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Analog Devices Inc. AD7705BRZ-REEL7
- Part No.:
- AD7705BRZ-REEL7
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD7705BRZ-REEL7.pdf
- Description:
- IC ADC 16BIT SIGMA-DELTA 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,010
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Product details
Overview
AD7705BRZ-REEL7 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 low-frequency sensor signal acquisition in industrial transmitters.
For engineers reviewing the AD7705BRZ-REEL7 datasheet, AD7705BRZ-REEL7 pinout, AD7705BRZ-REEL7 application, or AD7705BRZ-REEL7 equivalent, key selection criteria include differential input architecture, on-chip calibration support, filter notch programmability, unipolar/bipolar input range flexibility, and compatibility with microcontroller-based isolated measurement systems.
Technical Context
The AD7705BRZ-REEL7 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 50/60 Hz line interference. Its analog front end integrates a programmable-gain amplifier (PGA) and optional input buffer, supporting direct connection to low-level transducer outputs such as strain gauges and RTDs.
It features dual differential analog inputs (AIN1±, AIN2±), differential reference inputs (REF IN±), and a 3-wire serial interface (SCLK, DIN, DOUT) with Schmitt-triggered SCLK and active-low CS. The device supports self-calibration and system calibration to eliminate offset and gain errors, with standby current as low as 8 μA at 3 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16 bits with no missing codes - guarantees monotonicity and full code coverage across full-scale range. |
| Integral Nonlinearity | ±0.003% of FSR - ensures high accuracy in precision measurement without external correction. |
| Input Channels | 2 fully differential analog inputs - enables simultaneous high-accuracy acquisition from two independent sensors. |
| Programmable Gain | 1 to 128 - allows direct interfacing with mV-level transducers (e.g., ±20 mV to ±2.5 V) without external amplification. |
| Power Dissipation | 1 mW maximum at 3 V - supports battery-powered and thermally constrained embedded systems. |
| Reference Input | Differential REF IN(+) and REF IN(−) - permits ratiometric measurement and eliminates reference drift sensitivity. |
| Output Data Rate | Configurable via filter notch (e.g., 50 Hz notch → ~16.7 Hz update rate) - balances noise performance and response time. |
Pinout & Package
AD7705BRZ-REEL7 is housed in a 16-lead SOIC package (wide-body, 0.3 inch), RoHS-compliant and tape-and-reel packaged (REEL7 denotes 1000-unit reel).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SCLK | Serial clock input | Schmitt-triggered logic input controlling data transfer timing; supports continuous or burst-mode clocking. |
| MCLK IN | Master clock input | Accepts crystal (2.4576 MHz typical) or external CMOS clock (400 kHz–2.5 MHz); enables internal oscillator. |
| MCLK OUT | Master clock output | Provides inverted clock for external circuitry; can be disabled via CLKDIS bit to reduce power. |
| CS | Chip select | Active-low enable for 3-wire SPI mode; when hardwired low, reduces interface to SCLK/DIN/DOUT only. |
| RESET | Hardware reset | Active-low signal that resets all registers, filter state, calibration coefficients, and modulator to power-on defaults. |
| AIN1(+), AIN1(−) | Differential channel 1 input | High-impedance, fully differential pair accepting bipolar/unipolar signals up to ±2.5 V (5 V supply) or ±1.225 V (3 V supply). |
| AIN2(+), AIN2(−) | Differential channel 2 input | Independent second differential input with identical voltage range and PGA gain settings as AIN1. |
| 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. |
| DIN | Serial data input | Writes configuration data (setup, clock, calibration registers); compatible with SPI/QSPI/MICROWIRE protocols. |
| DOUT | Serial data output | Reads conversion results and register contents; tri-state when CS is high. |
| DRDY | Data ready indicator | Active-low open-drain output signaling valid conversion data; used for interrupt-driven read synchronization. |
| GND | Analog/digital ground | Single ground pin shared for analog and digital sections; requires careful PCB layout separation per datasheet guidelines. |
| VDD | Supply voltage | Accepts 2.7–3.3 V or 4.75–5.25 V; powers both analog and digital circuitry; decoupling capacitor mandatory. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip self- and system calibration | Eliminates zero-scale and full-scale errors without external equipment; supports recalibration at operating temperature. |
| Programmable digital filter notch | Adjustable first notch (20 Hz, 25 Hz, 50 Hz, 60 Hz) enables optimal 50/60 Hz rejection for industrial environments. |
| Buffered analog input option | Enables high-impedance sensor interfaces (e.g., thermocouples) while maintaining specified CMR and noise performance. |
| Low-power standby mode | Reduces current to 8 μA at 3 V, enabling rapid wake-up (<100 μs) for duty-cycled sensor monitoring. |
| CMOS process with rail-to-rail input capability | Supports analog input voltages from GND − 100 mV to VDD + 30 mV, accommodating overvoltage transients safely. |
Applications
| Pressure Measurement | Temperature Monitoring |
|---|---|
|
Use Scenario: High-accuracy pressure sensing in industrial process control using bridge-based pressure transducers with mV-level output. IC Role / Device Role / Timing Role: ADC front end performing PGA gain scaling, sigma-delta conversion, and digital filtering to reject 50/60 Hz noise. Use Value: Achieves <600 nV rms noise and ±0.003% INL, enabling 0.1% full-scale pressure resolution without external op-amps or filters. |
Use Scenario: Precision RTD or thermistor measurements in HVAC and environmental monitoring systems requiring stable long-term drift performance. IC Role / Device Role / Timing Role: Dual-channel ratiometric ADC acquiring both sensor and reference resistor simultaneously to cancel excitation current variation. Use Value: Differential input structure and on-chip calibration remove offset/gain drift, delivering <0.5 μV/°C zero-drift over −40°C to +85°C. |
| Smart Transmitter | Battery-Powered Sensor Node |
|
Use Scenario: 4–20 mA HART-enabled field transmitter integrating sensor signal conditioning, ADC, and microcontroller communication. IC Role / Device Role / Timing Role: Low-power, isolated ADC providing calibrated digital output to host MCU via 3-wire SPI, minimizing opto-isolator count. Use Value: 1 mW max power at 3 V and 8 μA standby enable extended loop-powered operation while maintaining 16-bit integrity. |
Use Scenario: Wireless IoT node measuring strain or load cell output with multi-year battery life requirements. IC Role / Device Role / Timing Role: Sleep-wake ADC acquiring single-shot conversions triggered by external event, then returning to 8 μA standby. Use Value: Programmable update rate and automatic power-down after conversion reduce average current to sub-μA levels in duty-cycled operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar sigma-delta ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7706BRZ | 3-channel pseudo-differential input vs. AD7705BRZ-REEL7's 2-channel fully differential input; identical core architecture, register map, and pinout except AIN3/COMMON replaces AIN2(−). | Supports three single-ended or pseudo-differential sensors sharing COMMON; less suitable for true differential bridge sensors requiring matched AIN± pairs. | Select AD7706BRZ when needing third channel with shared reference and lower channel count precision is acceptable. |
| ADS124S08IPWR | 24-bit resolution, integrated PGA (1–128), but uses different serial protocol (4-wire SPI), higher supply current (380 μA active), and lacks self-calibration registers. | Targeted at ultra-high-resolution applications where 16-bit performance is insufficient; requires external calibration routine implementation. | Choose ADS124S08IPWR only when >16-bit resolution is mandatory and system firmware can manage calibration. |
Compared with AD7706BRZ, AD7705BRZ-REEL7 provides superior common-mode rejection (>130 dB at high gains) and true differential channel independence, critical for bridge sensor accuracy; compared with ADS124S08IPWR, it offers proven low-power operation, simpler calibration, and drop-in compatibility in legacy 16-bit designs.
Availability
AD7705BRZ-REEL7 is available at Aetrix Electronics and suitable for industrial process transmitters, battery-powered sensor nodes, smart HVAC controllers, and precision test equipment requiring stable component supply, long-lifecycle availability, and traceable sourcing.
Supply support for AD7705BRZ-REEL7 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, serving industrial, automotive, communications, and healthcare markets.
The AD7705/AD7706 product line was designed specifically for low-frequency, high-accuracy sensor signal acquisition in resource-constrained embedded systems - emphasizing low power, integrated signal conditioning, and robust noise immunity in harsh electrical environments.
FAQ
What is the maximum sampling rate of the AD7705BRZ-REEL7?
The AD7705BRZ-REEL7 does not operate at a fixed sampling rate; its output data rate is determined by the selected digital filter notch frequency and PGA gain. With a 2.4576 MHz master clock and gain = 1, the maximum update rate is approximately 16.7 Hz (50 Hz notch). At gain = 128, the rate drops to ~1.04 Hz. This trade-off between speed and noise rejection is configurable via the clock register.
Does the AD7705BRZ-REEL7 support bipolar input ranges?
Yes, the AD7705BRZ-REEL7 supports bipolar input ranges (e.g., ±20 mV to ±2.5 V) when configured in bipolar mode (B/U bit = 0 in setup register). The differential input structure references the signal to AIN(−), enabling accurate measurement of centered AC or bidirectional DC signals without level-shifting circuitry.
Can the AD7705BRZ-REEL7 operate from a 3.3 V supply?
Yes, the AD7705BRZ-REEL7 is fully specified for operation from 2.7 V to 3.3 V. At 3 V, it achieves 1 mW max power dissipation, 8 μA max standby current, and supports reference voltages down to 1.225 V. All timing, noise, and linearity specifications in the datasheet Rev. C apply under these conditions.
How is calibration performed on the AD7705BRZ-REEL7?
The AD7705BRZ-REEL7 supports both self-calibration (zero- and full-scale) and system calibration via dedicated registers. Self-calibration corrects internal offset/gain errors using internal references; system calibration uses external known inputs to remove sensor and front-end errors. Both are initiated by writing to the test register and take ~200 ms to complete.
Is the AD7705BRZ-REEL7 pin-compatible with other devices in the AD7705/AD7706 family?
Yes, the AD7705BRZ-REEL7 shares identical pinout and register mapping with all AD7705 variants (e.g., AD7705BN, AD7705BRU) in 16-lead SOIC, PDIP, and TSSOP packages. However, it is not pin-compatible with the AD7706 due to differing analog input configurations (AIN2(−) vs. COMMON), though software register compatibility allows reuse of driver code.
AD7705BRZ-REEL7 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:
- Active
- 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:
- -
AD7705BRZ-REEL7 FAQ
1.How can I place an order for AD7705BRZ-REEL7 through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7705BRZ-REEL7 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 AD7705BRZ-REEL7 reliable?
The price and inventory of AD7705BRZ-REEL7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7705BRZ-REEL7 is usually 5 days.
3.What payment methods are accepted for AD7705BRZ-REEL7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7705BRZ-REEL7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7705BRZ-REEL7?
AD7705BRZ-REEL7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7705BRZ-REEL7 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 AD7705BRZ-REEL7?
For technical support, including AD7705BRZ-REEL7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7705BRZ-REEL7 requirements.
6.How does Aetrix verify that AD7705BRZ-REEL7 is sourced from the original manufacturer or authorized distributors?
All AD7705BRZ-REEL7 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 AD7705BRZ-REEL7 meets industry standards.
7.What is the process for return or replacement of AD7705BRZ-REEL7?
All AD7705BRZ-REEL7 units undergo pre-shipment inspection (PSI). If there is an issue with AD7705BRZ-REEL7, 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 AD7705BRZ-REEL7 part is unused and in its original packaging.
Return procedure for AD7705BRZ-REEL7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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