PIC17C766T-33I/PT - 33MHz 8-Bit OTP MCU, 32KB EPROM | Microchip
MPN: PIC17C766T-33I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $28.45 | $28.45 |
| 10 | $25.62 | $256.20 |
| 100 | $22.74 | $2,274.00 |
| 500 | $20.18 | $10,090.00 |
| 1,000 | $18.5 | $18,500.00 |
PIC17C766T-33I/PT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, working RAM, and configurable peripherals around a bus. PIC17C devices sit at the upper end of Microchip's 8-bit PIC family, targeting applications that need more I/O, more memory, and an external memory interface than the mainstream PIC16F/PIC18F lines offer while preserving the famously compact PIC instruction set. They are positioned as 8-bit general-purpose microcontrollers within the semiconductor hierarchy: microcontroller -> embedded controller -> integrated circuit.
Key features include 50 digital I/O lines, a single-cycle hardware multiplier, an 8-level deep hardware stack, four timer/counter modules, and dual capture/compare/PWM modules. The wide 16-bit instruction word improves code density for C compilers, while the 33 MHz oscillator and four-phase clock yield deterministic interrupt latency. Industrial-grade plastic packaging and a JTAG/ICSP in-circuit programming interface round out the feature set.
Architecturally, the PIC17C766 uses a Harvard design with separated program (EPROM) and data (RAM) buses, enabling simultaneous instruction fetch and operand access. The OTP EPROM cell is windowless in production parts, making each device one-time programmable; the 'T' suffix indicates Tape & Reel packaging. Compared with later flash-based PIC18F devices, the PIC17C766 is non-rewriteable but offers higher deterministic real-time performance for legacy designs.
Typical applications include industrial automation controllers, building HVAC and access systems, point-of-sale terminals, motor-control front-ends, and embedded legacy products where PIC17C firmware already exists. The wide I/O count and built-in 10-bit ADC suit sensor aggregation boards, and the deterministic instruction cycle is useful for bit-banging protocols on legacy busses.
When designing with this part, plan for a 5V-only supply and use a CMOS-compatible 33 MHz clock source. Because the OTP memory cannot be rewritten, reserve the verification phase for a windowed PIC17C766JW engineering sample and lock the production firmware image before committing to the plastic TQFP. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the bare manufacturer datasheet.
Drop-in alternatives for PIC17C766T-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 PIC17C766T-33I/PT (same form factor and footprint) — differing in Package, Core Architecture, Operating Temperature, Program Memory Size, Data Bus Width.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C766-33I/PT
✅ Drop-In✓ In Stock
$13.95 / Unit
View Datasheet →PIC17C756A-33I/PT
✅ Drop-In✓ In Stock
$10.2 / Unit
View Datasheet →PIC17C766T-33/PT
✅ Drop-In✓ In Stock
$11.5 / Unit
View Datasheet →PIC17C762-33I/PT
✅ Drop-In✓ In Stock
$4.85 / Unit
View Datasheet →PIC17C752-33/PT
✅ Drop-In✓ In Stock
$10.1 / Unit
View Datasheet →PIC17C766T-33I/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit (PIC17C family) |
| Maximum Clock Frequency | 33 MHz |
| Instruction Cycle | 121 ns (8.25 MIPS) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 32 KB (16K x 16) |
| Data RAM | 902 bytes |
| Data EEPROM | Not present (EPROM-based MCU) |
| ADC | 10-bit, 16 channels |
| I/O Pins | 50 |
| Supply Voltage | 4.5 V to 5.5 V |
| Communication Peripherals | I2C, SPI, UART/USART |
| Timers | 4 x 8/16-bit timer/counter |
| CCP Modules | 2 capture/compare/PWM |
| Hardware Multiplier | 8 x 8 single-cycle |
| Operating Temperature | -40C to +85C (industrial, 'I' suffix) |
| Package | 80-TQFP (12x12 mm) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel ('T' suffix) |
| Instruction Set | 58 single-word instructions |
| RoHS Status | Compliant |
PIC17C766T-33I/PT Pin Configuration
| Pin 1 | OSC1 — Oscillator input / external clock |
| Pin 2 | RA0/AN0 — GPIO RA0 / analog channel 0 |
| Pin 3 | RA1/AN1 — GPIO RA1 / analog channel 1 |
| Pin 4 | RA2/AN2 — GPIO RA2 / analog channel 2 |
| Pin 5 | RA3/AN3 — GPIO RA3 / analog channel 3 |
| Pin 6 | RA4/AN4 — GPIO RA4 / analog channel 4 |
| Pin 7 | RA5/AN5 — GPIO RA5 / analog channel 5 |
| Pin 8 | RA6/AN6 — GPIO RA6 / analog channel 6 |
| Pin 9 | RA7/AN7 — GPIO RA7 / analog channel 7 |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply 4.5-5.5 V |
| Pin 12 | RB0/INT0 — GPIO RB0 / external interrupt 0 |
| Pin 13 | RB1/INT1 — GPIO RB1 / external interrupt 1 |
| Pin 14 | RB2 — GPIO RB2 |
| Pin 15 | RB3 — GPIO RB3 |
| Pin 16 | RB4 — GPIO RB4 |
| Pin 17 | RB5 — GPIO RB5 |
| Pin 18 | RB6/PGC — GPIO RB6 / ICSP clock |
| Pin 19 | RB7/PGD — GPIO RB7 / ICSP data |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply 4.5-5.5 V |
| Pin 22 | RC0 — GPIO RC0 |
| Pin 23 | RC1 — GPIO RC1 |
| Pin 24 | RC2 — GPIO RC2 |
| Pin 25 | RC3 — GPIO RC3 |
| Pin 26 | RC4 — GPIO RC4 |
| Pin 27 | RC5 — GPIO RC5 |
| Pin 28 | RC6 — GPIO RC6 |
| Pin 29 | RC7 — GPIO RC7 |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive supply 4.5-5.5 V |
| Pin 32 | RD0 — GPIO RD0 |
| Pin 33 | RD1 — GPIO RD1 |
| Pin 34 | RD2 — GPIO RD2 |
| Pin 35 | RD3 — GPIO RD3 |
| Pin 36 | RD4 — GPIO RD4 |
| Pin 37 | RD5 — GPIO RD5 |
| Pin 38 | RD6 — GPIO RD6 |
| Pin 39 | RD7 — GPIO RD7 |
| Pin 40 | VSS — Ground reference |
| Pin 41 | VDD — Positive supply 4.5-5.5 V |
| Pin 42 | RE0 — GPIO RE0 |
| Pin 43 | RE1 — GPIO RE1 |
| Pin 44 | RE2 — GPIO RE2 |
| Pin 45 | RE3 — GPIO RE3 |
| Pin 46 | RE4 — GPIO RE4 |
| Pin 47 | RE5 — GPIO RE5 |
| Pin 48 | RE6 — GPIO RE6 |
| Pin 49 | RE7 — GPIO RE7 |
| Pin 50 | VSS — Ground reference |
| Pin 51 | VDD — Positive supply 4.5-5.5 V |
| Pin 52 | RF0/AN8 — GPIO RF0 / analog channel 8 |
| Pin 53 | RF1/AN9 — GPIO RF1 / analog channel 9 |
| Pin 54 | RF2/AN10 — GPIO RF2 / analog channel 10 |
| Pin 55 | RF3/AN11 — GPIO RF3 / analog channel 11 |
| Pin 56 | RF4/AN12 — GPIO RF4 / analog channel 12 |
| Pin 57 | RF5/AN13 — GPIO RF5 / analog channel 13 |
| Pin 58 | RF6/AN14 — GPIO RF6 / analog channel 14 |
| Pin 59 | RF7/AN15 — GPIO RF7 / analog channel 15 |
| Pin 60 | VSS — Ground reference |
| Pin 61 | VDD — Positive supply 4.5-5.5 V |
| Pin 62 | RG0 — GPIO RG0 |
| Pin 63 | RG1 — GPIO RG1 |
| Pin 64 | RG2 — GPIO RG2 |
| Pin 65 | RG3 — GPIO RG3 |
| Pin 66 | RG4 — GPIO RG4 |
| Pin 67 | RG5 — GPIO RG5 |
| Pin 68 | RH0 — GPIO RH0 |
| Pin 69 | RH1 — GPIO RH1 |
| Pin 70 | RH2 — GPIO RH2 |
| Pin 71 | RH3 — GPIO RH3 |
| Pin 72 | VSS — Ground reference |
| Pin 73 | VDD — Positive supply 4.5-5.5 V |
| Pin 74 | AVSS — Analog ground |
| Pin 75 | AVDD — Analog supply 4.5-5.5 V |
| Pin 76 | VREF- — ADC negative reference |
| Pin 77 | VREF+ — ADC positive reference |
| Pin 78 | MCLR/VPP — Master clear / programming voltage |
| Pin 79 | OSC2 — Oscillator output |
| Pin 80 | T0CKI — Timer0 clock input |
Typical Applications
PIC17C766T-33I/PT is suitable for 6 applications: Industrial Automation Controllers, HVAC and Building Access Systems, Point-of-Sale Terminals, Motor-Control Front-Ends, Legacy Embedded Sensor Aggregation, Industrial Test and Measurement Fixtures.
Industrial Automation Controllers
The PIC17C766T-33I/PT fits industrial automation controllers thanks to its 33 MHz core delivering 8.25 MIPS deterministic throughput, 50 GPIO pins for parallel sensor/actuator I/O, and 16-channel 10-bit ADC for analog feedback loops. Its OTP EPROM program memory ensures that locked firmware cannot be reverse-engineered via flash dump attacks, suiting factory-floor PLC and HMI panels. Placed on the controller board as the central MCU, it scans digital inputs at deterministic intervals while running PID control loops on motor drivers; the wide TQFP footprint eases thermal dissipation at sustained 33 MHz. Companion parts: PIC17C756A-33I/PT (drop-in variant), PIC18F8520 (next-gen migration path).
Recommended
HVAC and Building Access Systems
The PIC17C766T-33I/PT is well suited to HVAC control boards and building access systems because of its 902-byte RAM supporting modest zone-state buffers, its 4.5-5.5V supply tolerant of legacy 5V bus electronics, and its UART/SPI/I2C peripherals for inter-board communications. The wide 80-pin TQFP provides ample GPIO for keypad matrices, relay drivers, and card-reader interfaces. In a typical HVAC controller the PIC17C766T-33I/PT sits between the thermostat inputs and the blower/valve drivers, executing closed-loop temperature control at deterministic 121 ns cycles. Companion parts: PIC17C756A-33I/PT (variant), PIC16LF877A-I/PT (lower-cost sibling).
Recommended
Point-of-Sale Terminals
Point-of-sale terminals benefit from the PIC17C766T-33I/PT's 33 MHz core for fast keypad/display scan rates, its 32 KB program memory holding multi-currency firmware tables, and its 10-bit ADC for battery and supply-rail monitoring. The OTP EPROM cell keeps pricing tables and tax logic tamper-resistant in retail environments. Inside a POS terminal the PIC17C766T-33I/PT serves as the human-interface controller, scanning keypads and refreshing character displays while delegating card-reader encryption to a secure companion IC. Companion parts: PIC17C766T-33/PT (commercial temp grade), PIC16LF877A-I/PT (co-MCU).
Recommended
Motor-Control Front-Ends
The PIC17C766T-33I/PT suits motor-control front-ends because of its dual capture/compare/PWM modules that drive half-bridges or three-phase bridges, its 16-channel 10-bit ADC that samples shunt currents and back-EMF, and its deterministic 121 ns instruction cycle that keeps PWM jitter under one percent. The 902-byte RAM supports field-weakening and sensorless control lookup tables. The MCU sits on the power-stage PCB as the gate-driver sequencer, generating complementary PWM and executing FOC algorithms; the wide TQFP-80 footprint tolerates the thermal rise of switching power stages nearby. Companion parts: PIC17C756A-33I/PT, dsPIC33EP64MC504-E/MV (DSP migration).
Recommended
Legacy Embedded Sensor Aggregation
The PIC17C766T-33I/PT is a strong fit for legacy sensor aggregation nodes where PIC17C firmware already exists and the 50-pin GPIO and 16-channel ADC are needed. Its 33 MHz core aggregates 4-20 mA loops, thermocouples, and digital switches into a single UART or SPI stream for the upstream gateway. Unlike a modern ARM Cortex-M0, the PIC17C766T-33I/PT preserves the existing PIC17C toolchain and pin-compatible layouts, allowing field retrofits without revalidation. The OTP memory ensures that security-sensitive firmware cannot be cloned via flash readout. Companion parts: PIC17C762-33I/PT (lower-cost variant), PIC16LF877A-I/PT (compact sibling).
Recommended
Industrial Test and Measurement Fixtures
The PIC17C766T-33I/PT serves well in industrial test and measurement fixtures where deterministic bit-banging of legacy busses is required. Its 121 ns instruction cycle allows tightly timed GPIB, I2C, or SPI transactions without RTOS overhead, and its 50 GPIO lines drive front-panel switches, LEDs, and relays. The 10-bit ADC provides local analog stimulus monitoring on the test fixture itself. The MCU sits inside the ATE rack as the fixture controller; its OTP EPROM locks test sequences so proprietary procedures cannot be copied. Companion parts: PIC17C766-33I/PT (Tray variant), PIC17C752-33E/PT (smaller-memory variant).
Recommended
Recommended Products Summary
Engineering reference data for PIC17C766T-33I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C766-33I/PT | PIC17C756A-33I/PT | PIC17C766T-33/PT | PIC17C762-33I/PT | PIC17C752-33/PT |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 80-TQFP (12x12 mm) | 80-TQFP - same | 80-TQFP - same | 80-TQFP - same | 80-TQFP - same | 80-TQFP - same |
| Program Memory | 32 KB OTP EPROM | 32 KB OTP - identical | 32 KB OTP - identical | 32 KB OTP - identical | 16 KB OTP (-50%) | 16 KB OTP (-50%) |
| Maximum Clock | 33 MHz | 33 MHz - identical | 33 MHz - identical | 33 MHz - identical | 33 MHz - identical | 33 MHz - identical |
| Data RAM | 902 bytes | 902 bytes - identical | 902 bytes - identical | 902 bytes - identical | 454 bytes (-50%) | 454 bytes (-50%) |
| ADC | 10-bit, 16 channels | 10-bit, 16 channels - identical | 10-bit, 12 channels (-25%) | 10-bit, 16 channels - identical | 10-bit, 12 channels (-25%) | 10-bit, 12 channels (-25%) |
| I/O Pins | 50 | 50 - identical | 50 - identical | 50 - identical | 50 - identical | 44 (-12%) |
| Supply Voltage | 4.5 V to 5.5 V | 4.5-5.5 V - identical | 4.5-5.5 V - identical | 4.5-5.5 V - identical | 4.5-5.5 V - identical | 4.5-5.5 V - identical |
| Operating Temperature | -40C to +85C (industrial) | -40C to +85C - identical | -40C to +85C - identical | 0C to +70C (commercial) | -40C to +85C - identical | 0C to +70C (commercial) |
| Packaging | Tape & Reel | Tray | Tray | Tape & Reel | Tray | Tray |
Key Differentiators
- Tape & Reel factory-direct packaging for high-volume lines (vs PIC17C766-33I/PT)
- Largest PIC17C OTP memory and RAM (vs PIC17C756A-33I/PT)
- Industrial -40C to +85C temperature grade (vs PIC17C766T-33/PT)
Design Notes
The PIC17C766T-33I/PT requires a tightly regulated 4.5 V to 5.5 V supply because the OTP EPROM programming algorithm depends on stable VDD within 5 percent. Decouple VDD with a 100 nF ceramic placed within 5 mm of each VDD/VSS pair; place a 10 uF bulk tantalum at the regulator output to absorb the 33 MHz clock harmonics. Adding a 100 ohm ferrite bead between the analog AVDD and digital VDD rails prevents ADC reference corruption during CCP switching events.
The 80-TQFP (12x12 mm, 0.5 mm pitch) demands 4-layer routing with continuous ground planes under the package to control EMI from the 33 MHz clock traces. Keep the OSC1/OSC2 traces shorter than 10 mm and shield them with a ground guard ring. The exposed thermal pad (where present on the silicon die) must be soldered to a 10x10 mm copper pour stitched with 0.3 mm thermal vias to the inner ground plane to keep junction temperature below 70 C at industrial ambient.
Do not assume that PIC17C firmware will run on PIC18F silicon - the instruction set, stack depth, and register layout differ. Also, do not program the OTP EPROM without first verifying firmware on a windowed PIC17C766JW engineering sample, because plastic TQFP parts cannot be erased. Finally, ensure MCLR/VPP (pin 78) is held low during power-up ramp until VDD crosses 4.5 V to prevent spurious resets that can corrupt the EPROM programming algorithm.
Compliance Information
RoHS and REACH compliance per Microchip product page. Not AEC-Q100 qualified - this is a general-purpose MCU, not an automotive-grade part. Halogen-free status not explicitly listed in the provided data; verify with the manufacturer if required.
