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Microchip Technology AT42QT2120-MMH
- Part No.:
- AT42QT2120-MMH
- Manufacturer:
- Microchip Technology
- Category:
- Sensor, Capacitive Touch
- Package:
- 20-VFQFN Exposed Pad
- Datasheet:
-
AT42QT2120-MMH.pdf
- Description:
- IC TOUCH SENSOR 12CH 20VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,877
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Product details
Overview
AT42QT2120-MMH from Microchip Technology is a 12-channel QTouchADC capacitive touch sensor IC supporting up to 12 keys, or 9 keys plus wheel/slider, with programmable I²C interface (400 kHz), 1.8–5.5 V operation, and patented Adjacent Key Suppression (AKS®) for reliable multi-key detection in consumer HMI applications.
For engineers reviewing the AT42QT2120-MMH datasheet, AT42QT2120-MMH pinout, AT42QT2120-MMH application, or AT42QT2120-MMH equivalent, key selection considerations include comms vs. standalone mode configuration, AKS group assignment, proximity/guard channel allocation, and I²C address (0x1C) compatibility in embedded touch control systems.
Technical Context
The AT42QT2120-MMH implements spread-spectrum QTouchADC charge-transfer acquisition with self-calibration, auto-drift compensation, and noise filtering. It supports two operational modes: I²C-based comms mode (full register-level configuration) and hardware-mode standalone mode (fixed firmware parameters).
In comms mode, it provides 12 configurable sense channels-up to 12 keys, or 9 keys + wheel/slider-with 10 reassignable GPOs; in standalone mode, it delivers 5 keys + 1 guard + 1 proximity channel with fixed thresholds (10 counts), DI filter (1–32), and TRD (~30 s). Both modes use the same 20-pin SOIC/TSSOP or VQFN package with MODE pin selection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Touch Channels | 12-key max (comms); 5-key + guard + proximity (standalone) |
| I²C Interface | Slave-only at 400 kHz; fixed address 0x1C; supports multibyte read/write |
| Power Supply | 1.8 V to 5.5 V; internal LDO not required; 0.1 µF ceramic bypass mandatory |
| AKS Groups | Up to 3 groups; prevents simultaneous detection of adjacent keys in same group |
| Acquisition Time | Configurable LP mode (1–255 cycles × 16 ms); power-down at LP = 0 |
| Key Capacitance | Optimized for 1 pF–30 pF electrode capacitance; larger Cx reduces sensitivity |
| Guard/Proximity | Guard fixed on KEY1 (standalone); programmable in comms; PROX on KEY0 (standalone) |
Pinout & Package
AT42QT2120-MMH is available in RoHS-compliant 20-pin SOIC/TSSOP (5.3 mm × 7.6 mm) and 20-pad VQFN (3.5 mm × 4.5 mm) packages. Pin functions differ between comms and standalone modes; MODE pin selects mode at power-up.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| MODE | Mode selection input | Connect to VSS for comms mode; to VDD for standalone mode - sets internal configuration path at boot |
| SDA / SCL | I²C data/clock (comms only) | Open-drain lines requiring external 4.7 kΩ pull-ups; unused in standalone mode |
| CHANGE | Status change interrupt | Active-low open-drain signal indicating update in Detection/Key Status bytes; cleared by reading status registers |
| KEY0–KEY11 / GPO0–GPO9 | Configurable I/O | In comms mode: sense inputs or general-purpose outputs; in standalone mode: dedicated key inputs or push-pull outputs (OUT2–OUT6) |
| PROX / GUARD | Dedicated sensing channels | KEY0 serves as proximity sensor in standalone mode; KEY1 serves as guard channel with higher sensitivity and physical size requirement |
Key Features
| Feature | Design Value |
|---|---|
| Spread-spectrum QTouchADC | Eliminates external sampling capacitors; enables single-pin sensing with high noise immunity |
| Adjacent Key Suppression (AKS®) | Hardware-enforced mutual exclusion within user-defined groups - prevents false multi-key activation |
| Self-calibrating drift compensation | Towards-touch drift (3.2 s) and away-from-touch drift (0.8 s) automatically adapt reference levels |
| Programmable Touch Recalibration Delay | Global timer (1–255 × 160 ms) prevents stuck-key conditions during prolonged touch |
| Guard + Proximity dual-channel support | Single IC supports both proximity wake-up and guard shielding - reduces BOM count in HMI designs |
Applications
| Consumer Appliance Control Panel | Industrial Human-Machine Interface |
|---|---|
Use Scenario: Touch-sensitive front panel on washing machine or oven with 8 keys + 1 slider for temperature adjustment. IC Role / Device Role / Timing Role: AT42QT2120-MMH acts as primary capacitive sensor controller, acquiring raw electrode signals and delivering debounced key status via I²C to MCU. Use Value: Enables sealed, waterproof UI without mechanical buttons; AKS ensures accurate single-key selection even with wet fingers or gloves. | Use Scenario: Operator terminal on CNC machine with 5 function keys, proximity wake-up, and metal bezel integration. IC Role / Device Role / Timing Role: AT42QT2120-MMH operates in standalone mode to drive discrete LED indicators while detecting proximity for system wake-up and key presses. Use Value: Eliminates need for separate proximity IC and key controller; grounded metal compatibility allows direct mounting behind stainless-steel fascia. |
| Automotive Infotainment Trim | Medical Device Touch Overlay |
Use Scenario: Non-backlit center console overlay with 6 keys + wheel for volume control, operating under varying cabin temperatures and EMI conditions. IC Role / Device Role / Timing Role: AT42QT2120-MMH runs in comms mode with custom AKS grouping and LP mode tuning to balance response time (<100 ms) and EMC robustness. Use Value: Spread-spectrum modulation suppresses RF emissions to meet CISPR 25 Class 3; drift compensation maintains accuracy across –40°C to +85°C. | Use Scenario: Sterilizable touch interface on infusion pump using PET film overlay and ITO electrodes, requiring low-power operation and contamination resilience. IC Role / Device Role / Timing Role: AT42QT2120-MMH uses standalone mode with fixed thresholds and guard channel to reject false triggers from gloved hands or fluid splashes. Use Value: Single-layer PCB design enabled by one-side electrode placement; 1.8 V minimum supply supports battery-backed operation during AC loss. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar capacitive touch sensor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT42QT2120-MUH | VQFN package (3.5 mm × 4.5 mm); identical electrical specs and pinout mapping to SOIC version | Better thermal performance and smaller footprint; requires fine-pitch reflow profile | Select AT42QT2120-MUH for space-constrained PCBs where thermal dissipation is critical |
| CY8CMBR2110 | Cypress CapSense® device; 10-key capacity; different I²C address (0x3A); no standalone mode | Requires host MCU for all configuration; lacks guard/proximity hardware differentiation | Select CY8CMBR2110 when full firmware control is preferred and board space allows additional MCU overhead |
Compared with AT42QT2120-MMH, AT42QT2120-MUH offers identical functionality in a smaller VQFN package but demands tighter assembly tolerances, while CY8CMBR2110 shifts configuration burden to host software and omits hardware-guarded proximity sensing - making AT42QT2120-MMH optimal for cost-sensitive, low-MCU-footprint HMI designs requiring robust standalone operation.
Availability
AT42QT2120-MMH is available at Aetrix Electronics and suitable for consumer appliance control panels, industrial HMI terminals, automotive infotainment trims, medical device overlays, and smart home interface modules requiring stable component supply and long-term production continuity.
Supply support for AT42QT2120-MMH 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 company specializing in microcontrollers, analog devices, and human-interface solutions, with broad industrial and automotive qualification coverage.
The AT42QT2120-MMH belongs to Microchip's QTouchADC family, designed specifically for robust, low-cost capacitive touch sensing in cost-sensitive, high-volume HMI applications where reliability under variable environmental conditions is essential.
FAQ
What is the I²C address of the AT42QT2120-MMH and can it be changed?
The AT42QT2120-MMH has a fixed I²C slave address of 0x1C (28 decimal), and this address cannot be modified through hardware pins or software configuration. It is hard-coded in silicon and remains constant across all operating conditions and firmware versions of the AT42QT2120-MMH. This simplifies bus arbitration in multi-device systems but requires address conflict checking during system integration.
Does the AT42QT2120-MMH support both wheel and slider functionality simultaneously?
No, the AT42QT2120-MMH supports either a wheel or a slider - not both simultaneously. In comms mode, up to three keys (KEY2–KEY4) may be assigned to spatially interpolated wheel or slider operation, consuming those channels exclusively. The remaining keys (up to nine) function as standard touch keys. Wheel and slider configurations share the same interpolation engine and cannot operate in parallel on the same AT42QT2120-MMH device.
How does the guard channel function in standalone mode on the AT42QT2120-MMH?
In standalone mode, the AT42QT2120-MMH automatically assigns KEY1 as the guard channel with fixed higher sensitivity and no software configurability. It is physically implemented as a larger electrode surrounding other keys to detect hand proximity before actual key press, thereby suppressing false triggers. This guard behavior is hardcoded and cannot be reassigned or disabled in standalone mode - only in comms mode via Key Control register bit 4 (GUARD).
What is the maximum recommended panel thickness for glass overlays with the AT42QT2120-MMH?
The AT42QT2120-MMH supports up to 15 mm of glass for standard key sensing (size-dependent), and up to 4 mm of glass for wheel or slider operation. These limits assume optimized electrode design (e.g., ≥5 mm × 5 mm keys, ≥6 mm center-to-center spacing) and proper Rs series resistors (4.7–20 kΩ). Exceeding these thicknesses degrades signal-to-noise ratio and may require recalibration or reduced sensitivity settings in comms mode.
Can the AT42QT2120-MMH operate without an external microcontroller?
Yes, the AT42QT2120-MMH supports true standalone operation when the MODE pin is tied to VDD at power-up. In this mode, it delivers fixed-function outputs: KEY2–KEY6 drive OUT2–OUT6 push-pull outputs on touch, KEY0 serves as proximity output (PXOUT), and KEY1 functions as guard - all without I²C communication. No external MCU is needed for basic LED-driven or discrete logic interface applications.
AT42QT2120-MMH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Package/Case:
- 20-VFQFN Exposed Pad
- Series:
- QTouch™
- Packaging:
- Tray
- 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-VQFN (3x3)
AT42QT2120-MMH FAQ
1.How can I place an order for AT42QT2120-MMH through Aetrix?
Please submit a Request for Quotation (RFQ) for AT42QT2120-MMH 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-MMH reliable?
The price and inventory of AT42QT2120-MMH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT42QT2120-MMH is usually 5 days.
3.What payment methods are accepted for AT42QT2120-MMH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT42QT2120-MMH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT42QT2120-MMH?
AT42QT2120-MMH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT42QT2120-MMH 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-MMH?
For technical support, including AT42QT2120-MMH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT42QT2120-MMH requirements.
6.How does Aetrix verify that AT42QT2120-MMH is sourced from the original manufacturer or authorized distributors?
All AT42QT2120-MMH 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-MMH meets industry standards.
7.What is the process for return or replacement of AT42QT2120-MMH?
All AT42QT2120-MMH units undergo pre-shipment inspection (PSI). If there is an issue with AT42QT2120-MMH, 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-MMH part is unused and in its original packaging.
Return procedure for AT42QT2120-MMH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT42QT2120-MMH Tags
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IQS228B00000000TSR
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MTCH101T-I/OT
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IQS323001CSR
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