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Analog Devices Inc. AD7705BR-REEL
- Part No.:
- AD7705BR-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD7705BR-REEL.pdf
- Description:
- IC ADC 16BIT SIGMA-DELTA 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,221
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Product details
Overview
AD7705BR-REEL from Analog Devices is a 16-bit sigma-delta analog-to-digital converter with two fully differential input channels, programmable gain (1–128), 3-wire SPI-compatible serial interface, and operation at 2.7–3.3 V or 4.75–5.25 V. It delivers 0.003% nonlinearity, <600 nV rms noise, and 1 mW max power dissipation at 3 V - ideal for precision transducer signal conditioning in battery-powered industrial sensors.
For engineers reviewing the AD7705BR-REEL datasheet, AD7705BR-REEL pinout, AD7705BR-REEL application, or AD7705BR-REEL equivalent, key selection criteria include its dual-channel differential architecture, on-chip calibration support, 50/60 Hz notch filter programmability, and compatibility with microcontroller-based data acquisition systems requiring high-resolution DC measurement without external amplification.
Technical Context
The AD7705BR-REEL employs a charge-balancing sigma-delta modulator followed by an on-chip digital filter with programmable first-notch frequency (20 Hz to 60 Hz), enabling precise rejection of line-frequency interference. Its programmable-gain amplifier (PGA) front end accepts low-level signals directly from strain gauges or RTDs, eliminating external instrumentation amplifiers.
It supports unipolar (0 mV to 1.225 V) and bipolar (±10 mV to ±1.225 V) input ranges when using a 1.225 V reference at 3 V supply, with common-mode rejection up to 130 dB at gains ≥8. The device features self-calibration and system calibration registers to remove offset and full-scale errors across temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16 bits with no missing codes - guarantees monotonicity and full code coverage for precision DC measurements. |
| Integral Nonlinearity | ±0.003% of FSR - ensures accurate endpoint linearity critical for sensor calibration and metrology-grade applications. |
| Input Channels | 2 fully differential - enables simultaneous high-accuracy measurement of two isolated transducer outputs with inherent noise rejection. |
| Programmable Gain | 1 to 128 - allows direct interfacing with mV-range sensors (e.g., load cells, thermocouples) without external gain stages. |
| Power Dissipation | 1 mW max @ 3 V - supports long-life battery operation in portable instrumentation and remote monitoring nodes. |
| Reference Input | Differential (REF IN(+) and REF IN(−)) - permits ratiometric measurement and eliminates reference drift impact on accuracy. |
| Serial Interface | 3-wire SPI/QSPI/MICROWIRE/DSP-compatible - reduces MCU GPIO count and simplifies isolation in industrial I/O modules. |
Pinout & Package
AD7705BR-REEL is housed in a 16-lead SOIC package (wide-body, 0.3 inch), RoHS-compliant and tape-and-reel packaged per the "-REEL" suffix.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SCLK | Serial clock input | Schmitt-triggered input accepting variable-duty-cycle clocks; synchronizes all serial data transfers. |
| MCLK IN | Master clock input | Accepts crystal (500 kHz–5 MHz) or CMOS clock; drives internal sigma-delta modulator and digital filter timing. |
| MCLK OUT | Master clock output | Provides inverted clock for external circuitry; disableable via CLKDIS bit to reduce power in unused configurations. |
| CS | Chip select | Active-low enable for 3-wire mode; when tied low, eliminates need for address decoding in simple MCU interfaces. |
| RESET | Hardware reset | Asynchronous active-low signal that clears all registers, filter state, and calibration coefficients to power-on defaults. |
| AIN1(+), AIN1(−) | Channel 1 differential analog input | High-impedance inputs supporting ±10 mV to ±1.225 V bipolar or 0–1.225 V unipolar ranges with PGA gain applied. |
| AIN2(+), AIN2(−) | Channel 2 differential analog input | Independent second channel with identical input range and PGA configuration as Channel 1. |
| REF IN(+), REF IN(−) | Differential reference input | Defines full-scale range; supports 1.225 V (3 V supply) or 2.5 V (5 V supply) references with 1% tolerance for specified performance. |
| DIN | Serial data input | Loads configuration data into communication, setup, clock, and calibration registers via SPI protocol. |
| DOUT | Serial data output | Outputs conversion results and register contents; tri-state capable for bus sharing in multi-device systems. |
| DRDY | Data ready indicator | Open-drain output pulses low when new conversion result is available; used for interrupt-driven read operations. |
| VDD, GND | Power supply terminals | Support dual supply ranges: 2.7–3.3 V or 4.75–5.25 V; separate analog/digital ground not required due to integrated design. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip self-calibration | Removes internal offset and gain errors without external components; completes in under 100 ms at power-up or on command. |
| System calibration support | Allows zero- and full-scale calibration against external reference sources to eliminate sensor and PCB trace errors. |
| Programmable digital filter notch | Configurable first notch at 20 Hz, 25 Hz, 50 Hz, or 60 Hz - enables robust rejection of AC mains interference in industrial environments. |
| Buffered analog input option | Enable/disable via BUF bit; buffering increases input impedance (>1 GΩ) but raises current consumption by ~0.3 mA at 3 V. |
| Low standby current | 8 μA max at 3 V - extends battery life in sleep-mode sensor nodes while retaining register state and calibration data. |
Applications
| Pressure Measurement | Temperature Monitoring |
|---|---|
Use Scenario: High-accuracy pressure sensing in HVAC control panels using silicon piezoresistive bridges with mV-level output. IC Role / Device Role / Timing Role: ADC front end performing PGA gain scaling, sigma-delta conversion, and digital filtering before SPI transmission to MCU. Use Value: Eliminates external op-amp and anti-aliasing filter; achieves <0.1% FS accuracy over −25°C to +70°C with on-chip calibration. |
Use Scenario: Precision RTD (Pt100/Pt1000) readout in industrial process controllers requiring 0.1°C resolution. IC Role / Device Role / Timing Role: Dual-channel ADC measuring both RTD voltage and reference resistor voltage for ratiometric computation. Use Value: Differential input structure rejects common-mode noise from 4–20 mA loop coupling; 16-bit resolution supports >1000:1 dynamic range. |
| Smart Transmitter | Battery Monitoring |
Use Scenario: Field-mounted 4–20 mA smart transmitter with HART modulation, powered from loop with strict <4 mA budget. IC Role / Device Role / Timing Role: Low-power ADC digitizing sensor output and providing calibrated digital data to HART modem MCU. Use Value: 1 mW max dissipation at 3 V enables full functionality within 3.5 mA loop budget; DRDY interrupt minimizes MCU active time. |
Use Scenario: Multi-cell Li-ion battery pack monitoring in portable medical devices requiring voltage and current sensing. IC Role / Device Role / Timing Role: Simultaneous measurement of cell voltages (via resistive dividers) and shunt-based current with high CMR. Use Value: 130 dB CMR at gain=128 suppresses switching noise from DC-DC converters; bipolar mode captures charge/discharge polarity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar sigma-delta ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7706BRUZ | 3 pseudo-differential input channels vs. AD7705BR-REEL's 2 fully differential channels; identical core architecture, calibration, and filter engine. | Supports 3-sensor systems (e.g., 3-axis inertial measurement) without multiplexing; requires COMMON pin routing instead of AIN(−) pairs. | Select AD7706BRUZ when third channel is needed and pseudo-differential topology suffices for sensor interface. |
| ADS1220IPWR | 24-bit resolution, integrated PGA (1–128), VREF buffer, and burn-out current sources; higher power (~1.3 mW) and larger 20-pin TSSOP package. | Targets ultra-high-precision applications (e.g., weigh scales, analytical instruments); lacks 50/60 Hz notch programming flexibility. | Choose ADS1220IPWR only when 24-bit resolution and integrated diagnostics outweigh AD7705BR-REEL's lower cost, smaller footprint, and superior line-frequency rejection configurability. |
Compared with AD7706BRUZ, AD7705BR-REEL provides superior noise rejection for differential sensors but fewer channels; versus ADS1220IPWR, it trades resolution and on-chip diagnostics for lower power, smaller size, and field-proven 50/60 Hz interference suppression in harsh industrial settings.
Availability
AD7705BR-REEL is available at Aetrix Electronics and suitable for pressure measurement, temperature monitoring, smart transmitter design, and battery management systems requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for AD7705BR-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, headquartered in Norwood, MA, with design and manufacturing facilities worldwide.
The AD7705/AD7706 product line was engineered specifically for low-frequency, high-accuracy industrial and instrumentation applications - delivering integrated signal conditioning, sigma-delta conversion, and digital filtering in a single low-power IC.
FAQ
What is the maximum sampling rate of the AD7705BR-REEL at gain = 1 and MCLK IN = 2.4576 MHz?
The AD7705BR-REEL achieves a maximum output data rate of 38.4 Hz at gain = 1 and MCLK IN = 2.4576 MHz. This is calculated as fCLKIN/64 = 2.4576 MHz / 64. At higher gains (8–128), the data rate drops to fCLKIN/8, yielding 307.2 Hz maximum. The actual update rate is programmable via the digital filter's notch frequency setting, trading speed for noise rejection.
Does the AD7705BR-REEL support bipolar input ranges, and how is polarity configured?
Yes, the AD7705BR-REEL supports bipolar input ranges (e.g., ±10 mV to ±1.225 V) via the B/U bit in the Setup Register. When B/U = 0, the device operates in bipolar mode and outputs offset binary data; when B/U = 1, it operates in unipolar mode with straight binary coding. Input polarity is referenced to AIN(−) pins, and the full-scale range is ±VREF/gain.
Can the AD7705BR-REEL operate with an external 1.225 V reference, and what tolerance is recommended?
Yes, the AD7705BR-REEL is designed to operate with a 1.225 V reference when powered from a 3 V supply. Analog Devices specifies ±1% tolerance for the 1.225 V reference to ensure guaranteed performance across temperature and process variation. Using a reference outside this tolerance may degrade integral nonlinearity and full-scale accuracy beyond the ±0.003% specification.
How does the AD7705BR-REEL handle power-down mode, and what is the typical standby current?
The AD7705BR-REEL enters standby mode when the RESET pin is held low or when the internal oscillator is disabled via the CLKDIS bit while MCLK IN is inactive. Standby current is 8 μA maximum at 3 V, enabling ultra-low-power operation in battery-critical applications. Note that if MCLK IN remains active during standby, current rises to ~75 μA due to continued oscillator operation.
Is the AD7705BR-REEL pin-compatible with other members of the AD7705/AD7706 family, such as the AD7705BN?
Yes, the AD7705BR-REEL shares identical pinout and electrical characteristics with all AD7705 variants including AD7705BN (PDIP) and AD7705BR (SOIC). All AD7705 packages - 16-lead PDIP, SOIC, and TSSOP - are functionally and pin-for-pin compatible. Differences are limited to package type, moisture sensitivity level, and reel packaging format; no PCB redesign is required when substituting AD7705BR-REEL for AD7705BN in SOIC footprints.
AD7705BR-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Number of Bits:
- 16
- Sampling Rate (Per Second):
- 500
- Number of Inputs:
- 2
- Input Type:
- 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-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7705BR-REEL FAQ
1.How can I place an order for AD7705BR-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7705BR-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 AD7705BR-REEL reliable?
The price and inventory of AD7705BR-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7705BR-REEL is usually 5 days.
3.What payment methods are accepted for AD7705BR-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7705BR-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7705BR-REEL?
AD7705BR-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7705BR-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 AD7705BR-REEL?
For technical support, including AD7705BR-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7705BR-REEL requirements.
6.How does Aetrix verify that AD7705BR-REEL is sourced from the original manufacturer or authorized distributors?
All AD7705BR-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 AD7705BR-REEL meets industry standards.
7.What is the process for return or replacement of AD7705BR-REEL?
All AD7705BR-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7705BR-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 AD7705BR-REEL part is unused and in its original packaging.
Return procedure for AD7705BR-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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