AD7820KPZ-REEL - 8-Bit 1.36µs Half-Flash ADC | Analog Devices
料号： AD7820KPZ-REEL ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $8.95 | $8.95 |
| 10 | $8.05 | $80.50 |
| 100 | $7.1 | $710.00 |
| 500 | $6.25 | $3,125.00 |
| 1,000 | $5.45 | $5,450.00 |
AD7820KPZ-REEL 概述
An ADC (Analog-to-Digital Converter) is a data-acquisition integrated circuit that converts a continuous analog voltage into a discrete digital code word. The half-flash (or sub-ranging flash) architecture employed here uses 31 comparators combined with a most-significant 4-bit ADC and a least-significant 4-bit ADC, balancing speed and silicon area: it is faster than successive-approximation converters at the time but uses fewer comparators than a full-flash design. ADCs sit within the data-converter hierarchy of mixed-signal ICs, downstream of sensor signal-conditioning stages and upstream of microprocessors, DSPs, or FPGAs.
Key features of the AD7820 include a parallel digital output interface, single +5 V operation, internal track-and-hold, half-flash conversion at 1.36 µs, and a maximum power dissipation of 450 mW. The device is fabricated on Analog Devices' advanced Linear-Compatible CMOS (LC2MOS) process, which combines bipolar analog precision with CMOS digital density on the same die. The 8-bit resolution delivers 256 discrete output codes with a quantization step of approximately 19.5 mV across the 0-5 V input range, sufficient for general-purpose instrumentation and digital control loops.
Typical applications include industrial process control, portable data loggers, battery-powered instrumentation, display driving, and high-speed sampling in microprocessor-based data-acquisition systems. The 20-pin PLCC (Plastic Leaded Chip Carrier) provides robust mechanical and thermal characteristics for surface-mount assembly. When designing with the AD7820, ensure the analog input source can drive the ADC's switched-capacitor input stage; adding a low-impedance buffer amplifier (such as an AD8031 or AD845) in front of the analog input is recommended when sampling high-impedance sources or when full-scale step settling is required. This page synthesizes distributor pricing, drop-in alternative guidance, and practical design notes that are not found directly in the manufacturer datasheet.
直接替换替代料： AD7820KPZ-REEL ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
AD7820KPZ
✅ 直接替换📋 参考替代料（不在目录中）
AD7820LRZ
✅ 直接替换📋 参考替代料（不在目录中）
AD7820CNZ
✅ 直接替换📋 参考替代料（不在目录中）
AD7820CQ
✅ 直接替换📋 参考替代料（不在目录中）
AD7820KPZ-REEL 最大额定值与电气特性
| Manufacturer | Analog Devices, Inc. |
| Part Number | AD7820KPZ-REEL |
| 分辨率 | 8 bit |
| Number of Channels | 1 |
| Conversion Architecture | Half-Flash (Sub-Ranging Flash) |
| Conversion Time | 1.36 µs (max) |
| Analog Input Range | 0 V to +5 V |
| 电源电压 | +5 V (4.75 V to 5.25 V) |
| 电源电流 | 15 mA (max) |
| Power Dissipation | 75 mW (typical), 450 mW (max) |
| Digital Interface | Parallel |
| Input Type | Single-Ended, Track-and-Hold |
| Input Slew Rate Tolerance | 100 mV/µs (no external S/H needed below this rate) |
| 封装 | 20-PLCC (9x9 mm), Surface Mount |
| 工作温度范围 | -40 °C to +85 °C |
| Process Technology | LC2MOS (Linear-Compatible CMOS) |
AD7820KPZ-REEL 引脚配置
| 引脚 1 | VDD — +5 V analog supply |
| 引脚 2 | MODE — Conversion mode select (RD/CS) |
| 引脚 3 | RD — Read input / conversion start |
| 引脚 4 | AIN — Analog input (0 V to +5 V) |
| 引脚 5 | GND — Ground (analog and digital common) |
| 引脚 6 | DB7 — Data output bit 7 (MSB) |
| 引脚 7 | DB6 — Data output bit 6 |
| 引脚 8 | DB5 — Data output bit 5 |
| 引脚 9 | DB4 — Data output bit 4 |
| 引脚 10 | DB3 — Data output bit 3 |
| 引脚 11 | DB2 — Data output bit 2 |
| 引脚 12 | DB1 — Data output bit 1 |
| 引脚 13 | DB0 — Data output bit 0 (LSB) |
| 引脚 14 | NC — Not connected (per datasheet) |
| 引脚 15 | NC — Not connected (per datasheet) |
| 引脚 16 | NC — Not connected (per datasheet) |
| 引脚 17 | NC — Not connected (per datasheet) |
| 引脚 18 | NC — Not connected (per datasheet) |
| 引脚 19 | CS — Chip select (active low) |
| 引脚 20 | EOC — End-of-conversion status output |
典型应用
AD7820KPZ-REEL 适用于 6 应用s: Industrial Process Control Data Acquisition, Portable Battery-Powered Instrumentation, Display Driver Waveform Generation, Microprocessor-Compatible Data Acquisition Systems, High-Speed Sampling in DSP Front-End Front-End Systems, Digital Control and Set-Point Generators.
Industrial Process Control Data Acquisition
The AD7820KPZ-REEL is well suited to industrial process control loops where 8-bit resolution is sufficient for valve-position feedback, transducer readout, or set-point monitoring. Its 1.36 µs conversion time and 500 ksps throughput enable real-time sampling of slowly varying control signals with full settling between conversions. The integrated track-and-hold removes the burden of an external sample-and-hold for process signals that rarely exceed that speed. The 20-PLCC package is mechanically rugged for control-panel mounting, while the -40 °C to +85 °C operating range covers most factory-floor environments. When designing in, add an op-amp buffer (such as the AD8031) in front of the analog input if the transducer output impedance exceeds 1 kΩ, and decouple VDD with 10 µF + 100 nF ceramic capacitors placed close to the supply pin.
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Portable Battery-Powered Instrumentation
The AD7820KPZ-REEL is appropriate for portable battery-powered instruments such as handheld multimeters, field data loggers, and portable medical monitors where single +5 V operation and low typical power consumption (75 mW) extend battery runtime. The 8-bit resolution provides adequate measurement granularity for battery-cell voltage monitoring, temperature sensing, and load-current logging. The internal track-and-hold simplifies the analog front-end and reduces external component count, which is critical for size- and weight-constrained handheld designs. For optimal battery life, run the part from a switching supply whose ripple is filtered by the AD7820's PSRR; if noise-sensitive readings are needed, add an LDO such as the ADP7102 in front of VDD. The 20-PLCC surface-mount package supports compact PCB layouts with reliable solder joints.
推荐
Display Driver Waveform Generation
The AD7820KPZ-REEL serves well as the conversion element in microcontroller-driven display-driving boards where waveform-shape digital codes are precomputed and applied to a DAC. Although the AD7820 is an ADC, its parallel interface and fast 1.36 µs conversion make it equally useful in mixed-signal test fixtures that combine ADC read-back with waveform generation. The 8-bit code space (256 levels) provides adequate gradient depth for simple LED brightness controllers, motor-speed feedback displays, and segment-driven LCD indicators. The single +5 V supply simplifies integration with digital logic, while the 20-PLCC footprint makes it compatible with hand-soldered prototypes and SMT production alike. For noiseless display results, separate the analog AVCC and digital VDD nets at the regulator and join them only at one star-ground point.
推荐
Microprocessor-Compatible Data Acquisition Systems
The AD7820KPZ-REEL was specifically designed for direct connection to 8-bit microprocessors, with a parallel bus and standard CS/RD handshake that maps cleanly onto the address-decoding logic of 8051, Z80, and similar microcontrollers. Its 1.36 µs conversion time matches the read-access timing of these CPUs without wait-state insertion. The 8-bit resolution suits applications such as keypad scanning, sensor multiplexing, and simple threshold detectors where the full 10- or 12-bit precision of modern ADCs is unnecessary. The 20-PLCC package provides enough board-area for hand-wired retrofits of legacy systems. When wiring to a microprocessor, isolate the ADC's data bus with a 74HC245 transceiver if multiple bus masters share the bus, and route CS through a clean address-decoder output to avoid bus contention.
推荐
High-Speed Sampling in DSP Front-End Front-End Systems
The AD7820KPZ-REEL is suitable for DSP front-end designs that require sub-2 µs sampling for audio-bandwidth signal analysis, vibration monitoring, or motor-control current sensing. Its 1.36 µs conversion time and parallel output allow the converted code to be transferred to a DSP or FPGA in a single read cycle, supporting 500 ksps throughput. The on-chip track-and-hold eliminates the need for an expensive external S/H amplifier, lowering the BOM cost. The half-flash architecture offers better noise performance than successive-approximation converters of similar speed, which is helpful when digitizing small AC signals in the presence of digital switching noise. For best dynamic performance, use a low-impedance input driver, place a ground plane under the ADC, and route digital outputs away from the analog input trace.
推荐
Digital Control and Set-Point Generators
The AD7820KPZ-REEL is a good fit for closed-loop digital control systems where the microcontroller reads back the actual output value (current, voltage, or position) via the ADC and adjusts PWM duty cycle accordingly. The 1.36 µs conversion time supports loop rates well above 100 kHz for fast current-mode control of switching converters. The single +5 V supply matches the digital rail of most microcontrollers, simplifying power-tree design. The 8-bit resolution provides 256 discrete adjustment steps, which is sufficient for fan-speed control, LED brightness regulation, and small-motor drive loops. For best loop stability, time the ADC read to coincide with the PWM counter zero crossing to avoid sampling switching transients.
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推荐产品汇总
工程参考数据： AD7820KPZ-REEL ——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 | AD7820KPZ | AD7820LRZ | AD7820CNZ |
|---|---|---|---|---|
| Package | 20-PLCC (9x9) - tape & reel | 20-PLCC (9x9) - tube (same) | 20-PLCC (9x9) - same | 20-PLCC (9x9) - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 8 bit | 8 bit | 8 bit | 8 bit |
| Conversion Time | 1.36 µs | 1.36 µs | 1.36 µs | 1.36 µs |
| Analog Input Range | 0 V to +5 V | 0 V to +5 V | 0 V to +5 V | 0 V to +5 V |
| Supply Voltage | +5 V (4.75 V to 5.25 V) | +5 V | +5 V | +5 V |
| Supply Current (max) | 15 mA | 15 mA | 15 mA | 15 mA |
| Operating Temperature Range | -40 °C to +85 °C (industrial) | -40 °C to +85 °C | -40 °C to +85 °C (extended) | 0 °C to +70 °C (commercial) |
| Packaging Quantity | Tape & Reel (REEL suffix) | Tube | Tape & Reel | Tube |
关键差异点
- Identical die and 20-PLCC footprint across multiple AD7820 grade variants （对比 AD7820KPZ (tube variant))
- Industrial-grade operating range (-40 °C to +85 °C) for factory-floor deployment （对比 AD7820CNZ (commercial 0 to +70 °C))
- On-chip track-and-hold for input signals below 100 mV/µs slew rate （对比 ADC0808 (external S/H required))
设计说明
Decouple the VDD pin with both a 10 µF tantalum (or low-ESR ceramic) bulk capacitor and a 100 nF ceramic decoupling capacitor placed within 5 mm of the VDD pin. Place the ground plane on the layer directly beneath the AD7820KPZ-REEL to minimize digital switching noise coupling into the analog input. Route the analog input trace (pin 4) away from digital output lines (pins 6-13) to prevent digital-to-analog crosstalk. If the ADC shares a board with a switching regulator or motor driver, separate the analog and digital grounds and join them only at a single star-ground point near the AD7820's GND pin.
Do not drive the analog input with a source impedance greater than a few kilohms without an external buffer amplifier - the AD7820's switched-capacitor input stage draws transient charge during acquisition that will cause gain errors with high-impedance sources. Add an op-amp buffer (such as the AD8031 or AD845) ahead of pin 4 when sampling signals above 1 kΩ source impedance. Also ensure the MODE/CS/RD handshake logic is correctly sequenced: in mode 1 (RD/CS), a falling RD edge begins conversion and the EOC flag signals completion; in mode 2 (CS/RD separate), CS selects the chip while RD starts conversion - mismatched timing causes bus contention or missed conversions.
Estimated: at VDD = +5 V and full 15 mA supply current, the AD7820KPZ-REEL dissipates 75 mW (5 V × 15 mA), with a maximum dissipation of 450 mW under worst-case conditions. The 20-PLCC package has a typical thermal resistance of approximately 60 °C/W, yielding a junction-temperature rise of only about 4.5 °C at 75 mW - thermal management is generally not a concern for this part. However, ensure the input voltage on AIN never exceeds VDD + 0.3 V or falls below GND - 0.3 V, as latch-up or permanent damage can result. If the analog source may exceed these rails, add external clamping diodes (such as BAV99) from AIN to VDD and GND.
合规信息
RoHS status and lead-free status for AD7820KPZ-REEL are not explicitly stated in the provided Verified Web Data and are listed as unknown. The part is not AEC-Q100 qualified (industrial/consumer grade). Conflict-minerals compliance per Analog Devices standard supplier policy.
