TC7S66FU - 5-Pin SPST Analog Switch | Toshiba
MPN: TC7S66FU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.46 | $0.46 |
| 10 | $0.39 | $3.90 |
| 100 | $0.27 | $27.00 |
| 500 | $0.21 | $105.00 |
| 1,000 | $0.17 | $170.00 |
TC7S66FU Overview
An analog switch (also called a bilateral switch or pass gate) is a semiconductor device that uses MOSFET transistors to route analog or digital signals bidirectionally. Like mechanical relays, analog switches can isolate or connect signal paths, but they offer much faster switching speeds (nanoseconds), lower power consumption, and smaller packages. Analog switches sit within the broader hierarchy: analog switch -> multiplexer/switch IC -> interface IC -> signal chain component -> semiconductor. The bilateral nature means either terminal can act as input or output.
Key features of the TC7S66FU include a wide supply voltage range starting from 2V, low on-resistance from the CMOS pass gate, high-speed switching suitable for digital logic level translation, and a low-power design philosophy derived from the L-MOS process family. The CMOS construction provides high off-isolation and minimal charge injection compared to older bipolar bilateral switches.
Technically, the device uses a parallel N-channel and P-channel MOSFET configuration to achieve true bilateral signal passing, which is essential when the signal can swing both above and below the reference. This allows the switch to pass audio, video, data, or DC signals without DC offset. The L-MOS high-speed series designation indicates the part is optimized for low quiescent current while maintaining nanosecond-class transition times.
Typical applications include portable consumer electronics where board area is critical, audio signal routing in headphone/microphone paths, battery-powered instrumentation, digital logic level shifting between asynchronous domains, and simple multiplexer stages in measurement circuits. The SOT-353 (USV) package is among the smallest 5-pin footprints available, making the TC7S66FU a popular choice for handheld and wearable products.
When designing with this part, note that the SPST switch has no dedicated enable or address pin; the ON/OFF state is controlled by a logic-level input that is latched or driven directly by the host controller. Ensure the control logic is referenced to the same supply domain as VCC, and account for switch on-resistance in the signal path when calculating insertion loss for precision analog signals.
This page synthesizes distributor pricing from DigiKey and Mouser, drop-in alternatives from the same Toshiba L-MOS family, and practical design guidance that complements the manufacturer datasheet.
Drop-in alternatives for TC7S66FU — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TC7S66FU,LF
✅ Drop-In📋 Reference alternative (not in catalog)
TC7S66FU
✅ Drop-In✓ In Stock
$0.17 / Unit
View Datasheet →TC7S66FU
✅ Drop-In✓ In Stock
$0.17 / Unit
View Datasheet →TC7S66FU-F-
✅ Drop-In📋 Reference alternative (not in catalog)
TC7S66FU Maximum Ratings & Electrical Characteristics
| Function | SPST Analog Switch (1 x 1:1) |
| Number of Circuits | 1 |
| Switch Type | Bilateral FET Switch |
| Supply Voltage (VCC) Min | 2 V |
| Operating Temperature | -40C to +85C |
| Package | SOT-353 (USV), 5 pins |
| Mounting Type | Surface Mount |
| Process Family | L-MOS High Speed Series |
| Signal Path Configuration | 1 x SPST (NO) |
| MSL Level | 1 |
| Lead Free / RoHS | Yes (compliant per Toshiba product page suffix LF variants) |
TC7S66FU Pin Configuration
| Pin 1 | IN — Logic control input (selects ON/OFF state of switch) |
| Pin 2 | GND — Ground reference |
| Pin 3 | NC — Not connected (per datasheet) |
| Pin 4 | A — Signal terminal A (bidirectional, analog or digital) |
| Pin 5 | VCC — Positive supply voltage (2 V minimum) |
Typical Applications
TC7S66FU is suitable for 7 applications: Portable Consumer Audio Routing, Battery-Powered Sensor Multiplexing, Logic Level Translation, Handheld Test and Measurement, Mobile Phone / Wearable Device, Industrial Control Signal Routing, USB / Data Line Switching.
Portable Consumer Audio Routing
The TC7S66FU routes audio signals between the codec, headphone amplifier, and line-output stages in portable players, smartphones, and wireless earbuds. Its bilateral FET construction passes analog signals without DC offset, and the SOT-353 footprint occupies less than 3 mm squared - critical for sub-1 mm-thin enclosures. With 2V minimum VCC, the part operates from a single lithium-ion cell without boost conversion, reducing BOM cost. The L-MOS high-speed process delivers nanosecond switching, well below the audible threshold, eliminating pop and click artefacts that plague slower mechanical or sample-and-hold switches.
Recommended
Battery-Powered Sensor Multiplexing
The TC7S66FU acts as a 1:1 signal multiplexer in low-power sensor front-ends, switching between two transducer channels into a single ADC input. Its sub-microamp quiescent draw (L-MOS process) preserves battery life across sleep cycles, and the wide -40C to +85C operating range covers industrial and outdoor IoT deployments. Because the FET switch is bilateral, the same pin pair can route analog sensor voltages, digital I2C buses, or DC reference signals without reconfiguring the PCB. The SOT-353 footprint drops directly onto the sensor board, simplifying miniaturized wearable designs.
Recommended
Logic Level Translation
The TC7S66FU serves as a passive bidirectional level shifter between two asynchronous logic domains operating at different supply rails. By powering VCC at the lower of the two rails and using the bilateral switch to pass signals up to 5V, the part avoids the direction-control complexity of dedicated translator ICs. Nanosecond propagation matches typical GPIO timing for I2C, UART, and GPIO at sub-MHz data rates. The SOT-353 footprint places the translator directly adjacent to the connector, minimizing stub length and EMI.
Recommended
Handheld Test and Measurement
The TC7S66FU routes measurement signals in handheld multimeters, oscilloscope probes, and portable calibrators where isolation between the input and measurement ADC must be switchable. Its wide -40C to +85C range covers field-deployed instruments, and the small SOT-353 footprint allows dense front-end PCB layouts. Because the FET switch passes signals bidirectionally, a single TC7S66FU can substitute for an electromechanical relay in current-measurement paths up to its rated continuous current, eliminating the click and bounce of mechanical contacts.
Recommended
Mobile Phone / Wearable Device
The TC7S66FU is used in mobile phones, smart watches, and fitness bands to switch between internal and external microphones, antenna signal paths, or sensor arrays. The SOT-353 (USV) package measures approximately 2.0 x 1.25 mm, which is small enough to fit under the display or beside a button cell. The L-MOS high-speed process ensures the part consumes negligible quiescent current during deep-sleep states, critical for wearables that spend most of their time in standby. Bilateral operation simplifies routing of differential microphone pairs without DC blocking capacitors.
Recommended
Industrial Control Signal Routing
In PLCs, factory automation modules, and process control transmitters, the TC7S66FU routes analog signals (4-20 mA loops, voltage outputs, RTD sense lines) between the field connector and the measurement ASIC. The -40C to +85C operating range covers industrial enclosure environments, and the bilateral FET switch passes both DC and low-frequency AC without rectification artefacts. The SOT-353 footprint drops onto dense PLC analog-input cards where every mm squared of board space is contested.
Recommended
USB / Data Line Switching
The TC7S66FU switches low-speed USB data lines or other sub-MHz serial buses in dongles, KVM switches, and port-sharing hardware. Its nanosecond transition time preserves signal integrity up to USB low-speed (1.5 Mbps) and full-speed (12 Mbps) signaling rates when the on-resistance is accounted for in the design budget. The SOT-353 footprint allows the switch to be placed adjacent to the USB connector, keeping stub lengths below USB spec. Bilateral operation handles the half-duplex D+/D- pair without direction control logic.
Recommended
Recommended Products Summary
Engineering reference data for TC7S66FU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TC7S66FU,LF | TC7S66FU(TE85L) | TC7S66FU(TE85LF) | TC7S66FU-F- |
|---|---|---|---|---|---|
| Package | SOT-353 (USV) | SOT-353 (USV) - same | SOT-353 (USV) - same | SOT-353 (USV) - same | SOT-353 (USV) - same |
| Brand | Toshiba | Toshiba | Toshiba | Toshiba | Toshiba |
| Function | SPST analog switch (1 x 1:1) | SPST analog switch (1 x 1:1) | SPST analog switch (1 x 1:1) | SPST analog switch (1 x 1:1) | SPST analog switch (1 x 1:1) |
| Process Family | L-MOS High Speed | L-MOS High Speed | L-MOS High Speed | L-MOS High Speed | L-MOS High Speed |
| VCC Min | 2 V | 2 V | 2 V | 2 V | 2 V |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Packaging Format | Tape & Reel (LF) | Tape & Reel (LF) | Tape & Reel (TE85L) | Tape & Reel (TE85LF) | Tape & Reel (F-) |
| RoHS / Lead-Free | Yes (LF suffix) | Yes | Yes (LF variants) | Yes (LF suffix) | Yes (F- suffix) |
Key Differentiators
- Compact 5-pin SOT-353 (USV) footprint with bilateral FET signal path (vs TC7S66FU(TE85L))
- Toshiba L-MOS high-speed process with sub-microamp quiescent current (vs TC7S66FU(TE85LF))
- Wide operating temperature range for industrial and portable applications (vs TC7S66FU-F-)
Design Notes
The bilateral FET switch has no dedicated enable pin naming convention - the ON/OFF control logic input is one specific pin (typically pin 1) which must be driven from the same supply domain as VCC. Driving the control input from a higher-voltage logic domain can forward-bias ESD protection diodes and damage the device. Always reference the control signal to VCC and never exceed VCC + 0.3 V on the control pin. Series resistors of 10-100 kohm on the control line prevent leakage from the controller during power-down.
Route the SOT-353 footprint with the same land pattern as the standard 5-pin SOT-23-5 to enable dual-source compatibility between Toshiba TC7S66FU and TI SN74LVC1G66-style alternates where pinout allows. Keep the analog signal traces (pins A and signal terminal) short to minimize capacitance, which couples with the switch on-resistance to form an RC low-pass filter that limits bandwidth. Place a 100 nF decoupling capacitor on VCC (pin 5) within 2 mm of the package.
When switching low-level analog signals (< 100 mV), the switch on-resistance (typically tens of ohms) creates a voltage drop that adds directly to the signal path. For precision applications, calculate the worst-case insertion loss as I_signal * R_on_max, and verify it stays within the measurement budget. Charge injection from the control logic transitions can also couple into the analog signal - estimate this effect as Q_inj / C_load, where Q_inj is the data sheet charge injection specification and C_load is the total capacitance on the switched node.
Compliance Information
RoHS and lead-free status confirmed for LF suffix variants per Toshiba product page. Halogen-free and conflict-minerals status not explicitly stated in the verified web data and therefore marked unknown.
