MAX187CEPA - 12-Bit Serial ADC, +5V, 75ksps, DIP-8 | Maxim
N.º da peça: MAX187CEPA ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $16.55 | $16,55 |
| 10 | $14.2 | $142,00 |
| 100 | $12.05 | $1.205,00 |
| 500 | $10.5 | $5.250,00 |
| 1.000 | $9.45 | $9.450,00 |
MAX187CEPA Visão geral
An ADC (analog-to-digital converter) is a mixed-signal data-acquisition component that samples a continuous analog voltage and quantizes it into a discrete digital code. Within the power management and signal-chain hierarchy, ADCs sit downstream of analog signal conditioning (op-amps, filters) and upstream of microcontrollers, DSPs, or FPGAs. The MAX187 family belongs to the successive-approximation register (SAR) ADC category, which trades conversion speed for excellent static accuracy and low power consumption, making it a workhorse for industrial process control, instrumentation, and portable data-logger designs.
Key specifications include 12-bit resolution, +/-0.5 LSB integral nonlinearity (INL) for the MAX187A grade, 75kHz (75ksps) sampling rate, 1.5mA operating supply current, and a 2uA shutdown current that lets battery-powered systems gate power between conversions. The MAX187 variant includes the internal 4.096V reference; the pin-compatible MAX189 leaves REF open for an external reference. Internal calibration circuitry holds linearity over the full operating temperature range.
Typical applications include portable instrumentation, data loggers, process-control analog front ends, weigh scales, isolated sensor digitizers, and pen-digitizer / tablet digitizing systems. The wide analog input range (0 to 5V) plus internal reference make it a single-chip solution for many industrial 4-20mA loop and thermocouple-amplifier digitizing tasks.
When designing with the MAX187CEPA, place 0.1uF decoupling close to VDD and follow the recommended REF bypass (4.7uF) to keep the internal reference quiet. Use the SHDN pin aggressively in battery systems - the 2uA quiescent current drops total system standby power dramatically versus always-on operation.
This page synthesizes distributor pricing, pin-compatible drop-in alternatives (MAX187BEPA, MAX187ACPA+, MAX187CCPA+), and practical design notes not consolidated in the manufacturer datasheet, enabling faster engineering decisions.
Alternativas drop-in para MAX187CEPA — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com MAX187CEPA (mesmo formato e footprint) — diferindo em Package, Sampling Rate, Resolution, Integral Nonlinearity (INL), Internal Reference.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
MAX187BEPA
✅ Drop-In✓ Em estoque
$9.85 / unidade
Ver ficha técnica →MAX187AEPA+
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
MAX187CCPA+
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MAX187CEPA+
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MAX187BCPA+
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
MAX187BEPA+
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
MAX187CEPA Classificações máximas e características elétricas
| Resolução | 12 bits |
| Taxa de amostragem | 75 ksps |
| Conversion Time | 8.5 us (successive approximation) |
| Track/Hold Acquisition | 1.5 us |
| Integral Nonlinearity (INL) | +/-0.5 LSB (MAX187A/MAX189A grade) |
| Analog Input Range | 0 V to 5 V |
| Tensão de alimentação | +5 V single supply (4.75 V to 5.25 V) |
| Operating Supply Current | 1.5 mA (operating) |
| Corrente de desligamento | 2 uA |
| Internal Reference | 4.096 V buffered (MAX187 only; MAX189 requires external) |
| Serial Interface | 3-wire SPI/QSPI/MICROWIRE-compatible |
| Encapsulamento | 8-pin PDIP (DIP-8) |
| Tipo de montagem | Through-Hole |
| Temperature Grade | Industrial (C grade) |
| Power Consumption | 7.5 mW (operating); 10 uW (shutdown) |
| Status RoHS | Compliant (MAX187CEPA+ version); non-compliant for original CEPA suffix |
Configuração de pinos do MAX187CEPA
| Pino 1 | VIN — Analog input positive |
| Pino 2 | AIN — Analog input (0 to 5V range) |
| Pino 3 | GND — Ground |
| Pino 4 | REF — Reference input/output (internal 4.096V reference on MAX187; external reference on MAX189) |
| Pino 5 | SHDN — Shutdown input (active-high; tie low for always-on operation) |
| Pino 6 | DOUT — Serial data output (SPI MISO) |
| Pino 7 | CS — Chip select input (active-low) |
| Pino 8 | VDD — +5V positive supply |
Aplicações típicas
MAX187CEPA é adequado para 6 aplicaçãos: Portable Battery-Powered Data Loggers, Industrial Process Control Analog Front Ends, Precision Weigh Scales and Load-Cell Digitizers, Thermocouple and Temperature Sensor Digitizing, Isolated Sensor Digitizers and Field Instrumentation, Pen Digitizer and Tablet Input Digitizing Systems.
Portable Battery-Powered Data Loggers
The MAX187CEPA's 2uA shutdown current and 1.5 mA operating current make it a strong fit for 32-bit microcontrollers and ultra-low-power data loggers. The 12-bit resolution at 75 ksps captures temperature, pressure, and battery voltage with 1 mV/LSB granularity using the internal 4.096V reference - no external reference IC needed, reducing BOM count. The 3-wire SPI interface connects directly to most low-power MCUs without glue logic. In a typical logger, the host MCU holds SHDN high only during the 8.5us conversion window, dropping quiescent drain to microamps between samples and extending coin-cell or Li-ion battery life by 10-100x versus always-on designs.
Recomendado
Industrial Process Control Analog Front Ends
The MAX187CEPA's 0-5V input range maps directly to industrial 4-20mA current loop shunts (250 ohm) and 0-5V transducer outputs without signal conditioning. Its +/-0.5 LSB INL (A-grade variants) and 75 ksps sampling rate deliver 12-bit accuracy for pressure, flow, and level transmitters at update rates above 1 kHz. The internal 4.096V reference simplifies isolation barrier design - the host MCU sits on the digital side and reads conversions through optocouplers, while the analog side needs only the MAX187CEPA, bypass caps, and a precision op-amp front end. This combination is widely deployed in PLC analog input modules and distributed I/O systems.
Recomendado
Precision Weigh Scales and Load-Cell Digitizers
Weigh scales demand 12-bit-plus resolution, low integral nonlinearity, and excellent gain stability - exactly the niche the MAX187CEPA family addresses. The internal 4.096V reference drives a load-cell bridge excited at 5V, producing a ratiometric measurement where reference drift cancels out. Combined with a low-noise instrumentation amplifier such as the MAX174AEPI, the MAX187CEPA achieves 0.05% full-scale accuracy suitable for commercial bench scales. The 75 ksps throughput oversamples mechanically slow load changes, enabling digital filtering for stable readings and tare-zero calibration in firmware.
Recomendado
Thermocouple and Temperature Sensor Digitizing
The MAX187CEPA accepts the 0-5V output of thermocouple amplifier chains with cold-junction compensation, digitizing type K, J, and T thermocouple readings with 1 mV/LSB resolution at the reference. For type K thermocouples spanning -200 to +1250C at 41uV/C, the MAX187CEPA's noise floor (about 0.5 LSB rms at 75 ksps) translates to roughly 0.1-0.2 C rms temperature resolution - more than adequate for HVAC, appliance, and process-temperature monitoring. The 8.5us conversion time supports multiplexed thermocouple scanning across 4-8 channels with sub-millisecond cycle times.
Recomendado
Isolated Sensor Digitizers and Field Instrumentation
Field-mounted instrumentation requires galvanic isolation between the sensor analog side and the 4-20mA loop or digital bus. The MAX187CEPA's 3-wire SPI interface crosses isolation barriers using three standard digital isolators (one each for CS, SCLK, DOUT), with the analog side powered by an isolated DC-DC converter. The 2uA shutdown current is critical here because the isolated side typically has only milliwatts of available power. This architecture is the canonical pattern for IEC 61508 SIL-rated safety instrumentation, where the MAX187CEPA digitizes near the sensor and only digital bits cross the barrier, eliminating analog isolation errors.
Recomendado
Pen Digitizer and Tablet Input Digitizing Systems
The MAX187CEPA's combination of 75 ksps sampling and 1.5us track/hold acquisition supports digitizer tablets that scan a pen position across an XY resistive or capacitive matrix. With 12-bit resolution over a 5V input range, position sensing resolution reaches 1 mV/LSB which maps to roughly 0.025 mm position accuracy on a typical 10x15 cm tablet. The SHDN pin lets the host MCU power the ADC only during active pen strokes, reducing power consumption in battery-powered stylus tablets by 90%+ versus always-on architectures. This application was one of Maxim's original target markets for the MAX187 family in the 1990s.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para MAX187CEPA — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | MAX187BEPA | MAX187AEPA+ | MAX187CCPA+ | MAX187CEPA+ | MAX187BCPA+ | MAX187BEPA+ |
|---|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | PDIP-8 (DIP-8) | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 75 ksps | 75 ksps | 75 ksps | 75 ksps | 75 ksps | 75 ksps | 75 ksps |
| INL (max) | +/-2 LSB | +/-1 LSB (B-grade, tighter) | +/-0.5 LSB (A-grade, tightest) | +/-2 LSB (C-grade, same) | +/-2 LSB (same) | +/-1 LSB (B-grade, tighter) | +/-1 LSB (B-grade, tighter) |
| Operating Temperature Range | -40C to +85C (industrial) | -40C to +85C | -40C to +85C | 0C to +70C (commercial) | -40C to +85C | 0C to +70C (commercial) | -40C to +85C |
| Supply Current (operating) | 1.5 mA | 1.5 mA | 1.5 mA | 1.5 mA | 1.5 mA | 1.5 mA | 1.5 mA |
| Shutdown Current | 2 uA | 2 uA | 2 uA | 2 uA | 2 uA | 2 uA | 2 uA |
| Internal Reference | 4.096V (yes) | 4.096V (yes) | 4.096V (yes) | 4.096V (yes) | 4.096V (yes) | 4.096V (yes) | 4.096V (yes) |
Principais diferenciais
- Industrial temperature grade with +/-2 LSB INL at lower cost than A-grade (vs MAX187AEPA+)
- Internal 4.096V reference integrated (vs MAX189CEPA)
- Wide -40C to +85C industrial temperature range (vs MAX187CCPA+)
Notas de projeto
The MAX187CEPA's 2uA shutdown current is the key power-saving feature for battery systems. Drive the SHDN pin (pin 5) high only during the 8.5us conversion + 1.5us acquisition window - typically 20-30us total per conversion - then return it low. According to the Maxim datasheet, total power drops from 7.5 mW operating to 10 uW in shutdown, a 750x reduction. Do not tie SHDN to a noisy MCU output without a 100kohm pull-down to keep the ADC enabled (default-on) during MCU reset.
Place a 0.1uF ceramic decoupling capacitor within 5mm of the VDD pin (pin 8) and a 4.7uF tantalum or ceramic bypass on the REF pin (pin 4). The internal 4.096V reference is sensitive to load transients; without proper REF bypassing the conversion noise floor can degrade by 1-2 LSB. Route analog ground (AGND) and digital ground (DGND) separately and join them at a single point at the chip's GND pin (pin 3) to avoid digital-noise coupling into the analog input.
Do not apply analog input voltages exceeding VDD (5V) or going below GND by more than 0.3V - the ESD diodes will forward-conduct and corrupt the conversion. For signals exceeding 5V, add an external resistor divider or a unity-gain buffer such as the MAX174AEPI. Also note that the SPI interface requires the host MCU to provide SCLK edges during the conversion - read the datasheet timing diagram carefully; a CS transition without the correct SCLK count produces invalid output codes.
Informações de conformidade
Original MAX187CEPA (without + suffix) is not lead-free / not RoHS compliant per Maxim legacy product designation. The MAX187CEPA+ variant (with plus suffix) is the RoHS-compliant lead-free version. Neither variant is AEC-Q100 qualified; these are commercial/industrial-grade parts not intended for automotive safety-critical applications.
