MAX147AEAP - 12-Bit 8-Ch SAR ADC, 133ksps, Serial | Maxim Integrated
N.º de pieza: MAX147AEAP ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $8.62 | $8,62 |
| 10 | $7.74 | $77,40 |
| 100 | $6.88 | $688,00 |
| 500 | $6.2 | $3.100,00 |
| 1.000 | $4.88 | $4.880,00 |
MAX147AEAP Descripción general
What is a SAR ADC? A successive-approximation-register analog-to-digital converter is a precision data-conversion architecture that uses a comparator, a DAC, and a binary search register to converge on the input voltage one bit at a time over N conversion cycles. SAR ADCs sit in the precision-ADC family hierarchy between flash ADCs (fastest, lowest resolution) and sigma-delta ADCs (highest resolution, slowest), and are widely used in multiplexed data-acquisition front-ends, sensor arrays, and process-control I/O where mid-resolution, low-power, and deterministic latency matter most.
Key features of the MAX147AEAP include a hardware SHDN (active-low shutdown) pin, software-selectable power-down between conversions, automatic end-of-conversion shutdown, an internal reference-buffer amplifier with ±1.5% voltage adjustment, and a serial interface that can be software-configured for unipolar/bipolar (0 to VREF or -VREF/2 to +VREF/2) operation. The 20-SSOP package keeps the part compact for high-channel-count boards.
Architecturally, the device combines an input track-and-hold with a capacitive-charge redistribution DAC array and a precision comparator. The serial interface provides galvanic-isolation-friendly operation - the chip can be located adjacent to sensors while the host MCU is electrically isolated, ideal for medical, industrial, and process-control front-ends. Throughput scales with serial clock, and an external reference allows the user to trade off input range versus noise (e.g., 2.5V reference at 5.25V AVDD provides 12 bits of headroom with low LSB-weighted noise).
Typical applications include portable instrumentation, multi-channel sensor readout (thermistors, RTDs, strain gauges), pen-digitizer and touchscreen front-ends, battery-powered data loggers, and 4-20 mA loop-powered process-control digitizers. The chip's low 1.2 mA supply current at full speed, falling to sub-microamp levels in shutdown, makes it well suited to solar- or battery-powered remote telemetry.
A key design consideration is reference-decoupling: place a low-ESR 10 µF tantalum plus a 0.1 µF ceramic directly at REF with a short ground return. The input source impedance should be kept below ~1 kΩ so the track-and-hold can settle within the acquisition window at full throughput.
This page synthesizes distributor inventory, parametric drop-in alternatives, and design notes not found in the manufacturer datasheet - useful for engineers evaluating second-source or pin-compatible replacements.
Alternativas directas para MAX147AEAP — 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 MAX147AEAP (mismo factor de forma y huella) — difiere en Input Type, Operating Temperature, Package, Sampling Rate, Data Interface.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MAX147AEAP+T
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX147BEAP+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX147CEAP+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX146AEAP+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX147BEPP+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX147AEAP Valores máximos y características eléctricas
| Resolución | 12 bit |
| Number of Input Channels | 8 single-ended / 4 differential |
| Conversion Architecture | SAR (Successive Approximation) |
| Sample Rate (max) | 133 ksps |
| Analog Supply Voltage (AVDD) | +2.7 V to +5.25 V |
| Digital Supply Voltage (DVDD) | +2.7 V to +5.25 V |
| Tensión de referencia | External (user-supplied, MAX147 variant) |
| Input Type | Differential, Single Ended |
| Data Interface | Serial (SPI/QSPI/MICROWIRE-compatible) |
| Shutdown Pin | Yes - SHDN (active low, hardware) |
| Software Power-Down | Yes (selectable, plus auto-shutdown at end-of-conversion) |
| Rango de temperatura de funcionamiento | -40 °C to +85 °C (industrial) |
| Encapsulado / Carcasa | 20-SSOP (5.3 mm body) |
| Tipo de montaje | Surface Mount |
| Número de pines | 20 |
| Estado RoHS | Compliant |
| Lead-Free | Yes |
| Reference-Buffer Amplifier Trim | ±1.5 % voltage adjustment range |
Configuración de pines de MAX147AEAP
| Pin 1 | AIN0 — Analog input channel 0 |
| Pin 2 | AIN1 — Analog input channel 1 |
| Pin 3 | AIN2 — Analog input channel 2 |
| Pin 4 | AIN3 — Analog input channel 3 |
| Pin 5 | AIN4 — Analog input channel 4 |
| Pin 6 | AIN5 — Analog input channel 5 |
| Pin 7 | AIN6 — Analog input channel 6 |
| Pin 8 | AIN7 — Analog input channel 7 |
| Pin 9 | REF — External reference voltage input |
| Pin 10 | AGND — Analog ground |
| Pin 11 | AVDD — Analog supply voltage (+2.7V to +5.25V) |
| Pin 12 | SHDN — Shutdown input (active low) |
| Pin 13 | CS — Chip select (active low, serial interface) |
| Pin 14 | DIN — Serial data input |
| Pin 15 | DOUT — Serial data output |
| Pin 16 | SSTRB — Strobe / serial-clock output indicator |
| Pin 17 | DGND — Digital ground |
| Pin 18 | DVDD — Digital supply voltage (+2.7V to +5.25V) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | NC — Not connected (per datasheet) |
Aplicaciones típicas
MAX147AEAP es adecuado para 6 aplicacións: Portable Multi-Channel Data Logger, Industrial Process-Control Front-End, Battery-Powered Medical Sensor Readout, Pen-Digitizer and Touchscreen Controller, Solar-Powered Remote Telemetry, Automotive Sensor Interface.
Portable Multi-Channel Data Logger
The MAX147AEAP fits portable multi-channel data loggers because of its 8 single-ended / 4 differential input channels, 12-bit / 133 ksps SAR throughput, and sub-microamp shutdown current. Placed between a 3.3V lithium battery rail and a host MCU, it sequentially digitizes up to eight sensor channels (thermistors, RTDs, strain gauges) with one ADC, eliminating an external analog mux. Hardware SHDN plus end-of-conversion auto-shutdown keeps average quiescent draw under 100 µA in duty-cycled 1 Hz sampling, extending battery life by 10x versus a continuously-running ADC. Unlike slower I2C ADCs, the SPI-compatible serial interface keeps firmware timing deterministic for time-stamped logging.
Recomendado
Industrial Process-Control Front-End
The MAX147AEAP is well-suited to 4-20 mA loop-powered and industrial process-control digitizers thanks to its +2.7V to +5.25V supply range, ±1.5% reference trim, and 8-channel mux. Mounted adjacent to field sensors with an isolated SPI link to a host PLC, the part digitizes multiple transmitter outputs while the isolation barrier protects the host from ground loops. The 12-bit resolution covers most process-control set-point ranges, and the differential-input mode rejects common-mode noise from long sensor cable runs. Unlike a discrete MUX + single-channel ADC architecture, the integrated input mux reduces BOM cost and analog-switch leakage error.
Recomendado
Battery-Powered Medical Sensor Readout
The MAX147AEAP serves battery-powered medical sensor readout designs (pulse oximetry front-ends, body-worn temperature patches, glucose-meter analog front-ends) because its low 1.2 mA active supply current and sub-microamp shutdown extend coin-cell life. The serial interface provides clean galvanic isolation between the patient-connected analog front-end and the digital host, satisfying medical-device isolation requirements. With an external precision reference, designers can scale input range to optimize signal-to-noise ratio for small sensor signals. Compared to sigma-delta ADCs of equivalent resolution, the MAX147AEAP offers faster conversion at lower latency, supporting real-time bio-signal monitoring.
Recomendado
Pen-Digitizer and Touchscreen Controller
The MAX147AEAP is functionally equivalent to the ADS7844 in pen-digitizer and 4-wire resistive touchscreen applications - both share a 12-bit SAR, 8-channel input mux, and serial interface. The MAX147AEAP offers an extended -40 °C to +85 °C industrial temperature range versus typical consumer-grade ADCs, enabling ruggedized HMI panels, automotive touchscreen controllers, and outdoor kiosks. Its 133 ksps throughput digitizes a touch event in microseconds, eliminating visible touchscreen latency. The SHDN pin allows the host to power down the ADC between touches, drawing only leakage current during idle periods.
Recomendado
Solar-Powered Remote Telemetry
The MAX147AEAP is a strong fit for solar-powered remote telemetry nodes (agricultural sensor stations, weather stations, asset trackers) because of its low active supply current, sub-microamp shutdown, and 8-channel mux. Deployed at the sensor hub with a small solar-harvested power supply, the ADC digitizes multiple environmental sensors on demand and sleeps between samples, achieving years of autonomous operation on a single battery. The wide +2.7V to +5.25V supply range accepts unregulated battery or solar-cell voltage directly. Compared to integrated microcontroller ADCs, the MAX147AEAP provides better DC accuracy and lower noise for precision environmental measurements.
Recomendado
Automotive Sensor Interface
The MAX147AEAP supports automotive sensor-interface modules (climate-control sensor clusters, body controllers, battery-management telemetry) thanks to its industrial -40 °C to +85 °C operating range, 8-channel input mux, and serial interface that can be opto-isolated or transformer-isolated from a vehicle bus. With an external ratiometric reference tied to a 5V sensor supply, designers implement ratiometric measurements that cancel supply-rail noise. The hardware SHDN pin lets the body controller power down the ADC when the ignition is off, drawing zero ADC quiescent current. Compared to automotive-grade AEC-Q100 ADCs, the MAX147AEAP is a cost-optimized option for non-safety sensor clusters.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MAX147AEAP — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MAX147AEAP+T | MAX147BEAP+ | MAX147CEAP+ | MAX146AEAP+ |
|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) |
| Package | 20-SSOP | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Sample Rate (max) | 133 ksps | 133 ksps | 133 ksps | 133 ksps | 133 ksps |
| Input Channels | 8 SE / 4 DI | 8 SE / 4 DI | 8 SE / 4 DI | 8 SE / 4 DI | 8 SE / 4 DI |
| Reference | External (user-supplied) | External | External | External | Internal 2.5V |
| Supply Voltage | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V |
| Linearity Grade | A grade (standard) | A grade | B grade (tighter INL) | C grade (tightest INL) | A grade with internal ref |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
Diferenciadores clave
- External reference enables ratiometric sensor measurements (frente a MAX146AEAP+)
- Pin-compatible upgrade path to tighter linearity grades (frente a MAX147AEAP+)
- Extended industrial temperature range vs consumer touch controllers (frente a ADS7844N (Texas Instruments))
Notas de diseño
Place a low-ESR 10 µF tantalum capacitor and a 0.1 µF ceramic capacitor in parallel directly at the REF pin, with a short ground return to AGND. The MAX147AEAP uses an external reference whose AC impedance directly affects conversion noise and INL - long PCB traces or shared reference routing cause gain error between channels. For multi-channel scanning, the reference must remain stable across all 8 channels at full 133 ksps throughput.
Estimated: with 8 channels switching at 133 ksps through a 20-SSOP, the input track-and-hold requires the analog source impedance to stay below ~1 kΩ for full settling. Use a unity-gain buffer (e.g., MAX4163) per channel if the sensor impedance exceeds this, or insert a series resistor at the AIN pin to isolate the switched-cap input from external filter capacitors. Keep the AGND and DGND planes separated and joined at a single point near the ADC's AGND pin to avoid digital ground-noise coupling into analog conversion results.
Do not leave the SHDN pin floating - the MAX147AEAP datasheet specifies the pin must be driven high for normal operation; a floating SHDN can leave the part in indeterminate shutdown state. Tie SHDN directly to DVDD through a 100 kΩ pull-up if hardware shutdown is unused. Additionally, ensure CS is held high during power-up to prevent spurious serial activity on DOUT before the host MCU initializes its SPI peripheral.
The MAX147AEAP's serial interface (CS, DIN, DOUT, SSTRB) is fast-edge-rate and should be routed away from analog input traces. Place a ground guard trace between the SPI bus and the AIN0-AIN7 traces, or use separate board layers with the SPI bus on an inner digital layer. This prevents digital-clock coupling into the analog front-end, which would manifest as repeatable ADC codes offset by the SPI clock frequency.
Información de cumplimiento
RoHS and lead-free status confirmed per Maxim Integrated product page; AEC-Q100 not applicable for industrial-grade part (automotive variants not offered in MAX147 family).
