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Microchip Technology AT42QT2120-SU
- Part No.:
- AT42QT2120-SU
- Manufacturer:
- Microchip Technology
- Category:
- Sensor, Capacitive Touch
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AT42QT2120-SU.pdf
- Description:
- IC TOUCH SENSOR 12CH 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:886
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Product details
Overview
AT42QT2120-SU from Microchip Technology is a 12-channel QTouchADC capacitive touch sensor IC supporting up to 12 keys, or 9 keys plus wheel/slider, with integrated proximity and guard channel functionality. It operates from 1.8 V to 5.5 V, uses spread-spectrum charge-transfer sensing, and delivers debounced outputs via I²C (400 kHz) or standalone push-pull/open-drain outputs - deployed in industrial HMI, appliance control panels, and automotive interior interfaces.
For engineers reviewing the AT42QT2120-SU datasheet, AT42QT2120-SU pinout, AT42QT2120-SU application, or AT42QT2120-SU equivalent, key selection considerations include mode-dependent key count (12 in Comms, 5 in Standalone), programmable AKS groups, I²C address 0x1C, CHANGE interrupt behavior, and dual-package support (SOIC/TSSOP-20 and VQFN-20).
Technical Context
The AT42QT2120-SU implements patented QTouchADC charge-transfer acquisition with spread-spectrum modulation for noise immunity and RF emission suppression. It performs real-time self-calibration, auto drift compensation (TTD/ATD), Adjacent Key Suppression® (up to 3 groups), and hysteresis (12.5% of detect threshold).
In Comms Mode, it supports full I²C configuration of thresholds, AKS, LP mode (1–255), Detect Integrator (1–32), Touch Recalibration Delay (160 ms–40.8 s), and guard assignment. In Standalone Mode, it executes fixed firmware with hard-coded thresholds (10 counts), TRD (~30 s), DHT (~4 s), and preassigned guard (KEY1) and proximity (KEY0) channels.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Touch Channels | Up to 12 keys in Comms Mode; up to 5 keys + guard + proximity in Standalone Mode |
| Interface | I²C slave at 400 kHz (Comms Mode only); no interface required in Standalone Mode |
| Supply Voltage | 1.8 V to 5.5 V - enables direct integration with 1.8 V, 3.3 V, and 5 V logic systems |
| Power Modes | Configurable Low Power Mode (LP = 1–255, ~16 ms base cycle); LP = 0 enters Power-down |
| AKS Groups | Up to 3 independent groups - prevents simultaneous detection of adjacent keys in dense layouts |
| Key Capacitance Range | 1 pF to 30 pF - defines electrode size and overlay thickness compatibility (e.g., ≤10 mm plastic) |
| Proximity Support | Dedicated PROX channel (KEY0) with open-drain output (PXOUT) in Standalone Mode |
| Guard Channel | Fixed on KEY1 in Standalone Mode; programmable on any key in Comms Mode |
Pinout & Package
AT42QT2120-SU is available in RoHS-compliant 20-pin SOIC/TSSOP and 20-pad VQFN packages. Pin functions differ between Comms and Standalone modes; MODE pin selects operation (VSS for Comms, VDD for Standalone). Both packages support identical I/O mapping and electrical characteristics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| KEY0 / PROX | Input/Output | Comms: Key/slider/wheel 0; Standalone: Proximity sense channel with PXOUT output |
| KEY1 / GUARD | Input/Output | Comms: Key/slider/wheel 1; Standalone: Fixed guard channel with higher sensitivity |
| KEY2–KEY11 / GPO0–GPO9 | Input/Output | Comms: Configurable keys or general-purpose outputs; Standalone: Outputs OUT2–OUT6 mapped to KEY2–KEY6 |
| MODE | Input | Selects operating mode: tie to VSS for Comms, VDD for Standalone |
| SDA / SCL | Open-drain I/O | I²C data/clock lines active only in Comms Mode; require external pull-ups to VDD |
| CHANGE | Open-drain output | Active-low interrupt signaling status change - used to avoid polling in Comms Mode |
| RESET | Input | Active-low reset with internal 60 kΩ pull-up; minimum pulse width 2 µs |
| VDD / VSS | Power / Ground | Single-supply operation from 1.8 V to 5.5 V; requires local 0.1 µF ceramic bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| Spread-spectrum QTouchADC | Eliminates external sampling capacitors and improves SNR by modulating burst timing across spectrum |
| Adjacent Key Suppression® (AKS) | Enables reliable multi-key detection on tightly spaced electrodes (≤6 mm center-to-center) |
| Self-calibrating drift compensation | Tracks environmental drift with Toward-Touch (3.2 s) and Away-from-Touch (0.8 s) time constants |
| Programmable Detect Integrator | Filters noise via configurable consecutive-sample validation (1–32 cycles) before reporting touch |
| Touch Recalibration Delay (TRD) | Prevents lock-up during prolonged touch: 30 s default (Standalone), 160 ms–40.8 s adjustable (Comms) |
| Single-layer electrode design | Supports FR-4, PET, glass, and ITO/PEDOT electrodes - no second-layer ground plane required |
Applications
| Home Appliance Control Panel | Automotive Interior Interface |
|---|---|
Use Scenario: Touch-sensitive cooktop, oven, or washing machine control panel with glass overlay up to 10 mm thick. IC Role / Device Role / Timing Role: Primary touch sensor IC managing up to 12 keys and optional slider for temperature adjustment. Use Value: Enables seamless, waterproof, and wear-resistant user interface without mechanical buttons or complex shielding. | Use Scenario: Center console or door panel with proximity wake-up and guarded key clusters near HVAC controls. IC Role / Device Role / Timing Role: Standalone-mode AT42QT2120-SU provides proximity detection (KEY0) and guard channel (KEY1) to suppress false triggers from hand proximity. Use Value: Reduces system-level MCU wake events and eliminates false actuation when palm rests near controls. |
| Industrial HMI Keypad | Medical Device Front Panel |
Use Scenario: Dust- and chemical-resistant control panel for factory HMIs using FR-4 PCB electrodes under polycarbonate overlay. IC Role / Device Role / Timing Role: Comms-mode AT42QT2120-SU configured via I²C for dynamic threshold tuning and AKS group assignment across 9 keys + wheel. Use Value: Supports field calibration and adaptive sensitivity in varying EMI environments without hardware changes. | Use Scenario: Sterilizable medical monitor front panel with non-conductive paint and 4 mm glass overlay. IC Role / Device Role / Timing Role: AT42QT2120-SU operates in Comms Mode to enable programmable hysteresis and low-power burst scheduling compliant with IEC 60601 leakage limits. Use Value: Meets stringent safety requirements while delivering responsive, drift-compensated touch performance through sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar capacitive touch sensor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT42QT1070-MAH | 7-channel variant; no wheel/slider support; single 16-pin SOIC package; fixed 3.3 V operation | Limited to smaller keypads; lacks proximity/guard flexibility and spatial interpolation for sliders | Select when board space and channel count are constrained and wheel/slider functionality is unnecessary. |
| CY8CMBR2016-LQXI | Cypress CapSense® device; 16-channel; supports CapSense CSD and CSX; requires external crystal; different I²C address (0x38) | Higher channel density but needs additional timing components; more complex tuning workflow | Choose for designs requiring >12 channels or mixed-sensing topologies (e.g., button + proximity + gesture). |
Compared with AT42QT2120-SU, AT42QT1070-MAH offers reduced footprint and cost for simpler keypads but sacrifices wheel/slider, proximity, and flexible packaging. CY8CMBR2016-LQXI provides greater scalability and dual-sensing methods but increases BOM complexity and firmware integration effort.
Availability
AT42QT2120-SU is available at Aetrix Electronics and suitable for industrial HMI, home appliance control panels, and automotive interior interfaces requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for AT42QT2120-SU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and human interface solutions, with global manufacturing and quality certifications including ISO 9001 and IATF 16949.
The AT42QT2120-SU belongs to Microchip's QTouch family of capacitive touch controllers, designed specifically for robust, low-power, single-chip touch sensing in cost-sensitive consumer, industrial, and automotive applications.
FAQ
What is the I²C address of the AT42QT2120-SU?
The AT42QT2120-SU has a fixed I²C slave address of 0x1C (28 decimal), which cannot be modified. This address is used exclusively in Comms Mode for configuration and status reads; it is inactive in Standalone Mode where no I²C interface is employed. The device supports standard-mode I²C up to 400 kHz with open-drain SDA/SCL pins requiring external pull-up resistors to VDD.
How does the AT42QT2120-SU handle proximity detection?
The AT42QT2120-SU supports proximity sensing on KEY0 (PROX channel), which operates in both modes. In Standalone Mode, PROX drives the PXOUT open-drain output; in Comms Mode, it functions as a configurable key channel. Proximity detection uses the same QTouchADC engine with optimized oversampling and threshold settings - enabling reliable hand-detection up to 4 mm from glass or 3 mm from plastic overlays without additional components.
Can the AT42QT2120-SU drive LEDs directly in Standalone Mode?
Yes, in Standalone Mode the AT42QT2120-SU drives OUT2–OUT6 (mapped to KEY2–KEY6) as push-pull outputs that go high during touch detection. These outputs can directly drive standard LEDs with appropriate current-limiting resistors (e.g., 330 Ω for 5 V operation). No external drivers or transistors are needed, simplifying front-panel indicator design while maintaining low quiescent current (<1 µA in Power-down).
What is the maximum overlay thickness supported by the AT42QT2120-SU?
The AT42QT2120-SU supports up to 15 mm of glass or 10 mm of plastic for standard keys, and up to 4 mm glass or 3 mm plastic for wheel/slider electrodes. These limits assume recommended electrode sizes (≥5 mm × 5 mm keys, ≥12 mm wide slider segments) and proper layout practices (e.g., guard ring, grounded adjacent metal). Sensitivity degrades gradually beyond these values and must be validated per application using the device's programmable threshold and integrator settings.
Does the AT42QT2120-SU require external capacitors for touch sensing?
No, the AT42QT2120-SU uses QTouchADC charge-transfer technology that eliminates the need for external sampling capacitors (Cs). Only two external components are mandatory: a 0.1 µF ceramic bypass capacitor across VDD/VSS (placed close to the IC), and series Rs resistors (4.7 kΩ–20 kΩ) on each electrode line for ESD/RFI protection. No timing crystals, RC networks, or calibration capacitors are required.
AT42QT2120-SU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Series:
- QTouch™
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Buttons, Slider, Wheel
- Proximity Detection:
- Yes
- Number of Inputs:
- Up to 12
- LED Driver Channels:
- Up to 10
- Interface:
- I2C
- Resolution:
- -
- Voltage - Supply:
- 1.8V ~ 5.5V
- Current - Supply:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
AT42QT2120-SU FAQ
1.How can I place an order for AT42QT2120-SU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT42QT2120-SU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AT42QT2120-SU reliable?
The price and inventory of AT42QT2120-SU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT42QT2120-SU is usually 5 days.
3.What payment methods are accepted for AT42QT2120-SU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT42QT2120-SU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT42QT2120-SU?
AT42QT2120-SU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT42QT2120-SU order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AT42QT2120-SU?
For technical support, including AT42QT2120-SU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT42QT2120-SU requirements.
6.How does Aetrix verify that AT42QT2120-SU is sourced from the original manufacturer or authorized distributors?
All AT42QT2120-SU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AT42QT2120-SU meets industry standards.
7.What is the process for return or replacement of AT42QT2120-SU?
All AT42QT2120-SU units undergo pre-shipment inspection (PSI). If there is an issue with AT42QT2120-SU, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AT42QT2120-SU part is unused and in its original packaging.
Return procedure for AT42QT2120-SU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT42QT2120-SU Tags
-
IQS228B00000000TSR
Azoteq (Pty) Ltd
-
MTCH101T-I/OT
Microchip Technology
-
IQS323001CSR
Azoteq (Pty) Ltd
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Microchip Technology
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AT42QT1012-TSHR
Microchip Technology
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AT42QT1011-TSHR
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CAP1206-1-SL-TR
Microchip Technology
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MTCH102T-I/MS
Microchip Technology
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IQS323001DNR
Azoteq (Pty) Ltd
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AT42QT1070-SSUR
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