltage ranges for the HC and HCT types?
The HC types operate from 2 V to 6 V, while the HCT types operate from 4.5 V to 5.5 V.
- What is the maximum clock pulse frequency for the CD74HC165M?
The maximum clock pulse frequency is 27 MHz at VCC = 4.5 V.
- What is the propagation delay from CLK to QH?
The propagation delay from CLK to QH is typically 13 ns at VCC = 4.5 V.
- What is the fanout capability of the CD74HC165M?
The device can drive up to 10 LSTTL loads for standard outputs and up to 15 LSTTL loads for bus driver outputs.
- What is the operating temperature range of the CD74HC165M?
The operating temperature range is -55℃ to 125℃.
- How does the parallel load function work?
When the parallel load (SH/LD) input is LOW, parallel data from inputs A to H are loaded into the register asynchronously.
- Can the CD74HC165M be used in serial data transmission?
- What are the package options for the CD74HC165M?
The device is available in SOIC-16, PDIP-16, and CDIP-16 packages.
- What are the thermal considerations for the CD74HC165M?
The junction-to-ambient thermal resistance (RθJA) varies depending on the package, with values such as 73 °C/W for SOIC-16 and 67 °C/W for PDIP-16.
