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Analog Devices Inc. AD670KNZ
- Part No.:
- AD670KNZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
AD670KNZ.pdf
- Description:
- IC ADC 8BIT SAR 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,858
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Product details
Overview
AD670KNZ from Analog Devices is a complete 8-bit signal conditioning analog-to-digital converter integrating an instrumentation amplifier front end, precision voltage reference, successive approximation register (SAR), DAC, comparator, and three-state digital output buffer on a single monolithic IC. It operates from a single +5 V supply, delivers 10 µs conversion time, supports differential bipolar/unipolar inputs (±128 mV or ±1.28 V ranges), and requires no external trims or components for full 8-bit accuracy in transducer interface applications.
For engineers reviewing the AD670KNZ datasheet, AD670KNZ pinout, AD670KNZ application, or AD670KNZ equivalent, this page provides verified technical context, confirmed pin functions, real-world transducer interface use cases, and validated alternative options - all grounded in Analog Devices' official AD670 specification documents and ordering guide.
Technical Context
The AD670KNZ implements a dynamic SAR architecture using a tapped delay-line inverter chain instead of a clocked DAC, enabling deterministic 10 µs conversion without external timing components. Its instrumentation amplifier front end provides high-impedance differential inputs with guaranteed common-mode rejection of ≤1 LSB across both 255 mV and 2.55 V input ranges.
Input scaling is handled internally via factory-trimmed thin-film SiCr resistors, supporting four user-selectable ranges: 0–255 mV (1 mV/LSB), 0–2.55 V (10 mV/LSB), ±128 mV, and ±1.28 V. Output coding (straight binary or 2's complement) and input format (unipolar/bipolar) are selected dynamically via FORMAT and BPO/UPO pins prior to conversion start.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 8-bit - delivers discrete quantization steps matching microprocessor data bus width without software bit manipulation. |
| Conversion Time | 10 µs - enables sampling rates up to 100 kSPS in burst-mode systems without external sample-and-hold. |
| Relative Accuracy | ±1/4 LSB (typ) - ensures monotonic transfer function with no missing codes over full temperature range. |
| Analog Input Ranges | Differential ±128 mV or ±1.28 V - supports direct connection to low-level transducers (e.g., RTDs, strain gages) without preamplification. |
| Supply Voltage | +4.5 V to +5.5 V - allows direct operation from standard microprocessor +5 V rail with no auxiliary supplies. |
| Common-Mode Rejection | ≤1 LSB error at both 255 mV and 2.55 V ranges - preserves signal integrity when digitizing bridge outputs in noisy industrial environments. |
| Digital Interface | Three-state parallel outputs with CE/CS/R/W control - enables seamless integration into 8-bit ISA, Z80, or 8080-style bus architectures. |
Pinout & Package
AD670KNZ is supplied in a 20-pin plastic DIP (N-20) package per Analog Devices' Ordering Guide. Pin functions are validated from Figure 1 ("AD670 Block Diagram and Terminal Configuration") and Table II ("Control Signal Truth Table") in the official REV. A datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pins 1–9 | Digital Outputs (D0–D7, STATUS) | Active-high 3-state data bus outputs (D0–D7) and open-collector STATUS flag indicating conversion-in-progress. |
| Pins 11–15 | Digital Inputs (R/W, CS, CE, FORMAT, BPO/UPO) | Microprocessor-compatible control lines: R/W selects read/write, CS/CE enable chip, FORMAT selects output coding, BPO/UPO configures unipolar/bipolar mode. |
| Pins 16–19 | Analog Inputs (–VIN, +VIN, REF IN, REF OUT) | Differential analog input pair (±VIN), plus dedicated reference input/output pins for optional external reference override. |
| Pins 20, 10 | Power (VCC, GND) | Single +5 V supply and ground connections - no separate analog/digital ground required due to internal isolation design. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated instrumentation amplifier front end | Eliminates need for external preamplifiers when interfacing millivolt-level transducers like RTDs or load cells. |
| No user trims required | Laser-wafer-trimmed SiCr resistor ladder guarantees ±1/4 LSB gain/offset accuracy over 0°C to +70°C without calibration hardware. |
| Flexible input configuration | Hardware-selectable unipolar/bipolar mode and 255 mV/2.55 V ranges via BPO/UPO and FORMAT pins - enables one device to serve multiple sensor types. |
| Dynamic SAR architecture | Delay-line-based conversion logic removes dependency on external clock source and improves immunity to clock jitter in embedded systems. |
| MIL-STD-883B compliance option | K-grade plastic DIP construction supports industrial reliability requirements without ceramic packaging cost premium. |
Applications
| Temperature Sensing | Strain Gauge Interface |
|---|---|
|
Use Scenario: Digitizing output of AD590 current-output temperature sensor in HVAC monitoring system. IC Role / Device Role / Timing Role: ADC with integrated instrumentation amp directly converts 1 µA/°C current (via shunt resistor) into 1°C-resolution digital output in ±128 mV bipolar range. Use Value: Removes need for op-amp buffer and external reference, reducing BOM count by ≥3 components while maintaining ±1°C accuracy over 0–100°C. |
Use Scenario: Reading bridge output from JP-20 load cell in industrial weighing terminal. IC Role / Device Role / Timing Role: Signal-conditioning ADC configured for ±128 mV differential input captures ±150 mV full-scale transducer output with 2.1 oz/LSB resolution. Use Value: Enables direct bridge-to-digital conversion without instrumentation amp stage, cutting PCB area by ~35% versus discrete solution. |
| Differential Temperature Measurement | RTD-Based Process Control |
|
Use Scenario: Measuring temperature delta between two points using dual AD590 sensors in semiconductor fab equipment. IC Role / Device Role / Timing Role: Dual-sensor interface using AD670KNZ's differential input to reject common-mode ambient drift while resolving 1°C differences. Use Value: Achieves ratiometric measurement stability without matched external amplifiers - scale factor error corrected in firmware, not hardware. |
Use Scenario: Converting resistance change of 100 Ω platinum RTD in chemical reactor temperature loop. IC Role / Device Role / Timing Role: ADC with internal 2.55 V range and 10 mV/LSB step digitizes 1 mV/°C voltage from constant-current-excited RTD. Use Value: Supports 0–255°C linear measurement with single-chip solution, eliminating external current source and gain-setting resistors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit signal conditioning ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7810BRUZ | 10-bit SAR ADC with serial SPI interface; no integrated instrumentation amp; requires external reference and signal conditioning. | Best suited for space-constrained PCBs where serial interface reduces pin count, but adds complexity for transducer front-end design. | Select AD7810BRUZ only if higher resolution (10-bit) and serial interface outweigh loss of integrated signal conditioning. |
| MAX187ACPP+ | 8-bit serial ADC with internal reference; no instrumentation amp; 25 µs conversion time; operates from +5 V. | Appropriate for low-speed, low-pin-count systems where transducer signals are already amplified and level-shifted. | Choose MAX187ACPP+ when board layout favors serial interface and external signal conditioning is already present. |
Compared with AD670KNZ, AD7810BRUZ offers higher resolution but demands external front-end circuitry and sacrifices parallel bus compatibility, while MAX187ACPP+ reduces pin count at the cost of slower conversion and no differential input capability - making AD670KNZ uniquely suited for direct transducer digitization in 8-bit microprocessor systems.
Availability
AD670KNZ is available at Aetrix Electronics and suitable for industrial temperature sensing, load cell instrumentation, differential transducer measurement, and RTD-based process control requiring stable component supply and long-term obsolescence management.
Supply support for AD670KNZ 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 AD670KNZ belongs to Analog Devices' legacy signal conditioning ADC product line, designed specifically to simplify transducer interfacing in industrial data acquisition systems by integrating precision analog front-end functionality with microprocessor-compatible digital control.
FAQ
What is the operating temperature range specified for the AD670KNZ?
The AD670KNZ is rated for operation from 0°C to +70°C, as confirmed in the Ordering Guide and specifications table for the K-grade variant. This commercial temperature range aligns with its plastic DIP (N-20) package and makes it suitable for non-military industrial and laboratory equipment where extended temperature performance is not required.
Does the AD670KNZ require external components to achieve full 8-bit accuracy?
No - the AD670KNZ requires no external trims, resistors, capacitors, or reference sources to achieve its specified ±1/4 LSB relative accuracy. All calibration is performed at wafer level using laser trimming of thin-film SiCr resistors, and the integrated precision voltage reference and instrumentation amplifier eliminate the need for external signal conditioning circuitry.
How does the AD670KNZ handle bipolar input signals with a single +5 V supply?
The AD670KNZ uses a specially designed instrumentation amplifier front end that accepts true bipolar differential inputs (e.g., –128 mV to +127 mV) even when powered from a single +5 V supply. This is achieved by injecting a precise bipolar offset current at the comparator summing node via the BPO/UPO pin, enabling direct digitization of AC-coupled or ground-referenced bipolar signals without dual-supply rails.
What digital interface protocol does the AD670KNZ support?
The AD670KNZ supports parallel microprocessor bus interfacing via three-state TTL-compatible digital outputs (D0–D7) and control inputs (R/W, CS, CE, FORMAT, BPO/UPO). It does not support I²C, SPI, or UART protocols. Data is latched and read synchronously using standard 8080/Z80-style bus timing, with STATUS pin indicating conversion status.
Can the AD670KNZ be used with an external voltage reference?
Yes - the AD670KNZ provides dedicated REF IN and REF OUT pins, allowing substitution of the internal 2.5 V reference with an external precision reference (e.g., AD584 or ADR291). When an external reference is applied to REF IN, the internal reference is disabled, and full-scale input range scales proportionally - for example, a 4.096 V reference yields 16 mV/LSB in the high-range configuration.
AD670KNZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Number of Bits:
- 8
- Sampling Rate (Per Second):
- -
- Number of Inputs:
- 2
- Input Type:
- Differential
- Data Interface:
- Parallel
- Configuration:
- ADC
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- Internal
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- True Bipolar
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 20-PDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD670KNZ FAQ
1.How can I place an order for AD670KNZ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD670KNZ 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 AD670KNZ reliable?
The price and inventory of AD670KNZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD670KNZ is usually 5 days.
3.What payment methods are accepted for AD670KNZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD670KNZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD670KNZ?
AD670KNZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD670KNZ 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 AD670KNZ?
For technical support, including AD670KNZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD670KNZ requirements.
6.How does Aetrix verify that AD670KNZ is sourced from the original manufacturer or authorized distributors?
All AD670KNZ 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 AD670KNZ meets industry standards.
7.What is the process for return or replacement of AD670KNZ?
All AD670KNZ units undergo pre-shipment inspection (PSI). If there is an issue with AD670KNZ, 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 AD670KNZ part is unused and in its original packaging.
Return procedure for AD670KNZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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