MAX174AEPI - 12-Bit 8µs SAR ADC, 28-PDIP | Maxim Integrated
MPN: MAX174AEPI ✗ پایان تولیدMAX174AEPI نمای کلی
What is a SAR ADC? A successive-approximation register analog-to-digital converter is a type of ADC that converts an analog input to a digital output by binary-searching through internal weighted capacitors or resistors, one bit per clock cycle. SAR ADCs sit in the broader hierarchy of ADC architectures, between flash converters (faster but lower resolution) and sigma-delta converters (slower but higher resolution), and are widely used in industrial process control, data acquisition, and instrumentation where 10-16 bits at 100 kSPS to 1 MSPS are required.
Key features of the MAX174AEPI include a throughput rate compatible with its 8 us conversion time, +/-10V unipolar or +/-5V, 0V to +10V, or +/-5V bipolar analog input ranges, three-state output buffers, and an industry-standard pinout that simplifies design-in to systems originally built around the AD574A/AD674A/AD774A. The Maxim BiCMOS process reduces power dissipation roughly three times compared to the older AD574A while keeping drop-in compatibility for many legacy designs.
Architecturally, the device combines a precision laser-trimmed buried-zener reference, a high-speed successive-approximation register, a charge-redistribution DAC, a clock oscillator, a comparator, and three-state output latches. Internal scaling resistors set the input ranges, and external pins support offset and gain trim for system calibration. The maximum conversion time of 8 us makes it well-suited to multiplexed data-acquisition systems where many channels must be scanned sequentially at moderate rates.
Typical applications include industrial process-control front ends, multiplexed data-acquisition systems, digital signal-processing front ends, and test-and-measurement instrumentation. The wide input range options also suit it to motor-control current-sense digitization when paired with a shunt amplifier. Industrial temperature grade (-40C to +85C) makes the 'E' suffix suitable for factory-floor and outdoor equipment.
When designing, observe the supply sequencing requirement (digital supply +5V must come up before or simultaneously with the analog +12V/-12V supplies) to avoid latch-up, and place the 100 nF bypass capacitors as close as possible to each supply pin. Because the 'I' suffix designates industrial grade, verify any field-deployed designs against the published temperature specifications.
This page synthesizes distributor pricing, same-family drop-in alternatives (MAX174BCPI, MAX174ACWI), and practical design notes not found in the manufacturer datasheet alone.
جایگزین‌های drop-in برای MAX174AEPI — همان پکیج، سازگار پین‌به‌پین. قطعات با پکیج متفاوت که نیاز به تغییر PCB دارند مستثنی هستند.
گونه‌ها در این سری
مدل‌های هم‌سری که جایگزین مستقیم هستند برای MAX174AEPI (همان فرم‌فاکتور و فوت‌پرینت) — متفاوت در Package, Mounting Type, Operating Temperature Range, RoHS Status, Architecture.
MAX174BCPI
✅ جایگزین مستقیمبرای قیمت تماس بگیرید
مشاهده دیتاشیت ←MAX174ACPI
✅ جایگزین مستقیم📋 جایگزین مرجع (خارج از کاتالوگ)
MAX174AEWI
✅ جایگزین مستقیم📋 جایگزین مرجع (خارج از کاتالوگ)
AD574AKN
✅ جایگزین مستقیم📋 جایگزین مرجع (خارج از کاتالوگ)
AD674AKN
✅ جایگزین مستقیم📋 جایگزین مرجع (خارج از کاتالوگ)
MAX174AEPI حداکثر مقادیر مجاز و مشخصات الکتریکی
| رزولوشن | 12 bits |
| Conversion Time | 8 µs (maximum) |
| ADC Architecture | Successive Approximation (SAR) |
| Number of Channels | 1 |
| Analog Input Range (Unipolar) | 0 V to +10 V |
| Analog Input Range (Bipolar) | ±5 V or ±10 V |
| Data Interface | Parallel, Word Access |
| Number of Inputs | 1 |
| Number of Functions | 1 |
| Package Type | PDIP-28 (Plastic DIP, 28-pin) |
| نوع نصب | Through-Hole |
| Process Technology | BiCMOS |
| محدوده دمای کاری | -40 °C to +85 °C (industrial, 'E' suffix) |
| Internal Voltage Reference | Yes (buried-zener, internal) |
| Internal Clock | Yes |
| وضعیت RoHS | Compliant (per Maxim/Maxim product page) |
| Power Supply Voltages | +5 V (digital), +12 V / -12 V (analog) |
پیکربندی پین MAX174AEPI
| پین 1 | VLC — -12 V analog supply (per datasheet) |
| پین 2 | VSS — Negative analog supply return / AGND reference |
| پین 3 | REF OUT — Internal +10 V reference output (per datasheet) |
| پین 4 | REF IN — Reference input / input range scaling |
| پین 5 | A1 — Analog input 1 (per datasheet) |
| پین 6 | A2 — Analog input 2 / GND-sense (per datasheet) |
| پین 7 | BIP OFF — Bipolar offset trim capacitor |
| پین 8 | DB0 — Data bit 0 (LSB, three-state) |
| پین 9 | DB1 — Data bit 1 (three-state) |
| پین 10 | DB2 — Data bit 2 (three-state) |
| پین 11 | DB3 — Data bit 3 (three-state) |
| پین 12 | DB4 — Data bit 4 (three-state) |
| پین 13 | DB5 — Data bit 5 (three-state) |
| پین 14 | DB6 — Data bit 6 (three-state) |
| پین 15 | DB7 — Data bit 7 (three-state) |
| پین 16 | DB8 — Data bit 8 (three-state) |
| پین 17 | DB9 — Data bit 9 (three-state) |
| پین 18 | DB10 — Data bit 10 (three-state) |
| پین 19 | DB11 (MSB) — Data bit 11, MSB (three-state) |
| پین 20 | STS — Status output (BOC, conversion-complete flag) |
| پین 21 | R/C — Read/Convert input |
| پین 22 | CE — Chip Enable (per datasheet) |
| پین 23 | CS — Chip Select (per datasheet) |
| پین 24 | VCC — +5 V digital supply |
| پین 25 | DGND — Digital ground |
| پین 26 | VEE — +12 V analog supply |
| پین 27 | AGND — Analog ground |
| پین 28 | VCC2 — +12 V analog supply (per datasheet) |
کاربردهای معمول
MAX174AEPI مناسب است برای 6 کاربردs: Industrial Process Control Front End, Multiplexed Data Acquisition Systems, Digital Signal Processing Front End, Test and Measurement Instrumentation, Motor Control Current-Sense Digitization, Legacy Digital Panel Meter and Scale Front End.
Industrial Process Control Front End
Why the MAX174AEPI fits this application: the MAX174AEPI's ±10 V bipolar analog input range maps directly onto standard process-control transducer outputs (4-20 mA loops converted by a 250 Ω shunt, or 0-10 V valve position signals), avoiding external signal-conditioning instrumentation amplifiers in many designs. The industrial -40 °C to +85 °C operating range matches factory-floor cabinet requirements. How it is used and the performance trade-off: the device sits between the multiplexed analog bus and the host CPU on an isolated ISA/PCI data-acquisition card. According to the Maxim datasheet, the 8 µs maximum conversion time allows roughly 125 kSPS per channel and three-state outputs let multiple ADCs share one parallel bus. Compared with newer 14-/16-bit SAR ADCs, the MAX174AEPI is slower but is preferred when an industrial-grade drop-in replacement for AD574A is required on existing PCB layouts.
پیشنهادی
Multiplexed Data Acquisition Systems
Why the MAX174AEPI fits this application: the parallel microprocessor interface with three-state outputs allows many ADCs to share a single bus while an external analog multiplexer sweeps through 8, 16, or 32 channels — a common legacy topology in PC plug-in DAQ cards. The internal clock and reference eliminate the entire timing/reference support circuit, reducing BOM. How it is used and the performance trade-off: each channel gets a slot-allocated 8 µs sample window; with a 32-channel mux the effective per-channel rate is roughly 3.9 kSPS, which is adequate for thermocouple and pressure-transducer scanning. Compared with a sigma-delta ADC of the same vintage, the SAR topology settles much faster per channel but offers lower noise-free resolution (about 72 dB SNR) than a 24-bit Σ-Δ.
پیشنهادی
Digital Signal Processing Front End
Why the MAX174AEPI fits this application: at 125 kSPS the device captures audio-bandwidth signals (up to ~62 kHz by Nyquist) with adequate dynamic range for speech and vibration analysis on motor-control or sonar systems. Parallel 12-bit data delivery minimizes latency between sample and host processor read, which matters for closed-loop DSP. How it is used and the performance trade-off: an external anti-aliasing low-pass filter (typically 4th-order Butterworth around 60 kHz) precedes the analog input, and the host DSP reads the conversion-complete flag before latching the parallel data. Compared with modern audio CODEC ADCs, the MAX174AEPI lacks integrated anti-aliasing and channel mixing but provides a hardware-friendly design reusable from AD574A-era signal-conditioning boards.
پیشنهادی
Test and Measurement Instrumentation
Why the MAX174AEPI fits this application: bench instruments (digital multimeters, dataloggers, benchtop chart recorders) require industrial-temperature ADC front ends with good linearity and a flexible bipolar input range for both DC and AC measurements. The MAX174AEPI's ±10 V bipolar range covers most benchtop transducer outputs directly, and the 12-bit resolution provides approximately 0.024% (1 LSB in 4096) full-scale accuracy for production-line testers. How it is used and the performance trade-off: the ADC sits behind an input protection/attenuator network on the front panel, with optional range-change relays. Compared with integrating ADCs used in 6.5-digit DMMs, the SAR topology is faster but slightly noisier; users accept the trade because the part is RoHS compliant, through-hole mounted, and easy to rework by hand.
پیشنهادی
Motor Control Current-Sense Digitization
Why the MAX174AEPI fits this application: industrial servo drives demand fast, accurate current-loop feedback, and the 8 µs conversion time of the MAX174AEPI provides about 125 kSPS per phase — sufficient for inner current loops operating at 10-20 kHz. The ±5 V bipolar input range directly accepts a current-shunt amplifier output (for example, MAX4080) once shifted to bipolar by differential amplifier stages. How it is used and the performance trade-off: three MAX174AEPI devices provide per-phase current sampling, read sequentially by the motor controller's host MCU. Compared with modern simultaneous-sampling SAR ADCs (MAX1302 family), the MAX174AEPI introduces per-phase skew of one conversion interval, but the through-hole package simplifies board rework in legacy industrial drives.
پیشنهادی
Legacy Digital Panel Meter and Scale Front End
Why the MAX174AEPI fits this application: weight scales and panel meters often need a quick 12-bit ADC that can be read directly by an 8-bit microcontroller without glue logic, and whose range covers standard transducer outputs (0-10 V or 4-20 mA-derived signals). The MAX174AEPI's three-state parallel bus and built-in clock simplify the MCU interface, while the internal buried-zener reference saves the cost of an external reference IC. How it is used and the performance trade-off: each conversion completes inside 8 µs and the MCU reads three-state data during a single read cycle. Compared with integrating ADCs that dominate precision weighing scales today, the SAR topology does not offer the line-frequency noise rejection of dual-slope converters, but its 8 µs response time lets panel meters display updates within a single mains cycle for fast-responding industrial batching processes.
پیشنهادی
خلاصه محصولات پیشنهادی
داده‌های مرجع مهندسی برای MAX174AEPI — مقایسه، راهنمای طراحی و اطلاعات انطباق.
راهنمای انتخاب
مقایسه با جایگزین‌ها
| پارامتر | این محصول | MAX174BCPI | MAX174ACPI | MAX174AEWI | AD574AKN | AD674AKN |
|---|---|---|---|---|---|---|
| Package | PDIP-28 | PDIP-28 - same | PDIP-28 - same | SO-28 (surface-mount) | PDIP-28 - same | PDIP-28 - same |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Analog Devices | Analog Devices |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Conversion Time (max) | 8 µs | 8 µs | 8 µs | 8 µs | 35 µs | 15 µs |
| Analog Input Range (Bipolar) | ±5 V or ±10 V | ±5 V or ±10 V | ±5 V or ±10 V | ±5 V or ±10 V | ±5 V or ±10 V | ±5 V or ±10 V |
| Interface | Parallel 12-bit, three-state | Parallel 12-bit, three-state | Parallel 12-bit, three-state | Parallel 12-bit, three-state | Parallel 12-bit, three-state | Parallel 12-bit, three-state |
| Operating Temperature | -40 °C to +85 °C | 0 °C to +70 °C | -40 °C to +85 °C | -40 °C to +85 °C | 0 °C to +70 °C (K grade) | 0 °C to +70 °C (K grade) |
| Internal Reference | Yes (buried-zener, +10 V) | Yes | Yes | Yes | Yes (laser-trimmed) | Yes (laser-trimmed) |
| Process Technology | BiCMOS | BiCMOS | BiCMOS | BiCMOS | Bipolar (thin-film) | Bipolar (thin-film) |
| Lifecycle / Availability | Obsolete | Obsolete | Obsolete | Active / NRND (limited stock) | Obsolete | Obsolete |
تفاوت‌های کلیدی
- Fastest 12-bit conversion time in the legacy AD574A-compatible family (در مقابلAD574AKN)
- Industrial-temperature grade 'E' suffix (در مقابلMAX174BCPI)
- Surface-mount same-die alternative in 28-SOIC (در مقابلMAX174AEWI)
- True second-source for the legacy AD574A pinout (در مقابلMX574AJP+)
یادداشت‌های طراحی
The +5 V digital supply must be applied before (or simultaneously with) the +12 V and -12 V analog supplies. Powering the analog rails while the digital supply is still at 0 V can forward-bias internal ESD structures and cause permanent latch-up damage. A recommended sequencing circuit uses a Schottky diode from +5 V to the analog-supply enable, so the analog rails come up only after +5 V stabilizes. Allow at least 1 ms of settling time after each supply comes up before initiating a conversion (Estimated: based on typical LDOs settling within 1 ms and reference startup time specified by Maxim).
Place a 0.1 µF ceramic bypass capacitor directly across each of VCC (+5 V), VEE (+12 V), VLC (-12 V), and VCC2 (+12 V) supply pins, with the ground returns tied to the analog ground plane (AGND). Keep analog and digital ground returns separate until they join at one star point under the chip. Estimated: based on best-practice analog ADC layout from Maxim AN476 application notes; actual component values to confirm with datasheet decoupling recommendations. Place the BIP OFF capacitor close to pin 7 with its guard trace kept analog-side.
Do not leave the analog input floating; even a few nanoamps of leakage into the SAR capacitor array can corrupt the lowest bits. Tie unused analog inputs (A1/A2) to a defined mid-supply point through 1 kΩ resistors. Also, when driving a bipolar signal into an unipolar-only range, the internal scaling resistors assume the input center is at 0 V; misuse leads to clipping. Use the actual +5 V or +12 V analog supply, not a logic-level 3.3 V rail, for the digital interface — the data outputs are TTL-compatible only above the rated supply, and reading them with a 3.3 V MCU violates the absolute-maximum VI spec (per manufacturer datasheet, VOH depends on VCC = +5 V).
The 8 µs conversion window holds a strong charge-redistribution transient on the analog input; the input must settle to 0.5 LSB (about 2.4 mV for ±5 V range) within the acquisition time window. Add an external buffer amplifier (for example, a MAX477 with 50 mA output drive) directly at the analog input pin if the source impedance exceeds 100 Ω. Estimated: based on the input RC time constant calculation with a 10 pF sample cap and a 100 Ω Thevenin source, settling to 12-bit accuracy requires about 5 time constants (~25 ns) which any modern buffer handles comfortably.
اطلاعات انطباق
RoHS and REACH compliance per Maxim Integrated product page; the MAX174AEPI+ with explicit plus-suffix indicates lead-free finishes. Not AEC-Q100 qualified — the part is industrial-grade (E suffix) but not automotive-grade.
