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Analog Devices Inc. AD7859AP
- Part No.:
- AD7859AP
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 44-LCC (J-Lead)
- Datasheet:
-
AD7859AP.pdf
- Description:
- IC ADC 12BIT 8CH 200KSPS 44PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:635
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Product details
Overview
AD7859AP from Analog Devices is a 12-bit, 8-channel, 200 kSPS sampling ADC with integrated track-and-hold, self/system calibration, and flexible parallel interface. It operates from a single 3 V to 5.5 V supply, delivers 70 dB SNR at 10 kHz input, supports unipolar (0 to VREF) and bipolar (±VREF/2) input ranges, and targets battery-powered instrumentation requiring high accuracy and low power.
For engineers reviewing the AD7859AP datasheet, AD7859AP pinout, AD7859AP application, or AD7859AP equivalent, this page provides verified technical context, real-world timing and power behavior, package-specific pin mapping, calibrated DC accuracy specs, and validated alternative options for embedded data acquisition systems.
Technical Context
The AD7859AP uses a charge redistribution SAR architecture with on-chip 2.5 V reference, internal DAC, and calibration memory. Its pseudo-differential input multiplexer supports eight single-ended or four differential channels, selected via software-configurable control register bits (SGL/DIFF, CHSLT[2:0]).
Conversion is initiated by CONVST edge or software-controlled CONVST bit; BUSY signals completion; and CAL pin enables hardware-triggered self- or system-calibration. Power management is controlled by PMGT[1:0] bits and SLEEP pin, enabling full or partial power-down modes with sub-µW quiescent current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = 0.024% of full-scale range with guaranteed no missing codes |
| Throughput Rate | 200 kSPS - fixed conversion time of 4.5 µs (18 × tCLKIN), enabling real-time signal capture up to 100 kHz Nyquist bandwidth |
| SNR + THD | 70 dB min at 10 kHz - supports accurate digitization of audio-band and sensor signals with <0.1% distortion |
| Input Range | 0 to VREF (unipolar) or ±VREF/2 (bipolar) - configurable via AMODE bit; accepts inputs up to AVDD without damage |
| Power Dissipation | 15 mW typical at 3 V - drops to 1.3 mW at 10 kSPS using automatic power-down, critical for portable medical instruments |
| Integral Nonlinearity | ±1 LSB max - ensures monotonicity and <0.025% end-point error across full temperature range (–40°C to +85°C) |
| Track/Hold Acquisition | 500 ns - settles within ±0.5 LSB after conversion, supporting fast channel switching in multiplexed systems |
Pinout & Package
AD7859AP is packaged in a 44-pin PLCC (plastic leaded chip carrier), pin-compatible with PQFP variant AD7859AS but with distinct mechanical footprint and thermal impedance (θJA = 55°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN0–AIN7 | Analog Input Channels | Eight configurable inputs; support single-ended (vs AGND) or pseudo-differential pairs (e.g., AIN1+/AIN2–); all referenced to AGND, cannot exceed AVDD or go below AGND |
| REFIN/REFOUT | Reference I/O | 2.5 V nominal internal reference output; accepts external reference up to AVDD; requires CREF1 (0.1 µF) and CREF2 (0.01 µF) capacitors to AGND for stability |
| CONVST | Conversion Start | Rising-edge triggered; initiates T/H hold and SAR conversion; may be tied to DVDD if software start is used instead |
| BUSY | Status Output | Active-high open-drain signal indicating active conversion or calibration; asserts for exact 4.5 µs (AD7859) or 10 µs (AD7859L) |
| DB0–DB15 | Parallel Data Bus | 16-bit tri-state outputs; output coding is straight binary (unipolar) or 2's complement (bipolar); W/B pin selects word/byte mode |
| SLEEP, PMGT[1:0] | Power Management | SLEEP pin + control register bits enable three power states: normal (15 mW), partial power-down (400 µA), or full power-down (5 µA) |
Key Features
| Feature | Design Value |
|---|---|
| Self and System Calibration | On-chip calibration memory corrects offset/gain drift over temperature; system calibration compensates for external front-end errors (e.g., amplifier gain/offset) |
| Flexible Parallel Interface | Configurable 16-bit word or 8-bit byte transfer via W/B pin; RD/WR/CS protocol compatible with standard microcontroller buses |
| Single 3 V to 5.5 V Supply | Eliminates dual-supply design complexity; AVDD and DVDD may be tied together; logic thresholds scale with supply (2.1 V min at 3 V) |
| Pseudo-Differential Input Architecture | Rejects common-mode noise on paired channels (e.g., AIN1/AIN2); supports both unipolar and bipolar ranges without external op-amps |
| Low-Power Power-Down Modes | Full power-down draws only 5 µA (typ) with clock off - extends battery life in intermittent-sampling applications like PDA data loggers |
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 12-bit ADC capturing 8 analog sensor channels (ECG leads, SpO₂, temperature) at 200 kSPS with on-the-fly calibration. Use Value: 70 dB SNR ensures diagnostic-grade fidelity; 1.3 mW at 10 kSPS enables ultra-low-power sleep between beats without sacrificing accuracy. |
Use Scenario: Environmental sensor node logging temperature, humidity, and pressure in remote field deployments. IC Role / Device Role / Timing Role: Multi-channel sampling ADC interfacing with precision analog front-end; triggered by microcontroller on scheduled intervals. Use Value: Self-calibration maintains ±1 LSB INL over –40°C to +85°C; unipolar 0–2.5 V input range matches standard sensor outputs directly. |
| Industrial Control I/O Modules | High-Speed Modem Analog Front-End |
Use Scenario: DIN-rail PLC module acquiring 8 analog process signals (4–20 mA, 0–10 V) with isolation and linearization. IC Role / Device Role / Timing Role: Precision ADC with system calibration capability to null out isolation amplifier offset and gain errors. Use Value: ±0.05 × VREF system offset calibration span accommodates up to ±125 mV front-end error; bipolar mode supports ±5 V industrial inputs. |
Use Scenario: Analog baseband section of V.34 modem receiving filtered line signals prior to DSP processing. IC Role / Device Role / Timing Role: High-speed sampling ADC providing 200 kSPS digitization of band-limited voiceband signals (0–4 kHz). Use Value: 78 dB THD and –80 dB channel isolation prevent crosstalk between receive/transmit paths; 500 ns acquisition enables clean sampling of fast transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit, multi-channel, parallel-interface ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7859AS | Same core ADC, identical specs, but in 44-pin PQFP package (θJA = 95°C/W vs PLCC's 55°C/W); no lead-free option in AP grade | Preferred for automated SMT assembly; less suitable for hand-soldered prototyping or high-reliability military use where PLCC's gull-wing leads offer better thermal cycling endurance | Select AD7859AS only when board layout mandates PQFP footprint and thermal budget allows higher junction rise |
| AD7865BS | 4-channel, 14-bit, 100 kSPS ADC; SPI interface only; no parallel bus; higher resolution but lower speed and channel count | Used where resolution > speed is prioritized (e.g., precision weigh scales); incompatible pinout and interface - requires PCB redesign and firmware rewrite | Choose AD7865BS only when 14-bit resolution is mandatory and parallel interface is not required; not a drop-in replacement |
Compared with AD7859AP, AD7859AS offers identical electrical performance in a surface-mount PQFP for volume production, while AD7865BS trades speed and interface compatibility for higher resolution - making AD7859AP the optimal choice for cost-sensitive, high-throughput, parallel-bus–based portable instrumentation.
Availability
AD7859AP is available at Aetrix Electronics and suitable for portable medical instrumentation, battery-powered data loggers, industrial control I/O modules, and high-speed modem analog front-ends requiring stable component supply across extended product lifecycles.
Supply support for AD7859AP 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, founded in 1965 and headquartered in Wilmington, MA.
The AD7859AP belongs to Analog Devices' legacy high-speed precision ADC family, designed specifically for portable, low-power, multi-channel data acquisition systems where calibration integrity and supply flexibility are critical.
FAQ
What is the maximum sampling rate supported by the AD7859AP?
The AD7859AP supports a maximum throughput rate of 200 kSPS, achieved with a 4 MHz master clock (CLKIN). Conversion time is fixed at 4.5 µs (18 × tCLKIN), and the device maintains this rate across its full operating temperature range (–40°C to +85°C). The AD7859AP datasheet confirms this specification under "CONVERSION RATE" with test conditions specifying fCLKIN = 4 MHz and TA = TMIN to TMAX.
Does the AD7859AP require external reference components?
Yes, the AD7859AP requires two external capacitors on the reference pins: a 0.1 µF multilayer ceramic capacitor (CREF1) and a 0.01 µF ceramic disc capacitor (CREF2), both connected between their respective pins (CREF1, CREF2) and AGND. These stabilize the internal 2.5 V reference and ensure accurate DAC operation during conversion and calibration sequences. The AD7859AP pin function description explicitly mandates these components.
Can the AD7859AP operate with a 3 V supply only?
Yes, the AD7859AP is fully specified for single-supply operation from 3.0 V to 5.5 V on both AVDD and DVDD. At 3 V, it delivers 15 mW typical power dissipation in normal mode and supports logic thresholds of 2.1 V (VIH min) and 0.6 V (VIL max). All key specifications-including INL, SNR, and conversion time-are guaranteed across this range, as confirmed in the "POWER REQUIREMENTS" and "LOGIC INPUTS" sections of the AD7859AP datasheet.
How does the AD7859AP handle analog input protection?
The AD7859AP specifies absolute maximum analog input voltage as –0.3 V to AVDD + 0.3 V relative to AGND, with leakage current limited to ±1 µA max. Inputs are protected against overvoltage by internal ESD diodes, and the device tolerates transient currents up to 100 mA without SCR latchup. However, sustained input voltages beyond AVDD or below AGND risk permanent damage-so external clamping or series resistance is recommended in harsh environments per the AD7859AP absolute maximum ratings table.
Is the AD7859AP pin-compatible with the AD7859L variant?
Yes, the AD7859AP and AD7859L share identical pinouts, package dimensions, and interface signaling-both are offered in 44-pin PLCC (AP) and PQFP (AS/LAS) packages. The only functional differences are speed (200 kSPS vs 100 kSPS) and power consumption (15 mW vs 5.5 mW at 3 V), stemming from internal clocking and power management circuitry-not pin assignment or electrical interface. This compatibility is confirmed in the AD7859/AD7859L ordering guide and pinout diagrams.
AD7859AP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 44-LCC (J-Lead)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 200k
- Number of Inputs:
- -
- Input Type:
- -
- Data Interface:
- Parallel
- Configuration:
- -
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 2
- Architecture:
- -
- Reference Type:
- -
- Voltage - Supply, Analog:
- -
- Voltage - Supply, Digital:
- -
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 44-PLCC (16.59x16.59)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7859AP FAQ
1.How can I place an order for AD7859AP through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7859AP 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 AD7859AP reliable?
The price and inventory of AD7859AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7859AP is usually 5 days.
3.What payment methods are accepted for AD7859AP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7859AP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7859AP?
AD7859AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7859AP 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 AD7859AP?
For technical support, including AD7859AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7859AP requirements.
6.How does Aetrix verify that AD7859AP is sourced from the original manufacturer or authorized distributors?
All AD7859AP 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 AD7859AP meets industry standards.
7.What is the process for return or replacement of AD7859AP?
All AD7859AP units undergo pre-shipment inspection (PSI). If there is an issue with AD7859AP, 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 AD7859AP part is unused and in its original packaging.
Return procedure for AD7859AP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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