MX7821K/D - 660ns 8-Bit ADC Half-Flash Die | Maxim Integrated
MPN: MX7821K/D ✗ Cuối đờiMX7821K/D Tóm tắt
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.
Bộ thay thế dễ dàng lắp đặt cho MX7821K/D — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với MX7821K/D (cùng hình factor và footprint) — khác nhau ở Architecture, Conversion Time, Mounting Type, Resolution, Package.
MX7821KE
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MX7821CQ
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MX7821T
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MX7821TE
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX150AEWP+
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX153EAP+
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MX7821K/D Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 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) |
| Loại giao diện | 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) |
| Kiểu lắp đặt | Chip-on-board / hybrid (KGD handling) |
Cấu hình chân MX7821K/D
| Chân 1 | VSS — Analog ground (per datasheet bond-pad map) |
| Chân 2 | AIN+ — Analog input, non-inverting (single-ended or differential +) |
| Chân 3 | AIN- — Analog input, inverting (single-ended or differential -) |
| Chân 4 | VREF — Voltage reference input |
| Chân 5 | AGND — Analog ground for VREF |
| Chân 6 | VCC — Positive supply voltage |
| Chân 7 | DB0 — Digital output, bit 0 (LSB) |
| Chân 8 | DB1 — Digital output, bit 1 |
| Chân 9 | DB2 — Digital output, bit 2 |
| Chân 10 | DB3 — Digital output, bit 3 |
| Chân 11 | DB4 — Digital output, bit 4 |
| Chân 12 | DB5 — Digital output, bit 5 |
| Chân 13 | DB6 — Digital output, bit 6 |
| Chân 14 | DB7 — Digital output, bit 7 (MSB) |
| Chân 15 | INT/CLK — Conversion interrupt / clock input |
| Chân 16 | RD — Read strobe (microprocessor-compatible interface) |
| Chân 17 | WR — Write/CONVSTART (microprocessor-compatible interface) |
| Chân 18 | CS — Chip select, active-low |
| Chân 19 | DGND — Digital ground |
| Chân 20 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
MX7821K/D phù hợp cho 7 Áp dụngs: 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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MX7821K/D — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | 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 |
Bảo phân biệt quan trọng
- True bare-die half-flash 8-bit ADC for chip-on-board designs (vsMX7821KE)
- 660ns conversion is 2x faster than the 7820 industry standard (vsIndustry-standard 7820)
- On-chip track-and-hold reduces front-end BOM (vsMAX150AEWP+ SAR ADC)
Ghi chú thiết kế
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.
Thông tin tuân thủ
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.
