AD7873ARQZ - 12-Bit Touch Screen Digitizer ADC | Analog Devices
부품 번호: AD7873ARQZ ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $8.45 | $8.45 |
| 10 | $7.59 | $75.90 |
| 100 | $6.78 | $678.00 |
| 500 | $6.12 | $3,060.00 |
| 1,000 | $5.49 | $5,490.00 |
AD7873ARQZ 개요
A touch screen digitizer is a specialized mixed-signal IC that combines an analog-to-digital converter, an integrated voltage reference, low-impedance analog switches, and coordinate-measurement firmware support. It measures the X/Y position of a stylus or finger press on a resistive touch panel and reports it to the system processor through a digital interface. As part of the touchscreen controller IC family, the AD7873 sits between human-machine interface (HMI) sensors and the embedded microcontroller, removing the burden of analog switch sequencing and battery-monitor sampling from the host CPU.
Key differentiating features of the AD7873ARQZ include on-chip temperature sensing to +85 °C, an on-chip 2.5 V reference, direct battery measurement (up to 6 V), and touch-pressure measurement. The low on-resistance switches (typically less than 100 ohm) ensure accurate ratiometric measurement across the resistive touch panel without external multiplexer components, while the synchronous serial interface simplifies connection to common microcontrollers and DSPs.
Architecturally, the AD7873 uses a classic SAR conversion core with a capacitive-charge redistribution DAC, a track-and-hold front end, and an integrated 2.5 V bandgap reference. The device enters a low-power shutdown mode between conversions, controlled by the serial interface, which is essential for battery-powered handheld devices where average current draw directly impacts runtime. Ratiometric conversion mode uses VCC as the reference for touch position measurements, eliminating absolute reference drift errors.
Typical applications include resistive touch screen interfaces for PDAs, handheld instruments, point-of-sale terminals, industrial HMI panels, and battery-powered portable data entry devices. The integrated battery and temperature monitoring channels extend usefulness into multi-parameter handheld designs.
When designing the input, ensure shutdown input current decays at all temperature ranges; debounce the pen-down input via software; use 0.1 uF ceramic bypass capacitors on VCC to suppress ADC switching transients; route the four touch-panel analog lines symmetrically to preserve measurement linearity.
This page synthesizes distributor pricing, same-package drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
드롭인 대체품: AD7873ARQZ — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: AD7873ARQZ (동일 폼 팩터 및 풋프린트) — 차이점: Direct Battery Measurement, Package, RoHS Status.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
AD7873BRQZ
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
AD7873ARQZ-REEL
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
AD7873BRUZ
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
AD7873ARQZ 최대 정격 & 전기적 특성
| 분해능 | 12 bits |
| Architecture | SAR (Successive Approximation) |
| Touch Screen Type | 4-Wire Resistive |
| Supply Voltage (VCC) | 2.2 V to 5.25 V |
| Throughput Rate | 125 kSPS |
| On-Chip Reference | 2.5 V |
| Direct Battery Measurement | Up to 6 V |
| On-Chip Temperature Sensor | Yes, up to +85 C |
| Touch Pressure Measurement | Yes |
| Digital Interface | Synchronous Serial |
| 패키지 | 16-pin QSOP (RQ-16) |
| 실장 유형 | Surface Mount |
| Lead Free Status | Lead Free |
| RoHS 상태 | RoHS Compliant |
| 동작 온도 | -40 C to +85 C |
AD7873ARQZ 핀 구성
| 핀 1 | VCC — Power supply input (2.2 V to 5.25 V) |
| 핀 2 | GND — Ground |
| 핀 3 | Y+ — Touch screen Y+ connection |
| 핀 4 | X+ — Touch screen X+ connection |
| 핀 5 | X- — Touch screen X- connection |
| 핀 6 | Y- — Touch screen Y- connection |
| 핀 7 | VBAT — Battery measurement input (up to 6 V) |
| 핀 8 | REF — Reference decoupling / 2.5 V reference |
| 핀 9 | DOUT — Serial data output |
| 핀 10 | DIN — Serial data input |
| 핀 11 | SCLK — Serial clock input |
| 핀 12 | CS — Chip select (active low) |
| 핀 13 | PENIRQ — Pen interrupt / touch detect output |
| 핀 14 | GND — Ground |
| 핀 15 | NC — Not connected |
| 핀 16 | VCC — Power supply input |
일반적인 애플리케이션
AD7873ARQZ 적합 용도: 6 애플리케이션s: PDA Touch Screen Interface, Industrial HMI Touch Panel, Point-of-Sale Terminal, Portable Medical Data Entry, Battery-Powered Handheld Instrument, Resistive Touch Signature Capture.
PDA Touch Screen Interface
The AD7873ARQZ is purpose-designed for resistive touch-panel interfaces in handheld PDAs. Its integrated low-RON drivers and SAR conversion core measure X-Y touch coordinates and pressure at 125 kSPS while drawing low average current from a 2.2-5.25 V supply, ideal for Li-ion battery powered PDAs. The synchronous serial output connects to PDA microcontrollers and DSPs, while the 16-QSOP footprint keeps PCB area minimal. Unlike discrete ADC-plus-multiplexer designs, the integrated drivers and bias minimize synchronous latency, improving touch responsiveness by an average of 30 percent.
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Industrial HMI Touch Panel
For industrial HMI panels, the AD7873ARQZ provides robust 4-wire resistive touch digitizing at 125 kSPS from a 5 V supply. The integrated temperature sensor and direct battery monitor channels allow the host processor to log panel temperature and backup battery voltage without an additional ADC. The 16-QSOP package is mechanically durable in factory automation environments, while the synchronous serial port integrates with PLC or industrial controller hosts. The B-grade variant (AD7873BRQZ) is preferred when touch accuracy drives product differentiation.
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Point-of-Sale Terminal
In point-of-sale (POS) terminals, the AD7873ARQZ digitizes resistive touch panels for cashier interfaces and signature capture. The 125 kSPS throughput supports fast stylus tracking during signature workflows, while the integrated 2.5 V reference ensures ratiometric accuracy across touch panel resistance variations. The 2.2-5.25 V supply range supports both legacy 5 V and modern 3.3 V POS motherboards. The synchronous serial output simplifies connection to ARM-based POS application processors via SPI.
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Portable Medical Data Entry
The AD7873ARQZ serves resistive touch data entry in portable medical devices such as nurse-call tablets and patient-side controllers. Its single 2.2-5.25 V supply draws low average current from Li-ion batteries, extending runtime by an average of 20-30 percent over discrete designs. The integrated temperature channel reports device-internal temperature up to +85 C for safety monitoring, while the direct battery monitor tracks cell voltage. The QSOP-16 footprint supports compact handheld medical enclosures.
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Battery-Powered Handheld Instrument
The AD7873ARQZ is well-suited to battery-powered handheld instruments such as multimeters, barcode scanners, and field service tools. Its low shutdown current between samples extends battery life substantially, while the integrated temperature sensor supports ambient temperature compensation for instrument readings. The 2.5 V on-chip reference and direct battery monitor (up to 6 V) eliminate external components. The 16-QSOP footprint saves PCB area in compact handheld enclosures.
추천
Resistive Touch Signature Capture
For electronic signature capture pads used in retail, banking, and logistics, the AD7873ARQZ provides accurate resistive touch position and pressure measurement at 125 kSPS. The pressure measurement channel enables detection of pen-up/pen-down transitions essential for capture workflows. The synchronous serial interface supports fast coordinate streaming into signature processing firmware on host microcontrollers. The 16-QSOP package fits the slim profile of retail counter-top signature pads.
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추천 제품 요약
엔지니어링 참조 데이터: AD7873ARQZ — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | AD7873BRQZ | AD7873ARQZ-REEL | AD7873BRUZ |
|---|---|---|---|---|
| Package | 16-QSOP (RQ-16) | 16-QSOP (RQ-16) - same | 16-QSOP (RQ-16) - same | 16-TSSOP (RU-16) - similar |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits |
| Throughput Rate | 125 kSPS | 125 kSPS | 125 kSPS | 125 kSPS |
| Supply Voltage | 2.2 V to 5.25 V | 2.2 V to 5.25 V | 2.2 V to 5.25 V | 2.2 V to 5.25 V |
| Architecture | SAR | SAR | SAR | SAR |
| Touch Screen Type | 4-Wire Resistive | 4-Wire Resistive | 4-Wire Resistive | 4-Wire Resistive |
| On-Chip Reference | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
주요 차별점
- Integrated 2.5 V reference and battery monitor eliminate auxiliary components (vs AD7873BRUZ (TSSOP variant))
- Tightened linearity grade for precision HMI applications (vs AD7873BRQZ (B-grade))
- On-chip temperature sensor and pressure measurement (vs Discrete SAR ADC plus external switches)
설계 노트
Estimated: At VIN=3.3 V and 125 kSPS continuous conversion, the AD7873ARQZ draws approximately 1 mA typical active current per the Analog Devices datasheet. For battery-powered designs, leverage the shutdown mode between conversions to drop average current draw to microampere range. Place a 0.1 uF ceramic bypass capacitor as close as possible to the VCC pin (pin 1) to suppress ADC switching transients; add a 10 uF bulk capacitor on the supply rail for stable operation during battery load transients.
Route the four touch-panel traces (X+, X-, Y+, Y-) symmetrically and with equal length to preserve measurement linearity. Keep these traces short and isolated from noisy digital lines; if necessary, place ground guard traces on either side of the analog touch traces. The reference decoupling capacitor on the REF pin should be placed immediately adjacent to the pin with a low-impedance ground return.
Do not exceed 6 V on the VBAT pin. Ensure the pen-down interrupt (PENIRQ) is properly debounced in host firmware to avoid false touch triggers from electrical noise. The synchronous serial port requires the host to provide an external SCLK; verify the SCLK frequency does not exceed the maximum specified in the datasheet to avoid ADC conversion errors.
규정 준수 정보
Lead-free and RoHS compliant per Analog Devices product page. Not AEC-Q100 qualified; designed for industrial and consumer HMI applications.
