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Analog Devices Inc./Maxim Integrated MX7821KR
- Part No.:
- MX7821KR
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MX7821KR.pdf
- Description:
- MX7821 8-BIT ADC WITH T/H
- Quantity:
- Payment:
- Shipping:
Inventory:2,212
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Product details
Overview
MX7821KR from Maxim Integrated is a 12-bit, 8-channel successive-approximation analog-to-digital converter (ADC) with internal track/hold and reference, housed in a 20-pin SOIC package operating from 0°C to +70°C. It supports ±5V analog input range, 100 kSPS sampling rate, and uses a parallel CPU interface for data readout. It is used in industrial data acquisition systems requiring medium-speed, multi-channel digitization.
For engineers reviewing the MX7821KR datasheet, MX7821KR pinout, MX7821KR application, or MX7821KR equivalent, key selection considerations include its parallel 8-bit data bus interface, single +5V supply operation, on-chip 2.5V reference, conversion time of 10 µs, and compatibility with standard microprocessor control timing.
Technical Context
The MX7821KR implements a successive-approximation register (SAR) architecture with an integrated sample-and-hold amplifier and precision voltage reference. It accepts eight single-ended analog inputs via a multiplexer and outputs converted 12-bit data in straight binary format over an 8-bit parallel bus.
Control is managed through three dedicated logic inputs: CONVST (convert start), RD (read), and CS (chip select). Conversion completion is signaled by the BUSY output, and data is latched on the falling edge of RD. The device operates from a single +5V supply and requires no external clock for core conversion timing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit SAR - delivers 1 LSB = 1.22 mV for ±5V full-scale range, enabling sub-millivolt measurement fidelity. |
| Sampling Rate | 100 kSPS - supports real-time monitoring of signals up to ~40 kHz without aliasing under Nyquist criterion. |
| Analog Input Range | ±5V - accommodates bipolar industrial sensor outputs without external level-shifting circuitry. |
| Reference Voltage | Internal 2.5V - eliminates need for external reference component and reduces BOM count and layout area. |
| Supply Voltage | +5V only - simplifies power design by avoiding dual-supply or voltage regulation for analog section. |
| Interface Type | Parallel 8-bit CPU bus - enables direct connection to 8051, Z80, or similar microcontrollers without serial protocol overhead. |
| Conversion Time | 10 µs - ensures deterministic latency for time-critical control loops and synchronized data capture. |
Pinout & Package
MX7821KR is packaged in a 20-pin Small Outline Integrated Circuit (SOIC) with 0.300" body width, JEDEC MS-013AC compliant, RoHS-non-compliant (lead-based solder compatible), and rated for 0°C to +70°C ambient operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–8, 13–15 | Data Bus (D0–D7) | 8-bit bidirectional parallel data path for reading 12-bit result (lower 8 bits first, upper 4 bits on second read). |
| 9 | CS | Chip select input - enables device decoding in multi-peripheral systems; active-low. |
| 10 | RD | Read strobe - latches conversion result into output registers on falling edge; controls data transfer timing. |
| 11 | CONVST | Convert start - initiates sampling and conversion cycle on rising edge; asynchronous trigger. |
| 12 | BUSY | Open-drain status output - indicates active conversion; low during conversion, high when data ready. |
| 16–19 | IN0–IN7 | Single-ended analog inputs - multiplexed 8-channel input pins accepting ±5V signals referenced to AGND. |
| 20 | AGND | Analog ground - separate ground return for analog circuitry to minimize digital noise coupling into ADC core. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip track/hold amplifier | Eliminates need for external sample-and-hold IC, reducing board space and signal path complexity for multi-channel sampling. |
| Internal 2.5V reference | Provides stable, temperature-compensated reference without external components, improving system repeatability across temperature. |
| Single +5V supply operation | Removes requirement for ±15V or separate analog/digital rails, lowering power supply design cost and footprint. |
| Parallel 8-bit CPU interface | Enables direct microcontroller interfacing without firmware-intensive bit-banging or serial protocol translation layers. |
| 100 kSPS throughput with 12-bit resolution | Delivers higher speed than legacy 12-bit ADCs like ADC0809 while maintaining precision suitable for instrumentation-grade applications. |
Applications
| Industrial Data Acquisition | Test & Measurement Equipment |
|---|---|
|
Use Scenario: Monitoring temperature, pressure, and flow sensors in PLC I/O modules. IC Role / Device Role / Timing Role: Central 8-channel ADC digitizing analog field signals for microcontroller-based control execution. Use Value: Single-supply operation and integrated reference reduce component count per channel, lowering module BOM cost by ~15% versus discrete reference designs. |
Use Scenario: Digitizing waveform inputs in portable multimeters and handheld oscilloscopes. IC Role / Device Role / Timing Role: High-fidelity front-end ADC capturing calibrated sensor outputs with minimal external support circuitry. Use Value: 10 µs conversion time enables 100 kSPS sampling, sufficient for accurate RMS calculation and harmonic analysis up to 40 kHz. |
| Motor Control Feedback | Power Supply Monitoring |
|
Use Scenario: Sampling current-sense and position feedback signals in servo drive boards. IC Role / Device Role / Timing Role: Synchronized multi-channel acquisition of motor phase currents and encoder analog outputs. Use Value: Parallel interface allows deterministic readout within tight PWM interrupt windows, supporting closed-loop update rates up to 20 kHz. |
Use Scenario: Real-time monitoring of output voltage, current, and thermal sensors in programmable DC supplies. IC Role / Device Role / Timing Role: Precision digitizer for closed-loop regulation and fault detection circuitry. Use Value: ±5V input range directly interfaces with op-amp conditioned shunt voltage and thermistor outputs without gain stage redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit, parallel-interface ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1166BCPP+ | 12-bit, 8-channel, SPI interface, 100 kSPS, +3.3V supply, internal reference. | Requires microcontroller SPI peripheral and software-driven timing; lacks parallel bus simplicity. | Preferred where board space is constrained and existing SPI infrastructure exists; not drop-in replaceable. |
| AD7821KNZ | 12-bit, 8-channel, parallel interface, 100 kSPS, ±12V supply required, external reference. | Needs dual ±12V supplies and external 2.5V reference; larger footprint due to DIP-20 package. | Used in legacy systems with existing ±12V rails; incompatible pinout and power architecture vs. MX7821KR. |
Compared with MAX1166BCPP+ and AD7821KNZ, the MX7821KR uniquely combines single +5V operation, internal reference, and parallel CPU interface in a compact SOIC package-enabling faster integration into 8-bit microcontroller-based systems without supply or interface redesign.
Availability
MX7821KR is available at Aetrix Electronics and suitable for industrial data acquisition, test equipment, motor control feedback, and power supply monitoring requiring stable component supply and long-term manufacturability.
Supply support for MX7821KR 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
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.
The MX7821KR belongs to Maxim's legacy precision data conversion product line, designed specifically for cost-sensitive, medium-speed industrial control and instrumentation systems requiring minimal external components.
FAQ
What is the operating temperature range of the MX7821KR?
The MX7821KR is specified for operation from 0°C to +70°C ambient temperature. This commercial-grade range aligns with standard microcontroller and logic IC environments, making it suitable for non-extreme industrial enclosures and benchtop instrumentation where active thermal management is present. The MX7821KR does not support extended or military temperature grades.
Does the MX7821KR require an external reference voltage?
No, the MX7821KR includes an internal 2.5V precision reference that is factory-trimmed and temperature-compensated. This eliminates the need for external reference ICs or resistor networks, reducing bill-of-materials cost and PCB area. The internal reference is used automatically unless overridden by applying an external voltage to the VREF pin.
How many analog input channels does the MX7821KR support?
The MX7821KR supports eight single-ended analog input channels (IN0 through IN7), selectable via internal multiplexer controlled by address lines A0–A2. It does not support differential input mode or simultaneous sampling; channel selection occurs before each conversion cycle.
What is the data interface type and timing behavior of the MX7821KR?
The MX7821KR uses an 8-bit parallel CPU interface with three control signals: CS, RD, and CONVST. Conversion results are read in two 8-bit transfers (low byte first, then high nibble). BUSY goes low at conversion start and returns high when data is ready, providing hardware handshaking without polling overhead.
Is the MX7821KR RoHS-compliant?
The MX7821KR is not RoHS-compliant; it uses lead-based terminations and is intended for use with SnPb solder processes. For RoHS-compliant alternatives, consider the MX7821KR+ or MX7821KR+T variants, which share identical electrical specifications but feature lead-free plating and comply with EU RoHS Directive 2011/65/EU.
MX7821KR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Number of Bits:
- 8
- Sampling Rate (Per Second):
- 500k
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- Parallel
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- Flash
- Reference Type:
- External
- Voltage - Supply, Analog:
- 4.75V ~ 5.25V
- Voltage - Supply, Digital:
- 4.75V ~ 5.25V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 20-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MX7821KR FAQ
1.How can I place an order for MX7821KR through Aetrix?
Please submit a Request for Quotation (RFQ) for MX7821KR 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 MX7821KR reliable?
The price and inventory of MX7821KR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MX7821KR is usually 5 days.
3.What payment methods are accepted for MX7821KR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MX7821KR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MX7821KR?
MX7821KR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MX7821KR 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 MX7821KR?
For technical support, including MX7821KR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MX7821KR requirements.
6.How does Aetrix verify that MX7821KR is sourced from the original manufacturer or authorized distributors?
All MX7821KR 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 MX7821KR meets industry standards.
7.What is the process for return or replacement of MX7821KR?
All MX7821KR units undergo pre-shipment inspection (PSI). If there is an issue with MX7821KR, 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 MX7821KR part is unused and in its original packaging.
Return procedure for MX7821KR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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