PIC17C766-16/L - 8-Bit 16MHz OTP MCU 32KB 84-PLCC | Microchip
MPN: PIC17C766-16/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $10.12 | $10.12 |
| 10 | $9.61 | $96.10 |
| 100 | $8.6 | $860.00 |
| 500 | $7.59 | $3,795.00 |
| 1,000 | $6.83 | $6,830.00 |
PIC17C766-16/L Overview
What is an OTP microcontroller? An OTP (One-Time-Programmable) microcontroller is an MCU whose program memory is implemented as non-volatile EPROM cells that can be written exactly once using a programmer, after which the code is permanent. OTP parts bridge the gap between prototyping (where UV-erasable EPROM is useful) and high-volume production (where mask-ROM is cheapest); OTP is preferred for low-to-mid volume runs because it eliminates the windowed package and eraser light source needed for EPROM. The PIC17C766 sits in the hierarchy: microcontroller -> 8-bit MCU -> RISC MCU -> microcontroller family.
Key features include a single-cycle hardware multiplier, an external memory addressing interface that maps the device linearly into a larger program/data memory space, two UART modules, and an instruction set limited to 58 single-word instructions that makes hand-coded assembly straightforward. Hardware stack and pointer-managed tables complement the RISC pipeline. The 84-pin J-leaded PLCC (29.31 x 29.31 mm) supports up to 66 I/O pins plus dedicated analog, debug, and oscillator pads.
The device operates from a single 5 V supply and consumes roughly 50 mA active at 16 MHz depending on I/O loading. Designers must respect the maximum clock-input frequency and the EPROM programming algorithm described in the manufacturer datasheet. Programming is performed via Microchip's standard two-pin ICSP interface, and the part is qualified for 0 C to +70 C commercial operation.
Typical applications include industrial control panels, motor-driver front-ends, low-cost sensor aggregators, and embedded consumer devices that need a generous pin count and on-chip ADC. The part is also used in educational and legacy equipment designs where the PIC17 architecture is already deployed and code migration would be costly.
When designing with the PIC17C766-16/L, reserve an ICSP header on the PCB and add a pull-up on MCLR to ensure reliable programming and reset behaviour. Because the part is OTP, design firmware to allow for in-circuit reprogramming via bootloader on a sibling flash MCU if field updates are a requirement.
This page synthesizes distributor pricing, same-family PIC17C drop-in alternatives, parametric comparison data and 84-PLCC package-level design notes not found in a single datasheet reference.
Drop-in alternatives for PIC17C766-16/L — 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 PIC17C766-16/L (same form factor and footprint) — differing in Mounting Type, Package, Program Memory Size, Core Architecture, Data Bus Width.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C766-16I/L
✅ Drop-In✓ In Stock
$8.2 / Unit
View Datasheet →PIC17C766T-16/L
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17C766T-16I/L
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17C762-16/PT
✅ Drop-In✓ In Stock
$9.25 / Unit
View Datasheet →PIC17C752-16/L
✅ Drop-In✓ In Stock
$7.3 / Unit
View Datasheet →PIC17C766-16/L Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (PIC17C) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 32 KB (16K x 16) |
| RAM | 902 bytes |
| Maximum Clock Frequency | 16 MHz |
| Instruction Cycle Time | 121 ns (single-cycle) |
| MIPS (Dhrystone) | 8.25 MIPS |
| ADC | 10-bit, 16 channels |
| I/O Pins | 66 |
| Capture Modules | 4 |
| PWM Modules | 3 |
| Serial Interfaces | SPI (3-wire) / I2C (2-wire) configurable |
| UART | 2 |
| Supply Voltage | 5 V |
| Operating Temperature | 0 C to +70 C (Commercial) |
| Package | 84-PLCC (29.31 x 29.31 mm), J-Lead |
| Mounting Type | Surface Mount (socket-mountable) |
| Multiplier | Single-cycle hardware multiplier |
| External Memory Bus | Yes (linear addressing) |
PIC17C766-16/L Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / ADC input 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / ADC input 1 |
| Pin 3 | RA2/AN2 — PORTA bit 2 / ADC input 2 |
| Pin 4 | RA3/AN3 — PORTA bit 3 / ADC input 3 |
| Pin 5 | RA4/AN4 — PORTA bit 4 / ADC input 4 |
| Pin 6 | RA5/AN5 — PORTA bit 5 / ADC input 5 |
| Pin 7 | RA6/AN6 — PORTA bit 6 / ADC input 6 |
| Pin 8 | RA7/AN7 — PORTA bit 7 / ADC input 7 |
| Pin 9 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 10 | RB1 — PORTB bit 1 |
| Pin 11 | RB2 — PORTB bit 2 |
| Pin 12 | RB3 — PORTB bit 3 |
| Pin 13 | RB4 — PORTB bit 4 |
| Pin 14 | RB5 — PORTB bit 5 |
| Pin 15 | RB6 — PORTB bit 6 |
| Pin 16 | RB7 — PORTB bit 7 |
| Pin 17 | VSS1 — Ground reference 1 |
| Pin 18 | VDD1 — Positive supply 1 (5 V) |
| Pin 19 | OSC1 — Crystal/clock input |
| Pin 20 | OSC2 — Crystal/clock output |
| Pin 21 | MCLR — Master clear reset (active-low) |
| Pin 22 | RC0/T1CKI — PORTC bit 0 / Timer1 clock input |
| Pin 23 | RC1/CCP1 — PORTC bit 1 / Capture/Compare/PWM 1 |
| Pin 24 | RC2/CCP2 — PORTC bit 2 / Capture/Compare/PWM 2 |
| Pin 25 | RC3/CCP3/SCK — PORTC bit 3 / CCP3 / SPI clock |
| Pin 26 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 27 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 28 | RC6/TX1 — PORTC bit 6 / UART1 transmit |
| Pin 29 | RC7/RX1 — PORTC bit 7 / UART1 receive |
| Pin 30 | RD0 — PORTD bit 0 |
| Pin 31 | RD1 — PORTD bit 1 |
| Pin 32 | RD2 — PORTD bit 2 |
| Pin 33 | RD3 — PORTD bit 3 |
| Pin 34 | RD4 — PORTD bit 4 |
| Pin 35 | RD5 — PORTD bit 5 |
| Pin 36 | RD6 — PORTD bit 6 |
| Pin 37 | RD7 — PORTD bit 7 |
| Pin 38 | RE0/AN8 — PORTE bit 0 / ADC input 8 |
| Pin 39 | RE1/AN9 — PORTE bit 1 / ADC input 9 |
| Pin 40 | RE2/AN10 — PORTE bit 2 / ADC input 10 |
| Pin 41 | RE3/AN11 — PORTE bit 3 / ADC input 11 |
| Pin 42 | RE4/AN12 — PORTE bit 4 / ADC input 12 |
| Pin 43 | RE5/AN13 — PORTE bit 5 / ADC input 13 |
| Pin 44 | RE6/AN14 — PORTE bit 6 / ADC input 14 |
| Pin 45 | RE7/AN15 — PORTE bit 7 / ADC input 15 |
| Pin 46 | RF0 — PORTF bit 0 |
| Pin 47 | RF1 — PORTF bit 1 |
| Pin 48 | RF2 — PORTF bit 2 |
| Pin 49 | RF3 — PORTF bit 3 |
| Pin 50 | RF4 — PORTF bit 4 |
| Pin 51 | RF5 — PORTF bit 5 |
| Pin 52 | RF6 — PORTF bit 6 |
| Pin 53 | RF7 — PORTF bit 7 |
| Pin 54 | RG0 — PORTG bit 0 |
| Pin 55 | RG1 — PORTG bit 1 |
| Pin 56 | RG2 — PORTG bit 2 |
| Pin 57 | RG3 — PORTG bit 3 |
| Pin 58 | RG4 — PORTG bit 4 |
| Pin 59 | VSS2 — Ground reference 2 |
| Pin 60 | VDD2 — Positive supply 2 (5 V) |
| Pin 61 | ADRES — ADC voltage reference (unconnected on internal ref) |
| Pin 62 | AVSS — Analog ground |
| Pin 63 | AVDD — Analog positive supply |
| Pin 64 | VREF+ — ADC positive voltage reference |
| Pin 65 | VREF- — ADC negative voltage reference |
| Pin 66 | RX2/DT2 — UART2 receive / data |
| Pin 67 | TX2/CK2 — UART2 transmit / clock |
| Pin 68 | CCP4 — Capture/Compare/PWM 4 |
| Pin 69 | CCP5 — Capture/Compare/PWM 5 |
| Pin 70 | T0CKI — Timer0 clock input |
| Pin 71 | INT1 — External interrupt 1 |
| Pin 72 | INT2 — External interrupt 2 |
| Pin 73 | INT3 — External interrupt 3 |
| Pin 74 | PGM — Programming mode entry |
| Pin 75 | PGC — Programming clock / ICSP |
| Pin 76 | PGD — Programming data / ICSP |
| Pin 77 | EMU — Emulation mode / debug |
| Pin 78 | NC — Not connected (per datasheet) |
| Pin 79 | NC — Not connected (per datasheet) |
| Pin 80 | NC — Not connected (per datasheet) |
| Pin 81 | VMEM0 — External memory bus |
| Pin 82 | VMEM1 — External memory bus |
| Pin 83 | VMEM2 — External memory bus |
| Pin 84 | VMEM3 — External memory bus |
Typical Applications
PIC17C766-16/L is suitable for 6 applications: Industrial Control Panels, Sensor Aggregation Nodes, Motor Drive Front-Ends, Legacy Embedded Consumer Devices, Educational 8-Bit RISC Trainer Boards, Industrial Test and Measurement Equipment.
Industrial Control Panels
The PIC17C766-16/L fits industrial control panels because its 66 I/O lines can directly drive key matrix keypads, 7-segment LEDs, and high-side relay drivers without external glue logic, and its 16 MHz instruction rate supports closed-loop control loops within hundreds of microseconds. The 902-byte RAM is sufficient for soft-PLC ladder evaluation and stack-heavy CAN/Ethernet stacks. The 84-PLCC package sits on a socketed footprint that simplifies field replacement during factory commissioning. Compared with a switching power supply or FPGA the OTP MCU adds deterministic interrupt latency but no opportunity for firmware drift, which is desirable for safety-critical machinery.
Recommended
Sensor Aggregation Nodes
The PIC17C766-16/L aggregates sensors via its 16-channel 10-bit ADC and I2C/SPI bus in instrumentation that previously required a dedicated ADC ASIC plus microcontroller. The single-cycle hardware multiplier offloads sensor scaling in firmware, and 32 KB of OTP holds the calibration tables and Modbus/RTU stacks required by SCADA backbones. The 5 V rail and 0-70 C commercial temperature grade are well-matched to indoor cabinets. Unlike a discrete ADC + MCU the integrated ADC saves board space at the cost of dropped conversion throughput to roughly 50 ksps.
Recommended
Motor Drive Front-Ends
The PIC17C766-16/L drives brushed DC and stepper motor front-ends using its three PWM modules and four capture modules, closing current/tachometer loops faster than 50 us per cycle at 16 MHz. The external memory bus can be tied to a SRAM or specialized gate-driver ASIC for higher-power stages. Designers exploit the OTP memory to lock calibration parameters once a motor's BOM is finalized, eliminating field tampering. Compared with a dsPIC33 the PIC17C lacks DSP instructions and so trades quantitative throughput for simpler code and lower unit cost.
Recommended
Legacy Embedded Consumer Devices
The PIC17C766-16/L is retrofitted into legacy consumer devices (washing-machine controllers, HVAC thermostats and security panels) where the original firmware has been debugged for years and a code freeze is desired before the platform change-over. The OTP memory locks behaviour against field reprogramming accidents while the 84-PLCC package sits in the same IC socket the legacy PCB was tooled for. The 16 MHz core, 902-byte RAM and 32 KB OTP match the original firmware's resource envelope exactly. New designs should switch to PIC18F8520 or PIC18F67K22 instead.
Recommended
Educational 8-Bit RISC Trainer Boards
Universities and training institutes use PIC17C766-16/L on legacy 8-bit trainer boards because the 84-PLCC socketed footprint tolerates repeated insertion during student labs and the 58-instruction PIC17C RISC core provides a small, complete instruction set ideal for assembly-level teaching. The 16 MHz clock, 10-bit ADC and PWM peripherals support lab experiments on ADC sampling, PWM motor control and UART comms. The 0-70 C commercial grade is fine for indoor classrooms and the 32 KB OTP prevents accidental overwriting between sessions. New curricula should still gravitate to PIC18F for active silicon support.
Recommended
Industrial Test and Measurement Equipment
The PIC17C766-16/L powers bench-top test and measurement front-ends where the 66 I/O lines multiplex relays and attenuator pads, and the 10-bit ADC samples sensor inputs at sub-millisecond intervals. The 16 MHz instruction cycle and 902-byte RAM enable deterministic scan-list execution while the 5 V supply rails cleanly from a linear regulator on the instrument's analogue front end. Compared with a separate MCU+FPGA the PIC17C reduces BOM cost but lacks the parallelism an FPGA brings to instrument trigger logic; for new designs, a PIC18F67K22 plus low-cost CPLD is the modern equivalent.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C766-16/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C766-16I/L | PIC17C766T-16/L | PIC17C766T-16I/L | PIC17C762-16/PT | PIC17C752-16/L |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 84-PLCC (J-Lead, 29.31x29.31 mm) | 84-PLCC (J-Lead) - same | 84-PLCC (J-Lead) - same | 84-PLCC (J-Lead) - same | 64-TQFP - different | 68-PLCC - different |
| Program Memory Size | 32 KB OTP (16K x 16) | 32 KB OTP | 32 KB OTP | 32 KB OTP | 32 KB OTP | 16 KB OTP (-50%) |
| Maximum Clock Frequency | 16 MHz | 16 MHz | 16 MHz | 16 MHz | 16 MHz | 16 MHz |
| Temperature Grade | Commercial 0 C to +70 C | Industrial -40 C to +85 C | Commercial 0 C to +70 C | Industrial -40 C to +85 C | Industrial -40 C to +85 C | Commercial 0 C to +70 C |
| I/O Pins | 66 | 66 | 66 | 66 | 52 | 54 |
| ADC Channels / Resolution | 16 x 10-bit | 16 x 10-bit | 16 x 10-bit | 16 x 10-bit | 12 x 10-bit | 12 x 10-bit |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND | NRND |
Key Differentiators
- Highest memory density of the PIC17C sub-family (vs PIC17C752-16/L)
- More ADC channels than the smaller PIC17C devices (vs PIC17C762-16/PT)
- Industry-standard 84-PLCC footprint for socketed replacement (vs PIC17C762-16/PT (64-TQFP))
Design Notes
The PIC17C766-16/L is OTP (one-time programmable); once sealed, the firmware cannot be reprogrammed in-circuit. Design an ICSP header (PGD/PGC/MCLR/VSS/VDD) on every prototype PCB before taping out because a single firmware bug without access to those pads forces board rework. If field updates are a hard requirement migrate to PIC18F8520 instead, which shares the RISC ancestry but provides flash memory.
Provide separate analog (AVDD/AVSS) and digital (VDD1/VDD2/VSS1/VSS2) supply pairs on the 84-PLCC, each decoupled with a 100 nF ceramic plus a 10 uF tantalum at the pin. Long PCB traces between the two VSS planes cause ADC ground bounce; the analog section should reference a star-ground back to a single ferrite bead. Microchip's PIC17C family reference manual shows the canonical 4-pad layout for VDD/VSS and a quiet AVSS.
The 84-PLCC has a J-lead pitch of 1.27 mm (50 mil). On a 2-layer board flood both top and bottom with a ground pour and stitch with 4-6 vias per square inch to control EMI on the high-speed capture/PWM lines. Estimate: at 16 MHz the third harmonic (48 MHz) extends well into HF amateur-radio bands, so add a small ferrite bead on VDD1 and a 33 pF cap on OSC2 if the enclosure lacks shielding.
The PIC17C766-16/L lacks an internal oscillator; OSC1/OSC2 must be driven by an external crystal, ceramic resonator, or CMOS clock source up to 16 MHz. For low-jitter ADC sampling select a crystal with CLoad 18-30 pF (not 32 pF) and configure HS oscillator mode in the configuration word. The reference manual warns that start-up time from power-on can exceed the OST count's default and recommends the LP/HS mode bit selection before code execution proceeds.
Compliance Information
Compliance data not surfaced in the Verified Web Data. The PIC17C766 family predates the modern RoHS/REACH declarations common in newer Microchip datasheets; users should consult Microchip's environmental compliance portal for the specific /L package variant.
