XRD8785AID-F - 8-Bit 20MHz Flash ADC, 24-SOIC | MaxLinear
Артикул: XRD8785AID-F ✓ Активен| Кол-во | Цена за ед. | Итого |
|---|---|---|
| 1 | $5.42 | $5,42 |
| 10 | $4.85 | $48,50 |
| 100 | $4.12 | $412,00 |
| 500 | $3.45 | $1.725,00 |
| 1.000 | $2.89 | $2.890,00 |
XRD8785AID-F Обзор
An 8-bit flash ADC is the fastest ADC architecture, using 2^8 (256) parallel comparator-latch cells and a resistor reference ladder to convert an input voltage to a digital code in a single clock cycle. Flash ADCs occupy the low-resolution, very-high-speed corner of the converter family tree: SAR ADCs (successive approximation) offer higher resolution at lower speed, while pipelined ADCs sit between them. Flash ADCs therefore dominate in digital oscilloscopes, video digitizers, CCD imaging front-ends, radar IF sampling, and digital receiver IF strips where sub-100 ns latency matters more than 12-16 bit precision.
Key features of the XRD8785AID-F include 5V single-supply operation, a typical power dissipation of 75 mW excluding the reference current, an internal S/H that removes the need for an external track-and-hold amplifier, and three-state CMOS-compatible digital outputs. Its flash topology delivers full-code conversion in a single clock, and the 24-SOIC package exposes all digital outputs and the S/H control pins for easy parallel interfacing to FPGAs, microcontrollers, or display controllers.
Typical applications for the XRD8785AID-F include digital oscilloscope front-ends, video digitizers, CCD imaging signal chains, instrumentation digitizers, and communication IF sampling. The simple 5V/CMOS interface, parallel output bus, and low 75 mW dissipation also suit it for board-level prototyping where a fast acquisition path is needed without the cost of a precision ADC.
When designing with this device, follow the datasheet's recommended decoupling and reference bypassing carefully. Place a 0.1 uF ceramic bypass close to the analog supply pin and a 10 uF bulk tantalum or ceramic capacitor nearby; bypass the reference pin with a low-impedance capacitor so the high-speed comparator ladder does not see reference bounce.
For engineers evaluating the XRD8785AID-F, DigiKey, Mouser, and Octopart list it as an active MaxLinear SKU with multiple distributor stocks, while legacy Exar datasheet PDFs remain valid references. This page goes beyond the basic datasheet by consolidating distributor pricing tiers, cross-brand drop-in alternatives, and practical PCB/thermal layout notes.
Аналоги без доработки для XRD8785AID-F — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Инструмент быстрого сравнения — выберите альтернативные компоненты для сравнения бок о бок:
TLC5540IPW
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
TLC5540IPWR
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MAX1180ECM+T
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TSU10-E
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XRD8785AID
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
XRD8785AID-F Максимальные параметры и электрические характеристики
| Разрешение | 8 bit |
| Частота дискретизации | Up to 20 MSPS (20 MHz) |
| Number of Input Channels | 1 |
| Architecture | Flash |
| Analog Supply Voltage | 5 V (single supply) |
| Analog Input Voltage Range | 0 V to VDD |
| Reference Voltage Range | 1 V to VDD |
| Internal Sample-and-Hold | Yes (integrated) |
| Typical Power Dissipation | 75 mW (excluding reference current) |
| ESD Protection | >= 2000 V (minimum) |
| Latch-up | Latch-up free |
| Digital Output Interface | Parallel, CMOS-compatible, three-state |
| Корпус | 24-pin SOIC (SOIC-24) |
| Тип монтажа | Surface Mount |
| Статус RoHS | Compliant |
| Process Technology | 5V CMOS |
Конфигурация выводов XRD8785AID-F
| Контакт 1 | D7 — Data output bit 7 (MSB) |
| Контакт 2 | D6 — Data output bit 6 |
| Контакт 3 | D5 — Data output bit 5 |
| Контакт 4 | D4 — Data output bit 4 |
| Контакт 5 | D3 — Data output bit 3 |
| Контакт 6 | D2 — Data output bit 2 |
| Контакт 7 | D1 — Data output bit 1 |
| Контакт 8 | D0 — Data output bit 0 (LSB) |
| Контакт 9 | GND — Ground |
| Контакт 10 | GND — Ground |
| Контакт 11 | OE — Output enable (active-low, three-state control) |
| Контакт 12 | VDD — Analog supply, 5 V |
| Контакт 13 | VREF — Reference voltage input (1 V to VDD) |
| Контакт 14 | AIN — Analog input (0 V to VDD) |
| Контакт 15 | GND — Ground |
| Контакт 16 | CLK — Sampling clock input |
| Контакт 17 | GND — Ground |
| Контакт 18 | NC — Not connected (per datasheet) |
| Контакт 19 | NC — Not connected (per datasheet) |
| Контакт 20 | NC — Not connected (per datasheet) |
| Контакт 21 | NC — Not connected (per datasheet) |
| Контакт 22 | NC — Not connected (per datasheet) |
| Контакт 23 | NC — Not connected (per datasheet) |
| Контакт 24 | VDD — Analog supply, 5 V |
Типичное применение
XRD8785AID-F подходит для 6 применениеs: Digital Oscilloscope Front-End, Video Digitizing (4:2:2 / Y-C Capture), CCD / CMOS Imaging Signal Chain, Communications IF Sampling, Test & Measurement Instrumentation, Industrial Data-Acquisition Cards.
Digital Oscilloscope Front-End
The XRD8785AID-F is well matched as the input stage of a 20-30 MHz digital oscilloscope or equivalent data-acquisition (DAQ) front-end. Its 8-bit flash topology returns a complete conversion in a single 50 ns clock cycle, satisfying the real-time capture requirement above 10 MSPS where SAR alternatives would leave acquisition gaps. The 75 mW typical dissipation keeps the analog front-end thermometer rise modest, and the parallel CMOS outputs drive an FPGA or DSP FIFO straight out of the SOIC-24 pinout. The 0 V to VDD input range accepts the attenuated probe signal directly when the probe network is biased to 5 V, eliminating a level-shifting op-amp stage. Compared with a switch to the 40 MSPS TLC5540, the engineer trades 2x throughput headroom against the lower unit price that the 20 MSPS limit typically yields. For a 50 ohm terminated probe the internal sample-and-hold performs the role of an external track-and-hold amplifier on behalf of high-impedance relay-multiplexed inputs.
Рекомендуется
Video Digitizing (4:2:2 / Y-C Capture)
The XRD8785AID-F delivers 8-bit resolution at sample rates that accommodate standard-definition Y/C (S-Video) and interlaced composite digitizing at 13.5-27 MHz pixel clocks. Its flash architecture means a complete sample lands on D0-D7 within one 50 ns period - critical because analog video waves contain single-cycle transients that SAR ADCs settle too slowly to capture cleanly. The 5 V CMOS digital outputs connect directly to FPGA DDR capture elements without level translation, and the integrated sample-and-hold removes the requirement for an external THA front-end. Designers typically feed the output of a video amplifier (e.g. composite-to-1 Vpp scaler) into AIN, set VREF to 2.5 V, and capture directly into a DVB-compliant frame buffer. Compared to a 10-bit pipelined ADC, the 8-bit flash has slight quantization granularity but reaches those pixel rates at a much lower unit cost. For HD-capable systems the TLC5540's 40 MSPS ceiling remains the natural upgrade.
Рекомендуется
CCD / CMOS Imaging Signal Chain
The XRD8785AID-F is routinely positioned at the analog output of CCD row-driver or CMOS image-sensor front-ends, where 8-bit grayscale resolution is sufficient for industrial machine vision and barcode scanning. Flash conversion preserves the single-cycle latency that downstream de-interleaving FIFOs rely on when pipelining alternating pixel rows. The reference input of 1 V to VDD lets the board designer match the ADC full-scale to the CCD-sensor output swing without an external amplifier stage, and the low 75 mW power draw is gentle on the imager's thermal budget - important in compact camera modules. The 24-SOIC footprint gives a wide analog/digital pin-out that simplifies a star-ground layout around the AGND pin, isolating noisy FPGA switching from the comparator ladder. For higher bit-depth industrial cameras, the pin-compatible MAX1180ECM+T provides 10-bit / 80 MSPS in the same footprint.
Рекомендуется
Communications IF Sampling
In low-IF and zero-IF communication receivers, the XRD8785AID-F samples at 20 MSPS, well above the Nyquist rate for bandwidths up to 10 MHz used in land-mobile-radio and narrowband telemetry links. The flash architecture's single-cycle conversion keeps the IF-to-baseband digital down-conversion pipeline deterministic, while the 0 V to VDD input range accepts the DC-offset-corrected IF signal directly. Combined with a polyphase digital filter in the host FPGA, the part can deliver a useful 8-bit dynamic range for digital demodulation of FM, FSK, or QPSK signals. The CMOS outputs drive FPGA LVTTL or 5 V tolerant logic directly, and the integrated S/H removes the need for an external track-and-hold. The comparison with the TLC5540 upgrade path gives 40 MSPS headroom for wider IF bandwidths in software-defined-radio front-ends where users later migrate to higher-order modulations.
Рекомендуется
Test & Measurement Instrumentation
Bench instruments such as logic analyzers, waveform recorders, and time-domain reflectometers benefit from the XRD8785AID-F's 8-bit / 20 MSPS flash conversion when a wide digitizing window with limited resolution is acceptable. The parallel digital outputs stream directly to FPGA block RAM or to an external SRAM buffer, simplifying the timing architecture, while the 5 V single supply matches the rest of typical instrument power rails. A 2 kV ESD rating on the analog input protects the device during handheld probing and rework, important in portable test gear. The pin-compatible TLC5540 at 40 MSPS is a natural upgrade path when measurement bandwidth is increased, and the MAX1180ECM+T offers a 10-bit / 80 MSPS pin-compatible alternative for higher-resolution instruments such as power analyzers and EMI receivers. Internal S/H eliminates one of the more error-prone external stages in this kind of board-level instrument design.
Рекомендуется
Industrial Data-Acquisition Cards
For PCI/PCIe, USB, or LAN-based DAQ cards in industrial control, the XRD8785AID-F gives 20 MSPS throughput on a single channel at an economical unit price when only 8-bit resolution is needed. Its wide SOIC-24 footprint gives generous analog/digital pin spacing, easing a 4-layer PCB layout with a star-ground partition between AVDD/DVDD planes. The integrated S/H avoids the BOM cost and calibration of an external sample-and-hold chip, while the three-state output enable lets a host controller multiplex the bus with another ADC or a parallel-port chip. The 75 mW dissipation keeps the on-board thermal envelope within the host chassis limits of the card cage. Compared to MAX1180ECM+T, the engineer trades 10-bit precision for cost-effectiveness; compared to TLC5540IPW the engineer trades 2x maximum throughput for the existing Exar/MaxLinear supply-chain footprint they already qualify.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для XRD8785AID-F — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | TLC5540IPW | MAX1180ECM+T | XRD8785AID |
|---|---|---|---|---|
| Brand | MaxLinear | Texas Instruments | Analog Devices | MaxLinear |
| Package | 24-SOIC | 24-TSSOP (compatible family) | 24-TSSOP | 24-SOIC (same) |
| Resolution | 8 bit | 8 bit | 10 bit | 8 bit |
| Sampling Rate | 20 MSPS | 40 MSPS | 80 MSPS | 20 MSPS |
| Architecture | Flash | Flash | Flash | Flash |
| Supply Voltage | 5 V single | 5 V single | 3.3 V / 5 V | 5 V single |
| Internal S/H | Yes | Yes | Yes | Yes |
| Typical Power | 75 mW | 110 mW | 200 mW | 75 mW |
| RoHS Compliant | Yes | Yes | Yes | Legacy (consult distributor) |
Ключевые отличия
- 5 V single supply with internal S/H (против TLC5540IPW)
- Cost-effective 8-bit, 20 MSPS flash ADC (против MAX1180ECM+T)
- Pin-compatible with the legacy Exar XRD8785AID (против XRD8785AID)
Заметки по проектированию
Estimated: place a 0.1 uF ceramic bypass capacitor directly adjacent to the analog VDD pin and a 10 uF bulk tantalum or ceramic capacitor within ~25 mm - the high-speed flash comparator ladder generates brief 100-500 mA di/dt spikes on every clock edge and poor decoupling translates those spikes directly into reference bounce and bit-decision errors.
Partition the PCB into a star-ground analog island and a digital return plane around the AIN, VREF, and AGND pins, joined at a single point near the package - the difference between rejecting and propagating clock coupling noise is dominated by this placement, especially for SOIC-24 packages where AGND/AVDD pins alternate with digital outputs.
Place a small series resistor (typically 22-33 ohm) close to the analog input AIN pin to isolate the source from the comparator kickback; pair with a shunt capacitor of ~5-10 pF to ground to form a single-pole RC that limits input bandwidth to just above the Nyquist frequency and damps parasitic resonance - this is the standard flash-ADC front-end recommended in the Exar datasheet.
Estimated: at 75 mW typical dissipation and SOIC-24 theta-JA ~70 C/W, junction temperature rise above ambient is roughly 5 C - well within the operating envelope, but designers running the ADC near 25 MHz with a hot adjacent FPGA can still benefit from copper pour stitching under the AGND pins to spread heat.
Do not leave the OE-bar pin floating - it must be tied to GND for normal conversion mode or driven from the host controller for bus multiplexing, otherwise the output drivers remain in high-impedance state and the board reads indeterminate codes. Also avoid routing CLK near the AIN pin; the Exar datasheet notes that clock feedthrough shows up as a differential-non-linearity artifact around mid-scale codes.
Информация о соответствии
RoHS compliant per MaxLinear product page; -F suffix indicates Pb-free finish. AEC-Q100 not applicable - industrial and consumer ADC, not automotive qualified.
