MAX155ACPI+ - 8-Ch 8-Bit 250ksps ADC w/ Simultaneous T/H | Maxim
MPN: MAX155ACPI+ ✓ نشطMAX155ACPI+ نظرة عامة
A successive-approximation register (SAR) ADC is a type of analog-to-digital converter that uses a binary search algorithm to resolve an analog input voltage into a digital code, one bit per clock cycle. SAR ADCs are characterized by low latency (no pipeline delay), deterministic conversion time, and excellent DC accuracy, making them well-suited for multiplexed multi-channel systems, precision DC metering, industrial process control, and data-acquisition front-ends. The MAX155's simultaneous sampling T/Hs set it apart from a generic 8-channel SAR: by capturing all eight inputs at the same moment, downstream digital processing can compute true per-sample differential measurements across the array.
Key features include 250 ksps aggregate throughput (with simultaneous sampling across all channels), an internal 2.5 V reference with low drift, software-selectable 4-/8-channel operation, single +5 V supply operation, on-chip T/H per channel, parallel microprocessor interface, and a hardware power-down pin that reduces supply current between conversions. The wide input range supports both single-ended (0-VREF) and true bipolar (±VREF) signals.
The MAX155 is built on a BiCMOS process that combines low-noise bipolar analog front-ends with CMOS logic for low power dissipation. Internal clock generation and a self-calibrating architecture minimize external component count, while the parallel interface allows direct connection to microprocessors and FPGAs for high-speed system integration.
Typical applications include multi-channel instrumentation and data-acquisition systems, vibration and modal analysis, motor control feedback loops, multichannel process control, medical monitoring front-ends, and any system where multiple analog signals must be sampled simultaneously for time-coherent analysis.
When designing with the MAX155ACPI+, ensure the analog input source impedance stays below the value specified in the datasheet to maintain acquisition accuracy. Decouple VDD and AVDR with 10uF tantalum and 0.1uF ceramic capacitors placed close to the pins, and keep analog and digital grounds tied to a single star point to minimize crosstalk.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, including cross-brand comparison and pinout reference.
بدائل مباشرة لـ MAX155ACPI+ — 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 MAX155ACPI+ (نفس عامل الشكل والبصمة) — يختلف في Package, Resolution, RoHS Status, Sampling Rate, Track-and-Hold.
MAX155BCPI+
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MAX155AEPI+
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MAX155ACPI
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منها📋 بديل مرجعي (غير موجود في الكتالوج)
MAX156CPI+
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منها📋 بديل مرجعي (غير موجود في الكتالوج)
MAX1202ACAP
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منهاتواصل لمعرفة السعر
عرض ورقة البيانات ←MAX155ACPI+ الحدود القصوى والخصائص الكهربائية
| الدقة | 8 bit |
| Number of Channels | 8 (software-selectable to 4) |
| معدل أخذ العينات | 250 ksps |
| Architecture | SAR (Successive Approximation) |
| Input Configuration | Single-Ended or Differential |
| Data Interface | Parallel |
| Internal Reference Voltage | 2.5 V |
| جهد التغذية | +5 V single supply |
| نطاق جهد الدخل | 0 to VREF (unipolar) or ±VREF (bipolar) |
| Track-and-Hold | Yes - 1 per channel, simultaneous sampling |
| Power-Down Mode | Yes (hardware pin) |
| Polarity | Unipolar or Bipolar (software-selectable) |
| العلبة | 28-PDIP (300 mil, through-hole) |
| حالة RoHS | Compliant (Pb-free '+' suffix) |
| Manufacturer | Maxim Integrated (now Analog Devices) |
تكوين أطراف MAX155ACPI+
| دبوس 1 | AIN1 — Analog Input Channel 1 |
| دبوس 2 | AIN2 — Analog Input Channel 2 |
| دبوس 3 | AIN3 — Analog Input Channel 3 |
| دبوس 4 | AIN4 — Analog Input Channel 4 |
| دبوس 5 | AGND — Analog Ground |
| دبوس 6 | REF — Reference Voltage (2.5V internal, bypass cap) |
| دبوس 7 | AVDD — Analog +5V Supply |
| دبوس 8 | MODE — Mode Select (4-/8-channel, unipolar/bipolar) |
| دبوس 9 | PD — Power-Down Input (active high) |
| دبوس 10 | CS — Chip Select (active low) |
| دبوس 11 | RD — Read Strobe (active low) |
| دبوس 12 | WR — Write / Convert Start (active low) |
| دبوس 13 | INT — Interrupt / End-of-Conversion |
| دبوس 14 | D7 — Data Bit 7 (MSB) |
| دبوس 15 | D6 — Data Bit 6 |
| دبوس 16 | D5 — Data Bit 5 |
| دبوس 17 | D4 — Data Bit 4 |
| دبوس 18 | D3 — Data Bit 3 |
| دبوس 19 | D2 — Data Bit 2 |
| دبوس 20 | D1 — Data Bit 1 |
| دبوس 21 | D0 — Data Bit 0 (LSB) |
| دبوس 22 | DGND — Digital Ground |
| دبوس 23 | DVDD — Digital +5V Supply |
| دبوس 24 | CLK — External Clock Input (optional) |
| دبوس 25 | NC — Not connected (per datasheet) |
| دبوس 26 | AIN5 — Analog Input Channel 5 |
| دبوس 27 | AIN6 — Analog Input Channel 6 |
| دبوس 28 | AIN7/AIN8 — Analog Input Channels 7 and 8 (differential pair in 4-ch mode) |
التطبيقات النموذجية
MAX155ACPI+ مناسب لـ 6 التطبيقs: Multi-Channel Data Acquisition (DAQ), Vibration & Modal Analysis, Industrial Process Control, Motor Control Feedback, Medical Patient Monitoring, Audio Multichannel Capture.
Multi-Channel Data Acquisition (DAQ)
The MAX155ACPI+ fits multi-channel DAQ front-ends because its 8 simultaneous-sampling track-and-holds preserve time coherence across all inputs. Each channel captures its analog value at the same instant, so vibration, strain, and sensor-array measurements can be compared sample-by-sample. The 250 ksps aggregate throughput is sufficient for audio-bandwidth and most industrial control loops, while the parallel data interface streams results directly into an FPGA or microcontroller FIFO without handshake stalls. Designers pair the MAX155ACPI+ with external op-amp buffers to drive the analog inputs below the source-impedance limit stated in the datasheet, achieving full 8-bit accuracy across all channels.
موصى به
Vibration & Modal Analysis
Modal analysis and vibration testing require phase-coherent sampling from multiple accelerometers or strain gauges. The MAX155ACPI+'s eight simultaneous T/Hs ensure every channel sees the same mechanical event at the same sample instant, allowing FFT-based modal extraction without per-channel timing correction. The 250 ksps aggregate rate supports vibration analysis into the tens of kHz range per channel. With the on-chip 2.5 V reference and bipolar input capability, the device handles IEPE-type accelerometer outputs directly through external biasing. This dramatically simplifies test-rig and shaker-table instrumentation where time alignment is non-negotiable.
موصى به
Industrial Process Control
PLC and DCS analog input modules demand reliable multi-channel sampling with deterministic latency. The MAX155ACPI+'s SAR architecture has no pipeline delay, providing deterministic per-sample conversion timing that simplifies control-loop math. Its 0-VREF unipolar and ±VREF bipolar input ranges accommodate 4-20 mA current-loop and ±10 V industrial signals through external resistor scaling. The integrated power-down pin lets the module idle between conversions, reducing heat dissipation in densely packed I/O racks. The parallel interface connects directly to backplane microprocessors without serializer overhead.
موصى به
Motor Control Feedback
Three-phase motor drives require simultaneous sampling of phase currents and DC-bus voltage for field-oriented control. The MAX155ACPI+ provides the timing alignment needed for Park/Clarke transforms, with all eight channels sampled in the same clock cycle. The 250 ksps rate supports PWM frequencies up to ~25 kHz with current-sense settling margins. The bipolar input mode accepts Hall-sensor and shunt-resistor-derived signals directly, while the on-chip reference minimizes drift across the motor's operating temperature range. This makes the part an effective legacy solution in servo drives, robotics, and CNC controllers.
موصى به
Medical Patient Monitoring
Patient monitors sample ECG, EEG, SpO2, respiration, and temperature channels where time alignment is critical for event correlation. The MAX155ACPI+ captures all eight physiological inputs simultaneously, allowing algorithms to detect arrhythmias, sync events, and respiration-cardiac coupling with sample-accurate cross-channel math. The 8-bit resolution is appropriate for display-and-alarm ECG front-ends, and the bipolar input range supports electrode-derived millivolt signals through external instrumentation amplifiers. The integrated power-down mode reduces thermal dissipation in bedside units, helping meet patient-skin-temperature safety envelopes.
موصى به
Audio Multichannel Capture
Multi-microphone arrays for beamforming and acoustic scene analysis require phase-locked sampling across all channels. The MAX155ACPI+ samples eight audio-bandwidth channels simultaneously at up to 250 ksps aggregate, well above the 192 kHz professional audio rate. With proper anti-alias filtering, the 8-bit dynamic range is sufficient for ultrasonic and acoustic-event-detection front-ends. Designers pair the ADC with MEMS microphone pre-amplifiers and route the parallel data into an FPGA DSP fabric for beamforming weights. The bipolar/unipolar input modes accept line-level and microphone-level signals through external scaling.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ MAX155ACPI+ — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | MAX155BCPI+ | MAX155AEPI+ | MAX155ACPI | MAX156CPI+ | MAX1202ACAP |
|---|---|---|---|---|---|---|
| Package | 28-PDIP (300 mil) | 28-PDIP (300 mil) | 28-PDIP (300 mil) | 28-PDIP (300 mil) | 28-PDIP (300 mil) | 28-PDIP |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 8 bit | 8 bit | 8 bit | 8 bit | 8 bit | 12 bit |
| Channels (simultaneous) | 8 | 8 | 8 | 8 | 8 (sequential, not simultaneous) | 8 (sequential) |
| Sampling Rate | 250 ksps | 250 ksps | 250 ksps | 250 ksps | ~100 ksps | ~100 ksps |
| Internal Reference | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Supply Voltage | +5 V single | +5 V single | +5 V single | +5 V single | +5 V single | +5 V single |
| Linearit Grade | A grade | B grade | A grade, extended temp | A grade (leaded) | B grade | Higher resolution |
| RoHS (Pb-free) | Yes ('+' suffix) | Yes | Yes | No (leaded finish) | Yes | Yes |
أبرز الفروقات
- True simultaneous sampling on all 8 channels via on-chip T/Hs (مقابلMAX156CPI+)
- Higher aggregate throughput at 250 ksps (مقابلMAX1202ACAP)
- 'A' grade linearity at production cost (مقابلMAX155BCPI+)
ملاحظات التصميم
Decouple AVDD and DVDD separately with a 10 uF tantalum and a 0.1 uF ceramic capacitor placed within 5 mm of the respective supply pins. Tie AGND and DGND to a single star-point ground near the device to avoid digital return currents corrupting the analog ground reference. The internal +2.5 V reference requires its own 1 uF ceramic bypass cap directly on the REF pin; insufficient bypassing increases noise and degrades ADC linearity.
Do not exceed the maximum analog input source impedance specified in the datasheet. Excessive source impedance causes incomplete track-mode settling and degrades effective resolution. Drive each AIN through a low-impedance buffer (op-amp output impedance <10 ohm) when the source cannot meet the spec. Power-down mode retains the interface logic state but the analog inputs float - allow 1 ms recovery time after bringing PD low before the next conversion.
Keep analog input traces short, direct, and guarded by a ground plane. Avoid running digital data bus lines (D0-D7, CS, RD, WR) parallel to analog input traces for more than a few millimeters to prevent digital crosstalk into the analog front-end. Place a small RC anti-alias filter on each AIN where the signal bandwidth warrants it; for the 250 ksps maximum throughput, design the analog input bandwidth to ~125 kHz maximum.
معلومات الامتثال
The '+' suffix denotes lead-free, RoHS-compliant finish per Maxim/Analog Devices lead-free packaging standard. AEC-Q100 not applicable as this is a commercial-grade through-hole ADC; the MAX155AEPI+ offers extended industrial temperature range.
