MAX157BCPA - 10-Bit 108ksps 2-Ch Serial ADC | Maxim Integrated
N.º de pieza: MAX157BCPA ✗ Fin de vida| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $4.85 | $4,85 |
| 10 | $4.36 | $43,60 |
| 100 | $3.88 | $388,00 |
| 500 | $3.49 | $1.745,00 |
| 1.000 | $3.1 | $3.100,00 |
MAX157BCPA Descripción general
An SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a type of data converter that uses a binary-search algorithm and an internal capacitive DAC to resolve an analog input to N bits in N clock cycles. SAR ADCs sit within the broader data-converter family alongside flash, sigma-delta, and pipeline ADCs, and are valued for low power consumption, deterministic latency, and excellent DC accuracy - making them the standard choice for multiplexed low-frequency multi-channel measurement, instrumentation, and portable/battery-powered systems.
Key specifications include 108 ksps sampling rate, 7.4 µs successive-approximation conversion time, 2 analog input channels with channel-select input, ±1 LSB INL (max), and an 8-pin PDIP through-hole footprint. The MAX157 also features a dedicated shutdown pin that drops supply current to a few microamps between samples, which is critical for handheld or duty-cycled designs where average power dominates battery life.
Architecturally, the device uses a charge-redistribution capacitive DAC with an on-chip sample/hold, an internal 2.5 MHz oscillator for conversions, and a straight binary output code. The 3-wire serial interface (CS, SCLK, DOUT) allows direct connection to most microcontrollers and DSPs without glue logic, and the SPI/QSPI/MICROWIRE compatibility simplifies firmware porting from one host to another.
Typical applications include portable data loggers, battery-powered sensor read-out, pen-tablet digitizers, hand-held instruments, loop-powered 4-20 mA transmitters, and isolated multi-channel measurement front-ends. The wide +2.7V to +5.25V supply range supports both 3.3V and 5V MCU rails, and the two-channel mux allows dual-sensor sampling (e.g., temperature + pressure) with a single ADC.
When designing with the MAX157BCPA, ensure the analog input bandwidth (input RC) is limited appropriately for full-scale settling, and place 0.1 µF bypass capacitors close to the supply pin. Use the shutdown pin aggressively between conversions in low-duty-cycle applications - this is where the part earns its low-power reputation.
This page synthesizes distributor pricing, drop-in alternatives within the MAX157/MAX159 family, and practical design notes not collated in the manufacturer datasheet alone.
Alternativas directas para MAX157BCPA — 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 MAX157BCPA (mismo factor de forma y huella) — difiere en Package, Operating Temperature, Architecture, Conversion Time, Number of Channels.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MAX157BCPA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX159BCPA
✅ Sustitución directa✓ En stock
$4.42 / unidad
Ver hoja de datos →MAX159BCPA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX157BCPA Valores máximos y características eléctricas
| Resolución | 10 bit |
| Number of Channels | 2 |
| Frecuencia de muestreo | 108 ksps |
| Conversion Time | 7.4 µs |
| Tensión de alimentación | +2.7 V to +5.25 V |
| Supply Current (active at 3.6V) | 3.2 mW (typ) |
| Wake-Up Time | 2.5 µs |
| INL (max) | ±1 LSB |
| Architecture | SAR (Successive Approximation) |
| Interfaz | 3-wire SPI/QSPI/MICROWIRE-compatible serial |
| Shutdown Mode | Yes - auto power-down + SHDN pin |
| On-Chip Clock | Yes (internal oscillator) |
| Encapsulado | 8-pin PDIP |
| Tipo de montaje | Through-Hole |
| Temperatura de funcionamiento | 0°C to +70°C (commercial) |
| Estado RoHS | Compliant (Pb-free '+' suffix versions) |
Configuración de pines de MAX157BCPA
| Pin 1 | AIN — Analog input (channel 1 / 2 selected by channel-select pin per MAX157/MAX159 datasheet) |
| Pin 2 | GND — Ground |
| Pin 3 | REF — External reference voltage input |
| Pin 4 | VDD — Positive supply, +2.7V to +5.25V |
| Pin 5 | DOUT — Serial data output (3-wire SPI/QSPI/MICROWIRE) |
| Pin 6 | SCLK — Serial clock input |
| Pin 7 | CS — Chip select (active low) |
| Pin 8 | SHDN — Shutdown control input (active high = shutdown) |
Aplicaciones típicas
MAX157BCPA es adecuado para 7 aplicacións: Portable Data Loggers, Battery-Powered Sensor Read-Out, Hand-Held Instrumentation, Pen-Tablet / Digitizer Systems, Loop-Powered 4-20 mA Transmitters, Isolated Multi-Channel Measurement, Industrial Process Monitor.
Portable Data Loggers
The MAX157BCPA's 3.2 mW active power at 3.6V and automatic power-down between samples make it well suited to battery-powered multi-channel data loggers. With 108 ksps sampling and 10-bit resolution it is fast enough for vibration and temperature profiling while staying below the 5 mW budget of coin-cell designs. Place a 0.1 µF bypass on VDD and drive SHDN between conversions to drop average current below 100 µA at 1 kHz sample rate.
Recomendado
Battery-Powered Sensor Read-Out
The wide +2.7V to +5.25V supply of the MAX157BCPA lets it sit directly on a 3.3V or 5V MCU rail in handheld sensor modules. Its 2-channel input mux handles a sensor pair (e.g., temperature + humidity) with deterministic 7.4 µs conversion latency, ideal for time-stamped wireless telemetry packets. Combined with 2.5 µs wake-up, the part draws negligible current between samples, preserving battery life across long idle periods.
Recomendado
Hand-Held Instrumentation
The MAX157BCPA's small 8-pin PDIP footprint and integrated SPI/QSPI/MICROWIRE interface minimize MCU glue logic in handheld multimeters and probes. The 10-bit resolution is sufficient for bar-graph and digit-style readouts where 0.5% accuracy is acceptable, and the 108 ksps rate supports smooth auto-zero routines. Its ±1 LSB INL delivers consistent linearity across the operating temperature range required for laboratory-grade instruments.
Recomendado
Pen-Tablet / Digitizer Systems
The MAX157BCPA's 108 ksps throughput and dual-channel input make it a natural fit for digitizer pen-position read-out where a host MCU needs to sample two sensors at high rate. Its small 8-pin PDIP footprint simplifies hand-routed prototypes and its deterministic SAR latency simplifies stylus-timing calibration. The 3-wire serial interface shares an SPI bus with other peripherals without arbitration logic.
Recomendado
Loop-Powered 4-20 mA Transmitters
The MAX157BCPA's low 3.2 mW active consumption and single +2.7V supply make it well-suited to 4-20 mA loop-powered industrial transmitters where the entire sensor node must operate below 3.6 mA. Its automatic power-down keeps idle current below 100 µA so the loop's 3.6 mA budget can power the sensor, ADC, and a low-power MCU. Its robust SPI interface survives the long cable runs typical of industrial instrumentation.
Recomendado
Isolated Multi-Channel Measurement
The MAX157BCPA's serial interface minimizes the number of signals crossing an isolation barrier, a major cost saver in multi-channel isolated measurement modules. Only CS, SCLK, and DOUT must cross the isolator, and the ADC's deterministic SAR timing simplifies latency budgeting across the isolation latency. The +2.7V to +5.25V supply range lets the ADC run from either side of the barrier.
Recomendado
Industrial Process Monitor
The MAX157BCPA's deterministic SAR architecture and 108 ksps throughput let a process monitor digitize two transducer channels at fixed, predictable intervals - critical for closed-loop control loops. Its ±1 LSB INL provides repeatable linearity across the industrial temperature range, and its 3-wire SPI interface minimizes isolator cost when the front-end must be galvanically isolated from the controller.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MAX157BCPA — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MAX157BCPA+ | MAX159BCPA | MAX159BCPA+ | MAX157BCUA | MAX159BCUA |
|---|---|---|---|---|---|---|
| Package | 8-pin PDIP | 8-pin PDIP - same | 8-pin PDIP - same | 8-pin PDIP - same | 8-pin µMAX - different (SMD) | 8-pin µMAX - different (SMD) |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 10 bit | 10 bit | 10 bit | 10 bit | 10 bit | 10 bit |
| Sampling Rate | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps |
| Number of Channels | 2 | 2 | 2 | 2 | 2 | 2 |
| 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 | +2.7V to +5.25V |
| Interface | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE |
| RoHS / Lead Finish | Tin-lead (non-RoHS) | Pb-free RoHS | Tin-lead (non-RoHS) | Pb-free RoHS | Pb-free RoHS | Pb-free RoHS |
| Lifecycle Status | Obsolete | Obsolete (RoHS variant) | Obsolete | Obsolete (RoHS variant) | Obsolete (SMD variant) | Obsolete (SMD variant) |
Diferenciadores clave
- Pb-free RoHS upgrade without layout change (frente a MAX157BCPA+)
- Same package, inverse channel-select for second-source flexibility (frente a MAX159BCPA / MAX159BCPA+)
- Surface-mount option in same die family (frente a MAX157BCUA / MAX159BCUA)
Notas de diseño
Drive the SHDN pin high between conversions to put the device into its few-microamp shutdown state; pull SHDN low only while CS is active or a conversion is in progress. According to the Maxim datasheet, this is how the part achieves its low average-current reputation in duty-cycled battery applications. A 0.1 µF ceramic bypass capacitor must be placed within 5 mm of the VDD pin to keep digital noise out of the analog reference.
The analog input pin should be driven from a low-impedance source with the input RC settled within the 7.4 µs acquisition window. Add an external RC if your sensor cannot settle in time, or oversample to average out the residual. Place REF bypass capacitor (typically 0.1 µF ceramic + 10 µF electrolytic) close to the REF pin - reference noise directly determines INL and DNL of the conversion result.
Do not drive SHDN high while CS is low or the conversion will be aborted and DOUT will return an invalid code per the Maxim MAX157/MAX159 datasheet. Also, do not operate below the 2.7 V minimum supply - the internal oscillator can mis-trigger at lower voltages and produce noisy conversions. When migrating from MAX157 to MAX159, remember that the channel-select logic is inverted; check the firmware if swapping between the two.
Información de cumplimiento
MAX157BCPA (without '+' suffix) is tin-lead finish and is non-RoHS. The '+' suffix variants MAX157BCPA+, MAX159BCPA+ are Pb-free and RoHS compliant. AEC-Q100 is not applicable for this commercial-grade part.
