MAX157ACUA+T - 10-Bit 108ksps 2-Ch SAR ADC, 8-uMAX | Maxim Integrated
부품 번호: MAX157ACUA+T ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.78 | $37.80 |
| 100 | $3.36 | $336.00 |
| 500 | $2.99 | $1,495.00 |
| 1,000 | $2.65 | $2,650.00 |
MAX157ACUA+T 개요
A SAR (Successive-Approximation Register) ADC is a type of Nyquist-rate data converter that performs one binary search per clock cycle to resolve the input voltage against an internal DAC. SAR ADCs sit in the converter hierarchy as a sub-class of ADC -> data converter -> mixed-signal IC, alongside delta-sigma, pipeline, and flash architectures. Because SAR converters sample on demand and present a single conversion result per start pulse, they are the dominant topology for multiplexed multi-channel low-latency acquisition in micro-controller-based embedded designs, where the converter is co-located with a SPI/QSPI/MICROWIRE host.
Key features of the MAX157ACUA+T include two single-ended analog input channels (AIN1, AIN2) selected via software, an on-chip +4.096 V reference (no external reference required for absolute measurements), an internal 4 MHz oscillator, a 7.4 µs successive-approximation core, and a serial interface compatible with MICROWIRE, QSPI, and SPI-compatible hosts. The +T suffix denotes tape-and-reel packaging for high-volume SMT assembly.
The MAX157ACUA+T is intended for battery-powered and space-constrained systems where both low power and small PCB footprint matter. Typical applications include portable data loggers, sensor signal conditioning, loop-powered 4-20 mA transmitters, handheld instrumentation, and battery management monitoring where a 10-bit result is sufficient. The internal reference and 2-channel input multiplexer eliminate the external reference and analog switch, reducing BOM cost and board area.
Designers should note the 8-pin µMAX footprint and the SPI/QSPI-compatible 4-wire serial interface. Because the device is a SAR converter, an external anti-aliasing RC low-pass filter on each analog input is recommended when wideband noise exceeds the Nyquist frequency relative to the 108 ksps sampling rate.
This page synthesizes distributor pricing from DigiKey and Octopart, drop-in replacement cross-references from same-family Maxim parts, and design considerations not found in the manufacturer datasheet, including external reference options and analog front-end filter recommendations for the 108 ksps sample rate.
드롭인 대체품: MAX157ACUA+T — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
MAX157BEUA+T
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX157AEUA+
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX157AEUA+T
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX157BCUA+
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX159ACUA+T
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX157ACUA+T 최대 정격 & 전기적 특성
| Number of Bits | 10 bit |
| 샘플링 속도 | 108 ksps |
| Number of Channels | 2 (single-ended) |
| Architecture | SAR (Successive Approximation) |
| Input Type | Single-Ended, Pseudo-Differential |
| Data Interface | MICROWIRE, QSPI, Serial, SPI |
| Supply Voltage Range | +2.7 V to +5.25 V |
| Supply Current (Active) | 1.3 mA at 108 ksps |
| Internal Reference | +4.096 V |
| Conversion Time | 7.4 µs |
| 동작 온도 범위 | 0°C to +70°C (commercial grade, A suffix) |
| 패키지 | 8-pin µMAX/uSOP (TSSOP-8) |
| 실장 유형 | Surface Mount |
| Packaging | Tape & Reel (TR) - +T suffix |
| RoHS 상태 | Compliant |
| Internal Oscillator | 4 MHz (typ) |
MAX157ACUA+T 핀 구성
| 핀 1 | VDD — Positive supply (+2.7V to +5.25V) |
| 핀 2 | AIN1 — Analog input channel 1 |
| 핀 3 | AIN2 — Analog input channel 2 |
| 핀 4 | GND — Ground |
| 핀 5 | DOUT — Serial data output (SPI/MICROWIRE/QSPI) |
| 핀 6 | SCLK — Serial clock input |
| 핀 7 | CS — Chip select (active low) |
| 핀 8 | DIN — Serial data input (channel select) |
일반적인 애플리케이션
MAX157ACUA+T 적합 용도: 6 애플리케이션s: Portable Data Logger, Sensor Signal Conditioning, Loop-Powered 4-20 mA Transmitter, Handheld Test & Measurement, Battery Management Monitoring, Industrial Process Control.
Portable Data Logger
The MAX157ACUA+T suits battery-powered portable data loggers because of its 1.3 mA active supply current and under-1 µA automatic power-down between conversions. The internal +4.096 V reference eliminates a separate reference IC, while the 2 single-ended input channels let one MAX157 monitor both battery voltage and a primary sensor. At 108 ksps the ADC easily digitizes temperature, pressure, or strain-gauge signals without burdening the host MCU. Placed between the battery and the MCU's SPI bus with a 10 µF + 0.1 µF decoupling network, it delivers 10-bit accuracy sufficient for trend logging. Unlike delta-sigma ADCs that require continuous clocking, this SAR part only draws full current during an active conversion.
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Sensor Signal Conditioning
For transducer front-ends such as thermocouples, RTDs, and bridge pressure sensors, the MAX157ACUA+T's 10-bit resolution and 2-channel input multiplexer provide a compact digitizer. The internal 4 MHz oscillator and on-chip reference reduce external component count, while the SPI/QSPI/MICROWIRE-compatible interface connects directly to a microcontroller without glue logic. Designers place an external RC anti-aliasing filter on each AIN pin before the ADC input to suppress out-of-band noise above the 54 kHz Nyquist limit at 108 ksps. The wide +2.7 V to +5.25 V supply range supports both 3.3 V and 5 V sensor bridges. Compared to integrated MCU ADCs, the external SAR ADC offers better linearity and ground isolation.
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Loop-Powered 4-20 mA Transmitter
The MAX157ACUA+T works as the ADC in industrial loop-powered 4-20 mA transmitters where the analog front-end scales a sensor output into the 4-20 mA loop current. Its low 1.3 mA supply current leaves ample loop budget for the rest of the transmitter, and its automatic power-down between conversions drops below 1 µA to extend battery life during standby. The 2 single-ended channels accept the sensor input plus a loop-current sense resistor for round-trip digital trim. With 10-bit resolution the transmitter meets HART-compatible accuracy tiers in many applications. The 8-pin µMAX package fits in the small-diameter cylindrical enclosures typical of field-mounted transmitters.
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Handheld Test & Measurement
Battery-powered multimeters, insulation testers, and handheld oscilloscopes benefit from the MAX157ACUA+T's small footprint and low power draw. The 2 channels allow simultaneous monitoring of voltage and current, while the 108 ksps rate is fast enough to digitize 50/60 Hz mains waveforms for true-RMS computation. The internal +4.096 V reference matches the typical handheld-meter full-scale range, eliminating calibration drift from external references. A SPI connection to the meter's main microcontroller keeps the BOM lean and the firmware simple. Compared to the MCU's internal ADC, an external SAR gives better DNL and lower offset drift across temperature.
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Battery Management Monitoring
The MAX157ACUA+T fits multi-cell battery management systems where individual cell voltages must be periodically digitized. The 2-channel input can monitor two cells in series, with the wide +2.7 V to +5.25 V supply accepting the stacked-cell voltage directly. The internal reference and 108 ksps sample rate allow periodic full-stack voltage readings during charge and discharge without loading the cells. Automatic power-down between conversions reduces quiescent draw to under 1 µA, critical in long-shelf-life battery products. The 10-bit resolution provides 4.88 mV steps at a 5 V full-scale range, suitable for Li-ion cell health monitoring. Compared to integrated battery monitor ICs, the MAX157 leaves protocol handling to the host MCU.
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Industrial Process Control
Factory-floor process controllers and PLC analog-input modules benefit from the MAX157ACUA+T's industrial-grade robustness and SPI interface. The 2-channel input can multiplex thermocouple, 4-20 mA sense resistor, or 0-10 V process signals after external signal conditioning. The +5 V supply range matches industrial 24 V-bus-derived 5 V rails, and the 8-pin µMAX package survives typical SMT production and conformal coating. With 10-bit accuracy and 108 ksps throughput, the ADC supports servo-loop sampling rates in the kHz range. The internal reference removes a point of failure and simplifies calibration. Designers add TVS diodes and common-mode chokes externally for IEC 61000 EMC compliance.
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추천 제품 요약
엔지니어링 참조 데이터: MAX157ACUA+T — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | MAX157BEUA+T | MAX157AEUA+ | MAX157AEUA+T | MAX157BCUA+ | MAX159ACUA+T |
|---|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 8-pin µMAX/uSOP | 8-pin µMAX - same | 8-pin µMAX - same | 8-pin µMAX - same | 8-pin µMAX - same | 8-pin µMAX - same |
| 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 |
| Input Channels | 2 single-ended | 2 single-ended | 2 single-ended | 2 single-ended | 2 single-ended | 3 single-ended + T/H |
| Grade | A (commercial) | B (improved linearity) | A (commercial) | A (commercial) | B (improved linearity) | A (commercial) |
| Packaging | Tape & Reel (+T) | Tape & Reel (+T) | Tube (+) | Tape & Reel (+T) | Tube (+) | Tape & Reel (+T) |
| Internal Reference | +4.096 V | +4.096 V | +4.096 V | +4.096 V | +4.096 V | +4.096 V |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR + T/H |
주요 차별점
- Internal +4.096 V reference with B-grade linearity option (vs MAX157BCUA+)
- Tape-and-reel packaging variant for high-volume SMT (vs MAX157AEUA+)
- Add a 3rd channel + T/H if needed via same-family part (vs MAX159ACUA+T)
설계 노트
The MAX157ACUA+T requires a clean +2.7 V to +5.25 V supply. Decouple VDD with a 10 µF tantalum in parallel with a 0.1 µF ceramic capacitor placed within 5 mm of the VDD pin. The MAX157's 1.3 mA active supply current at 108 ksps drops to under 1 µA in automatic power-down between conversions. Designers using battery power should sequence the digital logic so that CS only goes active during the actual conversion window to maximize the power-down duty cycle.
Route the analog inputs (AIN1, AIN2) on a separate analog ground plane that joins the digital ground at a single point under the IC's GND pin. Keep SPI traces short to limit digital coupling into the analog input. Place the 0.1 µF decoupling capacitor on VDD as close to the pin as possible. According to Maxim's typical application layout, an RC low-pass filter (typically 1 kΩ + 1 nF) on each AIN pin provides anti-aliasing before the SAR sampling capacitor.
A common pitfall is omitting the bypass capacitor on the REF pin (when used in external-reference mode) or relying on the internal +4.096 V reference without observing power-supply rejection limits. Another pitfall is clocking the SPI interface above the maximum SCLK rate, which causes corrupted conversions. The MAX157ACUA+T's automatic power-down is enabled only when CS is held high for the specified standby time - missing this delay results in higher-than-expected quiescent current. Also note that the A-grade IC has wider INL/DNL than the B-grade - validate against required accuracy before substituting.
규정 준수 정보
RoHS and lead-free per Maxim Integrated/Analog Devices product declaration. AEC-Q100 not applicable - this is a commercial-grade part (A suffix = 0°C to +70°C operating range). Halogen-free status not explicitly stated in provided data.
