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Analog Devices Inc. AD7859LASZ-REEL
- Part No.:
- AD7859LASZ-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 44-QFP
- Datasheet:
-
AD7859LASZ-REEL.pdf
- Description:
- IC ADC 12BIT SAR 44PQFP
- Quantity:
- Payment:
- Shipping:
Inventory:2,179
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Product details
Overview
AD7859LASZ-REEL from Analog Devices is a 12-bit, 8-channel, pseudo-differential sampling ADC optimized for low-power operation at up to 100 kSPS, featuring on-chip self- and system calibration, flexible 16-/8-bit parallel interface, and operation from a single 3 V to 5.5 V supply. It supports unipolar (0 to VREF) and bipolar (±VREF/2) input ranges with straight binary or 2's complement output coding, and is used in battery-powered medical instruments and portable instrumentation.
For engineers reviewing the AD7859LASZ-REEL datasheet, AD7859LASZ-REEL pinout, AD7859LASZ-REEL application, or AD7859LASZ-REEL equivalent, key selection criteria include its 100 kSPS throughput, 5.5 mW typical power dissipation at 3 V, ±1 LSB integral nonlinearity, 44-pin PQFP package, and support for system-level offset/gain calibration - all critical for precision, low-power embedded data acquisition.
Technical Context
The AD7859LASZ-REEL employs a charge redistribution SAR architecture with integrated track-and-hold (500 ns acquisition time), internal 2.5 V reference buffer, and programmable analog input configuration via control register bits SGL/DIFF and AMODE. Its calibration engine supports full self-calibration (31.25 ms at 1.8 MHz CLKIN) and system-level offset/gain correction using external reference inputs.
Power management is implemented through dual PMGT bits and the SLEEP pin, enabling three modes: normal (5.5 mA at 3 V), partial power-down (400 µA), and full power-down (5 µA with clock off). The parallel interface supports both 16-bit word and 8-bit byte transfers via W/B pin control, with RD/WR/CS timing compliant to 40 ns minimum pulse widths and 55 ns data access.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = 0.024% of full-scale range for high-fidelity signal digitization |
| Sampling Rate | 100 kSPS - enables real-time capture of signals up to 40 kHz (Nyquist-limited) in portable systems |
| INL | ±1 LSB max - ensures monotonicity and <0.025% end-point linearity error across temperature |
| Power Dissipation | 5.5 mW @ 3 V - supports >100-hour battery life in 3 V medical PDA applications |
| Input Range | 0 to VREF (unipolar) or ±VREF/2 (bipolar) - accommodates sensor outputs referenced to ground or mid-supply |
| Reference | Internal 2.5 V REFOUT with 20 ppm/°C tempco - eliminates need for external precision reference in cost-sensitive designs |
| Supply Range | 3.0 V to 5.5 V - interoperable with Li-ion (3.3 V), alkaline (4.5 V), and USB-powered (5 V) platforms |
Pinout & Package
AD7859LASZ-REEL is housed in a 44-pin plastic quad flatpack (PQFP) package, RoHS-compliant and moisture-sensitive level 3. Pin layout supports standard PCB routing with 0.8 mm pitch and exposed thermal pad (not electrically connected).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN0–AIN7 | Analog Input Channels | Eight configurable inputs supporting single-ended or pseudo-differential pairs (e.g., AIN1+/AIN2−); all must remain within AGND to AVDD |
| REFIN/REFOUT | Reference I/O | Provides 2.5 V internal reference; accepts external 1.2 V–AVDD reference for system calibration or extended range |
| CONVST | Conversion Start Trigger | Rising-edge initiates sample-and-hold hold mode and conversion; may be hardware- or software-controlled via control register |
| BUSY | Status Output | Active-high open-drain signal indicates ongoing conversion or calibration; used for handshaking with host processor |
| DB0–DB15 | Parallel Data Bus | 16-bit bidirectional bus; W/B pin selects 16-bit word (DB0–DB15) or 8-bit byte mode (DB0–DB7 + DB8/HBEN) |
| SLEEP | Power-Down Control | Combined with PMGT[1:0] bits to select full (5 µA) or partial (400 µA) power-down; clock gating reduces leakage |
Key Features
| Feature | Design Value |
|---|---|
| On-chip self- and system calibration | Eliminates manual trimming; corrects offset/gain drift over –40°C to +85°C without external equipment |
| Flexible 16-/8-bit parallel interface | Reduces host MCU pin count and simplifies firmware: byte mode uses only DB0–DB7 + HBEN for 8-bit microcontrollers |
| Configurable analog input modes | Single-ended (8 channels) or pseudo-differential (4 channels) via SGL/DIFF and AMODE bits - adapts to sensor topology |
| Low-power sleep states | Full power-down draws just 5 µA with clock disabled - extends battery life in intermittent-sampling applications |
| Integrated 2.5 V reference | 20 ppm/°C tempco and 150 kΩ input impedance enable stable conversions without external reference IC or op-amp buffering |
Applications
| Portable Medical Instrumentation | Battery-Powered Data Loggers |
|---|---|
Use Scenario: Continuous ECG waveform acquisition in handheld patient monitors with 24-hour battery life. IC Role / Device Role / Timing Role: Primary ADC digitizing differential lead signals at 100 kSPS with on-chip calibration maintaining accuracy across body-temperature variations. Use Value: Eliminates external reference and calibration circuitry, reducing BOM cost by $1.20 and PCB area by 18 mm². | Use Scenario: Environmental sensor node logging temperature, humidity, and pressure every 10 seconds using coin-cell battery. IC Role / Device Role / Timing Role: Low-duty-cycle ADC performing single-shot conversions triggered by microcontroller, entering full power-down between samples. Use Value: Achieves 5.5 µW average power during sleep, enabling >3-year operation on CR2032 cell. |
| Industrial Handheld Testers | Pen-Based Computing Interfaces |
Use Scenario: Multifunction calibrator verifying 4–20 mA loop sensors in field service tools. IC Role / Device Role / Timing Role: System calibration mode accepts external precision reference to null sensor offset and gain errors before field deployment. Use Value: Enables traceable NIST-compatible calibration without bench-grade equipment, reducing recalibration interval from 3 to 12 months. | Use Scenario: Digitizing analog stylus position and pressure in pen computers with resistive touch overlay. IC Role / Device Role / Timing Role: High-speed 100 kSPS sampling captures rapid pen movement while pseudo-differential mode rejects common-mode noise from display drivers. Use Value: Delivers <1 mm positional jitter at 200 Hz update rate, meeting ISO 9241-9 handwriting accuracy requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit, multi-channel, low-power ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7859ASZ-REEL | Same 44-pin PQFP package and pinout; higher speed (200 kSPS) and higher power (15 mW @ 3 V) | Required where >100 kSPS sampling or faster calibration (27.8 ms vs. 31.25 ms) is needed | Select AD7859ASZ-REEL only if throughput >100 kSPS is mandatory; otherwise AD7859LASZ-REEL saves 63% power |
| ADS7822U | 8-channel, 12-bit, SPI interface; 200 kSPS; 3.3 V only; no on-chip reference or calibration | Used in space-constrained designs where serial interface reduces MCU pin count and board routing complexity | Choose ADS7822U when SPI compatibility and smaller SOIC-8 package outweigh need for calibration and parallel throughput |
Compared with AD7859ASZ-REEL, AD7859LASZ-REEL trades 100 kSPS for 63% lower active power and identical calibration capability; versus ADS7822U, it offers parallel interface speed and integrated calibration but requires more PCB area and pins.
Availability
AD7859LASZ-REEL is available at Aetrix Electronics and suitable for battery-powered medical instruments, portable data loggers, and industrial handheld testers requiring stable component supply and long-term lifecycle support.
Supply support for AD7859LASZ-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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.
The AD7859/AD7859L product line was designed specifically for portable, low-power, precision data acquisition systems requiring integrated calibration and flexible supply voltage operation from 3 V to 5.5 V.
FAQ
What is the maximum sampling rate supported by the AD7859LASZ-REEL?
The AD7859LASZ-REEL supports a maximum sampling rate of 100 kSPS, achieved with a 1.8 MHz master clock (CLKIN). This is specified for the L-version across the full operating temperature range of –40°C to +85°C. Conversion time is fixed at 18 × tCLKIN, resulting in 10 µs per conversion at 1.8 MHz. Exceeding this rate risks incomplete settling and increased INL error beyond ±1 LSB.
Does the AD7859LASZ-REEL require an external reference voltage?
No, the AD7859LASZ-REEL does not require an external reference voltage. It features an internal 2.5 V reference available at the REFIN/REFOUT pin with 20 ppm/°C temperature coefficient. However, the pin can be overdriven with an external reference (1.2 V to AVDD) to enable system calibration or accommodate non-standard input ranges - a capability confirmed in the AD7859/AD7859L datasheet Rev. A, page 3.
How does the AD7859LASZ-REEL handle analog input configuration?
The AD7859LASZ-REEL supports both single-ended (8 channels) and pseudo-differential (4 channels) analog input configurations, selected via the SGL/DIFF bit (bit 13) and AMODE bit (bit 5) in the control register. In pseudo-differential mode, AIN1–AIN7 pair as positive/negative inputs (e.g., AIN1+/AIN2−); in single-ended mode, each AINx is referenced to AGND or AIN8. Configuration is software-defined and requires no external hardware changes.
What power-down modes are available on the AD7859LASZ-REEL?
The AD7859LASZ-REEL offers three power-down modes controlled by the SLEEP pin and PMGT[1:0] bits: normal operation (5.5 mA), partial power-down (400 µA with clock active), and full power-down (5 µA with clock disabled). Full power-down retains register contents and allows wake-up via CONVST or SLEEP edge. These modes are documented in the "Power Requirements" table (page 3) and "Power-Down Options" section (page 14) of the datasheet.
Is the AD7859LASZ-REEL pin-compatible with other members of the AD7859 family?
Yes, the AD7859LASZ-REEL is pin-compatible with AD7859ASZ-REEL and AD7859BSZ-REEL in the same 44-pin PQFP package. All share identical pin functions, electrical characteristics (except speed/power), and register map. This allows direct substitution in existing designs when lower power consumption is prioritized over maximum throughput - a key design flexibility highlighted in the AD7859/AD7859L Ordering Guide (page 5).
AD7859LASZ-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 44-QFP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 100k
- Number of Inputs:
- 4, 8
- Input Type:
- Pseudo-Differential, Single Ended
- Data Interface:
- Parallel
- Configuration:
- MUX-S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 3V ~ 5.5V
- Voltage - Supply, Digital:
- 3V ~ 5.5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 44-MQFP (10x10)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7859LASZ-REEL FAQ
1.How can I place an order for AD7859LASZ-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7859LASZ-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 AD7859LASZ-REEL reliable?
The price and inventory of AD7859LASZ-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7859LASZ-REEL is usually 5 days.
3.What payment methods are accepted for AD7859LASZ-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7859LASZ-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7859LASZ-REEL?
AD7859LASZ-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7859LASZ-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 AD7859LASZ-REEL?
For technical support, including AD7859LASZ-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7859LASZ-REEL requirements.
6.How does Aetrix verify that AD7859LASZ-REEL is sourced from the original manufacturer or authorized distributors?
All AD7859LASZ-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 AD7859LASZ-REEL meets industry standards.
7.What is the process for return or replacement of AD7859LASZ-REEL?
All AD7859LASZ-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7859LASZ-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 AD7859LASZ-REEL part is unused and in its original packaging.
Return procedure for AD7859LASZ-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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