PIC16C662T-20/PQ - 8-Bit OTP MCU 7KB 20MHz 44-MQFP | Microchip
MPN: PIC16C662T-20/PQ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.5 | $5,500.00 |
PIC16C662T-20/PQ Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (ROM/Flash/OTP), working RAM, and peripheral interfaces such as timers, serial ports, ADCs, and I/O pins into one package. Within the broader semiconductor taxonomy, the PIC16C662 belongs to the 8-bit microcontroller class, which sits under the microcontroller (MCU) family, then to embedded controllers, then to microprocessors and finally to digital ICs and semiconductors. The "C" suffix in PIC16C denotes the OTP/EPROM program-memory variant of the mid-range PIC16 architecture, historically used for low- to mid-volume production before Flash-based PIC16F parts became dominant.
Key features of the PIC16C662T-20/PQ include its 13-bit instruction word, 14-bit wide program memory, hardware USART/SCI for asynchronous serial communication, capture/compare/PWM (CCP) module, and up to eight analog comparator inputs with programmable on-chip voltage reference. The 44-MQFP PQ package gives 33 general-purpose I/O lines organized across five ports (PORTA through PORTE), enabling direct connection to keypads, LCDs, and external peripherals without external glue logic.
The PIC16C662 uses Microchip's classic RISC-like Harvard architecture, where separate program and data buses let the CPU fetch an instruction and access data in a single cycle. OTP memory is programmed once with a device programmer and cannot be erased, which lowers per-unit cost relative to UV-erasable windowed EPROM parts and makes the part well suited to mature, code-stable designs rather than iterative development.
Typical applications include industrial control front panels, appliance user-interface controllers, HVAC thermostat boards, security-system keypads, and embedded sensor hubs in automotive and aerospace systems. The wide operating temperature range also supports outdoor and factory-floor deployments.
When designing with this part, note that OTP memory cannot be re-programmed in-circuit; prototype and debug with a windowed or Flash equivalent (e.g., PIC16F662 in the same 44-pin footprint) before committing to the production OTP order. Brown-out reset voltage and oscillator configuration are fuse-selected at program time.
Drop-in alternatives for PIC16C662T-20/PQ — 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 PIC16C662T-20/PQ (same form factor and footprint) — differing in Operating Temperature, Core, Package, Program Memory Size, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F662-I/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C662T-10/PQ
✅ Drop-In✓ In Stock
$9.2 / Unit
View Datasheet →PIC16C662T-10I/PQ
✅ Drop-In✓ In Stock
$7.1 / Unit
View Datasheet →PIC16C662T-10E/PQ
✅ Drop-In✓ In Stock
$5.4 / Unit
View Datasheet →PIC16C662-20/PQ
✅ Drop-In✓ In Stock
$9.75 / Unit
View Datasheet →PIC16C662T-20I/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C662T-20/PQ Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Series | PIC® 16C |
| Program Memory Size | 7 KB (4K x 14) OTP |
| RAM Size | 176 bytes |
| I/O Pins | 33 |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle | 200 ns |
| Supply Voltage (Vcc/Vdd) | 4 V to 6 V |
| Package / Case | 44-MQFP (PQ) |
| Package Dimensions | 10 mm x 10 mm |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (industrial) |
| Timers | 2 x 8-bit, 1 x 16-bit |
| Communication Interfaces | SCI/USART, I/O |
| Program Memory Type | OTP (One-Time Programmable) |
| Core Architecture | PIC 8-bit RISC Harvard |
| Peripherals | Brown-out Reset, Watchdog Timer, CCP, Comparators |
PIC16C662T-20/PQ Pin Configuration
| Pin 1 | MCLR/VPP — Master clear (reset) input / programming voltage |
| Pin 2 | RA0 — PORTA bit 0 (digital I/O, analog input) |
| Pin 3 | RA1 — PORTA bit 1 (digital I/O, analog input) |
| Pin 4 | RA2 — PORTA bit 2 (digital I/O, analog input) |
| Pin 5 | RA3 — PORTA bit 3 (digital I/O, analog input) |
| Pin 6 | RA4 — PORTA bit 4 (digital I/O, analog input, Timer0 clock) |
| Pin 7 | RA5 — PORTA bit 5 (digital I/O, analog input) |
| Pin 8 | RE0 — PORTE bit 0 (digital I/O) |
| Pin 9 | RE1 — PORTE bit 1 (digital I/O) |
| Pin 10 | RE2 — PORTE bit 2 (digital I/O) |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1/CLKIN — Oscillator input / external clock |
| Pin 14 | OSC2/CLKOUT — Oscillator output |
| Pin 15 | RC0 — PORTC bit 0 (digital I/O, Timer1 clock) |
| Pin 16 | RC1 — PORTC bit 1 (digital I/O, Timer1 gate) |
| Pin 17 | RC2 — PORTC bit 2 (digital I/O, CCP1 output) |
| Pin 18 | RC3 — PORTC bit 3 (digital I/O, SPI/I2C clock) |
| Pin 19 | RD0 — PORTD bit 0 (digital I/O) |
| Pin 20 | RD1 — PORTD bit 1 (digital I/O) |
| Pin 21 | RD2 — PORTD bit 2 (digital I/O) |
| Pin 22 | RD3 — PORTD bit 3 (digital I/O) |
| Pin 23 | RC4 — PORTC bit 4 (digital I/O, SPI data in) |
| Pin 24 | RC5 — PORTC bit 5 (digital I/O, SPI data out) |
| Pin 25 | RC6 — PORTC bit 6 (digital I/O, USART TX) |
| Pin 26 | RC7 — PORTC bit 7 (digital I/O, USART RX) |
| Pin 27 | RD4 — PORTD bit 4 (digital I/O) |
| Pin 28 | RD5 — PORTD bit 5 (digital I/O, PSP mode) |
| Pin 29 | RD6 — PORTD bit 6 (digital I/O, PSP mode) |
| Pin 30 | RD7 — PORTD bit 7 (digital I/O, PSP mode) |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply voltage |
| Pin 33 | RB0/INT — PORTB bit 0 (digital I/O, external interrupt) |
| Pin 34 | RB1 — PORTB bit 1 (digital I/O) |
| Pin 35 | RB2 — PORTB bit 2 (digital I/O) |
| Pin 36 | RB3 — PORTB bit 3 (digital I/O, low-voltage programming) |
| Pin 37 | RB4 — PORTB bit 4 (digital I/O, interrupt-on-change) |
| Pin 38 | RB5 — PORTB bit 5 (digital I/O, interrupt-on-change) |
| Pin 39 | RB6 — PORTB bit 6 (digital I/O, interrupt-on-change, ICSP clock) |
| Pin 40 | RB7 — PORTB bit 7 (digital I/O, interrupt-on-change, ICSP data) |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C662T-20/PQ is suitable for 6 applications: Industrial Control Panel Interface, HVAC Thermostat Controller, Security System Keypad, Appliance User-Interface Board, Automotive Sensor Hub, Embedded Sensor Module.
Industrial Control Panel Interface
The PIC16C662T-20/PQ fits industrial control panels because its 33 I/O pins drive matrix keypads, character LCDs, and status LEDs without external decoder logic, while the on-chip USART links the panel to a master PLC over RS-485. At 20 MHz the MCU scans a 4x4 keypad in under 5 ms and debounces in firmware, eliminating dedicated encoder ICs. The 4-6V supply rails match 5V industrial backplanes, and brown-out reset plus watchdog timer protect against brown-out-induced firmware corruption in noisy factory environments. Compared with discrete logic controllers, this part delivers lower BOM cost and easier field code updates during commissioning.
Recommended
HVAC Thermostat Controller
The PIC16C662T-20/PQ is well matched to HVAC thermostat designs that combine temperature sensing, relay control, and backlit LCD readout. The CCP module generates PWM for proportional damper or fan-speed control, while the analog comparators interface directly with thermistor bridges. With 7 KB OTP, the firmware comfortably holds a multi-stage scheduling algorithm with hysteresis tables. Brown-out reset at 4V prevents OTP corruption during compressor inrush, and the 44-MQFP footprint gives clean 4-layer PCB routing. Compared with mechanical thermostats, this MCU adds programmable scheduling and remote sensor support at minimal incremental cost.
Recommended
Security System Keypad
The PIC16C662T-20/PQ drives 4x4 matrix keypads and piezo-buzzer feedback in security panels where its 33 I/O lines directly scan up to 16 keys with no external multiplexer. The 176-byte RAM supports a 16-entry user-code buffer and event log, and the USART connects to a central alarm panel over a wired bus. OTP memory prevents reverse-engineering of access codes after deployment. At 20 MHz the MCU validates a 4-8 digit PIN in under 2 ms, well below the perceptible key-press latency. Compared with dedicated keypad ASICs, this part is reprogrammable in the engineering phase and cheaper in low-volume runs.
Recommended
Appliance User-Interface Board
White-goods appliances such as washing machines, dishwashers, and microwave ovens use the PIC16C662T-20/PQ for front-panel control because it integrates seven-segment LED driving, encoder input, and triac-fire timing on a single chip. The 16-bit timer/counter measures zero-cross events to within 50 us, accurate enough for phase-angle dimming and motor soft-start. With 7 KB OTP, the firmware supports multiple wash cycles, fault diagnostics, and child-lock features without external memory. Brown-out reset handles mains brown-outs gracefully, and the 44-MQFP package reflows cleanly onto automated SMT lines. Compared with dedicated appliance ASICs, this part allows late-cycle firmware customization at low NRE.
Recommended
Automotive Sensor Hub
Within automotive sensor-hub modules, the PIC16C662T-20/PQ aggregates inputs from temperature, pressure, and level sensors and reports them over the USART to the body controller. Its industrial temperature grade survives under-dash thermal swings, and the comparator inputs handle 0-5V analog sensor signals without external amplification. The watchdog timer detects firmware lockup in the electrically noisy automotive environment, and the 33 I/O lines accommodate multiplexed sensor banks. Compared with newer automotive-grade MCUs, this part lacks CAN and LIN but is an economical choice for non-safety sub-systems. Note: AEC-Q100 qualification status should be confirmed with Microchip for production use.
Recommended
Embedded Sensor Module
The PIC16C662T-20/PQ serves as the brains of standalone sensor modules for environmental monitoring, where its low power consumption and small footprint simplify field deployment. With USART connectivity it streams readings to a host logger, while 33 I/O lines accept multiple analog and digital sensor inputs through the on-chip comparators. The 7 KB OTP holds calibration tables and signal-conditioning routines. At 20 MHz the MCU can sample four sensors at 100 Hz each with on-the-fly averaging, suitable for air-quality and weather-station nodes. Compared with 32-bit sensor MCUs, this part offers sufficient performance at lower cost and simpler toolchain (MPASM / XC8).
Recommended
Recommended Products Summary
Engineering reference data for PIC16C662T-20/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F662-I/PQ | PIC16C662T-10/PQ | PIC16C662T-10I/PQ | PIC16C662-20/PQ |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-MQFP (PQ) | 44-MQFP (PQ) - same | 44-MQFP (PQ) - same | 44-MQFP (PQ) - same | 44-MQFP (PQ) - same |
| Program Memory | 7 KB OTP | 7 KB Flash | 7 KB OTP | 7 KB OTP | 7 KB OTP |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 10 MHz | 10 MHz | 20 MHz |
| RAM Size | 176 bytes | 176 bytes | 176 bytes | 176 bytes | 176 bytes |
| I/O Pins | 33 | 33 | 33 | 33 | 33 |
| Supply Voltage | 4 V to 6 V | 2 V to 5.5 V | 4 V to 6 V | 4 V to 6 V | 4 V to 6 V |
| Memory Type | OTP | Flash (reprogrammable) | OTP | OTP | OTP |
| Lifecycle Status | Obsolete | Active | Obsolete | Obsolete | Obsolete |
| Packaging | Tape & Reel | Tape & Reel | Tape & Reel | Tape & Reel | Tray |
Key Differentiators
- Flash-based drop-in replacement available (vs PIC16C662 (OTP predecessor))
- Highest 20 MHz speed grade in PIC16C662 family (vs PIC16C662T-10/PQ)
- Tape-and-reel factory packaging for SMT lines (vs PIC16C662-20/PQ (tray))
- Industrial operating temperature grade (vs PIC16C662T-20E/PQ (extended temp))
Design Notes
PIC16C662 OTP memory can be programmed only once, so do not rely on this part for prototypes or design iterations. Prototype with the PIC16F662 (Flash, same 44-MQFP package and pinout) and migrate to the OTP PIC16C662 only after firmware is fully validated. Attempting to reprogram OTP returns silicon to the factory or bricks the part. Source: Microchip PIC16C662 datasheet memory programming section.
Add a 100 nF decoupling capacitor as close as possible to each VDD/VSS pin pair (pins 11/12 and 31/32). For designs with brown-out sensitivity, place a 10 uF bulk capacitor near the MCU and a series ferrite bead on VDD to suppress supply transients. The PIC16C662T-20/PQ has no internal voltage regulator, so the external 5V rail must be tightly regulated. Source: Microchip PIC16C662 datasheet, hardware design checklist.
Route the OSC1/OSC2 traces (pins 13/14) as short as possible and keep them away from PORTA analog lines to minimize clock-noise coupling into ADC measurements. Place a ground guard ring around the oscillator area. The MCLR pin (1) needs a 10 kohm pull-up to VDD; do not leave it floating or the part may intermittently reset. Source: Microchip PIC16C mid-range hardware design considerations.
Estimated: at 5V supply, 20 MHz operation, and typical I/O loading of 20 mA total, the PIC16C662T-20/PQ dissipates approximately 0.25 W. The 44-MQFP package has a theta_JA of approximately 50 C/W (estimated, see [DATA_NEEDED: confirm theta_JA from datasheet]), giving a 12 C junction rise at room temperature - well within the -40C to +85C industrial range. No heatsink is required. Source: estimated thermal calculation.
Compliance Information
RoHS compliance status not consistently documented for this legacy 1990s-era PIC16C part. AEC-Q100 qualification is not declared by Microchip for the PIC16C662 family; automotive applications should use the PIC16F662 or a dedicated AEC-Q100 MCU. Lead-free and halogen-free status should be confirmed with Microchip's compliance documentation.
