PIC16C621T-20E/SO - 8-Bit 20MHz OTP MCU, 1.75KB | Microchip
MPN: PIC16C621T-20E/SO β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.56 | $25.60 |
| 100 | $2.18 | $218.00 |
| 500 | $1.94 | $970.00 |
| 1,000 | $1.72 | $1,720.00 |
PIC16C621T-20E/SO Overview
Background Knowledge. A microcontroller (MCU) is a single-chip computer containing a CPU core, program memory, RAM, and peripheral interfaces. The PIC16C family uses a RISC (Reduced Instruction Set Computer) Harvard architecture with separate program and data buses. OTP program memory allows the device to be programmed once at production; for re-programmable Flash variants in the same pinout, designers typically migrate to the PIC16F or PIC16C62x equivalents. The 16C family sits inside the broader taxonomy: microcontroller -> embedded controller -> integrated circuit -> semiconductor.
Key Features. Core/PIC16c621t-20e/so delivers 20 MHz maximum clock speed, 13 digital I/O pins, two 8-bit timers (TMR0 and TMR2 with prescaler), one analog comparator, a watchdog timer with on-chip RC oscillator, and an operating voltage range of 3.0 V to 6.0 V. The PIC16C621T-20E/SO operates over the extended temperature range of -40 C to +125 C. The wide-body 18-SOIC package is supplied on tape and reel (T/R) for surface-mount assembly.
Technical Depth. The device executes most instructions in a single 200 ns cycle at 20 MHz. Its 14-bit instruction word and 8-bit data path are characteristic of the baseline-plus PIC16C6xx sub-family. Brown-out reset and power-on reset are supported; in-circuit serial programming (ICSP) is available via RB6/RB7 for production programming despite the OTP memory architecture.
Typical Applications. The PIC16C621T-20E/SO suits industrial control, automotive body electronics, consumer appliances, security systems, and white-goods control boards requiring low-cost, fixed-function 8-bit control. Its -40 C to +125 C extended range allows deployment under-hood or in outdoor enclosures.
Design Consideration. The OTP memory cannot be erased; for prototyping or field updates choose the Flash-based PIC16F62x pin-compatible variant. A decoupling capacitor of 0.1 uF must be placed within 5 mm of VDD.
Unique Value. This page synthesizes distributor stock data, exact-spec drop-in alternates, and lifecycle context not aggregated on the manufacturer product page.
Drop-in alternatives for PIC16C621T-20E/SO 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 PIC16C621T-20E/SO (same form factor and footprint) β differing in Operating Temperature Range, Program Memory Size, Program Memory Type, Data EEPROM, I/O Pins.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C621AT-20E/SO
β Drop-Inβ In Stock
$2.18 / Unit
View Datasheet βPIC16C621-20I/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C620-20E/SO
β Drop-Inβ In Stock
$3.3 / Unit
View Datasheet βPIC16C620T-20E/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C620AT-20E/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C620A-20E/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C621T-20E/SO Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Series | PIC 16C |
| Core Processor | PIC |
| Core Size | 8-Bit |
| Maximum Clock Speed | 20 MHz |
| Program Memory Size | 1.75 KB (1K x 14) OTP |
| RAM Size | 80 x 8 bytes (80 B) |
| Number of I/O Pins | 13 |
| Supply Voltage Range | 3.0 V to 6.0 V |
| Operating Temperature Range | -40 C to +125 C (Extended) |
| Package / Case | 18-SOIC (0.295", 7.50 mm width) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (T/R) |
| Oscillator Type | External |
| Peripherals | Brown-out Reset, Watchdog Timer, Comparator |
| Connectivity | ICSP (In-Circuit Serial Programming) |
| Program Memory Type | OTP (One-Time Programmable) |
| RoHS Status | Non-Compliant (T suffix: tape & reel) |
PIC16C621T-20E/SO Pin Configuration
| Pin 1 | RA2 β Port A bit 2 / analog input |
| Pin 2 | RA3 β Port A bit 3 / analog input |
| Pin 3 | RA4 β Port A bit 4 / T0CKI (Timer0 clock input) |
| Pin 4 | MCLR β Master Clear (Reset) input |
| Pin 5 | VSS β Ground reference |
| Pin 6 | RB0/INT 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 voltage |
| Pin 15 | OSC2/CLKOUT β Oscillator output / clock out |
| Pin 16 | OSC1/CLKIN β Oscillator input / clock in |
| Pin 17 | RA0 β Port A bit 0 / analog input |
| Pin 18 | RA1 β Port A bit 1 / analog input |
Typical Applications
PIC16C621T-20E/SO is suitable for 6 applications: Industrial Automation Control, Automotive Body Electronics, Consumer Appliance Control, Security and Alarm Systems, Smart Home Sensor Nodes, Hobby and Education Development.
Industrial Automation Control
The PIC16C621T-20E/SO fits industrial automation controllers where its 20 MHz PIC core executes deterministic control loops with a 200 ns instruction cycle. With 13 digital I/O pins and 3.0 V to 6.0 V supply tolerance, the part interfaces directly to 5 V PLC backplanes and 3.3 V sensor bridges. The extended -40 C to +125 C temperature range allows deployment in factory-floor enclosures, motor-drive auxiliary boards, and conveyor controllers without thermal derating. The internal watchdog timer adds fail-safe recovery in a supervisor role, providing protection for unattended industrial nodes.
Recommended
Automotive Body Electronics
The PIC16C621T-20E/SO serves automotive body controllers including seat controllers, mirror adjusters, and lighting modules. Its -40 C to +125 C extended range covers under-hood and cabin environments. The 13 I/O pins handle switch scanning, relay drivers, and LIN-bus wake-up tasks. OTP memory secures the application code against unauthorized field reprogramming - a deliberate design choice for high-volume automotive ECUs where software stability outweighs field updates. Brown-out reset and watchdog ensure recovery from cranking-voltage dips during engine start.
Recommended
Consumer Appliance Control
The PIC16C621T-20E/SO targets white-goods controllers in washing machines, dishwashers, and microwave ovens. Its 1.75 KB OTP holds appliance cycle logic, sensor sampling, and user-interface state machines. The PIC16C62x instruction set simplifies C/assembly development for engineers familiar with baseline PIC cores. The 18-SOIC wide-body package supports through-hole-style hand-soldering repairs, lowering field-service cost in consumer markets. Low cost at 1.72 USD per 1k qty enables deployment in sub-30 USD retail appliances.
Recommended
Security and Alarm Systems
The PIC16C621T-20E/SO controls PIR motion detectors, door/window sensors, and siren drivers in security alarm panels. Its low power consumption and 13 I/O pins handle multiple zone inputs plus keypad scanning. OTP memory locks the alarm protocol against cloning attacks, while the analog comparator enables direct PIR sensor interfacing without external op-amps. The extended temperature range allows outdoor mounting in cold-climate security devices. Watchdog timer prevents lockup during brown-out events in battery-backed alarm panels.
Recommended
Smart Home Sensor Nodes
The PIC16C621T-20E/SO is a fit for low-cost smart-home sensor endpoints - thermostats, leak detectors, and HVAC zone controllers. Its 8-bit PIC core delivers predictable latency for control loops with minimum external BOM (no external EEPROM needed for fixed-function nodes). The 3.0 V to 6.0 V supply range accommodates both 3.3 V coin-cell and 5 V USB-powered nodes. Brown-out reset guarantees clean restart after battery brownout; ICSP allows factory programming and final test. Pin-compatible Flash variants ease firmware iteration during development.
Recommended
Hobby and Education Development
The PIC16C621T-20E/SO remains a teaching platform for embedded-systems courses thanks to its PIC baseline instruction set and abundant educational resources. With 1.75 KB OTP, students implement timers, PWM via Timer2, and analog comparator projects on the same die used in commercial products. The 18-SOIC is breadboard-friendly via SOIC-to-DIP adapters. ICSP allows students to program multiple iterations on the same board; once finalized, OTP locks the code for the final demonstration unit. Microchip MPLAB X IDE and XC8 compiler handle the legacy code.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C621T-20E/SO β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C621AT-20E/SO | PIC16C621-20I/SO | PIC16C620-20E/SO |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC (wide-body) | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same |
| Core Size | 8-Bit | 8-Bit | 8-Bit | 8-Bit |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Program Memory | 1.75 KB OTP | 1.75 KB OTP | 1.75 KB OTP | 1.75 KB OTP |
| RAM Size | 80 B | 80 B | 80 B | 80 B |
| Operating Voltage | 3.0 V to 6.0 V | 3.0 V to 6.0 V | 3.0 V to 6.0 V | 3.0 V to 6.0 V |
| Operating Temperature | -40 C to +125 C (Extended) | -40 C to +125 C (Extended) | 0 C to +70 C (Industrial) | -40 C to +125 C (Extended) |
| Number of I/O | 13 | 13 | 13 | 13 |
Key Differentiators
- Extended -40 C to +125 C operating temperature range (vs PIC16C621-20I/SO)
- Lower per-unit cost in 1k+ volume (vs PIC16C620-20E/SO)
- Tape & reel packaging for high-volume SMD assembly (vs PIC16C621-20/P (PDIP tube))
Design Notes
Estimated: at VDD = 5.0 V and 20 MHz active mode, typical IDD is approximately 5 mA; total power is roughly 25 mW. Add a 0.1 uF decoupling capacitor within 5 mm of VDD (pin 14) to suppress core-logic switching transients. A bulk 10 uF tantalum capacitor on the supply rail handles motor inrush and brown-out events. For battery-backed designs, switch the PIC16C621T-20E/SO to SLEEP mode (~1 uA) when idle; wake via the watchdog timer or external interrupt on RB0/INT.
Estimated: at 20 MHz, 5 V, 8 mA active load, the 18-SOIC dissipates roughly 40 mW - well within the 18-SOIC thermal envelope of approximately 800 mW. The -40 C to +125 C extended operating range is verified by Microchip characterization. For designs at the temperature extreme, derate clock frequency to 4 MHz and confirm oscillator start-up margins in cold-box qualification.
Estimated: route MCLR (pin 4) directly to the reset controller with a 10 kohm pull-up to VDD; do not place bypass capacitors on MCLR. Place the 18-SOIC crystal/oscillator within 5 mm of OSC1/OSC2 to minimize stray capacitance. Keep RB6/RB7 (ICSP clock/data) traces short to prevent programming interference from adjacent signal edges; avoid routing high-frequency signals across these traces. Maintain a ground plane under the part to reduce EMI from the oscillator.
Estimated: the PIC16C621T-20E/SO uses OTP program memory that cannot be electrically erased - prototype firmware development requires Flash-based PIC16F62x variants (e.g. PIC16F628A-I/SO) before committing to OTP production. Pin assignments for RA0-RA4 and RB0-RB7 differ in alternate-function modes; consult the PIC16C62x datasheet before final pin assignment to avoid conflicts with Timer0 clock input (RA4/T0CKI) and ICSP (RB6/RB7).
Compliance Information
T-suffix packaging. OTP program memory architecture. Not automotive-qualified; refer to Microchip PIC16F automotive-grade parts for AEC-Q100 designs. Reach status per Microchip product declaration.
