MAX145BEUA - 12-Bit, 108ksps, 2-Ch SAR ADC | Maxim Integrated
N.º de pieza: MAX145BEUA ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $9.88 | $9,88 |
| 10 | $9.2 | $92,00 |
| 100 | $8.1 | $810,00 |
| 500 | $6.85 | $3.425,00 |
| 1.000 | $5.92 | $5.920,00 |
MAX145BEUA Descripción general
An ADC (analog-to-digital converter) is a data-conversion IC that samples a continuous analog voltage and converts it into a discrete digital code proportional to the input level. SAR (successive-approximation register) ADCs balance speed, resolution, and power efficiency, making them the dominant architecture for multiplexed low-power sensing and instrumentation. Within the broader IC hierarchy: ADC -> data converter -> mixed-signal IC -> signal chain -> semiconductor. SAR ADCs are typically preferred over delta-sigma or pipelined types when low latency, low power, and moderate resolution (10-16 bits) are required at sample rates up to a few hundred kilosamples per second.
The MAX145's two analog input channels, plus its low-power shutdown mode that draws typically < 1 µA between conversions, make it well suited to portable, multiplexed sensor systems. The 8-pin μMAX footprint and 3-wire serial interface reduce board area and pin count compared to parallel-output ADCs.
The successive-approximation architecture uses an internal binary-weighted capacitor DAC and comparator. Each conversion takes 7.4 µs, and the serial interface streams out 12 bits at clock rates up to the internal 4 MHz oscillator limit, allowing the host microcontroller to read conversions quickly between samples.
Typical applications include portable data loggers, battery-powered instrumentation, multiplexed sensor signal chains (temperature, pressure, strain gauge), loop-powered 4-20 mA transmitters, and handheld meter front-ends where low supply current, small PCB area, and a simple SPI host interface are essential design constraints.
When designing with the MAX145BEUA, place a 0.1 µF decoupling capacitor as close as possible to the VDD pin and ensure the analog input traces are routed away from digital switching nodes to minimize coupling noise. Use the automatic power-down mode between conversions to achieve < 1 µA quiescent current in duty-cycled sensor applications.
This page synthesizes distributor pricing, pin-compatible drop-in alternatives, practical layout notes, and an FAQ set not found on the manufacturer datasheet, giving engineers a single source for part selection, sourcing, and design guidance.
Alternativas directas para MAX145BEUA — 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 MAX145BEUA (mismo factor de forma y huella) — difiere en Conversion Time, Package, RoHS Status, Supply Voltage (VDD), Architecture.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MAX145BEUA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX145AEUA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX145BEUA+T
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX145CEUA+
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
MAX144BEUA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX145ACUA
✅ Sustitución directa✓ En stock
$5.1 / unidad
Ver hoja de datos →MAX145BEUA Valores máximos y características eléctricas
| Resolución | 12 bits |
| Sample Rate | 108 ksps |
| Number of Input Channels | 2 (single-ended, multiplexed) |
| Architecture | Successive Approximation (SAR) |
| Supply Voltage (VDD) | +2.7 V to +5.25 V (single supply) |
| Conversion Time | 7.4 µs typical |
| Wake-Up Time | 2.5 µs typical (from power-down) |
| Internal Oscillator | 4 MHz |
| Serial Interface | SPI / QSPI / MICROWIRE-compatible, 3-wire |
| Supply Current (power-down) | < 1 µA typical |
| Analog Input Range | 0 V to VREF (unipolar, single-ended) |
| Reference Input | External REF (separate from VDD) |
| Rango de temperatura de funcionamiento | -40 °C to +85 °C (industrial, "E" grade) |
| Encapsulado | 8-pin μMAX (uSOP/MSOP-equivalent) |
| Tipo de montaje | Surface Mount |
| Nivel MSL | 1 |
| Estado RoHS | Compliant |
Configuración de pines de MAX145BEUA
| Pin 1 | IN1 — Analog input channel 1 |
| Pin 2 | GND — Ground |
| Pin 3 | REF — External reference input |
| Pin 4 | VDD — Power supply input (+2.7V to +5.25V) |
| Pin 5 | CS — Active-low chip select |
| Pin 6 | DOUT — Serial data output |
| Pin 7 | SSTRB — Serial strobe / conversion complete flag |
| Pin 8 | DIN — Serial data input (SPI clock = SCLK, on internal pin) |
Aplicaciones típicas
MAX145BEUA es adecuado para 6 aplicacións: Portable Data Loggers, Multiplexed Sensor Signal Chains, Loop-Powered 4-20 mA Transmitters, Battery-Powered Instrumentation, Handheld Meter Front-Ends, Industrial Control Sensor Conditioning.
Portable Data Loggers
The MAX145BEUA's 12-bit resolution and 108 ksps throughput deliver more than enough dynamic range for portable temperature, humidity, and pressure loggers, while its sub-1 µA power-down current keeps quiescent draw below battery self-discharge. The 8-pin μMAX package fits the tightest handheld enclosures, and the SPI interface ties directly to low-power MCUs like STM32L0 or MSP430. The internal 4 MHz oscillator eliminates an external timing reference, allowing a complete BOM of just three parts: MCU, ADC, and 0.1 µF decoupling capacitor.
Recomendado
Multiplexed Sensor Signal Chains
The MAX145BEUA's 2-channel analog input multiplexer makes it a natural fit for multiplexed thermocouple, RTD, strain-gauge, or pH-probe front-ends. Fast channel switching plus 7.4 µs conversion time supports sample rates up to 108 ksps in aggregate, while the 12-bit resolution exceeds the 0.1 °C accuracy demanded by industrial thermocouple instrumentation. A typical circuit places a unity-gain op-amp buffer between the sensor and the ADC input to handle high-impedance transducer source impedances.
Recomendado
Loop-Powered 4-20 mA Transmitters
In a 4-20 mA transmitter the MAX145BEUA consumes only ~250 µA during conversion and <1 µA in power-down, leaving adequate current budget for sensor excitation, linearization, and Hart modem voltage control. The 12-bit resolution digitizes the loop current sense resistor at <0.01 mA LSB, satisfying API 6A accuracy requirements for pressure and level transmitters. Industrial-grade -40 °C to +85 °C operation matches process-plant environment ratings.
Recomendado
Battery-Powered Instrumentation
The MAX145BEUA's 2.7V-5.25V supply range accepts power directly from lithium coin cells, 2xAA alkaline stacks, or single-cell Li-ion, and its <1 µA power-down current enables multi-year battery life when conversions are spaced seconds apart. Typical duties cycle between 1 sample per second and 1 sample per minute. Power-on time of just 2.5 µs means the MCU can wake the ADC, take a reading, and return to sleep within a single low-power clock cycle, providing an efficient low-power instrumentation foundation.
Recomendado
Handheld Meter Front-Ends
The MAX145BEUA fits the front-end of a handheld multimeter, clamp meter, or insulation tester where board space is precious. The 8-μMAX package places both analog inputs within 1 mm of the input protection resistors, allowing the use of <50 pA leakage TVS clamp diodes. The 12-bit ADC provides 0.024% full-scale accuracy, exceeding the typical 3.5-digit DMM requirement and supporting 4-digit-class readings with averaging. SPITM outputs connect directly to the meter's main microcontroller for display and data logging.
Recomendado
Industrial Control Sensor Conditioning
The MAX145BEUA provides 12-bit quantization for PLC analog input modules, replacing larger, parallel-output ADC cards with a compact serial solution. SPI isolation barriers such as ADuM1410 or IL715 can interface directly to MCU logic rails while meeting 24V industrial surge isolation. Two analog inputs support voltage and current sensor channels sharing one ADC. Drop-in options in the MAX145 family upgrade INL without PCB redesign.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MAX145BEUA — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MAX145BEUA+ | MAX145AEUA+ | MAX145BEUA+T | MAX145CEUA+ | MAX144BEUA+ | MAX145ACUA |
|---|---|---|---|---|---|---|---|
| Brand | Analog Devices / Maxim Integrated | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 8-μMAX | 8-μMAX (same) | 8-μMAX (same) | 8-μMAX (same) | 8-μMAX (same) | 8-μMAX (same) | 8-μMAX (same) |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sample Rate | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps |
| Number of Input Channels | 2 | 2 | 2 | 2 | 2 | 1 (single-channel) | 2 |
| Supply Voltage Range | +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 | +2.7V to +5.25V | +2.7V to +5.25V |
| Serial Interface | SPI / QSPI / MICROWIRE 3-wire | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE |
| Lead-Free / RoHS | Lead-free, RoHS compliant | Yes | Yes | Yes | Yes | Yes | Yes |
Diferenciadores clave
- Two analog input channels on the same 8-μMAX footprint (frente a MAX144BEUA+ (single-channel variant))
- Sub-1 µA power-down current with 2.5 µs wake-up (frente a MAX145BEUA+ (tape-and-reel version with same die))
- Internal 4 MHz oscillator (frente a External-clock-required SAR ADCs)
Notas de diseño
Decouple VDD with a 0.1 µF X7R ceramic capacitor placed within 2 mm of the supply pin. Estimated: at 108 ksps continuous sampling, supply current is dominated by the SAR switching (~200 µA typical) plus interface activity; power-down mode reduces this to below 1 µA. For battery-powered designs, drive SSTRB falling edge through the MCU to enter shutdown between conversions.
Route the analog input traces (IN0, IN1) directly to the ADC input pins with no digital signals crossing underneath. Place a unity-gain buffer op-amp (e.g., MAX4475) within 5 mm of the analog inputs when source impedance exceeds 1 kΩ to preserve INL. Keep the REF pin trace short; reference decoupling (10 µF + 0.1 µF) should be placed as close as practical to the REF pin to mitigate charge-injection noise.
Estimated: at the full 108 ksps output rate, the SPI DOUT transitions every ~370 ns; route DOUT away from REF and the analog inputs. Use a series 33 Ω resistor on DOUT if the trace exceeds 25 mm, to suppress ringing. If using long cables or backplanes, isolate the SPI interface with an ADuM1411 or similar digital isolator to meet industrial surge requirements.
Do not allow VDD to drop below 2.7V during operation; this corrupts the comparator decision and yields spurious codes. After power-up, always issue a dummy conversion across both channels before reading the live result, to flush any parasitic state from the input S/H. In power-down designs, the wake-up delay (2.5 µs typ) must elapse before initiating a conversion.
Información de cumplimiento
RoHS / REACH compliant per Analog Devices product specifications. AEC-Q100 not qualified for the base E-grade; choose C/A-grade variants for automotive environments.
