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Analog Devices Inc. AD7706BN
- Part No.:
- AD7706BN
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
AD7706BN.pdf
- Description:
- IC ADC 16BIT SIGMA-DELTA 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,199
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Product details
Overview
AD7706BN from Analog Devices is a 16-bit sigma-delta analog-to-digital converter with three pseudo-differential input channels, programmable gain (1–128), 0.003% nonlinearity, and 1 mW max power dissipation at 3 V. It integrates a buffered front end, on-chip digital filter, and self-calibration for precision sensor interfacing in low-power industrial measurement systems.
For engineers reviewing the AD7706BN datasheet, AD7706BN pinout, AD7706BN application, or AD7706BN equivalent, key selection criteria include its 3-channel pseudo-differential architecture, 2.7–3.3 V / 4.75–5.25 V dual-supply operation, SPI/QSPI/MICROWIRE-compatible 3-wire interface, ±2.5 V bipolar input range capability, and 16-lead PDIP package compatibility with legacy board layouts.
Technical Context
The AD7706BN employs a charge-balancing sigma-delta modulator followed by a programmable first-notch digital filter, enabling selectable output update rates and 50/60 Hz rejection via notch frequency configuration. Its analog front end includes a fully differential reference input and a programmable-gain amplifier optimized for direct transducer connection.
It supports unipolar (0 mV to 1.225 V) and bipolar (±10 mV to ±1.225 V) input ranges with 3 V supply and 1.225 V reference, or 0 V to 2.5 V / ±2.5 V ranges with 5 V supply and 2.5 V reference. Input buffering is software-selectable via the BUF bit in the setup register.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16 bits, no missing codes - guarantees monotonicity and full code coverage across full-scale range |
| Input Channels | 3 pseudo-differential - enables simultaneous monitoring of three independent sensor signals referenced to COMMON |
| Programmable Gain | 1 to 128 - allows direct interface with low-level sensors (e.g., strain gauges, RTDs) without external amplification |
| Nonlinearity | ±0.003% of FSR - ensures high accuracy in precision measurement applications such as smart transmitters |
| Power Dissipation | 1 mW max @ 3 V - supports battery-powered and energy-constrained embedded systems |
| Supply Range | 2.7–3.3 V or 4.75–5.25 V - dual-voltage compatibility simplifies integration into mixed-supply industrial designs |
| Interface | 3-wire serial (SPI/QSPI/MICROWIRE/DSP-compatible) - reduces MCU GPIO count and isolation component requirements |
| Standby Current | 8 μA max @ 3 V - enables ultra-low-power sleep modes during sensor idle periods |
Pinout & Package
AD7706BN is supplied in a 16-lead plastic dual in-line package (PDIP), 0.3 inch wide body, with through-hole mounting compatible with legacy PCB assembly processes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SCLK | Serial clock input | Schmitt-triggered logic input accepting variable-duty-cycle clocks; controls timing of serial data transfers |
| MCLK IN | Master clock input | Accepts external CMOS clock or crystal/resonator (500 kHz–5 MHz); required for internal timing generation |
| MCLK OUT | Master clock output | Provides inverted clock signal when crystal is used; configurable to disable via CLKDIS bit to reduce power |
| CS | Chip select | Active-low enable for 3-wire interface; allows multiple devices on shared DIN/DOUT lines |
| RESET | Reset input | Active-low signal that resets all registers, calibration coefficients, and digital filter state to power-on defaults |
| AIN1, AIN2, AIN3 | Analog input channels | Pseudo-differential inputs referenced to COMMON pin; each accepts ±2.5 V (5 V supply) or ±1.225 V (3 V supply) |
| COMMON | Common-mode reference | Shared negative reference for all three input channels; defines common-mode voltage for AIN1–AIN3 |
| REF IN(+), REF IN(−) | Differential reference inputs | Set full-scale range; support 1.225 V (3 V) or 2.5 V (5 V) references with ±1% tolerance for specified performance |
| DRDY | Data ready output | Open-drain logic output indicating valid conversion result; pulses low before new data is available in register |
| DIN | Serial data input | Accepts configuration commands (setup, clock, calibration registers) and control bits via 3-wire interface |
| DOUT | Serial data output | Transmits conversion results and register contents; synchronized to SCLK falling edge |
| VDD, GND | Power supply terminals | Single-supply operation; requires local decoupling (10 μF + 0.1 μF) per Analog Devices layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| On-chip self-calibration | Eliminates zero-scale and full-scale errors without external calibration equipment; reduces system-level offset/gain drift |
| Configurable digital filter | First-notch frequency programmable to reject 50 Hz or 60 Hz line interference while maintaining >98 dB normal-mode rejection |
| Input buffer enable | Software-selectable buffer (BUF bit) improves input impedance >1 GΩ and reduces source loading for high-impedance sensors |
| Bipolar/unipolar mode | Single-bit B/U control selects input polarity handling - supports both signed and unsigned sensor outputs in same hardware |
| Low-power standby mode | Reduces current to 8 μA @ 3 V; maintains register state and allows fast wake-up (<1 ms) for event-driven sampling |
| CMOS process construction | Ensures low leakage (<1 nA) and high ESD robustness (>4 kV HBM), critical for reliable field-deployed instrumentation |
Applications
| Pressure Measurement | Temperature Measurement |
|---|---|
Use Scenario: Digital pressure transmitter with piezoresistive bridge sensor operating in harsh industrial environments. IC Role / Device Role / Timing Role: ADC front end performing ratiometric conversion of bridge output referenced to excitation voltage, with integrated PGA gain scaling and 50/60 Hz noise rejection. Use Value: Enables direct digitization of sub-10 mV bridge outputs at 16-bit resolution without external op-amps or filters, reducing BOM cost and board area. | Use Scenario: Multi-point temperature monitoring in HVAC control panels using thermocouples and RTDs. IC Role / Device Role / Timing Role: Simultaneous acquisition of three temperature sensor channels (e.g., ambient, supply, exhaust) with cold-junction compensation support via COMMON-referenced inputs. Use Value: Eliminates need for multiplexing and external signal conditioning per channel, improving measurement throughput and thermal stability. |
| Smart Transmitters | Battery Monitoring |
Use Scenario: 4–20 mA loop-powered field transmitter with microcontroller-based diagnostics and HART communication. IC Role / Device Role / Timing Role: High-accuracy analog front end converting sensor signals to digital for microcontroller processing; operates from loop-derived 3.3 V supply. Use Value: 1 mW power consumption and 8 μA standby current extend loop compliance margin and enable low-power diagnostic cycles. | Use Scenario: Portable medical device with multi-cell Li-ion battery pack requiring precise voltage and current monitoring. IC Role / Device Role / Timing Role: Simultaneous sampling of cell voltages and shunt-based current sense with programmable gain to resolve mV-level differences across cells. Use Value: 0.003% nonlinearity and on-chip calibration ensure <10 mV absolute accuracy over temperature, critical for state-of-charge estimation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar sigma-delta ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7705BN | 2 fully differential input channels vs. AD7706BN's 3 pseudo-differential channels; identical gain range, resolution, and interface | Limited to two-sensor systems; lacks COMMON-referenced third channel required for 3-input topologies | Select AD7705BN only when exactly two fully isolated differential inputs are needed and board space permits same 16-lead PDIP footprint |
| ADS1115IDGSR | 4-channel, 16-bit delta-sigma ADC with I²C interface; 2–5.5 V supply; built-in oscillator; no external reference required | Requires I²C bus instead of SPI; lacks programmable digital filter notch; lower CMR (100 dB typ) than AD7706BN at gain=128 | Choose ADS1115IDGSR for space-constrained designs needing I²C simplicity and integrated oscillator, but verify 50/60 Hz rejection meets system EMC requirements |
Compared with AD7705BN, AD7706BN adds a third input channel with COMMON referencing-critical for 3-sensor systems-while retaining identical calibration, noise, and power specs. Versus ADS1115IDGSR, AD7706BN offers superior line-frequency rejection and SPI flexibility but requires external clock and reference components.
Availability
AD7706BN is available at Aetrix Electronics and suitable for pressure measurement, temperature monitoring, smart transmitters, and battery management systems requiring stable component supply, long-term industrial lifecycle support, and legacy PDIP package compatibility.
Supply support for AD7706BN 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 since 1965.
The AD7705/AD7706 product line was designed specifically for low-frequency, high-accuracy sensor signal conditioning in resource-constrained embedded systems-emphasizing integrated PGA, self-calibration, and low-power sigma-delta conversion without external support components.
FAQ
What is the maximum input voltage range supported by the AD7706BN with a 5 V supply?
The AD7706BN supports a bipolar input range of ±2.5 V and a unipolar range of 0 V to 2.5 V when operated with a 5 V supply and 2.5 V reference. These ranges are defined relative to the COMMON pin for pseudo-differential inputs. Absolute analog input voltages must remain between GND − 100 mV and VDD + 30 mV for specified performance. The AD7706BN achieves this via its programmable gain amplifier and differential reference architecture.
Does the AD7706BN require an external crystal or can it operate with an external clock signal?
Yes, the AD7706BN supports both configurations: a crystal or ceramic resonator may be connected between MCLK IN and MCLK OUT, or an external CMOS-compatible clock signal (500 kHz–5 MHz) may be applied directly to MCLK IN with MCLK OUT left unconnected. The AD7706BN's clock circuitry automatically adapts; no configuration change is needed. The AD7706BN datasheet specifies 2.4576 MHz as the standard test frequency for timing characterization.
How does the COMMON pin function in the AD7706BN's 3-channel architecture?
The COMMON pin serves as the shared negative reference for all three pseudo-differential analog inputs (AIN1, AIN2, AIN3). Unlike fully differential inputs, each channel measures voltage between its positive pin and COMMON-not against an independent negative pin. This architecture reduces pin count and simplifies routing for multi-sensor systems where sensors share a common reference point, such as grounded thermocouple junctions or single-supply transducers. The AD7706BN leverages COMMON to enable true 3-channel simultaneous sampling within a 16-pin PDIP package.
Can the AD7706BN perform self-calibration without external components?
Yes, the AD7706BN includes on-chip zero-scale and full-scale calibration routines executable via its serial interface-no external precision voltage sources or equipment are required. Calibration coefficients are stored in dedicated registers (0x1E and 0x1F) and automatically applied to conversions. System calibration is also supported by applying known input voltages during runtime. These features eliminate gain and offset errors inherent to the AD7706BN's analog path and significantly reduce production test time and cost.
What is the purpose of the BUF bit in the AD7706BN's setup register?
The BUF bit (bit D2 of the Setup Register) enables or disables the internal input buffer amplifier. When set (BUF = 1), the buffer provides high input impedance (>1 GΩ) and isolates the sigma-delta modulator from source impedance variations-critical for high-impedance sensors like thermistors or pH electrodes. When cleared (BUF = 0), the AD7706BN operates in buffered-bypass mode, reducing power consumption and input noise but requiring source impedances <2 kΩ for optimal performance. This setting directly affects the AD7706BN's effective input range and noise floor.
AD7706BN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Number of Bits:
- 16
- Sampling Rate (Per Second):
- 500
- Number of Inputs:
- 3
- Input Type:
- Pseudo-Differential
- Data Interface:
- SPI, DSP
- Configuration:
- MUX-PGA-ADC
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- Sigma-Delta
- Reference Type:
- External
- Voltage - Supply, Analog:
- 2.7V ~ 3.3V, 5V
- Voltage - Supply, Digital:
- 2.7V ~ 3.3V, 5V
- Features:
- PGA
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 16-PDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD7706BN FAQ
1.How can I place an order for AD7706BN through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7706BN 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 AD7706BN reliable?
The price and inventory of AD7706BN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7706BN is usually 5 days.
3.What payment methods are accepted for AD7706BN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7706BN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7706BN?
AD7706BN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7706BN 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 AD7706BN?
For technical support, including AD7706BN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7706BN requirements.
6.How does Aetrix verify that AD7706BN is sourced from the original manufacturer or authorized distributors?
All AD7706BN 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 AD7706BN meets industry standards.
7.What is the process for return or replacement of AD7706BN?
All AD7706BN units undergo pre-shipment inspection (PSI). If there is an issue with AD7706BN, 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 AD7706BN part is unused and in its original packaging.
Return procedure for AD7706BN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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