SN74HC165NS Texas Instruments Integrated Circuit (Small Outline Packages) In Stock
SN74HC165NS is an 8-bit parallel-in serial-out shift register from Texas Instruments operating from 2 V to 6 V. It features a 30 ns maximum propagation delay at 5 V and fits a 16-pin SOIC package for straightforward PCB integration.
- Manufacturer
- Texas Instruments
- Package
- Small Outline Packages
- Pin Count
- 16
- Lifecycle
- ACTIVE
- Datasheet
- SN74HC165NS Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 8-bit parallel-load capability converts 8 digital inputs to a serial bitstream in a single clock cycle, simplifying microcontroller GPIO expansion
- Wide 2 V to 6 V supply range ensures compatibility with both 3.3 V CMOS and 5 V TTL logic families
- Cascadable architecture allows chaining multiple SN74HC165 devices to read 16, 24, or more parallel inputs over 2 SPI-compatible wires
Applications
SN74HC165NS is widely used in keyboard matrix scanning, DIP switch reading, and sensor array interfacing where many parallel digital inputs must be serialized to a microcontroller SPI or bit-bang port. Its 2 V to 6 V operating range makes it suitable for both legacy 5 V industrial controllers and modern 3.3 V embedded systems. Cascading multiple devices provides a scalable input expansion solution without additional address decoding logic.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for SN74HC165NS:
Parallel In Serial Out, HC/UH Series, 8-Bit, Right Direction, Complementary Output, CMOS, PDSO16
Parallel In Serial Out, HC/UH Series, 8-Bit, Right Direction, Complementary Output, CMOS, PDSO16
Frequently Asked Questions
How fast can SN74HC165NS shift out 8 parallel inputs at 5 V supply?
At a 5 V supply, SN74HC165NS has a maximum propagation delay of 30 ns per stage and supports clock frequencies up to approximately 25 MHz. Loading 8 parallel inputs takes one load pulse, and shifting all 8 bits to the serial output requires only 8 clock cycles, completing a full read in roughly 320 ns at 25 MHz. This speed is more than adequate for keyboard scanning, switch debounce readback, and sensor polling in embedded control systems.
Can SN74HC165NS interface directly with a 3.3 V microcontroller without level shifting?
Yes. SN74HC165NS operates from 2 V to 6 V supply and its input high threshold (VIH) is typically 70% of VCC. When powered at 3.3 V, VIH is approximately 2.3 V, which is within the output range of standard 3.3 V CMOS logic. The shift register can therefore connect directly to a 3.3 V MCU SPI port without a level-shifter IC, reducing BOM cost and simplifying layout in space-constrained IoT and wearable designs.
How do you cascade multiple SN74HC165NS devices to read 16 parallel inputs over a 2-wire serial bus?
Chaining two SN74HC165NS devices requires connecting the serial output (QH) of the first device to the serial data input (DS) of the second, while sharing the same CLK and SH/LD lines. After asserting SH/LD low to load all 16 parallel inputs simultaneously, 16 clock pulses shift out two 8-bit words serially. This cascaded configuration reads 16 inputs using only 3 MCU GPIO pins — CLK, SH/LD, and MISO — with each additional device adding 8 channels at no extra wiring cost.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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