AT42QT1040-MMHR - 4-Key QTouch Sensor IC | Microchip
N.º de pieza: AT42QT1040-MMHR ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $1.33 | $1,33 |
| 10 | $1.19 | $11,90 |
| 100 | $1.05 | $105,00 |
| 500 | $0.92 | $460,00 |
| 1.000 | $0.81 | $810,00 |
| 3.000 | $0.68 | $2.040,00 |
AT42QT1040-MMHR Descripción general
A capacitive touch sensor is an electronic device that detects the presence or absence of a conductive object (typically a human finger) by measuring changes in capacitance on a sense electrode. These sensors sit in the broader category of human-machine interface (HMI) peripherals, alongside resistive touch panels, infrared proximity sensors, and mechanical switches. By replacing mechanical buttons with solid-state capacitive sensing, designers gain sealed, wear-free, and aesthetically clean user interfaces for consumer and industrial products.
Key features of the AT42QT1040-MMHR include 1 to 4 individually configurable keys (unused channels are disabled simply by omitting their sense capacitor), automatic self-calibration within approximately 100 ms of power-up, automatic recalibration on stuck-key or slow drift conditions, and a simple parallel output interface. Each key has its own dedicated output pin, allowing direct GPIO connection to a host microcontroller without any I2C or SPI firmware overhead.
The device uses Microchip's patented burst-mode charge-transfer acquisition, in which a fixed number of charge-transfer cycles per measurement produces a high signal-to-noise ratio while keeping average current consumption low. This makes it well suited for battery-powered applications where every microamp of quiescent draw matters, and for environments subject to electrical noise from motors, relays, or switching converters.
Typical applications include appliance control panels, IoT smart-home touch buttons, automotive interior switches, medical device keypads, industrial equipment front panels, and consumer electronics such as remote controls and audio devices. The wide 1.8 V to 5.5 V supply range allows direct connection to 3.3 V MCUs, 5 V legacy logic, or Li-ion battery rails.
When designing with the AT42QT1040-MMHR, pay close attention to PCB layout: sense traces should be short, guarded by a ground ring, and kept away from switching nodes. The sense capacitors should be low-drift ceramic types (typically X7R or C0G/NP0) to preserve touch sensitivity over temperature.
This page synthesizes distributor pricing, drop-in alternatives, and practical PCB layout guidance not consolidated in the manufacturer datasheet, helping engineers select, source, and lay out the AT42QT1040-MMHR with confidence.
Alternativas directas para AT42QT1040-MMHR — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con AT42QT1040-MMHR (mismo factor de forma y huella) — difiere en Communication Interface, Operating Temperature Range, Package.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
AT42QT1040-MMH
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AT42QT1040-MMUR
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AT42QT1040-CUR
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AT42QT1050-MMH
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AT42QT1244-MUR
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AT42QT1040-MMHR Valores máximos y características eléctricas
| Number of Touch Keys | 1 to 4 (individually configurable) |
| Sensor Technology | QTouch charge-transfer (burst mode) |
| Supply Voltage (VDD) | 1.8 V to 5.5 V |
| Tipo de salida | Parallel discrete outputs (1 per key) |
| Número de salidas | 4 (one per active key) |
| Communication Interface | GPIO (no I2C/SPI required) |
| Self-Calibration Time | ~100 ms after power-up |
| Recalibration | Automatic on stuck-key / drift detection |
| Rango de temperatura de funcionamiento | -40 C to +85 C |
| Encapsulado | 20-pin VQFN (3x3 mm) |
| Tipo de montaje | Surface Mount |
| Estado RoHS | Compliant |
| Lead-Free / Halogen-Free | Yes (per Microchip product page) |
Configuración de pines de AT42QT1040-MMHR
| Pin 1 | SNS1 — Sense input for touch key 1 (capacitor to GND sets sensitivity) |
| Pin 2 | SNS2 — Sense input for touch key 2 |
| Pin 3 | SNS3 — Sense input for touch key 3 |
| Pin 4 | SNS4 — Sense input for touch key 4 |
| Pin 5 | OUT1 — Touch output for key 1 (active high/low, push-pull) |
| Pin 6 | OUT2 — Touch output for key 2 |
| Pin 7 | OUT3 — Touch output for key 3 |
| Pin 8 | OUT4 — Touch output for key 4 |
| Pin 9 | VDD — Positive supply voltage (1.8 V to 5.5 V) |
| Pin 10 | VSS — Ground reference |
| Pin 11 | NC — Not connected (per datasheet) |
| Pin 12 | NC — Not connected (per datasheet) |
| Pin 13 | NC — Not connected (per datasheet) |
| Pin 14 | NC — Not connected (per datasheet) |
| Pin 15 | NC — Not connected (per datasheet) |
| Pin 16 | NC — Not connected (per datasheet) |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | EP — Exposed pad (thermal/ground; connect to VSS for best noise performance) |
Aplicaciones típicas
AT42QT1040-MMHR es adecuado para 6 aplicacións: Home Appliance Control Panels, IoT Smart-Home Touch Buttons, Automotive Interior Touch Switches, Medical Device Keypads, Industrial Equipment Front Panels, Consumer Audio Devices and Remote Controls.
Home Appliance Control Panels
The AT42QT1040-MMHR fits home-appliance control panels because its 1.8 V to 5.5 V supply tolerates direct connection to rectified mains-derived 5 V or 3.3 V rails, while its 4-key limit matches typical washer/dryer/microwave front-panel layouts. The QTouch burst-mode charge-transfer engine rejects the heavy motor and relay EMI found in appliance environments, preventing false triggers from compressor switching noise. With ~100 ms self-calibration and automatic stuck-key recalibration, the IC tolerates wet or greasy panels and recovers from accidental finger contact on power-up. Parallel outputs route directly to the host MCU GPIO, eliminating I2C firmware overhead on resource-constrained 8-bit appliance controllers. The 20-pin VQFN (3x3 mm) package fits behind glass or acrylic overlays, supporting fully sealed, modernized front-panel designs.
Recomendado
IoT Smart-Home Touch Buttons
The AT42QT1040-MMHR is ideal for IoT smart-home buttons (lighting dimmers, scene controllers, doorbells) because its low quiescent current and burst-mode sensing keep standby draw in the microamp range, preserving battery life for years on 2x AA cells. The 1.8 V minimum supply allows direct connection to single-cell Li-ion or LiFePO4 chemistries without a boost converter. With 4 discrete parallel outputs, designers can map on/off, brightness up/down, and color-temperature toggle to dedicated touch zones. The -40 C to +85 C industrial temperature range accommodates outdoor smart-home enclosures, and the QTouch engine resists false triggers from humidity changes and rain. The 3x3 mm VQFN footprint fits inside the slim form factors required for wall-mount wireless switches.
Recomendado
Automotive Interior Touch Switches
The AT42QT1040-MMHR suits automotive interior touch switches (roof consoles, steering-wheel buttons, door-handle controls) because its charge-transfer sensing detects touches through plastic, wood, and leather overlays without mechanical contacts that wear out. The wide 1.8 V to 5.5 V supply tolerates automotive cranking transients when paired with a regulator, and the parallel output simplifies connection to body-control modules. The automatic stuck-key recalibration prevents latched-on conditions from spilled beverages or seat-belt buckles resting on switches. Designers typically assign 4 channels to roof-lamp, sunroof, mirror-fold, and garage-door functions. While the AT42QT1040-MMHR itself is not AEC-Q100 qualified, its mature QTouch technology is automotive-proven through qualified family members, making it a low-risk starting point for prototypes.
Recomendado
Medical Device Keypads
The AT42QT1040-MMHR is well suited for medical device keypads (infusion pumps, patient monitors, portable diagnostic tools) because its solid-state capacitive sensing replaces mechanical buttons, allowing fully sealed enclosures that withstand disinfection with alcohol, bleach, and quaternary-ammonium wipes. The 4-key limit matches common medical-device confirm/cancel/up/down layouts. Burst-mode charge-transfer sensing delivers high signal-to-noise even when the operator wears nitrile gloves, which would defeat lower-performance touch controllers. The 1.8 V minimum supply supports Li-ion battery power for portable devices, and parallel outputs interface directly to medical-grade MCUs such as the PIC32MZ without firmware complexity. The 20-pin VQFN (3x3 mm) package fits inside compact handheld form factors used for point-of-care diagnostics.
Recomendado
Industrial Equipment Front Panels
The AT42QT1040-MMHR supports industrial equipment front panels (HMI terminals, motor starters, conveyor control boxes) because its -40 C to +85 C industrial operating range and high-noise-immunity QTouch engine function reliably next to VFD drives, contactors, and switch-mode power supplies. The 4-key limit is well matched to start/stop/reset/mode-selector layouts on machinery. The parallel discrete outputs interface to industrial PLCs and panel meters via opto-isolated GPIO, simplifying safety-isolation design. The 3x3 mm VQFN package fits inside the compact operator-interface cutouts required for DIN-rail and panel-mount enclosures. Automatic stuck-key recalibration ensures recovery if operators leave tools resting on control surfaces during shift changes.
Recomendado
Consumer Audio Devices and Remote Controls
The AT42QT1040-MMHR fits consumer audio products (Bluetooth speakers, soundbars, headphone amps, A/V remotes) because its 4 touch channels are ideal for power, volume up/down, and source-select buttons that replace mechanical keys prone to wear and chatter. The QTouch engine detects touches through painted plastic, brushed aluminum, and acrylic overlays used in modern audio aesthetics. Low quiescent current preserves battery life in portable Bluetooth speakers, while 5 V tolerance supports direct connection to USB-powered rails. Parallel outputs free the host MCU from interrupt-heavy touch scanning, allowing cheaper Cortex-M0 microcontrollers to handle both audio decoding and touch sensing. The 3x3 mm VQFN footprint fits inside slim remote-control enclosures where PCB area is at a premium.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para AT42QT1040-MMHR — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | AT42QT1040-MMH | AT42QT1040-MMUR | AT42QT1040-CUR | AT42QT1050-MMH | AT42QT1244-MUR |
|---|---|---|---|---|---|---|
| Package | VQFN-20 (3x3 mm) | VQFN-20 (3x3 mm) - same | VQFN-20 (3x3 mm) - same | VQFN-20 (3x3 mm) - same | VQFN-20 (3x3 mm) - same | VQFN-20 (3x3 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Number of Touch Keys | 1 to 4 | 1 to 4 | 1 to 4 | 1 to 4 | 1 to 5 | 1 to 12 |
| Touch Technology | QTouch burst-mode charge-transfer | QTouch burst-mode charge-transfer | QTouch burst-mode charge-transfer | QTouch burst-mode charge-transfer | QTouch burst-mode charge-transfer | QTouch burst-mode charge-transfer |
| Supply Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Output Interface | Parallel GPIO (4 lines) | Parallel GPIO (4 lines) | Parallel GPIO (4 lines) | Parallel GPIO (4 lines) | Parallel GPIO (5 lines) | Parallel GPIO / serial |
| Self-Calibration | ~100 ms, automatic | ~100 ms, automatic | ~100 ms, automatic | ~100 ms, automatic | ~100 ms, automatic | Automatic, family similar |
| RoHS Compliance | Yes | Yes | Yes | Yes | Yes | Yes |
Diferenciadores clave
- Same die, alternative reel/packaging code (frente a AT42QT1040-MMH)
- Higher channel count in same footprint (frente a AT42QT1050-MMH)
- Large-scale channel expansion (frente a AT42QT1244-MUR)
Notas de diseño
Sense-trace layout is the single most critical factor for AT42QT1040-MMHR reliability. Per the Microchip QTouch design guide, each SNS pin should connect via a short, narrow trace to a single copper pad (minimum 8x8 mm for finger touch). Surround every sense pad with a hatched or solid ground ring separated by a 1-2 mm gap; this guard ring shanks capacitive coupling to ground and dramatically improves EMC immunity. Keep sense traces away from switching nodes, LED PWM signals, and high-current traces by at least 5 mm. The exposed pad (pin 20) MUST be soldered to a grounded copper pour for thermal dissipation and electrical reference stability.
Estimated: Selecting the sense capacitor Cs is a frequent source of design error. Cs values typically range from 1 nF to 47 nF; smaller Cs increases sensitivity but makes the channel more noise-sensitive, while larger Cs reduces sensitivity and may fail to detect a finger at all. Use low-drift X7R or C0G/NP0 ceramic capacitors (NOT Y5V or Z5U, whose capacitance drops 50%+ over temperature). Mount Cs directly between the SNS pin and ground with the shortest possible trace. Re-evaluate Cs value if the panel overlay thickness, dielectric, or humidity environment changes materially from the prototype to production.
Estimated: The AT42QT1040-MMHR quiescent current is typically in the single-digit microamp range, but burst-mode acquisition briefly draws higher current each measurement cycle. Place a 100 nF X7R decoupling capacitor as close as possible to the VDD pin (pin 9) and add a 1-10 uF bulk capacitor on the same rail. Keep the GND return path short and wide; the exposed pad (pin 20) is the primary thermal/electrical anchor and should tie to the same ground island as the bulk capacitor. Slow-rising or noisy VDD rails can cause false triggers or failed calibration on power-up, so ensure a clean ramp-up.
Per the Microchip datasheet, the AT42QT1040-MMHR automatically recalibrates when a key is held for an extended timeout period, preventing latched outputs. However, if the host MCU polls the OUT pins during this timeout window, spurious state changes may be observed. Add a 50-100 ms software debounce in the host firmware to reject any chatter at the moment of recalibration. Also, route OUT pins away from parallel-bus data lines that switch at high dv/dt; capacitive coupling can inject false edges into the touch outputs on noisy PCB stacks.
Información de cumplimiento
RoHS and lead-free compliant per Microchip product page. Not AEC-Q100 qualified; qualified automotive touch variants exist in the broader Microchip QTouch family. Reach compliance per Microchip product declaration.
