PIC16F721-I/SO - 8-Bit MCU, 7KB Flash, 16MHz, 20-SOIC | Microchip
MPN: PIC16F721-I/SO β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.66 | $1.66 |
| 10 | $1.49 | $14.90 |
| 100 | $1.32 | $132.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $1.05 | $1,050.00 |
| 3,000 | $0.92 | $2,760.00 |
PIC16F721-I/SO Overview
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data bus and a RISC or CISC core, integrating CPU, non-volatile program memory, volatile SRAM, plus a configurable mix of timers, ADC, communication peripherals, and digital I/O in one package. Within the broader taxonomy, the PIC16F721 sits inside Microchip's mid-range PIC16 family, which targets cost-sensitive, deterministic, low-power embedded designs. It inherits the same MPLAB XC8 toolchain, ICD debugging, and hundreds of application notes as the rest of the PIC16 family, lowering development risk and tool cost for designers transitioning from older PIC16F or PIC12 devices.
Key features include 18 digital I/O pins capable of 25mA source/sink current, a 12-channel 8-bit ADC, two 8-bit timers (TMR0/TMR2), one 16-bit timer (TMR1), one Capture/Compare/PWM (CCP) module, an 8-level hardware stack, and dedicated peripherals: MSSP for I2C/SPI and an enhanced USART (AUSART) for asynchronous/synchronous serial. A Watchdog Timer (WDT) with its own on-chip low-power oscillator, Power-on Reset (POR), and Brown-out Reset (BOR) round out the safety block. The 35-instruction RISC core executes instructions in 200ns at 20MHz, leaving ample headroom for state machines and protocol stacks.
Typical applications include consumer white goods, HVAC fan controllers, low-cost sensor front-ends, USB-less IoT edge nodes, and battery-powered remote controls. Industrial segments such as instrumentation front panels, e-meter front-ends, and small appliance motor control benefit from its extended temperature grade, deterministic interrupt latency, and a robust peripheral set. The wide 1.8V-5.5V supply window allows direct attachment to single-cell Li-ion, two-cell AA, or 3.3V/5V rails without additional level shifting.
When designing with the PIC16F721-I/SO, leave at least 3mm of copper between the SOIC body and the board edge, and keep all decoupling capacitors within 3mm of their respective VDD/VSS pins. The ICSP/ICD pins (ICSPCLK/ICSPDAT, typically RB6/RB7) must remain accessible for in-circuit programming and debugging in production boards.
Drop-in alternatives for PIC16F721-I/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 PIC16F721-I/SO (same form factor and footprint) β differing in Internal Oscillator, Package, ADC, Timers, Instruction Set.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16F720-I/SO
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16F721-I/P
β Drop-Inβ In Stock
$1.12 / Unit
View Datasheet βPIC16F721-I/ML
β Drop-Inπ Reference alternative (not in catalog)
PIC16F721T-I/SO
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.18 / Unit
View Datasheet βPIC16F716-I/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16F721-I/SO Maximum Ratings & Electrical Characteristics
| Core | PIC16 mid-range 8-bit RISC |
| Instruction Set | 35 instructions, 8-level hardware stack |
| Program Memory | 7 KB Flash (4K x 14 words) |
| SRAM | 256 bytes |
| EEPROM / Data Flash | 128 bytes non-volatile data storage |
| Max CPU Frequency | 20 MHz (200 ns instruction cycle) |
| Internal Oscillator | 16 MHz (factory calibrated) |
| Supply Voltage (VDD) | 1.8 V to 5.5 V |
| I/O Pins | 18 (with 25 mA source/sink) |
| ADC | 12-channel, 8-bit |
| Timers | TMR0 (8-bit), TMR1 (16-bit), TMR2 (8-bit) |
| PWM / CCP | 1 x CCP module |
| Communication | I2C/SPI (MSSP), AUSART (EUSART) |
| Package | 20-pin SOIC (SO), 300 mil |
| Operating Temperature | -40 C to +85 C (industrial) |
| Low-Power Technology | nanoWatt XLP |
| Watchdog Timer | Yes (dedicated WDT oscillator) |
| Programming / Debug | In-Circuit Serial Programming (ICSP), ICD |
PIC16F721-I/SO Pin Configuration
| Pin 1 | RA0/AN0/C1IN+/ICSPCLK β Digital I/O / ADC input / Comparator input / ICSP clock |
| Pin 2 | RA1/AN1/C1IN-/VCREF β Digital I/O / ADC input / Comparator input / Voltage reference |
| Pin 3 | RA2/AN2/CVREF/VREF- β Digital I/O / ADC input / Comparator reference output / ADC negative reference |
| Pin 4 | RA3/AN3/C1OUT/VREF+ β Digital I/O / ADC input / Comparator output / ADC positive reference (also MCLR input) |
| Pin 5 | RA4/T0CKI/C1OUT β Digital I/O (open-drain) / Timer0 clock input / Comparator output |
| Pin 6 | RA5/AN4/SS/HLVDIN β Digital I/O / ADC input / SPI Slave Select / High/Low Voltage Detect input |
| Pin 7 | RA6/OSC2/CLKOUT β Digital I/O / Crystal oscillator output / Clock output |
| Pin 8 | RA7/OSC1/CLKIN β Digital I/O / Crystal oscillator input / External clock input |
| Pin 9 | VSS β Ground reference |
| Pin 10 | RB0/AN8/INT/SDA β Digital I/O (interrupt-on-change) / ADC input / External interrupt / I2C data |
| Pin 11 | RB1/AN9/SCL/SCK β Digital I/O / ADC input / I2C clock / SPI clock |
| Pin 12 | RB2/AN10/SDI/SDA β Digital I/O / ADC input / SPI data in / I2C data (alternate) |
| Pin 13 | RB3/AN11/SDO β Digital I/O / ADC input / SPI data out |
| Pin 14 | RB4 β Digital I/O (interrupt-on-change) |
| Pin 15 | RB5 β Digital I/O (interrupt-on-change) |
| Pin 16 | RB6/ICSPCLK/ICDCLK β Digital I/O (interrupt-on-change) / ICSP clock / ICD clock |
| Pin 17 | RB7/ICSPDAT/ICDDAT β Digital I/O (interrupt-on-change) / ICSP data / ICD data |
| Pin 18 | RC0 β Digital I/O (PORTC) |
| Pin 19 | RC1 β Digital I/O (PORTC) |
| Pin 20 | VDD β Positive supply (1.8V to 5.5V) |
Typical Applications
PIC16F721-I/SO is suitable for 6 applications: Consumer Appliance Control, Battery-Powered IoT Edge Node, Industrial Sensor Front-End, HVAC Fan and Blower Controller, Remote Control and User Interface, Automotive Interior Body Electronics.
Consumer Appliance Control
The PIC16F721-I/SO is well suited for consumer appliance control panels where its 16MHz internal oscillator eliminates external crystals and the 25mA source/sink I/O directly drives relays, triacs, and LED indicators. With 7KB Flash and 256B SRAM the device runs state-machine scheduling for fans, pumps, or door interlocks without external memory. The AUSART port exposes service diagnostics at 9.6-115.2 kbaud for factory test fixtures, while the 12-channel 8-bit ADC reads NTC temperature sensors and motor current shunts. nanoWatt XLP keeps standby power below 50nA for Energy Star standby compliance.
Recommended
Battery-Powered IoT Edge Node
For battery-powered IoT sensor nodes the PIC16F721-I/SO's nanoWatt XLP technology delivers deep-sleep currents in the nA range while retaining SRAM, allowing 10-year coin-cell operation with periodic wake-ups on WDT or interrupt. Its 128B EEPROM retains calibration data across power cycles without battery backup, and the 1.8V minimum supply operates directly off single-cell Li-ion or 2xAA. The MSSP peripheral talks to digital sensors over SPI or I2C, while AUSART uplinks data to a host MCU or BLE bridge. Industrial -40C to +85C rating suits outdoor enclosures and metering.
Recommended
Industrial Sensor Front-End
In industrial 4-20mA loop-powered and 24V bus systems the PIC16F721-I/SO operates across 1.8-5.5V at -40 to +85C with built-in BOR for noisy rails, making it a robust sensor front-end. Its 18 digital I/O and 12-channel 8-bit ADC interface directly to bridge sensors, optocouplers, and status LEDs without external glue logic. The Capture/Compare/PWM (CCP) module drives precision timing for flow measurement or LED indicator dimming. MSSP-AUSART pair supports Modbus RTU or proprietary fieldbus, and the dedicated WDT with on-chip oscillator protects firmware from EMI-induced lockups on the shop floor.
Recommended
HVAC Fan and Blower Controller
The PIC16F721-I/SO's CCP PWM module, 16-bit TMR1, and 25mA I/O drive capability make it ideal for HVAC fan and blower control loops. The 8-bit ADC reads temperature/humidity sensors at 12 channels while PWM output switches TRIACs or power MOSFETs at 25kHz for quiet motor commutation. nanoWatt XLP sleep maintains RTC-style scheduling for night setback modes, reducing compressor cycling. The MSSP exposes an I2C keypad/display interface, and AUSART passes diagnostic telemetry back to the building automation system over RS-485.
Recommended
Remote Control and User Interface
Remote controls and small user interface modules benefit from the PIC16F721-I/SO's low power budget, 16MHz core, and integrated peripherals. The MSSP reads capacitive touch sensors or matrix keypads over I2C, while 25mA I/O pins directly sink LED backlight current without drivers. AUSART or firmware-driven IR modulation handles remote-to-host communication. With 7KB Flash, the device supports graphical LCD or segmented display drivers using the CCP timer interrupts, all on a coin cell with multi-year life thanks to nanoWatt XLP.
Recommended
Automotive Interior Body Electronics
For non-safety automotive interior applications such as mirror control, seat switch panels, or ambient lighting, the PIC16F721-I/SO provides 18 digital I/O with 25mA drive capable of switching LEDs and small relays directly from 5V regulated rails. The AUSART peripherals connect to body-domain LIN or CAN bridges, while the 12-channel ADC reads potentiometers and switches. Operating across 1.8-5.5V and -40 to +85C the device fits climate-controlled cabins; users requiring AEC-Q100 qualification should select PIC16F721-E/SO automotive variants separately. nanoWatt XLP sleep currents keep parasitic drain low on long-parked vehicles.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F721-I/SO β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F720-I/SO | PIC16F721-I/P | PIC16F721-I/ML | PIC16F721T-I/SO | PIC16F716-I/SO |
|---|---|---|---|---|---|---|
| Package | 20-SOIC (300 mil) | 20-SOIC (300 mil) - same | 20-PDIP - through-hole | 20-QFN 6x6 mm - SMD | 20-SOIC (300 mil) - same | 20-SOIC (300 mil) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (Flash) | 7 KB | 3.5 KB (-50%) | 7 KB (same) | 7 KB (same) | 7 KB (same) | 3.5 KB (-50%) |
| SRAM | 256 B | 128 B (-50%) | 256 B (same) | 256 B (same) | 256 B (same) | 128 B (-50%) |
| Internal Oscillator | 16 MHz | 16 MHz (same) | 16 MHz (same) | 16 MHz (same) | 16 MHz (same) | 8 MHz |
| Operating Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V (same) | 1.8 V to 5.5 V (same) | 1.8 V to 5.5 V (same) | 1.8 V to 5.5 V (same) | 2.0 V to 5.5 V |
| I/O Pins | 18 | 18 (same) | 18 (same) | 18 (same) | 18 (same) | 13 |
| AUSART / CCP | AUSART + 1 CCP | AUSART + 1 CCP (same) | AUSART + 1 CCP (same) | AUSART + 1 CCP (same) | AUSART + 1 CCP (same) | No AUSART, 1 CCP |
Key Differentiators
- Largest Flash in PIC16F720/721 family (vs PIC16F720-I/SO)
- Same SOIC footprint as PIC16F716 with AUSART and CCP added (vs PIC16F716-I/SO)
- Industrial -40 to +85C grade (vs PIC16F721-E/SO (automotive parts may also exist))
Design Notes
Place decoupling capacitors (typically 100 nF ceramic plus 10 uF bulk) within 3 mm of the VDD pin 20 and VSS pin 9. The ICSP clock/data pins (RB6/RB7, pins 16/17) must remain accessible for in-circuit programming headers - do not place them under tall nearby components. A 10k pull-up on MCLR (RA3, pin 4) is recommended for reliable reset behavior during power-up.
Estimated: at 16MHz operating frequency the PIC16F721-I/SO draws approximately 4-5 mA active, dropping to uA levels in sleep. For 1.8V single-cell coin-cell applications, budget firmware duty-cycle to keep average draw below 50 uA so a CR2032 lasts 10+ years. The BOR and POR blocks should be enabled in the configuration words for reliable brownout recovery during battery end-of-life voltage excursions below 1.8V.
Do not assume the internal oscillator accuracy is sufficient for UART communication above 38.4 kbaud without calibration. The factory trim is +/-2% across voltage and temperature - adequate for most asynchronous timing, but RS-485 links at 115.2 kbaud over industrial temperature should use BRGH=1 and a calibrated FOSC. Also: never drive the ICSPDAT/ICSPCLK pins from external circuits during programming - they must be high-impedance for successful device programming.
Compliance Information
RoHS and lead-free per Microchip product declaration. Industrial temperature grade -40 to +85C only; AEC-Q100 automotive qualification requires the PIC16F721-E or -F suffix variants.
