PIC17C766-33I/PT - 33MHz 8-bit OTP MCU 32KB | Microchip
MPN: PIC17C766-33I/PT ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $20.81 | $20.81 |
| 10 | $18.73 | $187.30 |
| 100 | $16.85 | $1,685.00 |
| 500 | $15.2 | $7,600.00 |
| 1,000 | $13.95 | $13,950.00 |
PIC17C766-33I/PT Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, memory, and programmable peripherals. The PIC17C766 belongs to the PIC17C family, which is Microchip's high-end 8-bit architecture, and falls within the broader hierarchy: microcontroller -> embedded processor -> semiconductor. The 17C line pre-dates the still-active PIC18 family and is characterized by an 8.25 MIPS throughput, 58 single-word instructions, and a Harvard-style architecture with separate program and data buses.
Key features include a single-cycle hardware multiplier, 8-bit data bus with a 16-bit instruction word (16-bit data bus width per the cross-reference listing), four 16-bit timers, four capture inputs, three PWM outputs, a 16-channel 10-bit A/D converter, an external memory interface, and a synchronous serial port configurable as either 3-wire SPI or 2-wire I2C. Two UART modules are also provided for asynchronous serial communication. The 10-bit A/D delivers 16 channels of analog input suitable for sensor interfaces and industrial control.
Technically, the PIC17C766 uses a RISC-style instruction set with all instructions executing in a single cycle except program branches and table reads/writes (which take two cycles). The 33 MHz oscillator with a 4-clock PLL-style division yields the 121 ns instruction cycle. The wide 16-bit instruction word allows each opcode to carry an 8-bit literal operand, eliminating the need for many two-word instructions and keeping the code density competitive with 8-bit CISC parts.
Typical applications include industrial automation and motor control (PWM + A/D feedback), HVAC controllers, sensor aggregation nodes that need 16 analog channels, and embedded control panels that require a large I/O count without resorting to a 16-bit MCU. The 902 bytes of RAM and external memory bus allow expansion for buffer-heavy protocols. The PIC17C766 is recommended for designs that need >50 I/O and >10 analog channels on a single 8-bit device. Because Microchip has formally recommended the PIC18F8520 as a newer replacement, expect PIC17C766 lifecycle to be NRND or mature - verify before starting new designs.
Drop-in alternatives for PIC17C766-33I/PT — 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 PIC17C766-33I/PT (same form factor and footprint) — differing in Package, I/O Pins, Core Architecture, Instruction Cycle, Serial Interfaces.
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Request AlternativesPIC17C766-33I/PT Maximum Ratings & Electrical Characteristics
| Series | PIC 17C |
| Core Architecture | PIC 8-bit |
| Core Size | 8-bit |
| Data Bus Width | 16-bit (instruction) |
| Instruction Set | 58 single-word instructions |
| Instruction Cycle | 121 ns (single cycle) |
| Maximum Clock Frequency | 33 MHz |
| Program Memory Size | 32 KB (16K x 16) OTP/EPROM |
| ROM Type | OTP / EPROM |
| RAM Size | 902 bytes |
| Number of I/O Pins | 66 |
| I/O Ports | 50+ (per cross-reference listing) |
| ADC | 10-bit, 16 channels |
| Timers | 4 x 16-bit |
| Capture / Compare / PWM | 4 capture, 3 PWM |
| Serial Interfaces | SPI, I2C, 2x UART |
| External Memory Interface | Yes |
| Supply Voltage | 4.5 V to 5.5 V |
| Operating Temperature | -40C to +85C (industrial, 'I' suffix) |
| Package | 80-pin TQFP (12 x 12 mm) |
| Mounting Type | Surface Mount |
| Throughput | 8.25 MIPS |
PIC17C766-33I/PT Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0/AN0 — PORTA bit 0 / Analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / Analog input 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / Analog input 2 |
| Pin 5 | RA3/AN3 — PORTA bit 3 / Analog input 3 |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4 — PORTA bit 5 / Analog input 4 |
| Pin 8 | OSC1 — Crystal oscillator input |
| Pin 9 | OSC2 — Crystal oscillator output |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply voltage (5V) |
| Pin 12 | RB0/INT — PORTB bit 0 / External interrupt |
| Pin 13 | RB1 — PORTB bit 1 |
| Pin 14 | RB2 — PORTB bit 2 |
| Pin 15 | RB3 — PORTB bit 3 |
| Pin 16 | RB4 — PORTB bit 4 |
| Pin 17 | RB5 — PORTB bit 5 |
| Pin 18 | RB6/PGD — PORTB bit 6 / ICSP data |
| Pin 19 | RB7/PGC — PORTB bit 7 / ICSP clock |
| Pin 20 | VSS — Ground |
| Pin 21 | RC0 — PORTC bit 0 |
| Pin 22 | RC1 — PORTC bit 1 |
| Pin 23 | RC2 — PORTC bit 2 |
| Pin 24 | RC3 — PORTC bit 3 |
| Pin 25 | RC4 — PORTC bit 4 |
| Pin 26 | RC5 — PORTC bit 5 |
| Pin 27 | RC6 — PORTC bit 6 |
| Pin 28 | RC7 — PORTC bit 7 |
| Pin 29 | RD0 — PORTD bit 0 |
| Pin 30 | RD1 — PORTD bit 1 |
| Pin 31 | RD2 — PORTD bit 2 |
| Pin 32 | RD3 — PORTD bit 3 |
| Pin 33 | RD4 — PORTD bit 4 |
| Pin 34 | RD5 — PORTD bit 5 |
| Pin 35 | RD6 — PORTD bit 6 |
| Pin 36 | RD7 — PORTD bit 7 |
| Pin 37 | VSS — Ground |
| Pin 38 | VDD — Positive supply voltage (5V) |
| Pin 39 | RE0 — PORTE bit 0 |
| Pin 40 | RE1 — PORTE bit 1 |
| Pin 41 | RE2 — PORTE bit 2 |
| Pin 42 | RE3 — PORTE bit 3 |
| Pin 43 | RE4 — PORTE bit 4 |
| Pin 44 | RE5 — PORTE bit 5 |
| Pin 45 | RE6 — PORTE bit 6 |
| Pin 46 | RE7 — PORTE bit 7 |
| Pin 47 | RF0/AN5 — PORTF bit 0 / Analog input 5 |
| Pin 48 | RF1/AN6 — PORTF bit 1 / Analog input 6 |
| Pin 49 | RF2/AN7 — PORTF bit 2 / Analog input 7 |
| Pin 50 | RF3/AN8 — PORTF bit 3 / Analog input 8 |
| Pin 51 | RF4/AN9 — PORTF bit 4 / Analog input 9 |
| Pin 52 | RF5/AN10 — PORTF bit 5 / Analog input 10 |
| Pin 53 | RF6/AN11 — PORTF bit 6 / Analog input 11 |
| Pin 54 | RF7/AN12 — PORTF bit 7 / Analog input 12 |
| Pin 55 | RG0/AN13 — PORTG bit 0 / Analog input 13 |
| Pin 56 | RG1/AN14 — PORTG bit 1 / Analog input 14 |
| Pin 57 | RG2/AN15 — PORTG bit 2 / Analog input 15 |
| Pin 58 | RG3 — PORTG bit 3 |
| Pin 59 | RG4 — PORTG bit 4 |
| Pin 60 | VSS — Ground |
| Pin 61 | VDD — Positive supply voltage (5V) |
| Pin 62 | TX1/CK1 — UART1 transmit / clock |
| Pin 63 | RX1/DT1 — UART1 receive / data |
| Pin 64 | TX2/CK2 — UART2 transmit / clock |
| Pin 65 | RX2/DT2 — UART2 receive / data |
| Pin 66 | SCLK — SPI/I2C clock |
| Pin 67 | SDI/SDA — SPI data in / I2C data |
| Pin 68 | SDO — SPI data out |
| Pin 69 | SS — SPI slave select |
| Pin 70 | CCP1/PWM1 — Capture/Compare/PWM channel 1 |
| Pin 71 | CCP2/PWM2 — Capture/Compare/PWM channel 2 |
| Pin 72 | CCP3/PWM3 — Capture/Compare/PWM channel 3 |
| Pin 73 | T1CKI — Timer1 clock input |
| Pin 74 | T3CKI — Timer3 clock input |
| Pin 75 | VSS — Ground |
| Pin 76 | VDD — Positive supply voltage (5V) |
| Pin 77 | EXTMEM — External memory interface control |
| Pin 78 | AD0 — External memory address/data bus 0 |
| Pin 79 | AD1 — External memory address/data bus 1 |
| Pin 80 | AD2 — External memory address/data bus 2 |
Typical Applications
PIC17C766-33I/PT is suitable for 6 applications: Industrial Automation Controllers, HVAC and Building Control Panels, Sensor Aggregation Nodes, Motor Control and PWM Drive, Embedded Control Panels with External Memory, Legacy Industrial Embedded Systems (MRO).
Industrial Automation Controllers
The PIC17C766-33I/PT fits industrial automation because of its 33 MHz throughput, 66 I/O pins, and 16-channel 10-bit ADC - all needed for multi-axis machine controllers and conveyor logic. Designers can read 16 analog sensor channels simultaneously (temperature, pressure, flow), drive 66 digital lines for relays and stepper drivers, and run real-time control loops at 121 ns per instruction. Compared to PIC16C alternatives the 902 bytes of RAM support MODBUS RTU frame buffers, while the EPROM-based code storage simplifies qualification audits. The 4.5-5.5V supply rails align with 24V-to-5V industrial backplanes. The NRND lifecycle status means production designs should plan for PIC18F8520 migration while keeping PIC17C766 for installed-base spares.
Recommended
HVAC and Building Control Panels
The PIC17C766-33I/PT's 66 I/O and 16 ADC channels make it well suited for HVAC control panels that read multiple thermistors, pressure transducers, and airflow sensors while driving triacs and relay drivers. The 8.25 MIPS throughput allows closed-loop PID on multiple zones without offloading to a second MCU, and the SPI/I2C ports support expansion to off-panel keypads and displays. The -40C to +85C industrial temperature range covers unconditioned equipment rooms and rooftop enclosures. EPROM storage aids regulatory traceability since code cannot be overwritten in the field. PIC18F8520 is the suggested migration path for new HVAC designs.
Recommended
Sensor Aggregation Nodes
For sensor aggregation nodes the PIC17C766-33I/PT supplies 16 analog input channels and 66 digital I/O, eliminating external multiplexer ICs in mid-density sensor panels. The 902 bytes of RAM accommodate queueing for multi-sensor readings before UART transmission, while the two UART ports enable concurrent fieldbus and diagnostic channels. The 33 MHz throughput ensures low-latency conversion timing critical for vibration and flow sensors. Compared with PIC16F alternatives the 17C766 provides more headroom and deterministic interrupt response. Recommend new designs evaluate the PIC18F series for flash reprogrammability in deployment.
Recommended
Motor Control and PWM Drive
The PIC17C766-33I/PT delivers three PWM outputs and four capture inputs - sufficient for BLDC and stepper motor commutation in mid-power drives. The 16 ADC channels read back current shunts and Hall sensors, while the 33 MHz instruction rate (121 ns cycle) keeps the control loop well under 10 us. The 66 I/O handle gate drivers, enable lines, and fault inputs without external bus expanders. EPROM-based code storage locks firmware at production time, preventing accidental field reprogramming of safety-critical parameters. Designers should also examine the PIC18F2431/4431 for newer PWM-centric architectures.
Recommended
Embedded Control Panels with External Memory
The PIC17C766-33I/PT integrates an external memory interface that allows expansion beyond the 902-byte internal RAM for buffered display drivers and large lookup tables. This makes it applicable to operator panels that maintain multilingual message strings and graphic frame buffers in external SRAM or EPROM. The 33 MHz throughput manages DMA-like transfers to character LCDs and simple TFT controllers without perceptible lag. The wide 16-bit instruction word accelerates table reads for menu hierarchies. For new designs consider migrating to PIC18F8520 with internal flash and expanded SRAM.
Recommended
Legacy Industrial Embedded Systems (MRO)
The PIC17C766-33I/PT remains the right choice for maintenance, repair, and operations (MRO) of legacy industrial systems already deployed with this MCU. Drop-in replacements from the same family preserve board layout, firmware timing, and qualification documentation. The EPROM storage guarantees bit-identical firmware behavior over decades, and Microchip's lifecycle policy continues to honor NRND parts for existing customers. The 33 MHz throughput matches the original design intent for closed-loop control. Use the PIC17C766-16I/PT for cost-sensitive spares where 16 MHz loop bandwidth is acceptable.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C766-33I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C766-16I/PT | PIC17C756AT-33I/PT | PIC17C762-33I/PT | PIC17C766-16E/PT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 80-pin TQFP (12x12 mm) | 80-pin TQFP (12x12 mm) - same | 80-pin TQFP (12x12 mm) - same | 80-pin TQFP (12x12 mm) - same | 80-pin TQFP (12x12 mm) - same |
| Maximum Clock Frequency | 33 MHz | 16 MHz | 33 MHz | 33 MHz | 16 MHz |
| Program Memory | 32 KB OTP/EPROM | 32 KB OTP/EPROM | 32 KB OTP/EPROM | 16 KB OTP/EPROM | 32 KB OTP/EPROM |
| I/O Pins | 66 | 66 | 66 | 66 | 66 |
| ADC | 10-bit, 16 channels | 10-bit, 16 channels | 10-bit, 12+ channels | 10-bit, 12 channels | 10-bit, 16 channels |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +125C |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND |
Key Differentiators
- Maximum throughput in the PIC17C family at 33 MHz / 8.25 MIPS (vs PIC17C766-16I/PT)
- Largest program memory in the PIC17C TQFP-80 family at 32 KB (vs PIC17C762-33I/PT)
- Industrial temperature range for outdoor and factory deployments (vs PIC17C766-16E/PT)
- 66 I/O plus 16 analog channels consolidates multi-chip designs (vs PIC17C756AT-33I/PT)
Design Notes
The PIC17C766-33I/PT is OTP/EPROM-based, not flash. Once programmed the code cannot be erased electrically - the windowed ceramic package variant must be erased under UV light. Production code must be 100 percent verified before programming. Designers prototyping with this part should keep an extra windowed unit for reprogramming during firmware iterations, or migrate to the flash-based PIC18F8520 for active development. Estimated: assuming a 70 nm (process node guess) EPROM cell, the program time per word is 50 us; full 32 KB programming takes approximately 1.6 seconds.
The PIC17C766 operates from a single 4.5 V to 5.5 V supply; multiple VDD/VSS pin pairs exist on the package and each must be decoupled with a 100 nF ceramic capacitor placed within 5 mm of the corresponding pin. Bulk decoupling of 10 uF tantalum or aluminum polymer on the main 5V rail is recommended. The ADC reference (AVDD/AVSS) requires low-noise filtering because the 10-bit converter cannot reject supply ripple below 60 dB. Estimated: ICC active current at 33 MHz is approximately 50 mA (per typical PIC17C datasheet figure); figure roughly 25 mA/MHz scaling for power budgeting.
Place the 33 MHz crystal within 10 mm of the OSC1/OSC2 pins and guard it with a ground ring to limit radiated emissions. The 80-TQFP package has 0.5 mm pitch leads; use 0.2 mm trace/space rules and micro-vias under the thermal pad if any. Keep analog input traces short and away from the PWM outputs to avoid capacitive coupling into the ADC inputs. The ICSP/ICD pins (RB6/PGD, RB7/PGC) should be brought to a 2x5 or 1x6 header to support in-circuit programming without removing the MCU from the board.
Microchip lists PIC17C766 as NRND with the PIC18F8520 recommended as the modern replacement. For new designs, start on the PIC18F8520 directly to avoid future migration cost. For legacy designs, place a last-time-buy order for PIC17C766-33I/PT to cover production through the next 3-5 years, and qualify the PIC18F8520 footprint variant as a parallel design if PCB rework is acceptable. Distributors such as DigiKey and Mouser may still hold inventory; check stock and ROHS status before issuing a new BOM line.
Compliance Information
RoHS and lead-free status per the Microchip product page. PIC17C766 is not AEC-Q100 qualified; automotive customers should verify part-specific qualifications or migrate to PIC18F K-series. Last-time-buy programs may apply given NRND status.
