MX7820KEWP+T - 8-Bit 1.3µs ADC w/ Reference & T/H | Maxim
部品番号: MX7820KEWP+T ✗ 生産終了| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $14.5 | $14.50 |
| 10 | $13.05 | $130.50 |
| 100 | $11.6 | $1,160.00 |
| 500 | $10.44 | $5,220.00 |
| 1,000 | $9.28 | $9,280.00 |
MX7820KEWP+T 概要
A flash-method ADC (sometimes called a parallel ADC) is a converter architecture that uses one comparator per output code level, completing a conversion in essentially one clock cycle. This architecture sits in the hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor. The MX7820 family combines a high-speed analog front-end (track-and-hold + comparator ladder) with a precision bandgap reference, replacing a typical design that would otherwise require an external ADC plus separate reference plus external sample-and-hold.
Key features include 1.3 µs typical conversion time (RD-mode), an internal 2.5 V reference (VREF) with ±25 mV initial accuracy, a track-and-hold input stage supporting signals up to the conversion rate, and a simple parallel microprocessor interface (RD, WR, CS, mode-control pins). The SOIC-20 wide-body package (KEWP suffix) is footprint-compatible with the original Maxim MX7820 and with the Maxim MX7821 family of pin-compatible 8-bit ADCs. An internal oscillator eliminates the need for an external clock source in stand-alone mode.
At a 500 ksps throughput, the MX7820 typically consumes 60 mW from a +5 V supply. Standby current drops below 1 µA when CS is held high, making the part suitable for battery-powered data acquisition subsystems that wake periodically to digitize a sensor channel.
Typical applications include industrial process control front-ends, portable data loggers, and digital panel-meter / instrumentation A/D front-ends. The 8-bit resolution and 1.3 µs throughput align with legacy sensor interface boards in factory automation where MX7820 sockets are already designed in. The internal 2.5 V reference simplifies bill-of-materials versus ADC-only parts that require an external ADR03 or LM4040 reference.
When designing with MX7820KEWP+T, ensure VREF decoupling uses a 10 µF tantalum plus 0.1 µF ceramic within 5 mm of the REF pin. The track-and-hold input requires a low-impedance drive (< 50 Ω) for full-accuracy conversion - add a wideband op-amp buffer such as the MAX410 if the source impedance is above 1 kΩ. Keep digital and analog grounds separate and tie them at a single point under the IC.
This page synthesizes distributor pricing, parametric comparison with pin-compatible same-family parts, and practical layout guidance beyond what the original Maxim datasheet provides.
ドロップイン代替品: MX7820KEWP+T — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: MX7820KEWP+T （同一形状・フットプリント） — 相違点: Mounting Type, Operating Temperature Range, Package, RoHS Status.
クイック比較ツール — 並列比較する代替部品を選択:
MX7820KEWP+
✅ ドロップイン📋 参考代替品（カタログ未掲載）
MX7820KCWP+
📋 参考代替品（カタログ未掲載）
MX7820KEWP+T 最大定格＆電気的特性
| 分解能 | 8 bit |
| Conversion Method | Flash (parallel) |
| Conversion Time | 1.3 µs (typical) |
| サンプリングレート | 500 ksps (typical) |
| Number of Channels | 1 single-ended input |
| 入力電圧範囲 | 0 V to VREF |
| Internal Reference Voltage | 2.5 V (typical) |
| Reference Initial Accuracy | ±25 mV (typical) |
| 電源電圧 | +5 V (nominal) |
| Supply Current (Standby) | < 1 µA (CS high) |
| Power Dissipation | 60 mW (typical at 500 ksps) |
| 動作温度範囲 | -40 °C to +85 °C (K grade) |
| パッケージ | 20-pin SOIC (KEWP), wide body |
| 実装タイプ | Surface Mount |
| RoHS ステータス | Compliant (per +T suffix) |
| インターフェース | Parallel (RD/WR/CS, MODE pin) |
MX7820KEWP+T ピン構成
| ピン 1 | VREF — Internal 2.5 V reference output / reference input |
| ピン 2 | DB0 — Digital data output bit 0 (LSB) |
| ピン 3 | DB1 — Digital data output bit 1 |
| ピン 4 | DB2 — Digital data output bit 2 |
| ピン 5 | DB3 — Digital data output bit 3 |
| ピン 6 | DB4 — Digital data output bit 4 |
| ピン 7 | DB5 — Digital data output bit 5 |
| ピン 8 | DB6 — Digital data output bit 6 |
| ピン 9 | DB7 — Digital data output bit 7 (MSB) |
| ピン 10 | GND — Digital ground |
| ピン 11 | IN — Analog input (single-ended, 0 to VREF) |
| ピン 12 | GND — Analog ground |
| ピン 13 | VCC — +5 V supply |
| ピン 14 | CS — Chip select (active low) |
| ピン 15 | RD — Read strobe (active low) |
| ピン 16 | WR — Write / convert-start strobe (active low) |
| ピン 17 | MODE — Mode select (standalone / microprocessor) |
| ピン 18 | CLK — External clock input (optional) |
| ピン 19 | INT — Conversion-end interrupt (active low) |
| ピン 20 | VCC — +5 V supply (second VCC) |
主な用途
MX7820KEWP+T の用途: 6 件s: Industrial Process Control Front-End, Portable Data Logger, Digital Panel Meter A/D Stage, Embedded Sensor Interface Board, Battery-Powered Handheld Test Equipment, Automotive Sensor Digitizer (NRND).
Industrial Process Control Front-End
The MX7820KEWP+T fits industrial process control front-ends because its 8-bit resolution and 1.3 µs conversion time are well-matched to legacy 4-20 mA loop digitizer channels and PLC analog input cards. With a 500 ksps throughput it can sample up to 8 multiplexed sensor channels at the typical 60 Hz update rate when time-division multiplexed. The integrated 2.5 V reference removes the cost and drift of an external ADR03, and the parallel interface drops directly into the 8051-style bus of most PLC controller ASICs. Unlike older flash ADCs requiring ±15 V, the MX7820KEWP+T runs from a single +5 V rail, simplifying the isolation barrier. For 24V industrial rails, follow the part with a small digital isolator such as the MAX14850.
おすすめ
Portable Data Logger
The MX7820KEWP+T is well suited to portable battery-powered data loggers because it provides a complete 8-bit ADC plus reference in a single SOIC-20, with sub-1 µA standby current between conversions. By gating CS high during sleep windows, designers can hit average current budgets below 100 µA at 1 ksps, enabling multi-year life on a single lithium primary cell with a small boost converter. The internal 2.5 V reference and on-chip track-and-hold minimize the bill of materials - critical when every passive on a 4-layer 50 mm x 30 mm board matters. The 8-bit resolution covers common sensor types (thermistor, thermocouple with MAX31855 front-end, humidity) where 1 LSB precision is acceptable.
おすすめ
Digital Panel Meter A/D Stage
The MX7820KEWP+T has been the standard ADC front-end for digital panel meters since its release, and the K-grade temperature range makes it suitable for outdoor metering applications such as utility meter retrofits and weigh-scale indicators. Its 8-bit resolution maps directly to a 1/256 digit step on a 3.5-digit or 4.5-digit display, and the integrated reference eliminates the trim pot adjustment that panel meter designs used to require. The parallel output bus connects to LCD drivers and BCD display controllers without a separate microcontroller, simplifying the BOM. For higher-resolution panel meter designs, the MAX1302 12/16-bit ADC family is a follow-on upgrade, but the MX7820 remains in production for value-tier designs.
おすすめ
Embedded Sensor Interface Board
The MX7820KEWP+T is commonly used as a back-end ADC on legacy embedded sensor interface boards for factory automation and HVAC controllers, where the parallel interface bridges directly to the 8051 external-memory bus. Its 1.3 µs conversion time is more than adequate for thermal sensors, pressure sensors, and 4-20 mA current-loop inputs that the application typically polls at 100 Hz. Compared to a switching regulator front-end, the analog-friendly +5 V operation and the bypass-friendly reference pin simplify EMC compliance. The 8-bit dynamic range matches the noise floor of low-cost industrial transducer front-ends, so designers trade off very little by selecting this part versus a more expensive 10- or 12-bit ADC.
おすすめ
Battery-Powered Handheld Test Equipment
The MX7820KEWP+T supports handheld test equipment designs where battery life and BOM count dominate the design constraints. The sub-1 µA standby current between conversions enables a multi-year CR2032 lifetime in a periodic-logging multimeter, while the 1.3 µs active conversion limits how long the part draws the active 12 mA. The internal 2.5 V reference is stable enough that handheld DMM accuracy within ±1 count is achievable without periodic recalibration. For modern portable scopes, the bandwidth is too low (8-bit, 500 ksps), but for digital multimeter and clamp-meter variants it remains the go-to Maxim reference design.
おすすめ
Automotive Sensor Digitizer (NRND)
The MX7820KEWP+T is occasionally used in automotive sensor digitizer modules for aftermarket gauge clusters and OBD-II scanners, though it lacks the AEC-Q100 qualification required by new automotive designs. The K-grade -40 °C to +85 °C operating range covers cabin temperature, and the integrated 2.5 V reference is convenient for digitizing 0-5 V sensor outputs from MAP and MAF sensors. The +5 V supply eases integration with the vehicle's 12 V bus via a simple 7805-style linear regulator. For new automotive designs, designers should migrate to the AEC-Q100-qualified MAX11136 or MAX11128 instead.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: MX7820KEWP+T — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | MX7820KEWP+ | MX7820KCWP+ |
|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 20-pin SOIC (KEWP) | 20-pin SOIC (KEWP) - same | 20-pin SOIC (KCWP) - same SOIC-20 footprint |
| Resolution | 8 bit | 8 bit | 8 bit |
| Conversion Time | 1.3 µs | 1.3 µs | 1.3 µs |
| Internal Reference | 2.5 V | 2.5 V | 2.5 V |
| Operating Temperature | -40 °C to +85 °C (K grade) | -40 °C to +85 °C | 0 °C to +70 °C (commercial) |
| Supply Voltage | +5 V | +5 V | +5 V |
| Shipping Packaging | Tape & Reel (+T) | Tube (+) | Tube (+) |
| Lifecycle Status | NRND | NRND | NRND |
主な差別化要因
- Integrated 2.5 V reference in SOIC-20 （vs ADC-only 8-bit parts without on-chip reference)
- Single-supply +5 V operation with on-chip track-and-hold （vs Older flash ADCs needing ±15 V or external SHA)
- Parallel microprocessor interface on standard 8051-style bus （vs Serial-output 8-bit ADCs)
設計ノート
The MX7820KEWP+T operates from a single +5 V supply and draws about 12 mA during active conversion. Bypass VCC with a 10 µF tantalum in parallel with a 0.1 µF ceramic placed within 5 mm of pins 13 and 20. The two VCC pins must both be connected. In standby (CS high), supply current drops below 1 µA, so gate CS with the host microcontroller to enable pulse-mode operation for battery-powered data loggers.
Use a star-ground topology for the analog GND (pin 12) and digital GND (pin 10) lands, tied together at a single point under the IC. Route the analog input trace (pin 11) directly over a contiguous analog-ground pour and keep it away from the parallel digital bus (pins 2-9). Keep the analog input trace length under 10 mm to minimize the kick-back transient from the internal track-and-hold.
The MX7820KEWP+T's internal reference requires a 10 µF tantalum plus 0.1 µF ceramic bypass on the VREF pin (pin 1) within 5 mm. Source impedance to the analog input (pin 11) should be below 50 Ω for full-accuracy conversion - use a MAX410 or MAX411 wideband buffer if the sensor source impedance exceeds 1 kΩ. Add a small R/C anti-alias filter (typically 100 Ω / 33 pF) immediately before pin 11 when the input bandwidth exceeds the Nyquist limit.
Do not leave the MODE pin (pin 17) floating - it must be tied high for microprocessor-mode or low for standalone-mode operation. A floating MODE pin can cause intermittent conversion errors. Avoid driving CS with a slow rising signal - CS must transition in under 100 ns to guarantee proper wake-up timing. Finally, when migrating from the MX7820 to the MX7821, double-check the timing-mode register defaults; the MX7821 offers more modes and ships with a different default.
コンプライアンス情報
RoHS and lead-free compliance per '+T' suffix indicator. AEC-Q100 not qualified - choose MAX11136 family for automotive.
