PIC16C745-I/SO - 8-Bit 24MHz USB MCU, 14KB OTP, 28-SOIC | Microchip
MPN: PIC16C745-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.42 | $7.42 |
| 10 | $6.68 | $66.80 |
| 100 | $5.95 | $595.00 |
| 500 | $5.31 | $2,655.00 |
| 1,000 | $4.78 | $4,780.00 |
PIC16C745-I/SO Overview
An 8-bit microcontroller (MCU) is a single-chip microprocessor optimized for embedded control, integrating CPU, memory, and peripherals. Within the broader taxonomy, the PIC16C745 belongs to: microcontroller -> 8-bit MCU -> PIC16 family -> PIC16C7x sub-family -> USB-capable PIC16C. Its RISC architecture with 35 single-word instructions simplifies firmware development, while the Harvard memory bus allows simultaneous instruction and data access for deterministic throughput.
Key differentiating features include USB 1.1 Low-Speed certification (a notable differentiator at this 8-bit tier), 5 channels of 8-bit Analog-to-Digital (A/D) conversion, a USART/SCI serial port, and a programmable Watchdog Timer. The OTP program memory allows one-time factory or in-circuit programming, making the part economical for medium-volume production. Operating voltage spans 4.0V to 5.5V from a single 5V rail typical of USB bus-powered designs.
The PIC16C745 uses Microchip's PIC16 RISC core with a 14-bit instruction word. Its 8-level hardware stack and 35-instruction instruction set enable compact code; a single 24 MHz oscillator yields 4 MHz instruction rate (one instruction per four oscillator cycles, or 167 ns per instruction). Internal peripherals include a Universal Synchronous/Asynchronous Receiver Transmitter, an 8-bit A/D converter with five input channels, and standard PIC timer/counter blocks, providing enough capability for human-interface-device (HID) class USB applications.
Typical applications include USB Human Interface Devices such as custom keyboards, mice, and game controllers; low-speed USB peripherals including barcode readers and POS terminals; embedded industrial controllers requiring USB diagnostics ports; legacy PC accessories; and educational/development boards where an easy-to-program USB-capable 8-bit MCU is desired. Its 28-pin SOIC footprint supports hand prototyping and through-hole-style PCB layouts.
When designing with this device, allocate I/O pins carefully because the USB D+/D- lines share package pins; an external pull-up on D- is required for Low-Speed enumeration per USB 1.1 specification. OTP memory cannot be re-programmed, so firmware validation on a windowed or flash-based equivalent is recommended during development.
This page synthesizes distributor pricing, certified USB 1.1 LS capability details, drop-in package-compatible alternatives within the PIC16C family, and practical design notes that complement the manufacturer datasheet.
Drop-in alternatives for PIC16C745-I/SO — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PIC16C745-I/SO (same form factor and footprint) — differing in ADC, Core Architecture, Package, Timers, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C745T-I/SO
✅ Drop-In✓ In Stock
$3.65 / Unit
View Datasheet →PIC16F745-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C745-I/SP
✅ Drop-In✓ In Stock
$4.12 / Unit
View Datasheet →PIC16C73B-04I/SO
✅ Drop-In✓ In Stock
$7.1 / Unit
View Datasheet →PIC16C73A-10I/SO
✅ Drop-In✓ In Stock
$3.55 / Unit
View Datasheet →PIC16C745-I/SO Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Core Architecture | PIC16 (RISC) |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 14 KB (8K x 14) |
| RAM Size | 256 x 8 bytes |
| Instruction Set Size | 35 single-word instructions |
| Instruction Word Width | 14-bit |
| Maximum Clock Frequency | 24 MHz |
| Instruction Execution Time | 167 ns (at 24 MHz) |
| Operating Voltage Range | 4.0 V to 5.5 V |
| Number of I/O Pins | 22 |
| ADC | 5 channels, 8-bit |
| USB Interface | USB 1.1 Low-Speed certified |
| Serial Interface | USART / SCI |
| Package | 28-pin SOIC (0.295 inch / 7.50 mm body width) |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40 C to +85 C (Industrial) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC16C745-I/SO Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / Programming voltage |
| Pin 2 | RA0/AN0 — Port A bit 0 / Analog input channel 0 |
| Pin 3 | RA1/AN1 — Port A bit 1 / Analog input channel 1 |
| Pin 4 | RA2/AN2 — Port A bit 2 / Analog input channel 2 |
| Pin 5 | RA3/AN3/VREF — Port A bit 3 / Analog input 3 / ADC reference voltage |
| Pin 6 | RA4/T0CKI — Port A bit 4 / Timer 0 clock input |
| Pin 7 | RA5/AN4/SS — Port A bit 5 / Analog input 4 / SPI slave select |
| Pin 8 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 9 | OSC2/CLKOUT — Oscillator crystal output / clock output |
| Pin 10 | RC0/T1OSO/T1CKI — Port C bit 0 / Timer 1 oscillator output / Timer 1 clock input |
| Pin 11 | RC1/T1OSI — Port C bit 1 / Timer 1 oscillator input |
| Pin 12 | RC2/CCP1 — Port C bit 2 / Capture/Compare/PWM 1 |
| Pin 13 | RC3 — Port C bit 3 |
| Pin 14 | RC4/D- — Port C bit 4 / USB D- data line (Low-Speed) |
| Pin 15 | RC5/D+ — Port C bit 5 / USB D+ data line (Low-Speed) |
| Pin 16 | RC6/TX/CK — Port C bit 6 / USART TX / clock line |
| Pin 17 | RC7/RX/DT — Port C bit 7 / USART RX / data line |
| Pin 18 | RB0/INT — Port B bit 0 / External interrupt |
| Pin 19 | RB1 — Port B bit 1 |
| Pin 20 | RB2 — Port B bit 2 |
| Pin 21 | RB3 — Port B bit 3 |
| Pin 22 | RB4 — Port B bit 4 |
| Pin 23 | RB5 — Port B bit 5 |
| Pin 24 | RB6/PGC — Port B bit 6 / ICSP clock |
| Pin 25 | RB7/PGD — Port B bit 7 / ICSP data |
| Pin 26 | VSS — Ground reference |
| Pin 27 | VDD — Positive supply (4.0V to 5.5V) |
| Pin 28 | NC — Not connected (per datasheet pinout) |
Typical Applications
PIC16C745-I/SO is suitable for 6 applications: USB Keyboard HID Controller, USB Barcode Scanner, USB Game Controller / Joystick, Industrial USB Diagnostic Port, USB Mouse / Pointing Device, Educational USB Development Board.
USB Keyboard HID Controller
The PIC16C745-I/SO is purpose-built for USB Human Interface Device class designs such as custom keyboards. Its USB 1.1 Low-Speed certification matches the 1.5 Mbps rate that HID keyboards require per the USB specification. The 14 KB OTP program memory holds keymap tables, debounce logic, and HID report routines for full 104-key matrices, while the 22 I/O pins comfortably drive an 8x16 key scan matrix. Placed as the sole IC on a bus-powered keyboard PCB, the MCU enumerates automatically when the host detects the D- pull-up. Compared with discrete USB implementations using an 8-bit MCU plus FTDI-style bridge, the integrated USB peripheral saves roughly USD 1.50 in BOM and several square millimeters of board area.
Recommended
USB Barcode Scanner
Point-of-sale barcode scanners require a USB HID or CDC-class interface that the PIC16C745-I/SO delivers via its USB 1.1 Low-Speed certification. The 24 MHz instruction clock executes the 35-instruction PIC16 instruction set in 167 ns per instruction, allowing real-time decoding of 1D barcode symbologies such as Code 128 and UPC-A. The 5-channel 8-bit A/D converter reads analog sensor outputs from laser or CCD scan engines without an external ADC. The 28-SOIC footprint fits inside the slim scanner housing, and the 4.0-5.5V operating range matches USB VBUS power directly without an additional LDO.
Recommended
USB Game Controller / Joystick
Game controllers and joysticks benefit from the PIC16C745-I/SO's USB 1.1 LS HID certification, which provides plug-and-play compatibility with PC and console USB stacks. The 22 digital I/O pins read button matrices and analog joystick potentiometers via the integrated 5-channel 8-bit ADC. The 256-byte RAM buffer holds HID report packets between USB polls, and the 14 KB OTP stores HID descriptors, debounce state machines, and button remapping tables. Compared with custom HID implementations on non-USB PIC16 MCUs, the integrated USB peripheral eliminates 200+ lines of bit-banged USB code and reduces firmware size by approximately 1.5 KB.
Recommended
Industrial USB Diagnostic Port
Adding a USB diagnostic port to industrial controllers is straightforward with the PIC16C745-I/SO, which provides USB 1.1 LS connectivity without external transceiver ICs. Industrial equipment operates across wide temperature ranges, and the -40 C to +85 C industrial temperature grade matches factory-floor environments. The MCU can sit on a daughter board that taps the host controller's 5V rail and exposes service logs, fault codes, or firmware updates over USB HID or CDC. Compared with adding a full-speed USB controller, the LS-certified PIC16C745 reduces BOM cost by 40% while delivering sufficient bandwidth for telemetry and configuration channels.
Recommended
USB Mouse / Pointing Device
USB mice and pointing devices use the PIC16C745-I/SO to handle USB 1.1 LS enumeration and HID mouse reporting. The 5-channel 8-bit ADC reads the optical sensor's analog motion signals, while the 22 I/O pins accommodate additional buttons, scroll wheels, and DPI selectors. The 24 MHz clock and 167 ns instruction execution provide sufficient throughput for 500 Hz to 1000 Hz mouse report rates commonly used in gaming peripherals. Compared with specialized mouse-controller ICs, the general-purpose PIC16C745 allows custom firmware that integrates macro recording or wireless dongle logic on the same silicon.
Recommended
Educational USB Development Board
Universities and training programs use the PIC16C745-I/SO to teach USB protocol fundamentals because it integrates USB 1.1 LS support on a familiar PIC16 RISC core with the 35-instruction instruction set. Students learn enumeration, HID descriptors, and interrupt-driven USB transfers without the complexity of external transceivers. The 28-SOIC package is breadboard-compatible via SOIC-to-DIP adapters, while the 4.0-5.5V supply range allows direct USB bus powering. Compared with full-speed USB microcontrollers, the LS-capable PIC16C745 keeps assembly-language exercises tractable, with each subsystem including advanced peripherals such as timers and A/D converters for full embedded systems curricula.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C745-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C745T-I/SO | PIC16F745-I/SO | PIC16C745-I/SP | PIC16C73B-04I/SO | PIC16C73A-10I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC | 28-SOIC | 28-SOIC | 28-SOIC (SPDIP through-hole, same pinout) | 28-SOIC | 28-SOIC |
| Program Memory Type | OTP (14 KB) | OTP (14 KB) | Flash (14 KB) | OTP (14 KB) | OTP (4 KB) | OTP (4 KB) |
| Maximum Clock Frequency | 24 MHz | 24 MHz | 24 MHz | 24 MHz | 4 MHz | 10 MHz |
| USB Interface | USB 1.1 Low-Speed certified | USB 1.1 Low-Speed certified | USB 1.1 Low-Speed certified | USB 1.1 Low-Speed certified | None | None |
| RAM Size | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 192 bytes | 128 bytes |
| Number of I/O Pins | 22 | 22 | 22 | 22 | 22 | 22 |
| ADC Channels | 5 x 8-bit | 5 x 8-bit | 5 x 8-bit | 5 x 8-bit | 5 x 8-bit | 5 x 8-bit |
Key Differentiators
- Integrated USB 1.1 Low-Speed certified peripheral (vs PIC16C73B-04I/SO)
- Four times more program memory than PIC16C73A (vs PIC16C73A-10I/SO)
- Higher clock speed than PIC16C73A variants (vs PIC16C73A-10I/SO)
Design Notes
Place a 1.5 kOhm pull-up resistor on the USB D- line (pin 14, RC4) to signal Low-Speed device presence to the USB host per USB 1.1 specification. Keep the D+/D- traces short and matched in length (within 2 mm) to maintain signal integrity at 1.5 Mbps. Add 100 nF decoupling on VDD (pin 27) and a 10 uF bulk capacitor near the USB VBUS input to suppress switching transients during host enumeration. Estimated: signal integrity at LS USB is tolerant of moderate trace mismatches but violated D- pull-up placement is the most common cause of enumeration failures.
OTP program memory cannot be erased or rewritten. Validate firmware on a windowed or Flash-equivalent part (e.g., PIC16F745-I/SO with same pinout) before committing to OTP volume production. If a code bug is found post-production, the silicon must be discarded. Budget firmware development time for at least one full prototype cycle on Flash silicon before locking the OTP order.
The 28-SOIC package has a thermal resistance of approximately 50-60 C/W, which is acceptable because the PIC16C745 typically consumes under 50 mW. Provide at least 100 mils of copper around the VDD pin for thermal spreading and adequate ground plane under the device. Keep the 24 MHz crystal within 5 mm of OSC1/OSC2 (pins 8/9) with short traces to minimize parasitic capacitance that could shift the oscillator off-frequency. A series resistor on MCLR/VPP (pin 1) of 10 kOhm prevents programming voltage transients during in-circuit serial programming.
Compliance Information
RoHS compliant per Microchip product page. USB 1.1 Low-Speed compliance certified by USB-IF. Halogen-free status not stated in verified data; AEC-Q100 not applicable (industrial/commercial MCU, not automotive qualified).
