MAX187BEPA - 12-Bit Serial ADC, +5V, 75ksps | Maxim Integrated
MPN: MAX187BEPA ✗ انتهى عمره الإنتاجيMAX187BEPA نظرة عامة
An ADC is a mixed-signal integrated circuit that converts a continuous analog voltage into a discrete digital code. The MAX187 sits in the successive-approximation register (SAR) ADC family - which combines a sample-and-hold front end, an internal DAC, and a comparator running a binary-search algorithm - offering a favorable trade-off between speed and accuracy for low-bandwidth instrumentation. As part of the broader data-converter hierarchy, the SAR ADC falls between high-speed flash converters (>100 MSPS) and high-resolution sigma-delta converters (>16 bits), making the MAX187 well suited to industrial control loops, panel meters, and portable data-acquisition front ends where single +5V supply operation simplifies power design.
Key features include ±1/2 LSB integral nonlinearity (MAX187A/B grade), 1.5 µs acquisition-time track-and-hold, internal 4.096 V buffered reference (no external reference required), 3-wire SPI/QSPI/MICROWIRE-compatible serial interface, 1.5 mA typical operating current, and a 2 µA power-down shutdown mode. The 8-pin PDIP package (suffix E) supports breadboard-friendly through-hole prototyping and is the standard format for the B-temperature-grade (-40 °C to +85 °C) industrial variant.
The MAX187 internal architecture combines an on-chip clock, a sample/hold amplifier, an internal reference buffer, and a digital serial output stage in a single die. Its true-differential analog input stage accepts a 0 V to 5 V unipolar range, while the internal 4.096 V reference and 12-bit resolution yield a 1 mV per LSB step size ideal for transducer digitisation.
Typical applications include portable data loggers, industrial process control, isolated front-end signal conditioning with opto-isolated serial interfaces, battery-powered instrumentation, and panel-meter digitiser circuits. Designers select the MAX187 when board area is constrained, an external reference must be avoided, and a 3-wire serial interface to a microcontroller is sufficient.
When designing with the MAX187, place the supply bypass capacitor (10 µF electrolytic plus 0.1 µF ceramic) within 5 mm of the VDD pin, keep the analog input traces short and guarded by ground, and observe the 8.5 µs minimum conversion time. The MAX187 differs from the pin-compatible MAX189 only in reference topology: the MAX187 integrates the 4.096 V reference, while the MAX189 requires an external reference. The MAX187 also differs from the MAX187A (tighter linearity) and MAX187C (commercial grade) only in linearity spec and temperature range, all of which share the 8-pin PDIP footprint.
This page synthesises distributor pricing, drop-in 8-pin PDIP alternatives drawn from the same Maxim MAX187 family, and practical design notes not found in the manufacturer datasheet alone, providing engineers a single decision-ready resource.
بدائل مباشرة لـ MAX187BEPA — نفس الحزمة، متوافق دبوس بدبوس. تُستثنى القطع ذات الحزم المختلفة التي تتطلب تعديل PCB.
الطرازات في هذه السلسلة
طرازات من نفس السلسلة متوافقة تمامًا مع MAX187BEPA (نفس عامل الشكل والبصمة) — يختلف في Sampling Rate, Shutdown Current, Supply Voltage, Conversion Time, Package.
MAX187AEPA
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MAX187BCPA
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←MAX187CCPA
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MAX189EPA
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MAX187BEPA الحدود القصوى والخصائص الكهربائية
| الدقة | 12 bits |
| Architecture | SAR (Successive Approximation) |
| Input Channels | 1 single-ended |
| معدل أخذ العينات | 75 ksps (8.5 µs conversion time) |
| Analog Input Range | 0 V to 5 V |
| جهد التغذية | +5 V (single supply) |
| Integral Nonlinearity (INL) | ±1/2 LSB (B grade) |
| Internal Reference | 4.096 V buffered |
| Operating Current | 1.5 mA typical |
| تيار الإيقاف | 2 µA |
| Track/Hold Acquisition Time | 1.5 µs |
| Serial Interface | 3-wire SPI/QSPI/MICROWIRE compatible |
| العلبة | 8-pin PDIP (E) |
| نطاق درجة حرارة التشغيل | -40 °C to +85 °C (B/EPA grade, industrial) |
| نوع التركيب | Through-Hole |
تكوين أطراف MAX187BEPA
| دبوس 1 | VDD — +5V power supply input |
| دبوس 2 | AIN — Analog input (0V to 5V) |
| دبوس 3 | GND — Ground |
| دبوس 4 | SCLK — Serial clock input |
| دبوس 5 | DOUT — Serial data output |
| دبوس 6 | CS — Chip select (active low) |
| دبوس 7 | REF — Reference pin / internal 4.096V buffered reference output |
| دبوس 8 | SHDN — Shutdown input (active high to enter 2 µA shutdown mode) |
التطبيقات النموذجية
MAX187BEPA مناسب لـ 6 التطبيقs: Portable Data Logger, Industrial Process Control Front End, Panel Meter and Instrumentation Digitiser, Isolated Serial Sensor Digitiser, Battery-Powered Remote Sensor Node, Legacy Industrial Replacement / Maintenance.
Portable Data Logger
The MAX187BEPA's 75 ksps throughput and 12-bit resolution make it well suited to portable battery-powered data loggers sampling sensor signals at moderate rates. The internal 4.096V reference yields a 1 mV per LSB step that directly digitises thermocouple and thermistor bridge outputs after a low-offset front-end amplifier; the 2 µA shutdown current drops total supply drain to negligible levels between conversions, extending battery life for months of unattended field logging.
موصى به
Industrial Process Control Front End
In 4-20 mA current-loop and 0-10V process-control panels, the MAX187BEPA provides 12-bit resolution that maps naturally to 0-5V transducer signals after a 250 Ω sense resistor or voltage divider. The 3-wire SPI interface is opto-isolator-friendly, enabling isolated front-end digitisation that protects the host microcontroller from ground loops and 24V industrial transients; the -40 °C to +85 °C B-grade industrial temperature range ensures reliable operation across factory-floor environments.
موصى به
Panel Meter and Instrumentation Digitiser
Digital panel meters for voltage, current, and temperature require a single-channel 12-bit ADC with a stable internal reference - exactly what the MAX187BEPA provides. The integrated 4.096V reference removes the cost and board area of an external reference IC, while the 1.5 mA operating current suits mains-powered meter enclosures; the 8-pin PDIP package also eases hand-soldered prototype builds for low-volume test instruments and laboratory bench meters.
موصى به
Isolated Serial Sensor Digitiser
Opto-isolated ADC front ends benefit from the MAX187BEPA's 3-wire serial interface (CS, SCLK, DOUT) that crosses the isolation barrier with only three optocouplers instead of a parallel bus. The internal 4.096V reference remains on the field side and is digitised before crossing the barrier, eliminating reference ground loops that plague isolated designs using external references; the 2 µA shutdown mode powers down the ADC between conversions to minimise field-side dissipation.
موصى به
Battery-Powered Remote Sensor Node
Remote sensor nodes for environmental monitoring, agriculture, and asset tracking need an ADC that combines low operating current, a small package, and a stable reference. The MAX187BEPA's 1.5 mA operating current and 2 µA shutdown current keep average drain in the tens of microamps when sampling once per minute, while the internal 4.096V reference and 12-bit resolution deliver 1 mV quantisation suitable for soil-moisture, temperature, and light-sensor digitisation over a 0-5V input range.
موصى به
Legacy Industrial Replacement / Maintenance
The MAX187BEPA's 8-pin PDIP through-hole package is the preferred form factor for maintenance of installed industrial controllers, PLC analogue input cards, and SCADA remote terminal units whose original designs used through-hole ADCs. The pin-compatible MAX187AEPA / MAX187BCPA / MAX189EPA family lets maintenance technicians swap a failed ADC on the same PCB without layout changes, while the B-grade industrial temperature range matches the original BOM specification.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ MAX187BEPA — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | MAX187AEPA | MAX187BCPA | MAX187CCPA | MAX189EPA |
|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | PDIP-8 (through-hole) | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 75 ksps (8.5 µs conversion) | 75 ksps | 75 ksps | 75 ksps | 75 ksps |
| Integral Nonlinearity (INL) | ±1 LSB (B grade) | ±1/2 LSB (A grade, tighter) | ±1 LSB (B grade) | ±2 LSB (C grade) | ±1 LSB (B grade) |
| Reference | Internal 4.096 V buffered | Internal 4.096 V buffered | Internal 4.096 V buffered | Internal 4.096 V buffered | External reference required |
| Supply Voltage | +5 V single supply | +5 V | +5 V | +5 V | +5 V |
| Operating Temperature Range | -40 °C to +85 °C (industrial, B grade) | -40 °C to +85 °C (industrial, A grade) | 0 °C to +70 °C (commercial, B grade) | 0 °C to +70 °C (commercial, C grade) | -40 °C to +85 °C (industrial, B grade) |
أبرز الفروقات
- Internal 4.096 V buffered reference eliminates external reference cost and PCB area (مقابلMAX189EPA)
- B-grade ±1 LSB INL balances linearity with cost for most industrial designs (مقابلMAX187AEPA (A-grade))
- Industrial -40 °C to +85 °C B/EPA grade covers factory-floor temperature requirements (مقابلMAX187BCPA (commercial 0-70 °C))
ملاحظات التصميم
Place a 10 µF electrolytic (or tantalum) plus a 0.1 µF ceramic bypass capacitor within 5 mm of the VDD pin (pin 1) to suppress switching-noise coupling from the digital 3-wire SPI interface into the analog front end. When the SHDN pin (pin 8) is driven high, the supply current drops to 2 µA, but the internal reference may take up to 1 ms to settle on wake-up; budget an extra 1 ms in low-duty-cycle sampling loops. Estimated: with VIN = 5 V, I_op = 1.5 mA, quiescent dissipation is ~7.5 mW during conversion.
Route the AIN analog trace as a short, guarded path with a ground fill on both sides to minimise digital-noise pickup. Keep the AIN trace away from the SCLK trace (pin 4) and DOUT trace (pin 5) by at least 3 mm; cross only at right angles if unavoidable. For breadboard layouts, decouple the reference pin (pin 7) with a 10 µF tantalum plus 0.1 µF ceramic to absorb the reference-buffer transient current steps that occur during the internal DAC settling phase of each SAR bit decision.
Do not drive AIN (pin 2) beyond 0 V to +5 V - signals outside this range cause ESD latch-up and degrade linearity. Do not tie SHDN (pin 8) to VDD unconditionally - the ADC must be brought out of shutdown for at least 200 µs before a conversion to allow reference-buffer wake-up. Do not rely on the internal reference as a low-noise precision source for downstream circuits (e.g. transducer excitation); the reference is trimmed for the ADC's own quantisation but adds ~50 µV noise. When migrating from MAX187 to MAX189, do not leave the REF pin floating - the MAX189 requires an external reference, otherwise DOUT emits all-ones conversions.
معلومات الامتثال
RoHS/REACH compliant per Maxim Integrated (now Analog Devices) product page; lead-free and halogen-free per PDIP-8 standard device ratings. Not AEC-Q100 qualified - the MAX187 family is not rated for automotive applications; engineering teams needing AEC-Q100 should select the MAX11131 or similar qualified automotive ADC.
