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Analog Devices Inc. AD7877ACPZ-REEL
- Part No.:
- AD7877ACPZ-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Touch Screen Controllers
- Package:
- 32-VFQFN Exposed Pad, CSP
- Datasheet:
-
AD7877ACPZ-REEL.pdf
- Description:
- IC SCREEN CNTRL 12BIT 32LFCSP
- Quantity:
- Payment:
- Shipping:
Inventory:2,142
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Product details
Overview
AD7877ACPZ-REEL from Analog Devices is a 12-bit successive approximation ADC touch screen controller with integrated 4-wire resistive touch interface, on-chip 2.5 V reference, 8-bit DAC, and dual battery monitor channels (0.5 V to 5 V). It delivers 125 kSPS throughput, supports LCD noise reduction via STOPACQ pin, and operates from a single 2.7 V to 5.25 V supply - ideal for portable medical devices and handheld POS terminals.
For engineers reviewing the AD7877ACPZ-REEL datasheet, AD7877ACPZ-REEL pinout, AD7877ACPZ-REEL application, or AD7877ACPZ-REEL equivalent, key selection criteria include its 32-lead LFCSP package, 12-bit resolution with ±2 LSB INL, integrated temperature sensor (−40°C to +85°C), programmable acquisition timing, and SPI-compatible serial interface with DAV/ALERT/PENIRQ interrupt outputs.
Technical Context
The AD7877ACPZ-REEL integrates a track-and-hold ADC with 9:1 analog multiplexer supporting X+/X−/Y+/Y− touch inputs, two battery monitors (BAT1/BAT2), three auxiliary analog inputs (AUX1–AUX3), and temperature sensing. Its conversion sequencer enables automatic channel scanning or host-directed selection, with up to 16-sample averaging per channel.
It features dual-domain power control: VCC powers analog/digital core circuitry (2.7 V–5.25 V), while VDRIVE independently sets logic I/O voltage (1.65 V–VCC). The STOPACQ pin halts ADC acquisition during LCD refresh cycles to suppress coupling noise, and the on-chip 2.5 V reference can be disabled to reduce current draw below 1 µA in shutdown mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit SAR ADC with no missing codes - ensures monotonic position reporting across full touch range. |
| Throughput Rate | 125 kSPS - supports fast touch response in high-refresh-rate displays without firmware polling overhead. |
| INL | ±2 LSB - guarantees sub-0.05% linearity error for accurate coordinate mapping in PDA and medical touchscreen UIs. |
| Supply Range | VCC = 2.7 V to 5.25 V - compatible with Li-ion, Li-poly, and 3.3 V/5 V system rails without level-shifting. |
| Shutdown Current | ≤1 µA - enables ultra-low-power wake-on-touch operation in battery-critical portable equipment. |
| Reference | On-chip 2.5 V ±50 ppm/°C - eliminates external reference component count and improves thermal stability over temperature. |
| DAC Resolution | 8-bit voltage/current output - provides precise LCD backlight or contrast control with 0–VCC/2 or 0–VCC range selection. |
Pinout & Package
AD7877ACPZ-REEL is housed in a 32-lead, 5 mm × 5 mm lead frame chip scale package (LFCSP) with exposed thermal pad. Pin 1 is marked by a dot; NC pins (1, 8, 9, 16, 24, 25, 32) must remain unconnected. The exposed pad is not internally connected but must be soldered to PCB ground for thermal reliability and mechanical robustness.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 10–13 (X−, Y−, X+, Y+) | Touch screen excitation/sense nodes | Drive and measure 4-wire resistive touch panel; low 14 Ω on-resistance minimizes position error at low VCC. |
| 14, 15 (AGND, DGND) | Analog/digital ground references | Separate AGND/DGND pins enable star-ground layout to prevent digital switching noise from corrupting ADC measurements. |
| 17 (PENIRQ) | Active-low pen interrupt | Open-drain output with internal 50 kΩ pull-up - signals touch initiation to host processor without external components. |
| 18 (CS) | Chip select input | Active-low SPI frame sync; falling edge initiates conversion sequence and enables serial register access. |
| 19, 26, 27 (DIN, DCLK, DOUT) | SPI serial interface | Full-duplex 3-wire interface compliant with standard SPI timing; DOUT tri-states when CS is high. |
| 20 (STOPACQ) | Acquisition halt control | External logic signal that suspends ADC sampling during LCD frame updates - directly reduces display-induced measurement noise. |
| 22 (ALERT) | Out-of-limit interrupt | Asserts low when AUX1, TEMP1, BAT1, or BAT2 exceeds user-programmed high/low limits - enables autonomous fault monitoring. |
| 23 (DAV) | Data available flag | Active-low pulse indicates valid conversion result in results registers - eliminates need for status polling in real-time systems. |
Key Features
| Feature | Design Value |
|---|---|
| LCD noise suppression | STOPACQ pin synchronizes ADC acquisition pause with LCD refresh, reducing coupling-induced position jitter by >20 LSB in noisy environments. |
| Integrated battery monitoring | Dual 0.5 V–5 V input channels with 3.2% accuracy - enables direct Li-ion cell voltage tracking without external signal conditioning. |
| Programmable averaging | 1–16 sample averaging per conversion - improves effective resolution by up to 2 bits for low-noise touch coordinate extraction. |
| Temperature sensing | On-chip sensor with ±2°C accuracy (calibrated at 25°C) - supports thermal compensation of touch calibration coefficients in medical-grade devices. |
| Flexible GPIO configuration | Four GPIOs (one dedicated, three shared with AUX inputs) - allows dynamic reassignment for system-level control signaling or status feedback. |
Applications
| Personal Digital Assistants | Point-of-Sale Terminals |
|---|---|
Use Scenario: Resistive touch interface in compact handheld PDAs with integrated stylus input and battery management. IC Role / Device Role / Timing Role: Primary touch digitizer and auxiliary analog monitor - performs X/Y coordinate acquisition, temperature readback, and dual-cell voltage measurement in one IC. Use Value: Eliminates discrete ADC, reference, and GPIO expanders; 125 kSPS throughput ensures <8 µs per coordinate pair, enabling responsive UI navigation. | Use Scenario: Touchscreen checkout kiosk in retail environments requiring reliable operation across temperature extremes and long service life. IC Role / Device Role / Timing Role: Touch controller with built-in limit-comparison logic - triggers ALERT output when battery voltage drops below threshold or temperature exceeds safe operating range. Use Value: Reduces BOM count and firmware complexity; ±2°C temperature accuracy enables predictive maintenance alerts before thermal derating occurs. |
| Medical Handheld Devices | Smart Industrial Sensors |
Use Scenario: Portable diagnostic tool with touch UI, battery health monitoring, and ambient temperature logging for calibration traceability. IC Role / Device Role / Timing Role: Dual-role analog front-end - digitizes touch coordinates while concurrently measuring patient ambient temperature and battery state-of-charge. Use Value: On-chip 2.5 V reference and 12-bit resolution meet IEC 60601-1 accuracy requirements for Class II medical electronics without external trimming. | Use Scenario: Ruggedized field sensor node with touch-enabled configuration and self-monitoring capability in factory automation settings. IC Role / Device Role / Timing Role: System supervisor IC - uses GPIO4 and ALERT outputs to drive local status LEDs and report out-of-spec conditions to PLC via isolated UART. Use Value: Three auxiliary inputs support analog sensor integration (e.g., pressure, humidity); STOPACQ compatibility ensures stable readings near variable-frequency motor drives. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar touch screen controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7843IPWR | 12-bit SAR ADC, no on-chip reference or DAC; requires external 2.5 V reference and separate backlight control IC. | Lacks integrated temperature sensor and battery monitor - necessitates additional components for medical or industrial diagnostics. | Preferred where cost sensitivity outweighs integration benefits and board space permits discrete reference/DAC. |
| TSC2007IPWPR | 12-bit ADC with integrated reference and touch-pressure measurement, but no DAC or STOPACQ functionality. | Supports 4-wire touch and battery monitoring, yet lacks LCD noise suppression - unsuitable for high-noise display environments. | Selected when touch-pressure analytics are required but LCD interference is minimal or mitigated externally. |
Compared with ADS7843IPWR and TSC2007IPWPR, AD7877ACPZ-REEL uniquely combines STOPACQ-driven noise immunity, on-chip 2.5 V reference, 8-bit DAC, and dual battery monitoring in a single LFCSP package - reducing total solution size by ≥35% and eliminating four external components in typical handheld designs.
Availability
AD7877ACPZ-REEL is available at Aetrix Electronics and suitable for personal digital assistants, point-of-sale terminals, and medical handheld devices requiring stable component supply, automotive-qualified performance, and long-term production continuity.
Supply support for AD7877ACPZ-REEL 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
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The AD7877ACPZ-REEL belongs to Analog Devices' precision data acquisition product line, engineered specifically for low-power, high-accuracy touch screen interfaces in battery-operated portable electronics with stringent EMI and thermal constraints.
FAQ
What is the maximum sampling rate supported by the AD7877ACPZ-REEL?
The AD7877ACPZ-REEL supports a specified throughput rate of 125 kSPS, corresponding to an 8 µs conversion time from CS falling edge to DAV assertion. This rate is achievable with fDCLK = 2 MHz and internal reference enabled, and remains stable across the full −40°C to +85°C operating temperature range.
Does the AD7877ACPZ-REEL require an external reference voltage?
No, the AD7877ACPZ-REEL includes a factory-trimmed 2.5 V on-chip reference with ±50 ppm/°C tempco, which can be used directly or disabled to reduce power. An external reference from 1 V to VCC may be applied to the VREF pin if higher precision or custom scaling is needed - but the AD7877ACPZ-REEL functions fully without it.
How does the STOPACQ pin improve touch accuracy in LCD-based systems?
The STOPACQ pin halts ADC acquisition during LCD refresh cycles, preventing electromagnetic coupling from display drivers from corrupting touch coordinate measurements. When asserted, it disables the track-and-hold amplifier input stage - reducing noise-induced position errors by up to 25 LSB in high-resolution 4-wire touch panels driven by active-matrix LCDs.
Can the AD7877ACPZ-REEL measure battery voltage directly?
Yes, the AD7877ACPZ-REEL provides two dedicated battery monitor inputs (BAT1 and BAT2) supporting 0.5 V to 5 V ranges with 3.2% accuracy using the internal 2.5 V reference. Input impedance is 14 kΩ during sampling and rises to 1 GΩ when inactive, minimizing loading on battery cells during quiescent periods.
What GPIO capabilities does the AD7877ACPZ-REEL offer?
The AD7877ACPZ-REEL includes four GPIOs: one dedicated (GPIO4) and three shared with auxiliary analog inputs (AUX1–AUX3). All can be configured as inputs or outputs via control registers, supporting interrupt generation, status signaling, or peripheral control - with programmable pull-up/down and edge-triggered interrupt modes.
AD7877ACPZ-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Package/Case:
- 32-VFQFN Exposed Pad, CSP
- Touchscreen:
- 4 Wire Resistive
- Resolution (Bits):
- 12 b
- Interface:
- SPI
- Voltage Reference:
- External, Internal
- Voltage - Supply:
- 2.7V ~ 5.25V
- Current - Supply:
- 1 µA
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 32-LFCSP-VQ (5x5)
AD7877ACPZ-REEL FAQ
1.How can I place an order for AD7877ACPZ-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7877ACPZ-REEL 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 AD7877ACPZ-REEL reliable?
The price and inventory of AD7877ACPZ-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7877ACPZ-REEL is usually 5 days.
3.What payment methods are accepted for AD7877ACPZ-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7877ACPZ-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7877ACPZ-REEL?
AD7877ACPZ-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7877ACPZ-REEL 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 AD7877ACPZ-REEL?
For technical support, including AD7877ACPZ-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7877ACPZ-REEL requirements.
6.How does Aetrix verify that AD7877ACPZ-REEL is sourced from the original manufacturer or authorized distributors?
All AD7877ACPZ-REEL 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 AD7877ACPZ-REEL meets industry standards.
7.What is the process for return or replacement of AD7877ACPZ-REEL?
All AD7877ACPZ-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7877ACPZ-REEL, 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 AD7877ACPZ-REEL part is unused and in its original packaging.
Return procedure for AD7877ACPZ-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AD7877ACPZ-REEL Tags
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