Interface ICs
USB bridges, transceivers, expanders, and level shifters: driver situations, reference pins, and bus speed limits.
Written and verified by John Merton · verified 2026-07-14
Interface ICs sit between different protocols, voltage domains, or physical media. This category covers USB-UART bridges like the CH340C and CP2102N, CAN transceivers like the SN65HVD230, and level shifters. The gotcha that recurs across this category is bus-pin fault tolerance: the transceiver's absolute maximum ratings on the bus pins are the ceiling for harness faults, and a short to a higher supply rail that the datasheet limits cannot survive needs external protection.
The SN65HVD230 is the 3.3 V CAN transceiver that proves mixed-supply CAN buses work: its dominant differential output meets ISO 11898-2 levels, so it drops onto 5 V CAN buses without a second supply rail. The CH340C is the USB-UART bridge on a large share of cheap dev boards, and its page documents the driver situations that break on Windows, macOS, and Linux — because the chip itself is fine, but the driver situation is not.
How to choose
The axes below are the criteria you actually weigh when selecting a part in this category.
- Bus-pin fault tolerance and external protection needs
- The absolute maximum voltage on the bus pins is the transceiver's survival ceiling. If your harness can short to a supply above that ceiling, you need external TVS or series protection before the transceiver.
- See:SN65HVD230CH340CCP2102N
- Logic-side voltage domain and 5 V tolerance
- The SN65HVD230's D and R pins are 3.3 V-only — 5 V logic on them exceeds absolute maximum. Check whether the logic pins are 5 V-tolerant before connecting directly to a 5 V MCU.
- See:SN65HVD230CH340CCP2102N
- Driver availability across operating systems
- USB-UART bridges differ mainly in driver availability. The CH340C needs a driver install on most platforms. The CP2102N has better OS support. The silicon is rarely the problem; the driver situation is.
- See:CH340CCP2102N
- Mode pin configuration and standby behavior
- Transceivers with mode pins (RS on the SN65HVD230) can silently enter standby and disable the driver. A floating mode pin that wanders into standby looks like a dead transmitter in the field.
- See:SN65HVD230
Standout parts
A small curated group of parts in this category that represent different positions on the selection axes. Start here if you are new to the category.
All parts in this category
- FT232RLNRND USB-to-UART bridge with integrated oscillator and EEPROM in SSOP-28; FTDI recommends the pin-compatible FT232RNL for new designs.NRND
- CH340CUSB-to-UART bridge with internal oscillator; dominant on budget dev boards.Active
- 74HC14Hex inverter with Schmitt-trigger inputs for squaring up slow and noisy signals.Active
- 74HC1658-bit parallel-load shift register for serializing switch and sensor inputs.Active
- 74HC5958-bit serial-in parallel-out shift register with latched 3-state outputs.Active
- ADS111516-bit I2C delta-sigma ADC with PGA, comparator, and a four-input mux.Active
- CD40174000-series Johnson decade counter: ten decoded outputs, one high per clock, 3–18 V supply.Active
- SN65HVD2303.3 V ISO 11898-2 CAN transceiver with slope control and listen-only standby.Active
- CP2102NUSB-to-UART bridge with internal oscillator and 3 Mbaud throughput; 3 package options down to 3x3 mm QFN.Active
- MCP2301716-bit I2C GPIO expander with two interrupt outputs, three address pins, and per-pin pull-ups.Active
Compare specs
Parts in this guide verified against manufacturer datasheets; latest 2026-07-14.
| MPN | Package | Lifecycle | Headline spec |
|---|---|---|---|
| FT232RL | SSOP-28 (FT232RL); also available as QFN-32 (FT232RQ) | NRND | VCC supply (internal oscillator): 4.0 V min / 5.25 V max |
| CH340C | SOP-16, 3.9 mm body, 1.27 mm pitch | Active | Supported baud range: 50 bps – 2 Mbps |
| 74HC14 | SOIC-14 (TI package code D) | Active | Supply voltage (recommended): VCC 2 V min / 5 V nom / 6 V max |
| 74HC165 | SOIC-16 (TI package code D) | Active | Supply range: VCC 2 V min / 5 V nom / 6 V max |
| 74HC595 | SOIC-16, 9.90 mm x 3.90 mm body (TI package code D) | Active | Supply voltage range: 2 V min / 5 V nom / 6 V max (VCC, SN74HC595 and SN54HC595) |
| ADS1115 | VSSOP-10 (TI package code DGS); also X2QFN-10 and SOT-5X3-10 | Active | Supply range: 2 V min to 5.5 V max (power supply, VDD to GND) |
| CD4017 | SOIC-16 (TI package code D) | Active | Supply voltage (recommended): VDD 3 V min / 18 V max (for TA = full package-temperature range) |
| SN65HVD230 | SOIC-8 (TI package code D), 4.90 × 3.91 mm body | Active | Supply voltage: 3 V min / 3.6 V max (features: 'Operates with a single 3.3 V Supply') |
| CP2102N | QFN28 (5x5 mm), QFN24 (4x4 mm), QFN20 (3x3 mm) | Active | Supply voltage (VDD): 3.0 V min / 3.3 V typ / 3.6 V max |
| MCP23017 | 28-pin QFN, wide SOIC, SPDIP, or SSOP | Active | Port: 16-bit remote port; GPA7 and GPB7 are output only on MCP23017 |
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