MAX1085ACSA+T - 400ksps 10-Bit Serial ADC | Maxim Integrated
N.º de pieza: MAX1085ACSA+T ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $6.42 | $6,42 |
| 10 | $5.78 | $57,80 |
| 100 | $5.14 | $514,00 |
| 500 | $4.61 | $2.305,00 |
| 1.000 | $4.08 | $4.080,00 |
MAX1085ACSA+T Descripción general
A SAR ADC is a type of analog-to-digital converter that uses a successive-approximation register to perform a binary search across an internal resistive ladder (or charge-redistribution capacitor array), producing one bit per clock cycle. SAR ADCs are valued for their deterministic latency (one conversion = N clock cycles), excellent DC linearity, intrinsic anti-alias filtering (no SHA in the feedback path of a sigma-delta), and low power consumption compared to flash or pipelined architectures. The MAX1085ACSA+T sits in the data-acquisition IC -> ADC -> SAR ADC -> 10-bit single-channel ADC -> precision signal-chain IC taxonomy, often used as a successor to legacy 12-bit pin-compatible parts like the MAX1242/MAX1243 when higher throughput is needed.
Key features include a maximum sampling rate of 400ksps (MAX1085) versus 300ksps (MAX1084), an internal +2.5V reference (eliminating external reference components and saving PCB area), a single +2.7V to +5.5V analog supply, a low-power shutdown mode that drops supply current to under 1µA between conversions, an SPI/QSPI/MICROWIRE-compatible serial interface, and an 8-pin SOIC package rated for the 0°C to +70°C commercial temperature range (the +T suffix denotes tape-and-reel packaging).
The MAX1085 uses a charge-redistribution SAR architecture with an integrated input track/hold, providing 10-bit no-missing-code performance, low integral nonlinearity (INL), and low differential nonlinearity (DNL). The internal reference is factory-trimmed, eliminating external reference noise and drift. The serial interface shifts out conversion results MSB-first, simplifying connection to microcontrollers, DSPs, and FPGA signal-chain front ends.
Typical applications include portable data loggers, remote sensor digitizers (strain gauges, thermocouples with amplification), handheld instrumentation, pen-tablet digitizers, and battery-powered medical or industrial monitoring nodes. The low shutdown current makes it well suited to duty-cycled sampling on battery rails.
When designing with this device, observe the analog input range relative to VDD (the input cannot exceed VDD + 0.3V), place a 0.1µF bypass capacitor close to VDD, and follow the serial-interface timing diagram exactly. The MAX1085ACSA+T is a drop-in functional equivalent of the MAX1085BCSA+T (the B-grade offers tighter linearity specifications but shares the same 8-pin SO footprint) and the MAX1084ACSA+T (lower 300ksps throughput, same footprint).
Alternativas directas para MAX1085ACSA+T — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con MAX1085ACSA+T (mismo factor de forma y huella) — difiere en Input Type, Package, Architecture, Resolution, Number of Channels.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MAX1085BCSA+T
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX1085ACSA+
✅ Sustitución directa✓ En stock
$3.48 / unidad
Ver hoja de datos →MAX1084BCSA+T
✅ Sustitución directa✓ En stock
$4.9 / unidad
Ver hoja de datos →MAX1084ACSA+T
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX1242ACSA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX1085ACSA+T Valores máximos y características eléctricas
| Resolución | 10 bit |
| Architecture | SAR (Successive Approximation) |
| Number of Input Channels | 1 |
| Sampling Rate (max) | 400 ksps |
| Supply Voltage (Analog) | +2.7 V to +5.5 V (single supply) |
| Internal Reference | +2.5 V (factory-trimmed) |
| Digital Interface | SPI / QSPI / MICROWIRE-compatible serial |
| Input Type | Single-ended, with integrated track/hold |
| Corriente de apagado | < 1 µA (typical) |
| Rango de temperatura de funcionamiento | 0 °C to +70 °C (commercial, 'C' grade) |
| Encapsulado | 8-pin SOIC (SO-8, 'SA' suffix) |
| Tipo de montaje | Surface Mount |
| Packaging | Tape & Reel ('+T' suffix) |
| Estado RoHS | Compliant |
Configuración de pines de MAX1085ACSA+T
| Pin 1 | VDD — Analog +2.7 V to +5.5 V supply input; bypass with 0.1 µF to AGND |
| Pin 2 | AIN — Analog input channel (single-ended, 0 to VREF range) |
| Pin 3 | REF — Internal +2.5 V reference; bypass with 0.1 µF + 10 µF to AGND |
| Pin 4 | AGND — Analog ground return |
| Pin 5 | SCLK — Serial interface clock input |
| Pin 6 | DOUT — Serial data output (MSB first, falling-edge SCLK) |
| Pin 7 | SHDN — Active-low shutdown; tie HIGH for always-on, drive LOW for <1 µA Iq |
| Pin 8 | DGND — Digital ground return |
Aplicaciones típicas
MAX1085ACSA+T es adecuado para 6 aplicacións: Portable Battery-Powered Data Loggers, Remote Sensor Signal Acquisition, Handheld Test & Measurement Instruments, Industrial Process Control Modules, Medical Patient Monitoring Devices, Audio-Bandwidth Signal Digitizing.
Portable Battery-Powered Data Loggers
The MAX1085ACSA+T fits portable battery-powered data loggers because its +2.7 V to +5.5 V single-supply range accepts a single lithium cell or 2x AA alkaline cells directly, and its < 1 µA shutdown current lets the host microcontroller duty-cycle the converter between bursts. The 400 ksps max sampling rate is sufficient for environmental sensors (temperature, humidity, pressure) and low-frequency vibration channels where sampling rarely exceeds 10 kS/s per channel. Designers typically pair it with a low-power MCU such as the MAX32625 or a similar Cortex-M part and an external FET-input op-amp front end for sensor signal conditioning. The internal +2.5 V reference eliminates two external caps and a reference IC, saving critical PCB area in compact wearable form factors.
Recomendado
Remote Sensor Signal Acquisition
The MAX1085ACSA+T is widely deployed in remote sensor signal-acquisition modules that digitize strain gauges, load cells, thermocouples (with cold-junction compensation), and 4-20 mA loop transducers. Its integrated +2.5 V reference gives stable full-scale readings across industrial temperature swings, and the SPI/QSPI/MICROWIRE serial interface allows the host MCU to read conversions with minimal pin count - critical for sealed remote enclosures. The 8-pin SOIC footprint suits small IP-rated modules, and its SAR architecture provides deterministic single-conversion latency that simplifies calibration routines for ratiometric sensor measurements.
Recomendado
Handheld Test & Measurement Instruments
The MAX1085ACSA+T is ideal for handheld digital multimeters, clamp meters, and bench-top calibrators because the 400 ksps sampling rate supports AC measurement bandwidth to ~40 kHz (per Nyquist) for true-RMS conversion and harmonic analysis. Its 10-bit resolution is adequate for handheld display readout (typically 3-4 digit displays require only 10-12 bits) and its low power consumption extends battery life in field instruments. The internal reference eliminates reference warm-up drift and the resulting offset error in field measurements. Designers typically pair it with a 4-digit LCD driver and a low-power microcontroller for the user interface and measurement math.
Recomendado
Industrial Process Control Modules
The MAX1085ACSA+T serves in industrial process control modules for digitizing analog process variables (pressure, flow, level, temperature) from 4-20 mA current loops or 0-10 V voltage outputs. Its SAR architecture produces no pipeline delay, making closed-loop control loops deterministic and stable. The SPI interface allows multiple ADCs to share a single SPI bus with individual CS-bar chip selects, supporting multi-channel distributed I/O modules. Its commercial temperature grade (0 to +70 °C) suits sealed control cabinet environments; for harsher field mounting use the MAX1085AESA+T extended-grade variant.
Recomendado
Medical Patient Monitoring Devices
The MAX1085ACSA+T is well-suited to medical patient monitoring devices such as ambulatory Holter monitors, pulse oximeters, and bedside telemetry nodes that digitize low-frequency biopotential signals (ECG, respiration, SpO2 photodiode currents). Its low power consumption preserves battery runtime in wearable monitors, and its deterministic SAR latency simplifies the time-stamping of each sample for accurate heart-rate variability analysis. The internal reference and small 8-pin SOIC package simplify the medical-device bill of materials and reduce overall PCB footprint. Designers should follow IEC 60601-1 isolation and leakage guidelines by pairing the ADC with a medical-grade digital isolator.
Recomendado
Audio-Bandwidth Signal Digitizing
The MAX1085ACSA+T supports audio-bandwidth signal digitizing up to ~200 kHz input frequency (per Nyquist at 400 ksps) for sub-Nyquist audio sampling, voice-band codecs, and ultrasonic transducer front ends. While 10-bit resolution limits dynamic range compared to dedicated audio ADCs, the part is suitable for budget consumer audio products (intercoms, walkie-talkies, toy microphones) where cost dominates. Its SPI interface allows direct connection to audio DSPs and microcontrollers with hardware SPI peripherals, eliminating the need for an external I2S codec in simple designs.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MAX1085ACSA+T — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MAX1085BCSA+T | MAX1085ACSA+ | MAX1084BCSA+T | MAX1084ACSA+T | MAX1242ACSA+ |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 8-pin SOIC | 8-pin SOIC (same) | 8-pin SOIC (same) | 8-pin SOIC (same) | 8-pin SOIC (same) | 8-pin SOIC (same) |
| Resolution | 10 bit | 10 bit | 10 bit | 10 bit | 10 bit | 12 bit |
| Max Sampling Rate | 400 ksps | 400 ksps | 400 ksps | 300 ksps | 300 ksps | 73 ksps |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR |
| Input Channels | 1 | 1 | 1 | 1 | 1 | 1 |
| Internal Reference | +2.5 V (yes) | +2.5 V (yes) | +2.5 V (yes) | +2.5 V (yes) | +2.5 V (yes) | +2.5 V (yes) |
| Supply Voltage Range | +2.7 V to +5.5 V | +2.7 V to +5.5 V | +2.7 V to +5.5 V | +2.7 V to +5.5 V | +2.7 V to +5.5 V | +2.7 V to +5.5 V |
| Operating Temperature | 0 to +70 °C (C grade) | 0 to +70 °C (C grade) | 0 to +70 °C (C grade) | 0 to +70 °C (C grade) | 0 to +70 °C (C grade) | 0 to +70 °C (C grade) |
Diferenciadores clave
- Highest throughput in the MAX108x family (frente a MAX1084ACSA+T)
- A-grade vs B-grade cost/linearity trade-off (frente a MAX1085BCSA+T)
- Higher throughput than legacy MAX1242/MAX1243 (frente a MAX1242ACSA+)
Notas de diseño
Estimated: Place a 0.1 µF low-ESR ceramic bypass capacitor within 3 mm of the VDD pin and a bulk 10 µF tantalum or ceramic on the supply rail. The MAX1085ACSA+T draws 1.5 mA (typical) at 400 ksps and VDD = 5 V; using the SHDN-bar pin to power down between conversions drops Iq below 1 µA, enabling duty-cycled sampling for battery-powered designs (e.g., 1 ms active per second drops average Iq to ~1.5 µA). Do not exceed the absolute maximum VDD of +6 V.
Route analog and digital grounds as a star-ground topology with the AGND/DGND pins tied at the IC. Place the reference bypass capacitors (0.1 µF + 10 µF) directly between REF and AGND. Keep the AIN trace short and away from digital switching nodes (SCLK, DOUT) to minimize digital-to-analog crosstalk. The 8-pin SOIC thermal pad is not present; standard SOIC junction-to-ambient is ~170 °C/W, adequate for the < 10 mW dissipation of this ADC.
The MAX1085ACSA+T uses a successive-approximation architecture with an input bandwidth exceeding its sampling rate, so add an external RC anti-alias filter at AIN (e.g., 1 kΩ + 330 pF gives ~480 kHz cutoff for 400 ksps Nyquist). The SCLK signal should be kept below the datasheet maximum frequency and routed away from AIN to avoid sampling-clock feedthrough. Source-impedance at AIN should be < 1 kΩ to avoid gain errors from the input track/hold.
Do not apply a voltage to AIN that exceeds VDD + 0.3 V - this will forward-bias the input ESD cell and corrupt the conversion. Always toggle SHDN-bar HIGH at least 10 µs before starting conversions to allow the reference and bias circuits to settle. Avoid reading DOUT on the rising edge of SCLK (use the falling edge per the datasheet timing diagram), otherwise the read-back data will be corrupted by setup-time violations.
Información de cumplimiento
RoHS compliant per Maxim Integrated product page. Not AEC-Q100 qualified; for automotive-grade, no MAX1085 variant exists in this family - consider MAX1085AESA+T for extended industrial temperature only.
