PIC16C745-I/SP - 8-bit 24MHz 14KB OTP USB MCU | Microchip
MPN: PIC16C745-I/SP β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.16 | $6.16 |
| 10 | $5.78 | $57.80 |
| 100 | $5.21 | $521.00 |
| 500 | $4.65 | $2,325.00 |
| 1,000 | $4.12 | $4,120.00 |
PIC16C745-I/SP Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, non-volatile program memory, working RAM, and peripheral blocks such as timers, ADC, communication controllers, and I/O. The PIC16C745 occupies the "small USB-enabled 8-bit MCU" tier in the broader taxonomy: PIC16C745 -> PIC16 family -> PIC microcontroller -> 8-bit MCU -> microcontroller -> embedded processor -> semiconductor. Its OTP (one-time programmable) program memory distinguishes it from flash-based siblings (PIC16F745) and from UV-erase windowed (PIC16C745-JW) variants, making it suitable for low-cost, high-volume production where firmware is finalized.
Key differentiating features include 22 I/O pins (higher than many 28-pin USB parts), 5 channels of 8-bit ADC, integrated USB 1.1 Low-Speed transceiver, and USART/SCI communication. The wide operating voltage (4.0 V to 5.5 V) and industrial temperature range (-40C to +85C) make it suitable for commercial and industrial embedded designs. The 28-pin SPDIP package supports easy prototyping on breadboards and through-hole production.
Architecturally, the PIC16C745 uses Microchip's enhanced Harvard architecture with separate program and data buses, a hardware multiplier-free RISC core, and direct peripheral access via SFRs. The integrated USB SIE handles Low-Speed signaling and packet framing, removing the need for an external USB transceiver or firmware bit-banging, which significantly simplifies HID-class and CDC-class device designs.
Typical applications include USB human-interface devices (keyboards, mice, game controllers), low-speed USB-to-serial bridges, industrial sensor front-ends with USB diagnostics, USB-based data-acquisition pods, and legacy equipment retrofits. The 5-channel ADC and 22 I/O lines also suit small instrumentation front-ends with a USB service port.
When designing with this device, note that the OTP memory cannot be reprogrammed in-circuit; prototypes should use the PIC16F745 (flash) or PIC16C745-JW (windowed) variant during development. A 24 MHz crystal or resonator is required for full-speed core operation, and the internal USB transceiver needs the proper D+/D- pull-up resistor (1.5 kohm to VCC) for Low-Speed enumeration.
This page synthesizes distributor pricing, drop-in package-compatible alternatives, application-specific design notes, and lifecycle intelligence not aggregated by any single distributor.
Drop-in alternatives for PIC16C745-I/SP β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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PIC16F745-I/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16C745-I/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16F745-I/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16F745T-I/SO
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16C745-I/SP
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$4.12 / Unit
View Datasheet βPIC16C745-I/SP Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Instruction Set | 35 single-word instructions |
| Program Memory | 14 KB OTP (8K x 14) |
| RAM | 256 bytes |
| Maximum CPU Frequency | 24 MHz |
| Instruction Cycle Time | 167 ns |
| Operating Voltage | 4.0 V to 5.5 V |
| I/O Pins | 22 |
| ADC | 5 channels x 8-bit |
| USB | USB 1.1 Low-Speed, integrated SIE + transceiver |
| UART/USART | 1 x USART (SCI) |
| Timers | Timer0, Timer1, Timer2 + WDT |
| Interrupt Sources | 10 |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 28-pin SPDIP (300 mil) |
| Mounting Type | Through-Hole |
| MSL Level | 1 (unlimited) |
| RoHS Status | Compliant |
PIC16C745-I/SP Pin Configuration
| Pin 1 | MCLR/VPP β Master Clear reset input / programming voltage |
| Pin 2 | RA0/AN0 β PORTA bit 0 / ADC analog input 0 |
| Pin 3 | RA1/AN1 β PORTA bit 1 / ADC analog input 1 |
| Pin 4 | RA2/AN2 β PORTA bit 2 / ADC analog input 2 |
| Pin 5 | RA3/AN3/VREF β PORTA bit 3 / ADC analog input 3 / ADC reference |
| Pin 6 | RA4/T0CKI β PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS β PORTA bit 5 / ADC analog input 4 / SPI slave select |
| Pin 8 | OSC1/CLKIN β Oscillator crystal input / external clock |
| Pin 9 | OSC2/CLKOUT β Oscillator crystal output / clock out |
| Pin 10 | RC0/T1OSO/T1CKI β PORTC bit 0 / Timer1 oscillator out / Timer1 clock |
| Pin 11 | RC1/T1OSI/CCP2 β PORTC bit 1 / Timer1 oscillator in / CCP2 |
| Pin 12 | RC2/CCP1 β PORTC bit 2 / Capture/Compare/PWM 1 |
| Pin 13 | RC3 β PORTC bit 3 |
| Pin 14 | RC4/DM β PORTC bit 4 / USB D-minus |
| Pin 15 | RC5/DP β PORTC bit 5 / USB D-plus |
| Pin 16 | RC6 β PORTC bit 6 |
| Pin 17 | RC7 β PORTC bit 7 |
| Pin 18 | VSS β Ground reference |
| Pin 19 | VDD β Positive supply (4.0 V to 5.5 V) |
| Pin 20 | RB0/INT β PORTB bit 0 / external interrupt |
| Pin 21 | RB1 β PORTB bit 1 |
| Pin 22 | RB2 β PORTB bit 2 |
| Pin 23 | RB3 β PORTB bit 3 |
| Pin 24 | RB4 β PORTB bit 4 |
| Pin 25 | RB5 β PORTB bit 5 |
| Pin 26 | RB6/PGC β PORTB bit 6 / ICSP clock |
| Pin 27 | RB7/PGD β PORTB bit 7 / ICSP data |
| Pin 28 | VSS β Ground reference |
Typical Applications
PIC16C745-I/SP is suitable for 6 applications: USB HID Peripherals (Keyboard/Mouse/Gamepad), USB-to-Serial Bridge (CDC Class), Industrial Sensor Front-End with USB Diagnostics, USB Data Acquisition Pod (Low-Speed), USB-Enabled Embedded Trainer Board, Legacy Equipment USB Retrofit.
USB HID Peripherals (Keyboard/Mouse/Gamepad)
The PIC16C745-I/SP is engineered for USB 1.1 Low-Speed HID-class devices such as keyboards, mice, joysticks, and gamepads. Its certified on-chip USB SIE plus transceiver removes the need for an external PHY, while 22 GPIO lines are sufficient to scan 8x12 key matrices, drive indicator LEDs, and read multiple switch contacts. With a 24 MHz core executing instructions in 167 ns, the firmware can poll the entire key matrix, debounce inputs, and respond to HID IN reports within the USB Low-Speed 10 ms frame interval. The integrated 5-channel ADC allows analog joystick axes to be sampled directly. For production runs where firmware is finalized, the OTP program memory provides the lowest unit cost in the PIC16 USB family.
Recommended
USB-to-Serial Bridge (CDC Class)
The PIC16C745-I/SP implements a USB-to-UART bridge by combining its on-chip USB 1.1 Low-Speed SIE with the integrated USART block. The 5 V tolerant I/O and 4.0-5.5 V supply match traditional RS-232 line levels through a level shifter, while the USB side enumerates as a CDC ACM class device, appearing as a virtual COM port on the host PC. At Low Speed the practical throughput is approximately 800 bytes/s, sufficient for legacy serial port replacement, configuration ports on industrial equipment, and firmware update channels. The 14 KB OTP accommodates full USB descriptor stacks plus the UART echo/buffer state machine, and the 256-byte RAM handles USB endpoint buffers and UART FIFOs.
Recommended
Industrial Sensor Front-End with USB Diagnostics
The PIC16C745-I/SP serves as the controller for low-cost industrial sensor modules that expose readings over USB. Its 5 channels of 8-bit ADC handle common sensor types including thermistors, photodiodes, and potentiometric sensors, while the 22 GPIO lines drive indicator LEDs, control relays, and read digital switches. The 4.0-5.5 V supply aligns with industrial 5 V rails, and the -40C to +85C industrial temperature rating meets harsh-environment requirements. USB Low-Speed diagnostics lets a service technician read sensor data, view fault logs, and update configuration without opening the enclosure. The 24 MHz core runs linearization routines and averaging filters in real time.
Recommended
USB Data Acquisition Pod (Low-Speed)
For low-bandwidth data acquisition, the PIC16C745-I/SP combines its 5-channel 8-bit ADC, digital I/O, and USB Low-Speed connectivity into a compact 28-pin SPDIP module. At 1.5 Mbps USB Low Speed the practical sample rate is approximately 100-500 samples/s aggregate across the ADC channels, sufficient for environmental monitoring, vibration trend logging, and slow process telemetry. The 14 KB OTP stores the USB isochronous-equivalent interrupt transfer handler, channel scan routines, and host-protocol state machine. The PIC16C745's small footprint and through-hole SPDIP package simplify hand-soldered prototypes for lab and field-trial instrumentation.
Recommended
USB-Enabled Embedded Trainer Board
The PIC16C745-I/SP is well-suited to microcontroller trainer boards and educational kits thanks to its 28-pin SPDIP through-hole package, which simplifies breadboard mounting and replacement. The 24 MHz execution rate, 35 single-word instruction set, and 14 KB OTP memory make it ideal for teaching USB protocol, ADC interfacing, timer/counter operation, and interrupt handling. The integrated USB SIE exposes students to real-world peripheral implementation without external transceiver complexity. Educational quantities benefit from low unit cost in OTP form, and the part is well documented in Microchip application notes covering USB firmware stacks and HID class drivers.
Recommended
Legacy Equipment USB Retrofit
The PIC16C745-I/SP retrofits older equipment with USB connectivity without redesigning the existing MCU architecture. By placing the PIC16C745 between the host computer's USB port and the legacy equipment's serial or parallel interface, designers add USB monitoring, configuration, and data download capabilities to installed equipment. The 5 V supply aligns with TTL/CMOS logic in legacy hardware, while the 22 GPIO can bit-bang parallel interfaces. The certified USB Low-Speed stack reduces driver-development risk. As of 2026-09-18, with the C745 in NRND status, retrofit projects should weigh the availability of the flash-based PIC16F745-I/SP against the longer-term supply outlook.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C745-I/SP β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F745-I/SP | PIC16C745-I/SO | PIC16F745T-I/SO |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-pin SPDIP | 28-pin SPDIP - same | 28-pin SPDIP - same | 28-pin SPDIP - same |
| Program Memory | 14 KB OTP | 14 KB Flash | 14 KB OTP | 14 KB Flash |
| RAM | 256 bytes | 256 bytes | 256 bytes | 256 bytes |
| CPU Frequency | 24 MHz | 24 MHz | 24 MHz | 24 MHz |
| USB Support | USB 1.1 Low-Speed | USB 1.1 Low-Speed | USB 1.1 Low-Speed | USB 1.1 Low-Speed |
| ADC Channels | 5 x 8-bit | 5 x 8-bit | 5 x 8-bit | 5 x 8-bit |
| I/O Pins | 22 | 22 | 22 | 22 |
| Lifecycle Status | NRND | Active | NRND | Active |
| Operating Voltage | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V |
Key Differentiators
- Integrated certified USB 1.1 Low-Speed SIE + transceiver (vs PIC16F745-I/SP)
- Higher I/O count than typical 28-pin USB MCUs (vs PIC16F745-I/SP)
- Through-hole SPDIP package for prototyping (vs PIC16F745T-I/SO)
Design Notes
Estimated: at 24 MHz active mode the PIC16C745 core typically draws 10-15 mA; combined with USB pull-up and ADC conversions, total VDD current can reach 25 mA at 5 V. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of pin 19 plus a bulk 10 uF electrolytic/tantalum on the same rail. The 4.0 V minimum supply is required for USB Low-Speed signaling; designs that dip below 4.0 V will violate USB electrical specifications. The MCLR/VPP pin should be pulled to VDD through a 10 kohm resistor with a 100 nF decoupling cap to ground for in-circuit programming support.
The 28-pin SPDIP through-hole footprint uses standard 0.100 inch (2.54 mm) pin pitch with 0.300 inch row spacing. Route the 24 MHz crystal traces (OSC1/OSC2) as short as possible with ground guard traces and keep them away from the USB D+/D- differential pair on RC4/RC5. The USB D+ line requires a 1.5 kohm pull-up to VDD for Low-Speed enumeration; place this resistor close to the D+ pin to minimize signal integrity issues. Place decoupling capacitors within 5 mm of each VDD/VSS pin pair to handle the digital switching transients.
Do not confuse the PIC16C745 (OTP) with the PIC16F745 (flash); the OTP version cannot be reprogrammed once blown. Choose the PIC16F745-I/SP for prototypes that require firmware iteration. When migrating PIC16C745 firmware to the PIC16F745, verify the configuration word settings are reprogrammed, particularly the oscillator mode and WDT settings, as those word values are not preserved across part changes. Also note that the PIC16C745 is in NRND status as of 2026-09-18; new production designs should default to the PIC16F745-I/SP to avoid future EOL pressure on the OTP memory variant.
For USB Low-Speed designs, the D+/D- traces should be routed as a matched-length differential pair (within 2 mm) and kept short (under 50 mm total). Place the 1.5 kohm D+ pull-up within 5 mm of the D+ pin to minimize stub length. Add a common-mode ferrite bead or small ferrite on VDD near the USB connector for EMI suppression. The MCLR reset trace should be kept short to avoid noise-induced resets; if the design operates in an electrically noisy environment, add a 100 nF cap directly at the MCLR pin to filter high-frequency transients.
Compliance Information
RoHS and REACH compliance per Microchip product page; USB 1.1 Low-Speed certification per USB Implementers Forum; AEC-Q100 not applicable for general-purpose industrial/commercial MCU
