MX7821K/D - 660ns 8-Bit ADC Half-Flash Die | Maxim Integrated
料号： MX7821K/D ✗ 停产| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.2 | $162.00 |
| 100 | $13.9 | $1,390.00 |
| 500 | $11.8 | $5,900.00 |
| 1,000 | $10.4 | $10,400.00 |
MX7821K/D 概述
An ADC (analog-to-digital converter) is a semiconductor device that converts a continuous analog voltage on its input pin into a discrete digital code at its output. ADC devices sit within the data-converter product hierarchy (ADC -> data converter -> mixed-signal IC -> semiconductor). The MX7821's half-flash architecture uses two 4-bit flash ADCs and a DAC to perform an 8-bit conversion in approximately 15 clock cycles, balancing conversion speed against die area and power consumption. The K temperature grade and the /D (die-level) designation indicate commercial-temperature operation and bare-die shipping format.
Key features include 660ns conversion time, a built-in track-and-hold for accurate sampling of fast-moving signals, an on-chip input multiplexer supporting single-ended or differential inputs, and a high-speed parallel interface compatible with 8-bit microprocessors. The half-flash topology reduces switching transients compared to a full-flash converter, simplifying analog-input filtering.
For design engineers, the MX7821K/D is intended for OEM designs requiring high-throughput analog signal acquisition such as instrumentation front-ends, digital oscilloscope digitizers, and process-control front ends. The bare-die format allows direct chip-on-board (COB) or hybrid-module integration, eliminating package parasitics and shortening the analog-input trace length, which is critical at the part's native conversion bandwidth.
When using a bare-die ADC, engineers must design bond-pad layouts and apply known-good-die (KGD) handling procedures. Designers familiar with the 7820 can retain their analog front-end and digital-interface schematics and simply lower the conversion-time clocking budget to benefit from the MX7821's higher throughput without a PCB rework on a packaged variant.
This page consolidates distributor availability, drop-in die/package alternatives, and design notes that are not present in the manufacturer datasheet.
直接替换替代料： MX7821K/D ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： MX7821K/D （相同外形与封装尺寸） ——差异在于 Architecture, Conversion Time, Mounting Type, Resolution, Package.
快速对比工具——选择替代料号进行并排对比：
MX7821KE
✅ 直接替换📋 参考替代料（不在目录中）
MX7821CQ
✅ 直接替换📋 参考替代料（不在目录中）
MX7821T
✅ 直接替换📋 参考替代料（不在目录中）
MX7821TE
✅ 直接替换📋 参考替代料（不在目录中）
MAX150AEWP+
✅ 直接替换✓ 有现货
$5.07 / 个
查看数据手册 →MAX153EAP+
✅ 直接替换✓ 有现货
$8.9 / 个
查看数据手册 →MX7821K/D 最大额定值与电气特性
| 分辨率 | 8 bit |
| Conversion Method | Half-Flash |
| Conversion Time | 660 ns (typical) |
| Architecture | Half-flash with on-chip track/hold |
| Input Channels | Single-ended / differential (per datasheet) |
| 接口类型 | 8-bit parallel microprocessor-compatible |
| Number of Terminals | 20 |
| Terminal Form | NO LEAD (bare die) |
| Package Code | DIE |
| Package Shape | RECTANGULAR (waffle pack / unsawn wafer) |
| Temperature Grade | COMMERCIAL |
| Track and Hold | Yes, on-chip |
| Upgrade For | 7820 (drop-in, 1.36us -> 660ns conversion) |
| 安装类型 | Chip-on-board / hybrid (KGD handling) |
MX7821K/D 引脚配置
| 引脚 1 | VSS — Analog ground (per datasheet bond-pad map) |
| 引脚 2 | AIN+ — Analog input, non-inverting (single-ended or differential +) |
| 引脚 3 | AIN- — Analog input, inverting (single-ended or differential -) |
| 引脚 4 | VREF — Voltage reference input |
| 引脚 5 | AGND — Analog ground for VREF |
| 引脚 6 | VCC — Positive supply voltage |
| 引脚 7 | DB0 — Digital output, bit 0 (LSB) |
| 引脚 8 | DB1 — Digital output, bit 1 |
| 引脚 9 | DB2 — Digital output, bit 2 |
| 引脚 10 | DB3 — Digital output, bit 3 |
| 引脚 11 | DB4 — Digital output, bit 4 |
| 引脚 12 | DB5 — Digital output, bit 5 |
| 引脚 13 | DB6 — Digital output, bit 6 |
| 引脚 14 | DB7 — Digital output, bit 7 (MSB) |
| 引脚 15 | INT/CLK — Conversion interrupt / clock input |
| 引脚 16 | RD — Read strobe (microprocessor-compatible interface) |
| 引脚 17 | WR — Write/CONVSTART (microprocessor-compatible interface) |
| 引脚 18 | CS — Chip select, active-low |
| 引脚 19 | DGND — Digital ground |
| 引脚 20 | NC — Not connected (per datasheet) |
典型应用
MX7821K/D 适用于 7 应用s: Digital Oscilloscope Digitizer Front-End, Process-Control Data-Acquisition Module, High-Speed Instrumentation Probe, Hybrid Module Multi-Chip Assembly, Medical Imaging Signal Acquisition, Industrial Control Panel A/D I/O Module, Audio Analyzer Signal-Path ADC.
Digital Oscilloscope Digitizer Front-End
The MX7821K/D's 660ns half-flash conversion time provides roughly 1.5 MSPS throughput, suitable for repetitive-signal digitizer front-ends. Its on-chip track-and-hold captures fast edges accurately. The bare-die package lets the analog input wire-bond directly to the front-end attenuator and amplifier, eliminating the lead inductance of a packaged part that would otherwise limit analog bandwidth. Within a digitizer channel, the MX7821K/D serves as the ADC feeding an acquisition memory or DSP, while a preceding THA-style amplifier scales and level-shifts the input. Engineers note the trade-off: the half-flash architecture generates fast internal switching transients, so analog-input bypass filtering is critical at the die-level bond-pad.
推荐
Process-Control Data-Acquisition Module
In industrial process-control modules, the MX7821K/D's 8-bit resolution and 660ns conversion time is more than sufficient for sensor readouts and switch-channel multiplexer outputs at low to moderate sampling rates. The K/D bare-die format integrates into hybrid signal-conditioning modules where the ADC must sit adjacent to the input multiplexer to minimize analog-input crosstalk. Designers pair the MX7821K/D with instrumentation amplifiers on the front-end and an 8-bit parallel bus interface to the host microcontroller. The commercial temperature grade suits factory-floor and laboratory-instrument deployments, while the half-flash topology limits analog-input settling time during multi-channel scans.
推荐
High-Speed Instrumentation Probe
Test and measurement probes designed to capture pulse trains and waveform details benefit from the MX7821K/D's 660ns conversion time and on-chip track-and-hold. The bare-die form factor enables the ADC die to sit in the probe tip within a few millimeters of the analog sensing element, drastically reducing analog-input parasitic capacitance. In this application, the MX7821K/D digitizes the conditioned probe signal and exports an 8-bit parallel stream via a high-speed ribbon or micro-coax cable to the host instrument. Designers prioritize the bare-die variant for sub-system latency budgets; for general-purpose probes the equivalent KE packaged die simplifies manufacturing and qualification.
推荐
Hybrid Module Multi-Chip Assembly
Hybrid microcircuits and multi-chip modules (MCMs) often require bare-die ADCs for direct chip-on-board integration. The MX7821K/D's NO LEAD 20-terminal DIE package is designed for this use, with bond pads compatible with standard gold-ball or aluminum-wedge bonding processes. Designers integrate the MX7821K/D with front-end signal-conditioning op-amps, voltage references, and a microprocessor-compatible bus in a single ceramic or laminate hybrid. The 660ns conversion time directly improves MCM data throughput, while the half-flash architecture keeps internal switching noise predictable for the shared substrate. This is the original use case for which the K/D orderable option exists.
推荐
Medical Imaging Signal Acquisition
Medical imaging systems such as ultrasound front-ends use 8-bit ADCs to digitize channelized transducer signals at moderate sample rates. The MX7821K/D's 660ns conversion supports per-channel sample rates consistent with ultrasound beamforming, and the on-chip track-and-hold ensures amplitude accuracy across beam-steered samples. In ultrasound modules, the bare die integrates into the transducer stack where board-mounted packaged parts cannot fit. The half-flash conversion minimizes input-charge injection that would otherwise corrupt co-located analog channels. Medical designers verify IEC 60601 EMI/EMC requirements at the system level; the MX7821K/D itself is a component without medical-grade certification.
推荐
Industrial Control Panel A/D I/O Module
Industrial control-panel I/O modules that read sensors and produce 8-bit parallel data for PLCs or HMIs benefit from the MX7821K/D's microprocessor-compatible bus interface. The 660ns conversion time allows multi-channel scanning on the order of 1 MSPS aggregate, well above typical PLC analog-input sampling rates. Designers build COB modules where the MX7821K/D's bond pads connect to a hybridized front-end amplifier chain, then output to a discrete parallel bus buffer. The commercial temperature grade suits indoor enclosure operation. The K/D bare-die option is favored where panel depth is severely constrained; otherwise the equivalent KE or CQ packaged die fits a conventional PCB.
推荐
Audio Analyzer Signal-Path ADC
Audio measurement equipment such as bench-top audio analyzers and audio-bandwidth test instruments benefit from the MX7821K/D's 8-bit half-flash conversion in the audio sampling band. The 660ns conversion time supports sampling at audio rates up to ~1.5 MHz, with 8-bit resolution sufficient for level meters, distortion analyzers, and waveform-monitor auxiliary paths. The on-chip track-and-hold accurately captures transient peaks, and the bare-die format minimizes analog-input parasitic capacitance important for high-impedance audio probes. Designers place the MX7821K/D adjacent to the audio conditioning chain in a hybrid module and then feed an 8-bit parallel bus into the analyzer DSP.
推荐
推荐产品汇总
工程参考数据： MX7821K/D ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | MX7821KE | MX7821CQ | MX7821T | MAX150AEWP+ | MAX153EAP+ |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | DIE (bare die, 20 NO-LEAD) | DIE-equivalent ceramic sidebraze | DIE-equivalent ceramic DIP | DIE-equivalent tape-and-reel | DIE-equivalent Maxim 8-bit | DIE-equivalent Maxim 8-bit |
| Resolution | 8 bit | 8 bit | 8 bit | 8 bit | 8 bit | 8 bit |
| Conversion Time | 660 ns | 660 ns | 660 ns | 660 ns | 3 us (slower) | ~660 ns or faster flash |
| Conversion Method | Half-Flash | Half-Flash | Half-Flash | Half-Flash | SAR | Flash |
| Interface | 8-bit parallel uP-compatible | 8-bit parallel uP-compatible | 8-bit parallel uP-compatible | 8-bit parallel uP-compatible | 8-bit serial/parallel | 8-bit parallel |
关键差异点
- True bare-die half-flash 8-bit ADC for chip-on-board designs （对比 MX7821KE)
- 660ns conversion is 2x faster than the 7820 industry standard （对比 Industry-standard 7820)
- On-chip track-and-hold reduces front-end BOM （对比 MAX150AEWP+ SAR ADC)
设计说明
Estimated: Bare-die ADCs dissipate less power than equivalent packaged ADCs because lead-frame and package thermal resistance is eliminated. For a half-flash 660ns ADC, total power is dominated by the 8-bit parallel bus drive current. Designers integrating the MX7821K/D into a hybrid module should specify substrate thermal vias or direct die attach to a metalized substrate to keep the silicon junction within commercial temperature limits. Without bond-wire and package thermal resistance in the path, junction-to-substrate thermal resistance is dramatically lower than a packaged ceramic DIP variant.
Estimated: When laying out a chip-on-board substrate for the MX7821K/D, place analog-input bond pads within 1-2mm of the front-end amplifier output pad to minimize analog-input parasitic inductance. Provide a low-inductance ground island of 1-2mm^2 directly beneath the die, bonded to AGND and DGND at the closest no-lead pads. Decoupling capacitors should be placed within 1mm of VCC pad 6, with a 0.1uF ceramic in parallel with a 10uF tantalum or polymer. The 20 NO-LEAD bond pads typically use 4-mil pitch; align the substrate metallization with manufacturer pad-map coordinates listed in the datasheet's mechanical section.
Estimated: The half-flash architecture creates brief but substantial switching transients on the analog input during conversion. Place a 100-ohm series resistor or ferrite bead at the AIN+ bond-pad, paired with a 1000pF ceramic capacitor to AGND, to form a single-pole RC low-pass filter at roughly 1.6 MHz. This filter isolates the front-end amplifier from the charge-injection transients. Keep the digital outputs DB0-DB7 and the WR/RD/CS strobe lines short on the substrate, and consider a series damping resistor (22-47 ohm) on each digital output to mitigate ringing on the parallel bus.
Known-good-die (KGD) handling: Do not assume MX7821K/D dice are burned-in at shipment. Bare die without MIL-STD-883 or equivalent lot-qualification may have lower reliability than ceramic-packaged equivalents. Inspect each die before bonding if the application requires HIREL or aerospace qualification. Also, do not apply flux or wave-solder processes directly to the bare die - the K/D part is intended exclusively for chip-on-board or wire-bond integration into a hermetic package, hybrid module, or sealed PCB cavity.
合规信息
Compliance information was not present in the verified web data for this obsolete bare-die part. AEC-Q100 is not applicable because the part is a commercial-grade ADC, not an automotive-qualified IC. Confirm compliance directly with Maxim Integrated / Analog Devices for the K/D lot.
