PIC16F684T-I/ST - 8-bit 20MHz 3.5KB Flash MCU 14-TSSOP | Microchip
MPN: PIC16F684T-I/ST ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.05 | $2.05 |
| 10 | $1.84 | $18.40 |
| 100 | $1.62 | $162.00 |
| 500 | $1.38 | $690.00 |
| 1,000 | $1.15 | $1,150.00 |
PIC16F684T-I/ST Overview
What is a PIC16 microcontroller? A PIC16 (Peripheral Interface Controller) is an 8-bit RISC microcontroller family from Microchip Technology built on a Harvard architecture with separate program and data buses. Within the broader hierarchy, PIC16 sits between the baseline PIC10/12/16 families and the higher-performance PIC18/PIC24 families; it is a flash-programmable CMOS MCU belonging to the microcontroller -> embedded controller -> semiconductor category. Mid-range PIC16 devices are characterized by a 14-bit instruction word, 35 single-word instructions, and on-chip peripherals including timers, ADC, comparators, and PWM.
Key features include an 8-channel 10-bit ADC, two comparators with hysteresis, a Capture/Compare/PWM (CCP) module, an Enhanced Universal Synchronous/Asynchronous Receiver/Transmitter (EUSART), and nanoWatt power management that reduces quiescent current below 1 µA in sleep mode. The device exposes 12 I/O pins (11 GPIO plus 1 input-only), supports in-circuit serial programming (ICSP) via two pins, and offers a wide operating voltage window that simplifies battery-powered and 5 V designs.
The architecture separates program and data buses for simultaneous instruction fetch and operand access, and the internal 31 kHz and 8 MHz oscillators reduce BOM cost. The -I/ST suffix denotes the industrial temperature grade and 14-pin TSSOP package; the T-suffix indicates tape-and-reel packaging. The 14-TSSOP footprint has a body size of 5.0 mm x 4.4 mm with a 0.65 mm pitch.
Typical applications include low-power sensor nodes, white-goods and appliance control, automotive body modules, lighting ballasts, and small consumer appliances. The PIC16F684 is also AEC-Q100 qualified (variants), making it suitable for automotive under-hood and cabin subsystems that require a robust 8-bit controller.
When designing, ensure the ICSP/PGD and PGC pins are reserved for programming; place a 0.1 µF decoupling capacitor close to VDD, and use the internal 8 MHz HFINTOSC to minimize external component count. Compared to a switching regulator, the PIC16F693 remains operational during brown-outs as low as 2.0 V.
This page synthesizes distributor pricing, same-family drop-in alternatives (e.g., PIC16F684-I/ST, PIC16F684-I/SL) and design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC16F684T-I/ST — 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 PIC16F684T-I/ST (same form factor and footprint) — differing in Core Architecture, Timers, Comparators, ADC, Internal Oscillator.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F684-I/ST
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →PIC16F684T-I/SL
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC16F684-E/ST
✅ Drop-In✓ In Stock
$1.2 / Unit
View Datasheet →PIC16F684-I/SL
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC16F676-I/ST
✅ Drop-In✓ In Stock
$1.02 / Unit
View Datasheet →PIC16F677-I/SS
✅ Drop-In✓ In Stock
$1.27 / Unit
View Datasheet →PIC16F684T-I/ST Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 mid-range (x14) 8-bit RISC |
| Program Memory | 3.5 KB Flash (2K x 14 words) |
| Data EEPROM | 256 B |
| SRAM | 128 B |
| Maximum Clock Frequency | 20 MHz (200 ns instruction cycle) |
| Operating Voltage | 2.0 V to 5.5 V |
| Operating Temperature | -40 °C to +85 °C (industrial) |
| I/O Pins | 12 (11 GPIO + 1 input-only) |
| ADC | 8-channel, 10-bit |
| Comparators | 2 with hysteresis |
| PWM/CCP Modules | 1 Enhanced CCP |
| Communication | 1 EUSART |
| Timers | 1 x 8-bit, 2 x 16-bit |
| Package | 14-pin TSSOP (ST) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| ICSP | Yes (2-wire) |
| Internal Oscillator | 31 kHz + 8 MHz HFINTOSC |
PIC16F684T-I/ST Pin Configuration
| Pin 1 | VDD — Positive supply voltage (2.0 V to 5.5 V) |
| Pin 2 | RA5/AN4/C2OUT — GPIO RA5 / Analog input 4 / Comparator 2 output |
| Pin 3 | RA4/AN3/T0CKI — GPIO RA4 / Analog input 3 / Timer0 clock input |
| Pin 4 | RA3/MCLR/VPP — GPIO RA3 (input only) / Master Clear reset / ICSP programming voltage |
| Pin 5 | RC5/CCP1/RX/DT — GPIO RC5 / CCP1 PWM / EUSART RX / Data |
| Pin 6 | RC4/C2OUT/TX/CK — GPIO RC4 / Comparator 2 output / EUSART TX / Clock |
| Pin 7 | RC3/AN7/C12IN3- — GPIO RC3 / Analog input 7 / Comparator 1/2 inverting input |
| Pin 8 | RC2/AN6/C12IN2- — GPIO RC2 / Analog input 6 / Comparator 1/2 inverting input |
| Pin 9 | RC1/AN5/C12IN1- — GPIO RC1 / Analog input 5 / Comparator 1/2 inverting input |
| Pin 10 | RC0/AN4/C2IN+ — GPIO RC0 / Analog input 4 / Comparator 2 non-inverting input |
| Pin 11 | RA2/AN2/COUT/T0CKI — GPIO RA2 / Analog input 2 / Comparator output / Timer0 clock input |
| Pin 12 | RA1/AN1/C1IN- — GPIO RA1 / Analog input 1 / Comparator 1 inverting input |
| Pin 13 | RA0/AN0/C1IN+ — GPIO RA0 / Analog input 0 / Comparator 1 non-inverting input |
| Pin 14 | VSS — Ground reference |
Typical Applications
PIC16F684T-I/ST is suitable for 6 applications: Low-Power Sensor Node, White Goods Appliance Control, Automotive Body Module (AEC-Q100), LED Lighting Ballast / Driver Control, Small Consumer Appliance, Industrial Sensor Transmitter.
Low-Power Sensor Node
The PIC16F684T-I/ST is well-suited to battery-powered sensor nodes because of its 2.0 V to 5.5 V operating range, nanoWatt sleep currents under 1 µA, and integrated 8-channel 10-bit ADC for direct sensor readout. The 20 MHz instruction clock at 200 ns cycle time enables responsive event handling, while the on-chip 31 kHz and 8 MHz internal oscillators eliminate external timing components and reduce BOM cost by 1-2 USD per board. The 12 I/O pins can drive SPI/I2C sensors, status LEDs, and an interrupt input. With 3.5 KB of Flash and 128 B RAM, the device can run a small RTOS-style loop, periodic ADC sampling, and a low-power duty-cycle scheduler. Designers should place the MCU in sleep between samples, wake on WDT or external interrupt, and use the HFINTOSC + ADC combination for sub-microsecond wake-and-measure cycles.
Recommended
White Goods Appliance Control
The PIC16F684T-I/ST is widely deployed in white-goods control boards (washing machines, dishwashers, microwave ovens, refrigerators) because it offers reliable 8-bit processing at 5 V, 12 I/O for triac/relay drivers, and the EUSART for user-interface display communication. Its 200 ns instruction cycle handles real-time motor control loops via the Enhanced CCP PWM module, and the two on-chip comparators provide overcurrent/zero-cross feedback without external parts. The industrial -40 °C to +85 °C temperature rating suits indoor appliance enclosures, and the 14-TSSOP footprint saves PCB space versus 20-pin DIP predecessors. The 3.5 KB Flash fits typical state-machine control firmware, and the 256-byte EEPROM stores user settings and calibration constants across power cycles. Designers can pair the MCU with an MCP6002 op-amp for current sensing and an MCP23S08 port expander for keypad input.
Recommended
Automotive Body Module (AEC-Q100)
AEC-Q100 qualified variants of the PIC16F684 are used in non-safety automotive body modules such as interior lighting controllers, seat-position memories, and HVAC damper drives. The wide 2.0-5.5 V supply handles 12 V battery transients after a pre-regulator, and the 8-channel 10-bit ADC reads multiple position sensors (potentiometers, thermistors) for closed-loop control. The EUSART and I2C/SPI blocks enable LIN bus via external transceiver, and the 14-TSSOP package withstands automotive vibration profiles when properly soldered with under-body pads. Automotive designers choose the E-suffix variant for -40 °C to +125 °C operation; the standard -I suffix is acceptable for cabin modules. The small Flash footprint (3.5 KB) keeps per-MCU cost low in production runs of hundreds of thousands of units per year.
Recommended
LED Lighting Ballast / Driver Control
The PIC16F684T-I/ST is a popular choice for dimmable LED ballasts and architectural lighting controllers, leveraging the Enhanced CCP module for high-resolution PWM dimming (up to 10-bit at 20 kHz typical). The two on-chip comparators can implement zero-current detection for hysteretic PFC or critical-conduction-mode buck topologies without external components. With 8 ADC channels, the MCU can read multiple photodiodes, color sensors, and potentiometer-based dim knobs. The wide 2.0-5.5 V supply allows direct operation from rectified 5 V rails. The 14-TSSOP package integrates into compact GU10 and MR16 form factors. Designers typically pair the PIC16F684 with a constant-current LED driver MOSFET pair and use the HFINTOSC + PLL for accurate PWM frequency without external timing parts.
Recommended
Small Consumer Appliance
The PIC16F684T-I/ST fits small consumer appliances such as coffee makers, blenders, toasters, and air purifiers, where the 14-TSSOP package minimizes PCB size and the integrated peripherals eliminate external drivers. The MCU's Enhanced CCP can drive triac gates for AC load switching, the ADC reads temperature or humidity sensors, and the EUSART enables Bluetooth module communication (HC-05/HC-06) for smart-appliance variants. The 2.0-5.5 V operating voltage accepts rectified mains 3.3 V rails. With 3.5 KB Flash and 256-byte EEPROM for user presets, the part is well-suited to cost-sensitive consumer designs requiring IEC 60730 Class B software safety routines. Designers should reserve MCLR/RA3 for ICSP programming.
Recommended
Industrial Sensor Transmitter
The PIC16F684T-I/ST is used in 4-20 mA loop-powered sensor transmitters and industrial sensor interfaces, leveraging its low-power operation, 8-channel 10-bit ADC, and industrial -40 °C to +85 °C temperature rating. The MCU can read thermocouples, RTDs, or strain gauges through external signal conditioning, run linearization in software, and drive a current loop via PWM-controlled MOSFET. The EUSART supports RS-485 via external transceiver for industrial networks, and the I2C/SPI blocks read digital sensors. The 14-TSSOP footprint fits 24 mm x 24 mm transmitter enclosures. With 3.5 KB Flash, the firmware can include self-calibration routines. Designers should use the internal 31 kHz LFINTOSC for low-power timing and the HFINTOSC for ADC conversions.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F684T-I/ST — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F684-I/ST | PIC16F684T-I/SL | PIC16F684-E/ST | PIC16F676-I/ST | PIC16F677-I/SS |
|---|---|---|---|---|---|---|
| Package | 14-TSSOP | 14-TSSOP - same | 14-SOIC | 14-TSSOP - same | 14-TSSOP - same | 20-SSOP |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 3.5 KB Flash | 3.5 KB Flash | 3.5 KB Flash | 3.5 KB Flash | 1.75 KB Flash | 14 KB Flash |
| SRAM | 128 B | 128 B | 128 B | 128 B | 64 B | 368 B |
| Operating Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| I/O Pins | 12 | 12 | 12 | 12 | 12 | 18 |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +125 °C | -40 °C to +85 °C | -40 °C to +85 °C |
Key Differentiators
- Industrial -40 °C to +85 °C rating at 14-TSSOP (vs PIC16F684T-I/SL (14-SOIC))
- 8-channel 10-bit ADC integrated with comparators (vs PIC16F676-I/ST)
- 3.5 KB Flash with EUSART and CCP (vs PIC16F677-I/SS (20-SSOP))
Design Notes
Place a 0.1 µF decoupling capacitor as close as possible to the VDD pin (pin 1) and a bulk 10 µF capacitor near the 14-TSSOP supply input. For battery-powered designs, enable the nanoWatt sleep modes (datasheet document 41202C) and use the 31 kHz LFINTOSC during idle to achieve quiescent current below 1 µA; this can extend CR2032 battery life by 3-5x.
Reserve pins RA3/MCLR/VPP (pin 4) and RC4/ICSPDAT (pin 6 or pin 10, depending on configuration) for in-circuit serial programming. Provide a 10 kΩ pull-up on MCLR unless the internal MCLR is disabled in configuration bits. Keep traces to the ICSP connector under 50 mm to avoid programming failures; use a 4-pin header (VDD, GND, PGD, PGC) for the standard Microchip ICD layout.
Do not load the RA3 pin as a GPIO output; it is input-only and serves dual purpose as MCLR/VPP. Misconfiguring RA3 as output can prevent ICSP programming and cause permanent configuration lock-out. When using the ADC, ensure the input voltage does not exceed VDD + 0.3 V, or use a 1 kΩ series resistor to limit input current during overvoltage events.
Estimated: with HFINTOSC selected, ADC readings may show 1-2 LSB of noise at 5 V VDD; averaging 16 samples reduces effective noise to ~10-bit clean resolution. For precision analog designs, use the 31 kHz oscillator during ADC conversions and dedicate a separate analog ground via if the board carries >100 mA switching currents within 10 mm of the MCU.
Compliance Information
RoHS compliant per Microchip product page. AEC-Q100 qualification varies by suffix; E-suffix variants are AEC-Q100 qualified for automotive. The -I suffix is industrial temperature grade, not automotive qualified.
