PIC16C620-20/SS - 8-bit OTP MCU, 896B, 20MHz, 20-SSOP | Microchip
MPN: PIC16C620-20/SS β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.09 | $4.09 |
| 10 | $3.65 | $36.50 |
| 100 | $3.12 | $312.00 |
| 500 | $2.74 | $1,370.00 |
| 1,000 | $2.41 | $2,410.00 |
PIC16C620-20/SS Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, and configurable peripherals onto one piece of silicon. It sits one level above a microprocessor in system hierarchy because it removes the need for external program storage and bus glue. The PIC16C6x family uses a Harvard architecture with separate code and data buses, OTP EPROM for the program store, and a RISC instruction set - the original 'peripheral interface controller' lineage that established Microchip in the embedded market. Designers selected this family in the 1990s and early 2000s for compact, deterministic control loops.
Key features include a hardware 8-bit timer/counter (TMR0) with an 8-bit prescaler, a 16-bit timer/counter (TMR1) with its own prescaler, a Watchdog Timer with its own on-chip RC oscillator, power-on reset, brown-out detection, in-circuit serial programming (ICSP) via two pins, code protection, and low-power SLEEP mode. Two analog comparators are integrated and can be tied to the timer capture input, enabling slope A/D or simple threshold detection without an external ADC. Each of the 13 I/O pins can source or sink 25 mA and directly drive LEDs or small relays.
Architecturally, the PIC16C620 implements a 14-bit instruction word, 8-bit data path, two-level hardware stack, and an interrupt controller with both edge-selectable RB0/INT and pin-change interrupts on PORTB. The brown-out reset and power-up timer are configurable in the configuration word, allowing the device to come up in a deterministic state regardless of supply ramp rate.
Typical applications include appliance control, security alarm panels, smoke detectors, automotive body modules, fan controllers, and small sensor interface boards. The internal comparators are particularly useful in battery chargers and threshold-detect products, while the 13 high-current I/Os allow direct LED matrix driving without external transistors.
When designing with this OTP device, remember that OTP memory cannot be erased, so firmware bugs require device replacement. For prototyping, choose a windowed CERDIP variant (PIC16C620-20/JW) or migrate to the flash-based PIC16F627/628 family which is code- and pin-compatible with the PIC16C620.
This page synthesizes distributor pricing, OTP/flash pin-compatible alternatives, and practical design notes that go beyond the basic Microchip datasheet - helping engineers weigh the PIC16C620-20/SS against newer flash parts and obsolete-stock risks.
Drop-in alternatives for PIC16C620-20/SS β 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 PIC16C620-20/SS (same form factor and footprint) β differing in Program Memory Size, Program Memory Type, Operating Temperature, Timers, Analog Comparators.
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Request AlternativesPIC16C620-20/SS Maximum Ratings & Electrical Characteristics
| Program Memory Size | 896 B (512 x 14) OTP EPROM |
| RAM Size | 80 x 8 (80 bytes) |
| Number of I/O Pins | 13 |
| CPU Speed | 20 MHz (200 ns instruction cycle) |
| Instruction Set | 35 RISC instructions, 14-bit wide |
| Supply Voltage (Vdd) | 4.5 V to 6.0 V |
| Oscillator Type | External |
| Package / Case | 20-SSOP (0.209", 5.30 mm width) |
| Mounting Type | Surface Mount |
| Operating Temperature | 0 C to +70 C (commercial) |
| Timers | TMR0 (8-bit + prescaler), TMR1 (16-bit + prescaler), WDT |
| Analog Comparators | 2 on-chip |
| A/D Converter | None (comparator-based threshold detect only) |
| I/O Sink/Source Current | 25 mA per pin |
| Program Memory Type | OTP EPROM (one-time programmable) |
| RoHS Status | Non-RoHS (legacy OTP product, non-green) |
PIC16C620-20/SS Pin Configuration
| Pin 1 | RA2 β Port A bit 2 / analog comparator output |
| Pin 2 | RA3 β Port A bit 3 / MCLR (reset) input |
| Pin 3 | RA4 β Port A bit 4 / TOCKI (Timer 0 clock input) |
| Pin 4 | RA5 β Port A bit 5 / analog comparator input |
| Pin 5 | GND β Ground reference |
| Pin 6 | RB0 β Port B bit 0 / external interrupt |
| Pin 7 | RB1 β Port B bit 1 |
| Pin 8 | RB2 β Port B bit 2 |
| Pin 9 | RB3 β Port B bit 3 |
| Pin 10 | RB4 β Port B bit 4 |
| Pin 11 | RB5 β Port B bit 5 |
| Pin 12 | RB6 β Port B bit 6 / ICSP clock |
| Pin 13 | RB7 β Port B bit 7 / ICSP data |
| Pin 14 | VDD β Positive supply (4.5 V - 6.0 V) |
| Pin 15 | OSC2 β Crystal/oscillator output |
| Pin 16 | OSC1 β Crystal/oscillator input |
| Pin 17 | RA0 β Port A bit 0 / analog comparator input |
| Pin 18 | RA1 β Port A bit 1 / analog comparator input |
| Pin 19 | RA7 β Port A bit 7 |
| Pin 20 | RA6 β Port A bit 6 |
Typical Applications
PIC16C620-20/SS is suitable for 6 applications: Appliance Control Board, Security Alarm Panel, Smoke and CO Detector, Battery Charger Controller, Automotive Body Module, LED Lighting Controller.
Appliance Control Board
The PIC16C620-20/SS fits washing-machine and dishwasher control boards because it integrates two analog comparators (useful for line-voltage zero-cross detection and motor current sensing), a hardware 16-bit timer (TMR1) for precise PWM generation at 20 MHz, and 13 high-current GPIO pins rated 25 mA each that directly drive triac interfaces, relay coils, and seven-segment displays without external drivers. The 200 ns single-cycle instruction execution enables deterministic 50/60 Hz line-frequency timing critical for phase-angle dimming. Using the internal comparators instead of an external op-amp saves board space and BOM cost.
Recommended
Security Alarm Panel
The PIC16C620-20/SS is well-suited for residential security alarm panels because its 13 I/O pins easily scan a 4x4 keypad matrix with four zone inputs and four siren/LED indicators remaining, and its pin-change interrupt on PORTB provides immediate response to zone-trip events without polling overhead. The hardware Watchdog Timer with its own dedicated RC oscillator recovers the panel from software lockup after brown-outs. The two on-chip comparators can be configured as window comparators for sensor-line fault detection (open or shorted loop), a feature normally requiring an external quad op-amp.
Recommended
Smoke and CO Detector
The PIC16C620-20/SS powers standalone smoke-detector heads because its SLEEP mode drops current consumption to microampere levels while leaving the Watchdog Timer active to wake the processor periodically. The internal analog comparators interface directly to ionization-chamber or photoelectric smoke sensors through simple resistor dividers, eliminating the external op-amp typically required for low-level signal conditioning. The 896 B OTP program memory holds a complete sensor-sampling, hysteresis, and alarm-decision state machine for UL 217 compliance algorithms.
Recommended
Battery Charger Controller
In NiCd, NiMH, or small lead-acid charger designs, the PIC16C620-20/SS uses its two internal analog comparators for precise charge-termination detection (peak voltage for NiMH, -dV for NiCd) and its 16-bit TMR1 to time charge and discharge cycles to the second. The 25 mA per-pin drive directly switches power-MOSFET gates through 100 ohm gate resistors without buffer stages. Brown-out reset at 4.5 V prevents deep-discharge damage by forcing the processor into a known reset state when the battery voltage collapses under load.
Recommended
Automotive Body Module
Although the commercial-temperature PIC16C620-20/SS itself is rated only 0-70 C, the same silicon die ships in industrial (PIC16C620-20I/SS) and automotive variants qualified to -40/+125 C and AEC-Q100. With 13 GPIO capable of driving 25 mA, the part directly interfaces to 12 V automotive loads through pre-driver transistors, eliminating external relay-driver ICs. The hardware Watchdog Timer and brown-out reset provide the fault-tolerance expected in body-control modules controlling lighting, mirrors, and seat positioning.
Recommended
LED Lighting Controller
The PIC16C620-20/SS drives small-to-medium LED arrays and decorative lighting controllers because each of its 13 GPIO pins can sink 25 mA continuously, allowing direct multiplexing of a 4-digit seven-segment display or 13 individual high-brightness LEDs without any external driver. The TMR1 16-bit timer generates accurate PWM dimming frequencies (up to 78 kHz at 20 MHz clock) above the flicker fusion threshold, while the comparator inputs provide ambient-light sensing for automatic brightness adjustment. Internal EEPROM emulation in flash-mode variants preserves user-set dim levels across power cycles.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C620-20/SS β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C620-20/SO |
|---|---|---|
| Brand | Microchip Technology | Microchip Technology |
| Package | 20-SSOP (5.30 mm) | 20-SOIC (7.50 mm) - different footprint |
| Program Memory | 896 B OTP EPROM | 896 B OTP EPROM |
| RAM | 80 B | 80 B |
| CPU Speed | 20 MHz | 20 MHz |
| I/O Pins | 13 | 13 |
| Memory Type | OTP EPROM (one-time) | OTP EPROM (one-time) |
| Operating Temperature | 0 C to +70 C (commercial) | 0 C to +70 C (commercial) |
Key Differentiators
- True drop-in die equivalent in SOIC-20 package (vs PIC16C620-20/SO)
- Obsolete lifecycle flagged (vs PIC16F628-20/SS (flash successor))
- Industry-standard PIC16C6x pinout enables direct migration (vs PIC16F88-20/SS)
Design Notes
Estimated OTP cost-of-error: Because the PIC16C620 uses one-time-programmable EPROM, every firmware revision deployed to a production board consumes a device. Always prototype with the flash-based PIC16F628-20/SS (same SSOP-20 footprint, same peripherals plus USART and 128 B EEPROM) and only migrate to the PIC16C620 for the final production run after firmware is locked. Burning a 4 USD part during development quickly erodes any unit-cost savings.
The PIC16C620-20/SS has a narrow 4.5-6.0 V Vdd range. For battery applications under 4.5 V (two alkaline cells or single Li-ion below 3.3 V), the PIC16F628-20/SS or PIC16LF1827-I/SS is required. Always include a 100 nF decoupling capacitor within 5 mm of the Vdd pin and a 10 uF bulk capacitor at the board power entry. Brown-out reset should be enabled in the configuration word (BODEN bit) to force a clean restart when the supply droops below 4.0 V.
The two ICSP programming pins (RB6/clock and RB7/data) are shared with general-purpose PORTB I/O. Place a 4.7 kohm pull-up on RB6 and RB7 to keep them defined during normal operation; the in-circuit programmer requires no isolation resistors. Keep the OSC1/OSC2 traces short (< 10 mm) and surround the crystal with a ground pour to reduce EMI radiation. The MCLR pin (RA3) needs a 10 kohm pull-up to Vdd; do not leave it floating or the device will randomly reset.
Compliance Information
PIC16C620-20/SS is a legacy OTP product and is NOT RoHS compliant per Microchip's product family classification. Lead-free variants do not exist for the OTP C62x family - migrate to PIC16F62x (flash) for RoHS/lead-free compliance.
