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Analog Devices Inc. AD7859BS
- Part No.:
- AD7859BS
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 44-QFP
- Datasheet:
-
AD7859BS.pdf
- Description:
- IC ADC 12BIT 8CH LP 44-MQFP
- Quantity:
- Payment:
- Shipping:
Inventory:765
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Product details
Overview
AD7859BS from Analog Devices is a 12-bit, 8-channel, 200 kSPS sampling ADC with integrated track-and-hold, self- and system calibration, and flexible parallel interface. It operates from a single 3 V to 5.5 V supply, delivers ±0.5 LSB integral nonlinearity, supports unipolar (0 to VREF) and bipolar (±VREF/2) input ranges, and targets precision data acquisition in battery-powered instrumentation.
For engineers reviewing the AD7859BS datasheet, AD7859BS pinout, AD7859BS application, or AD7859BS equivalent, this page provides verified technical context, calibrated performance metrics, package-specific pin functions, real-world use cases, and validated alternative options for embedded analog front-end design.
Technical Context
The AD7859BS employs a charge redistribution SAR architecture with on-chip 2.5 V reference, programmable pseudo-differential or single-ended input multiplexing, and a 500 ns track/hold acquisition time. Its control register enables channel selection, analog mode configuration (unipolar/bipolar), power management (PMGT1/PMGT0), and calibration mode (self/system) via parallel writes.
It features dual power domains (AVDD/DVDD), separate analog/digital grounds (AGND/DGND), external reference decoupling via CREF1 (0.1 µF) and CREF2 (0.01 µF), and supports both 16-bit word and 8-bit byte data transfers using the W/B and DB8/HBEN pins. Calibration spans are ±0.05 × VREF (offset) and ±0.025 × VREF (gain).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = VREF/4096 quantization step for precise measurement resolution |
| Throughput Rate | 200 kSPS - supports real-time signal capture up to 100 kHz full-power bandwidth |
| Integral Nonlinearity | ±0.5 LSB max - ensures monotonicity and <0.012% end-point linearity error over temperature |
| SNR + Distortion | 71 dB min at 10 kHz - enables >11.5 effective bits (ENOB) for clean signal digitization |
| Power Dissipation | 15 mW at 3 V - balances speed and efficiency for portable systems without active cooling |
| Input Range | 0 to VREF (unipolar) or ±VREF/2 (bipolar) - configurable via AMODE bit for sensor or AC-coupled inputs |
| Reference Voltage | 2.5 V internal (REFIN/REFOUT) - stable, low-drift source; externally overdrivable from 1.2 V to AVDD |
Pinout & Package
AD7859BS is supplied in a 44-pin plastic quad flatpack (PQFP), S-44 package per Analog Devices ordering guide. Pin assignments match the PQFP pinout shown in Rev. A datasheet Figure on page 6.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN0–AIN7 | Analog Input Channels | Eight configurable inputs; selectable as single-ended (vs AGND) or pseudo-differential pairs (e.g., AIN1+/AIN2−) |
| REFIN/REFOUT | Reference I/O | 2.5 V nominal internal reference; can be overdriven externally or used as output; requires CREF1/CREF2 decoupling |
| CONVST | Conversion Start Trigger | Rising-edge initiates sample-and-hold hold mode and conversion; may be hardware- or software-controlled (via CONVST bit) |
| BUSY | Conversion Status Flag | Active-high open-drain output signals ongoing conversion or calibration; used for handshaking with host processor |
| DB0–DB15 | Parallel Data Bus | 16-bit bidirectional bus; mode selected by W/B: 16-bit word (W/B = 1) or 8-bit byte with HBEN (W/B = 0) |
| SLEEP, PMGT1/PMGT0 | Power Management Control | Combined with SLEEP pin, enables full power-down (10 µA typ), partial power-down (400 µA typ), or normal operation |
| CS, RD, WR | Parallel Interface Control | Standard 8080-style control: CS enables device, RD reads registers, WR writes to control/calibration registers |
Key Features
| Feature | Design Value |
|---|---|
| Self- and System Calibration | On-chip calibration engine corrects offset/gain drift over temperature; system calibration compensates external front-end errors |
| Flexible Power Management | Three power-down modes reduce current to 10 µA (full) or 400 µA (partial); 1 mW typical @ 10 kSPS enables ultra-low-duty-cycle sensing |
| Pseudo-Differential Input Architecture | Eight inputs support four differential pairs with common-mode rejection; eliminates need for external instrumentation amplifiers in many sensor interfaces |
| Configurable Analog Input Ranges | Software-selectable unipolar (0 to VREF) or bipolar (±VREF/2) operation via AMODE bit - simplifies interface to diverse transducers |
| Robust Parallel Interface | 16-bit/8-bit mode support, standard 8080 timing, and register-addressable control enable direct connection to microcontrollers without glue logic |
Applications
| Portable Medical Instrumentation | Battery-Powered Data Loggers |
|---|---|
Use Scenario: Continuous ECG waveform acquisition in handheld patient monitors with 3 V coin-cell supply. IC Role / Device Role / Timing Role: Primary analog front-end ADC performing synchronized 8-channel sampling at 200 kSPS with on-chip calibration. Use Value: ±0.5 LSB INL and 71 dB SNR ensure diagnostic-grade fidelity; 15 mW dissipation extends battery life beyond 24 hours. |
Use Scenario: Multi-sensor environmental monitoring (temperature, humidity, pressure) in remote field nodes. IC Role / Device Role / Timing Role: Central 12-bit ADC interfacing to conditioned analog outputs of MEMS sensors via pseudo-differential inputs. Use Value: Self-calibration maintains accuracy across –40°C to +85°C; flexible power-down cuts average current to µA-level between samples. |
| Industrial Control I/O Modules | High-Speed Modem Analog Front-End |
Use Scenario: Analog input section of DIN-rail PLC modules acquiring 4–20 mA loop signals and thermocouple outputs. IC Role / Device Role / Timing Role: Precision ADC with system calibration capability to compensate for PCB trace resistance and op-amp offsets. Use Value: ±0.05 × VREF system offset calibration span accommodates up to ±125 mV front-end error; REFOUT drives external buffers. |
Use Scenario: Digitizing baseband IF signals in V.34/V.90 modem designs requiring low distortion at 10–20 kHz. IC Role / Device Role / Timing Role: High-fidelity sampling stage preceding digital signal processing; THD ≤ –78 dB prevents harmonic interference. Use Value: 71 dB SNR + distortion and –78 dB THD meet ITU-T spectral mask requirements; 500 ns acquisition supports fast settling filters. |
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 speed (200 kSPS) and package, but ±1 LSB INL (vs ±0.5 LSB for AD7859BS) | Acceptable where cost sensitivity outweighs need for highest linearity in medical or metrology use | Select AD7859AS when ±1 LSB INL meets system accuracy budget and B-version premium is unjustified |
| AD7859LAS3 | Low-power variant: 100 kSPS max, 5.5 mW at 3 V (vs 200 kSPS, 15 mW for AD7859BS) | Targeted at ultra-low-power, lower-throughput applications like static sensor monitoring | Choose AD7859LAS3 only if throughput ≤100 kSPS suffices and sub-6 mW operation is mandatory |
Compared with AD7859AS and AD7859LAS3, the AD7859BS uniquely delivers the tightest linearity (±0.5 LSB) at full 200 kSPS speed in the PQFP package-making it optimal for high-fidelity, battery-constrained instrumentation where accuracy and bandwidth must coexist.
Availability
AD7859BS 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 and long-term manufacturability.
Supply support for AD7859BS 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, headquartered in Norwood, MA.
The AD7859BS belongs to Analog Devices' legacy high-speed precision ADC product line, designed specifically for portable, low-power, multi-channel data acquisition systems requiring on-chip calibration and flexible parallel interfacing.
FAQ
What is the maximum sampling rate supported by the AD7859BS?
The AD7859BS supports a maximum throughput rate of 200 kSPS, achieved with a 4 MHz master clock (CLKIN). This corresponds to a conversion time of 4.5 µs. The part maintains specified dynamic performance-including 71 dB SNR + distortion and ≤–78 dB THD-at this rate when driven with a 10 kHz sine wave input and 2.5 V reference.
Does the AD7859BS require external reference components?
Yes, the AD7859BS requires two external capacitors on its reference pins: a 0.1 µF multilayer ceramic capacitor (CREF1) between CREF1 and AGND, and a 0.01 µF ceramic disc capacitor (CREF2) between CREF2 and AGND. These stabilize the internal 2.5 V reference and support DAC charge redistribution during conversion. The REFIN/REFOUT pin itself may be overdriven with an external reference from 1.2 V to AVDD.
How does the AD7859BS handle analog input configuration?
The AD7859BS supports both single-ended and pseudo-differential input modes via the SGL/DIFF bit in its control register. In pseudo-differential mode, AIN0–AIN7 form four differential pairs (e.g., AIN1+/AIN2−); in single-ended mode, each input references AGND. The AMODE bit further selects unipolar (0 to VREF) or bipolar (±VREF/2) range, with corresponding output coding (straight binary or 2's complement).
Can the AD7859BS operate from a 3.3 V supply?
Yes, the AD7859BS is fully specified for operation from 3.0 V to 5.5 V on both AVDD and DVDD. At 3.3 V, it delivers 15 mW typical power dissipation in normal mode, ±0.5 LSB INL, and maintains all timing and dynamic specifications-including 200 kSPS throughput-provided the master clock (CLKIN) is set to 4 MHz and reference voltage remains stable at 2.5 V.
What calibration options are available on the AD7859BS?
The AD7859BS offers both self-calibration (correcting internal DAC and comparator offsets) and system calibration (compensating external gain/offset errors in the signal chain). Calibration is initiated via the CAL pin (hardware) or CONVST bit (software), with durations of ~31 ms (full self-cal) and ~3.5 ms (system offset cal) at 4 MHz CLKIN. Calibration spans are ±0.05 × VREF (offset) and ±0.025 × VREF (gain).
AD7859BS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 44-QFP
- Packaging:
- Bag
- 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-MQFP (10x10)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7859BS FAQ
1.How can I place an order for AD7859BS through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7859BS 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 AD7859BS reliable?
The price and inventory of AD7859BS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7859BS is usually 5 days.
3.What payment methods are accepted for AD7859BS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7859BS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7859BS?
AD7859BS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7859BS 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 AD7859BS?
For technical support, including AD7859BS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7859BS requirements.
6.How does Aetrix verify that AD7859BS is sourced from the original manufacturer or authorized distributors?
All AD7859BS 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 AD7859BS meets industry standards.
7.What is the process for return or replacement of AD7859BS?
All AD7859BS units undergo pre-shipment inspection (PSI). If there is an issue with AD7859BS, 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 AD7859BS part is unused and in its original packaging.
Return procedure for AD7859BS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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