PIC16C781/JW - 8-Bit 20MHz MCU, 1.75KB EPROM, 20-CDIP Windowed | Microchip
MPN: PIC16C781/JW ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.95 | $18.95 |
| 10 | $17.1 | $171.00 |
| 100 | $15.25 | $1,525.00 |
| 500 | $13.45 | $6,725.00 |
| 1,000 | $11.9 | $11,900.00 |
PIC16C781/JW Overview
Background: An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, RAM, I/O peripherals, and often analog blocks onto one silicon die. The PIC16C mid-range family is the classic Microchip architecture that uses a Harvard memory layout, a small RISC instruction set with fixed 14-bit instruction width, and a 35-instruction opcode table. The /JW suffix specifically designates a UV-erasable windowed ceramic CDIP package used for prototype development and code iteration, whereas production units ship in OTP plastic packages (/P, /SO, /SS).
Key features include 14-bit wide instructions, 8-level deep hardware stack, internal oscillator support, watchdog timer with on-chip RC oscillator, in-circuit serial programming (ICSP), and Brown-out Reset. The PIC16C781 is engineered for analog-intensive embedded control, replacing multi-chip op-amp and ADC front-ends with a single MCU.
The architecture pairs a 20 MHz oscillator with a four-clock-per-instruction cycle, delivering up to 5 MIPS sustained throughput. The 12-bit slope ADC achieves up to 50 ksps by digitising via a 1-bit comparator against a programmable ramp, eliminating the need for a dedicated SAR core. Its 8-bit DAC, two comparators, and 2.048 V bandgap reference can be combined to build fully software-defined closed-loop systems.
Typical applications include industrial process control loops, sensor signal conditioning, battery chargers with constant-current/constant-voltage profiles, mixed-signal instrumentation front-ends, automotive body controllers (non-AEC-Q), and consumer appliance user interfaces. The integrated analog set makes the PIC16C781 especially attractive where a low-cost MCU must replace several discrete analog ICs.
When designing, ensure VDD decoupling uses a 0.1 uF ceramic placed within 5 mm of the supply pin and that MCLR is pulled high through 10 kohm for normal operation. The /JW windowed package allows approximately 1000 EPROM erase cycles under UV exposure, after which data retention degrades.
This page synthesises distributor pricing, package-level drop-in equivalents within the same Microchip PIC16C family, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C781/JW — 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 PIC16C781/JW (same form factor and footprint) — differing in Program Memory Size, Mounting Type, I/O Pins, Operating Temperature, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C717/JW
✅ Drop-In✓ In Stock
$11.8 / Unit
View Datasheet →PIC16C715/JW
✅ Drop-In✓ In Stock
$9.75 / Unit
View Datasheet →PIC16C712/JW
✅ Drop-In✓ In Stock
$11.2 / Unit
View Datasheet →PIC16C711/JW
✅ Drop-In✓ In Stock
$10.95 / Unit
View Datasheet →PIC16C774/JW
✅ Drop-In✓ In Stock
$10.2 / Unit
View Datasheet →PIC16C781/JW Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C (Enhanced Mid-Range RISC) |
| Data Bus Width | 8 bit |
| Instruction Set Width | 14 bit |
| Maximum Clock Frequency | 20 MHz |
| Program Memory Size | 1.75 KB (1K x 14) EPROM, UV-erasable |
| RAM Size | 128 B |
| Number of I/O Pins | 13 |
| Package / Case | 20-CDIP Windowed (0.300", 7.62 mm) |
| Mounting Type | Through Hole |
| Supply Voltage (VDD) | 2.5 V to 5.5 V |
| ADC | 12-bit slope (8+4), up to 50 ksps |
| DAC | 8-bit |
| Analog Comparators | 2 with programmable reference |
| Internal Oscillator | Yes |
| Watchdog Timer | Yes, with on-chip RC oscillator |
| Brown-out Reset (BOR) | Yes |
| In-Circuit Serial Programming (ICSP) | Yes |
| Hardware Stack | 8 levels |
| Lead-Free / RoHS | Contains lead (windowed ceramic) - not RoHS compliant for Pb-free exemption logic |
PIC16C781/JW Pin Configuration
| Pin 1 | MCLR — Master Clear (Reset) input, active low |
| Pin 2 | RA0/AN0 — PORTA bit 0 / Analog input 0 / Comparator input |
| Pin 3 | RA1/AN1 — PORTA bit 1 / Analog input 1 / Comparator input |
| Pin 4 | RA2/AN2 — PORTA bit 2 / Analog input 2 / DAC output |
| Pin 5 | RA3/AN3 — PORTA bit 3 / Analog input 3 |
| Pin 6 | RA4 — PORTA bit 4 (digital only) |
| Pin 7 | RA5 — PORTA bit 5 (digital only) |
| Pin 8 | OSC1 — Oscillator input or external clock |
| Pin 9 | OSC2 — Oscillator output (crystal mode) |
| Pin 10 | RC0 — PORTC bit 0 |
| Pin 11 | RC1 — PORTC bit 1 |
| Pin 12 | RC2 — PORTC bit 2 |
| Pin 13 | RC3 — PORTC bit 3 |
| Pin 14 | VSS — Ground reference |
| Pin 15 | RC4 — PORTC bit 4 |
| Pin 16 | RC5 — PORTC bit 5 |
| Pin 17 | RC6 — PORTC bit 6 |
| Pin 18 | RC7 — PORTC bit 7 |
| Pin 19 | RB0 — PORTB bit 0 (interrupt-on-change) |
| Pin 20 | VDD — Positive supply voltage 2.5 V to 5.5 V |
Typical Applications
PIC16C781/JW is suitable for 6 applications: Industrial Process Control Loop, Sensor Signal Conditioning Front-End, Battery Charger Controller (CC/CV Profiles), Mixed-Signal Instrumentation, Automotive Body Controller (Legacy / Non-AEC-Q), Consumer Appliance User Interface.
Industrial Process Control Loop
The PIC16C781/JW's integrated 12-bit slope ADC, dual comparators and 8-bit DAC form a closed-loop controller that digitises a 4-20 mA process variable, computes a PID output and drives a 0-10 V actuator - all on one chip. With 20 MHz operation delivering 5 MIPS, the firmware can execute PID maths at 1 kHz loop rate while leaving CPU headroom for serial HMI traffic. Unlike discrete solutions using an external ADC plus op-amp front-end, the PIC16C781 collapses BOM by 4-6 components. The windowed EPROM allows engineers to re-tune control coefficients during factory calibration without scrapping the silicon, which is critical for low-volume industrial OEM spares that have been qualified for decades.
Recommended
Sensor Signal Conditioning Front-End
The PIC16C781's 12-bit slope ADC, 2.048 V bandgap reference and two programmable comparators are designed to interface directly to resistive bridge sensors, thermistors and photocells without external signal conditioning. The slope ADC inherently averages over its conversion window, giving 50 Hz / 60 Hz line-noise rejection that would otherwise require hardware filtering. The 8-bit DAC can source the bridge excitation or drive a 4-20 mA transmitter, eliminating a separate DAC IC. With 13 I/O pins the MCU can multiplex several sensors and drive indicator LEDs or a local LCD. Engineers designing low-channel-count instrumentation modules use the PIC16C781 to replace what was historically a quad op-amp + ADC + MCU design with a single chip.
Recommended
Battery Charger Controller (CC/CV Profiles)
The PIC16C781's two on-chip comparators can sense charge current via a sense resistor and battery voltage via a divider, enabling constant-current / constant-voltage charge profiles for lead-acid, NiMH and Li-ion packs without external analog ICs. The 8-bit DAC programs the reference voltage that sets the CV terminal voltage, while the comparators implement hardware current limit independent of firmware. The 5 MIPS core is sufficient to log charge cycles, run a Coulomb counter and drive a 7-segment display. The windowed JW package allows charger firmware to be tuned across battery chemistries during product development without re-silicon.
Recommended
Mixed-Signal Instrumentation
Instruments such as bench multimeters, process calibrators and laboratory data loggers benefit from the PIC16C781's combination of 12-bit ADC, 8-bit DAC and dual comparators in a single 20-pin part. The 128 B RAM is adequate for sample buffering at sub-ksps rates, while the 1.75 KB EPROM fits user menus, calibration tables and serial protocol stacks. The 2.5 V to 5.5 V VDD range supports direct operation from a single Li-ion cell or USB rail. Brown-out Reset and watchdog timer with on-chip RC oscillator provide the supervisory functions required by portable instrumentation. The /JW windowed package lets metrology labs iterate calibration firmware across instrument revisions without EPROM inventory churn.
Recommended
Automotive Body Controller (Legacy / Non-AEC-Q)
Pre-AEC-Q100 automotive body modules for lighting, door locks and HVAC blend doors used the PIC16C781 because of its 5 MIPS throughput and on-chip analog front-end that interfaces directly to 12 V automotive sensors through external dividers. While the PIC16C781 is not AEC-Q100 qualified, it remains in service in long-lived non-safety automotive aftermarket products. The internal oscillator and brown-out reset survive the 6 V to 16 V automotive transient range (with external clamping). The windowed JW package supports firmware iteration for vehicle-specific variants without re-spinning ROMs.
Recommended
Consumer Appliance User Interface
Washing machines, dishwashers, microwave ovens and coffee makers use the PIC16C781 to drive 7-segment or character LCD displays while reading capacitive touch buttons, rotary encoders and NTC temperature sensors through its integrated ADC and comparators. The 13 I/O pins are sufficient for matrix-scanned keypads, status LEDs and TRIAC firing outputs. The 2.5 V to 5.5 V supply range allows direct operation from a rectified 5 V wall-adapter rail. The 5 MIPS core runs display refresh, button debouncing and motor control simultaneously. The /JW windowed ceramic CDIP allows engineers to iterate user-interface firmware across model variants without mask-ROM NRE.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C781/JW — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C717/JW | PIC16C715/JW | PIC16C712/JW | PIC16C711/JW | PIC16C774/JW |
|---|---|---|---|---|---|---|
| Package | 20-CDIP Windowed (0.300") | 20-CDIP Windowed (0.300") - same | 20-CDIP Windowed (0.300") - same | 20-CDIP Windowed (0.300") - same | 20-CDIP Windowed (0.300") - same | 20-CDIP Windowed (0.300") - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 1.75 KB EPROM | 2 KB EPROM (+14%) | 2 KB EPROM (+14%) | 1 KB EPROM (-43%) | 1.75 KB EPROM same | 4 KB EPROM (+128%) |
| RAM Size | 128 B | 256 B (+100%) | 128 B same | 128 B same | 128 B same | 256 B (+100%) |
| Number of I/O | 13 | 16 (+23%) | 13 same | 13 same | 13 same | 13 same |
| ADC Type | 12-bit slope (8+4) | 10-bit SAR | none | 8-bit ADC | 8-bit ADC | 12-bit SAR |
| DAC | 8-bit | none | none | none | none | 12-bit |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
| Package Type | JW windowed ceramic (UV-erasable) | JW windowed ceramic | JW windowed ceramic | JW windowed ceramic | JW windowed ceramic | JW windowed ceramic |
Key Differentiators
- Highest analog peripheral integration in 20-pin PIC16C family (vs PIC16C717/JW)
- Most compact mixed-signal PIC16C in 20-CDIP JW form (vs PIC16C774/JW)
- Windowed EPROM allows up to 1000 erase cycles for development (vs PIC16C781-I/P (plastic OTP))
Design Notes
Estimated EPROM endurance: the JW windowed EPROM supports approximately 1000 erase/program cycles before data retention degrades, after which bit errors may appear in code or calibration memory. For long-lived production programs, move code to a one-time-programmable plastic PIC16C781-I/P or migrate to flash-based PIC16F88 / PIC16F1827. Avoid exposing the quartz window to direct sunlight or UV sterilization sources because ambient UV erases the EPROM over weeks of exposure.
Place a 0.1 uF ceramic decoupling capacitor within 5 mm of the VDD pin (pin 20) and a bulk 10 uF tantalum or aluminum electrolytic on the same node. The PIC16C781 analog comparators and 12-bit slope ADC are sensitive to supply noise; separate AVCC-style filtering (10 ohm + 10 uF) is recommended if VDD is shared with digital switching loads. MCLR (pin 1) must be pulled to VDD through a 10 kohm resistor and may carry a 100 nF capacitor for noise immunity; do not leave MCLR floating because the internal weak pull-up is unreliable in noisy industrial environments.
The 12-bit slope ADC achieves its specified resolution only when the comparator input settles within the integration window. Source impedance above 10 kohm introduces gain error and integral non-linearity because the slope capacitor sees finite input bias current. Add an external op-amp buffer (e.g. MCP6001) when sensing high-impedance sensors such as pH probes or strain gauges. Slope ADC integration time is programmable; for 50 Hz / 60 Hz mains-rejection select an integration period equal to an integer number of line cycles (20 ms or 16.67 ms).
Estimated: at 20 MHz clock with all peripherals active, the PIC16C781/JW consumes approximately 20 mA from a 5 V supply, dissipating roughly 100 mW. The 20-CDIP ceramic package has theta_JA of approximately 60 C/W in still air, giving a 6 C temperature rise above ambient at full load. The windowed ceramic package dissipates slightly more heat than the plastic OTP variant because of its larger thermal mass; in enclosed housings above 50 C ambient ensure airflow or de-rate clock frequency.
Compliance Information
JW windowed ceramic CDIP contains lead-bearing glass frit and tin-lead solder finish and is not RoHS compliant. Not AEC-Q100 qualified - do not use in new automotive safety applications. REACH compliance per Microchip product statements; halogen status unknown for legacy ceramic package.
