MAX157ACUA - 10-Bit 108ksps 2-Ch SAR ADC | Maxim Integrated
Référence : MAX157ACUA ✗ Fin de vie| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $6.92 | $6,92 |
| 10 | $6.18 | $61,80 |
| 100 | $5.42 | $542,00 |
| 500 | $4.78 | $2 390,00 |
| 1 000 | $4.15 | $4 150,00 |
MAX157ACUA Présentation
An SAR ADC (Successive-Approximation Register Analog-to-Digital Converter) is a type of data converter that uses a binary search algorithm combined with an internal DAC to convert an analog input to a digital code, typically one sample at a time with no pipeline latency. SAR ADCs sit within the broader hierarchy of analog-to-digital converters, alongside delta-sigma, pipeline, and flash architectures; they are valued for low power consumption, deterministic latency, and good DC accuracy at moderate sampling rates, making them well-suited for instrumentation, sensor read-out, and embedded data-acquisition designs.
Key differentiating features of the MAX157ACUA include a 2-channel input mux (2 analog inputs selectable through software), an integrated +2.5V reference (factory-trimmed, with REF option on select variants), an external reference input for flexibility, low operating supply current, and hardware/software shutdown mode that drops the supply current to < 1 µA in standby. The wide 2.7V-5.25V supply range permits operation directly from a single-cell Li-ion battery or a 3.3V/5V regulated rail.
Architecturally, the MAX157ACUA employs a charge-redistribution DAC with a built-in sample-and-hold, controlled by an SAR logic core that produces 10-bit results over four internal clock cycles. The device supports both unipolar (0-VREF) and pseudo-bipolar (VREF/2 offset) input ranges when driven in two's-complement mode, providing flexibility for single-supply signal-chain applications.
Typical applications for the MAX157ACUA include portable data loggers, battery-powered sensor read-out boards, industrial process-control loops, panel meters, and embedded system front-ends where low power and small footprint matter more than extreme sampling speed. This page synthesizes distributor pricing, drop-in alternatives, and practical design guidance not found in the manufacturer datasheet alone.
When designing with this device, place a 0.1 µF decoupling capacitor close to the VDD pin and a 10 µF bypass on the reference output if the internal reference is used. Operating at the higher 5 V supply yields the best dynamic range, but always observe the absolute-maximum VDD rating from the datasheet.
Alternatives de remplacement direct pour MAX157ACUA — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec MAX157ACUA (même facteur de forme et même empreinte).
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
MAX157AEUA+
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX157ACUA+
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX157BCUA+
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX157BEUA+
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX157CCUA+
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
MAX157ACUA Valeurs maximales et caractéristiques électriques
| Résolution | 10 bits |
| Fréquence d'échantillonnage | 108 ksps |
| Number of Input Channels | 2 (single-ended) |
| Conversion Time | 7.4 us |
| Supply Voltage (VDD) | +2.7 V to +5.25 V |
| Supply Current (power-down) | < 1 uA |
| Tension de référence | Internal +2.5 V (external reference option) |
| Input Voltage Range (unipolar) | 0 V to VREF |
| Data Interface | SPI / QSPI / MICROWIRE compatible, serial |
| Boîtier | 8-pin uMAX (UMAX) |
| Plage de température de fonctionnement | 0 C to +70 C (commercial, AC suffix) |
| Type de montage | Surface Mount |
| Niveau MSL | 1 (unlimited floor life at <30 C / 85% RH) |
Configuration des broches de MAX157ACUA
| Broche 1 | AIN1 — Analog input channel 1 (single-ended) |
| Broche 2 | GND — Ground |
| Broche 3 | AIN2/REF- — Analog input channel 2 / reference negative |
| Broche 4 | REF/VREF — Internal +2.5V reference output or external reference input |
| Broche 5 | VDD — Positive supply, +2.7V to +5.25V |
| Broche 6 | DOUT — Serial data output (tri-state, SPI-compatible) |
| Broche 7 | CS/SHDN — Active-low chip select / shutdown (combined function) |
| Broche 8 | SCLK — Serial clock input (Schmitt trigger) |
Applications typiques
MAX157ACUA convient pour 6 applications: Portable Data Logger, Industrial Process-Control Sensor Read-Out, Panel Meter / Digital Voltmeter Front-End, Embedded System Sensor Hub, Battery-Powered Medical Monitor, Consumer Touch-Panel Controller.
Portable Data Logger
The MAX157ACUA fits portable data loggers thanks to its 10-bit / 108 ksps throughput, 2-channel mux, and sub-1 uA power-down current. The Maxim datasheet cites automatic shutdown between conversions as the key power-saving feature for battery-driven designs. With a 3.6 V Li-ion supply the device draws only milliamps during conversion and drops to <1 uA in standby. Two ADC inputs can sample a sensor pair (temperature + pressure, for example) without external multiplexing. Pin-compatible and footprint-compatible with modern replacements, the MAX157ACUA remains a reference design choice for low-power logging.
Recommandé
Industrial Process-Control Sensor Read-Out
The MAX157ACUA handles 4-20 mA or 0-10 V sensor signals through its 0-VREF input range and 2.7V-5.25V supply. In a typical 3.3V industrial loop, AIN1 samples a voltage-clamped transducer signal while AIN2 reads a reference, allowing software calibration. The integrated +2.5 V reference and external reference option simplify ratiometric or absolute measurements. The 8-pin uMAX package keeps the analog front-end within a 6 mm footprint, suitable for distributed I/O cards where each channel needs its own ADC.
Recommandé
Panel Meter / Digital Voltmeter Front-End
The MAX157ACUA suits handheld DVMs and panel meters that need a 10-bit reading across two ranges (e.g., voltage and current). The internal +2.5 V reference of the MAX157ACUA establishes a 2.5 V full-scale that pairs naturally with a 4:1 resistive divider for a 10 V range. SPI/QSPI/MICROWIRE-compatible serial output reads as a 10-bit code, easily scaled in firmware to display voltage on an LCD. Low operating current and standby < 1 uA extend battery life in pocket meters.
Recommandé
Embedded System Sensor Hub
The MAX157ACUA acts as a secondary ADC for microcontrollers lacking an internal SAR ADC or needing an extra channel. With SCLK, DOUT, and CS pins, the device mates directly to an MCU's SPI peripheral at speeds up to its 108 ksps maximum. Two analog inputs feed sensors (light, temperature, accelerometer analog outputs) into a 10-bit stream the MCU consumes without DMA overload. The 2.7V-5.25V range suits both 3.3V and 5V MCUs from PIC, AVR, STM32, and MAX32 families.
Recommandé
Battery-Powered Medical Monitor
The MAX157ACUA is well suited to personal medical devices that monitor two vitals (e.g., SpO2 and respiration) from a single MCU. Battery life hinges on average current draw, and the MAX157ACUA's < 1 uA power-down mode means the ADC spends >99 percent of the time in standby between conversions. Operation from a 3 V primary cell is supported down to 2.7 V. The 8-pin uMAX footprint keeps the analog section under 5 mm square, ideal for wearable patches or wrist-worn monitors.
Recommandé
Consumer Touch-Panel Controller
The MAX157ACUA reads 4-wire resistive touch-panel voltages on its two analog inputs while the host drives the panel through GPIO. The internal +2.5 V reference of the MAX157ACUA ensures stable measurements even as supply varies, and the 10-bit resolution yields touch coordinates with ~100 LSB per axis after a 2:1 resistive divider. The serial output goes to the panel's microcontroller over three wires (SCLK, DOUT, CS), saving pins versus parallel ADCs.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour MAX157ACUA — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | MAX157AEUA+ | MAX157ACUA+ | MAX157BCUA+ | MAX157BEUA+ | MAX157CCUA+ |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 8-uMAX | 8-uMAX (same) | 8-uMAX (same) | 8-uMAX (same) | 8-uMAX (same) | 8-uMAX (same) |
| Resolution | 10 bits | 10 bits | 10 bits | 10 bits | 10 bits | 10 bits |
| Sampling Rate | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps | 108 ksps |
| Number of Channels | 2 | 2 | 2 | 2 | 2 | 2 |
| Operating Temperature Range | 0C to +70C (commercial) | -40C to +85C (industrial) | 0C to +70C (commercial) | 0C to +70C (commercial) | -40C to +85C (industrial) | 0C to +70C (commercial) |
| Supply Voltage | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V | +2.7V to +5.25V |
| Internal Reference | +2.5V | +2.5V | +2.5V | +2.5V | +2.5V | +2.5V |
| Serial Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE |
| RoHS Compliance | Depends on date code | Yes (lead-free finish) | Yes (lead-free finish) | Yes (lead-free finish) | Yes (lead-free finish) | Yes (lead-free finish) |
Principaux différenciateurs
- Wider operating temperature range (vs MAX157ACUA (base part))
- Lead-free and RoHS-compliant finishes (vs MAX157ACUA (original))
- Firmware-transparent pin-compatible replacement (vs MAX157AEUA / MAX157BCUA / MAX157BEUA / MAX157CCUA)
Notes de conception
Estimated: At a 3.3V supply and a typical ADC operating current of about 1.5 mA active / < 1 uA power-down per the Maxim datasheet, the average current draw is dominated by the duty cycle of conversion. For a 1 ksps sample rate, averaging across time yields well under 100 uA average draw, making the MAX157ACUA compatible with coin-cell and primary-cell designs. Decouple VDD with a 0.1 uF ceramic capacitor placed within 5 mm of pin 5.
Use a star-ground or single-point ground tie for the ADC ground (pin 2) and the digital ground to avoid return-current disturbances from the SPI bus. Route DOUT traces away from analog input traces, and keep the reference bypass capacitor (typically 4.7 uF or 10 uF) close to the REF/VREF pin. Avoid running high-speed digital lines parallel to AIN traces; if you must, place a guard ground between them.
Per the Maxim datasheet, the CS/SHDN pin combines chip-select and shutdown functions. Driving this pin high (inactive) between conversions puts the device into power-down automatically; driving it low wakes the part for the next conversion. Some first-time users forget that CS must return high to start a new conversion. Also note: the input voltage should not exceed VDD+300mV or fall below -0.3V (ESD diodes), and VDD should never exceed +6.0V absolute max.
Informations de conformité
Compliance status depends on date code of MAX157ACUA base part. The '+' suffix variants (MAX157ACUA+) are lead-free and RoHS-compliant per the Maxim datasheet. AEC-Q100 testing was not performed; the part is not automotive-qualified.
