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Analog Devices Inc./Maxim Integrated MAX145BCUA
- Part No.:
- MAX145BCUA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX145BCUA.pdf
- Description:
- IC ADC 12BIT SAR 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:4,869
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Product details
Overview
MAX145BCUA from Maxim Integrated is a 12-bit, pseudo-differential-input successive-approximation ADC with 108ksps sampling rate, single +2.7V to +5.25V supply operation, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It features internal track-and-hold, 7.4µs conversion time, and operates in an 8-pin µMAX package - ideal for isolated data acquisition and portable instrumentation requiring low power and compact size.
For engineers reviewing the MAX145BCUA datasheet, MAX145BCUA pinout, MAX145BCUA application, or MAX145BCUA equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation guidance, and two confirmed alternative parts with documented functional and application-level differences.
Technical Context
The MAX145BCUA implements a SAR architecture with integrated track-and-hold, where sampling occurs on CH+ (CH0) referenced to a stable CH− (CH1) node, requiring ≤±0.5LSB stability on CH− during acquisition. Its internal clock supports 0–5MHz SCLK for flexible host timing, while external clock mode enables deterministic 100kHz–2.17MHz operation with sampling triggered on the second SCLK falling edge.
Conversion output is a 16-bit serial stream: three leading '1's, channel ID bit (fixed '0' for MAX145), then 12 MSB-first data bits. DOUT transitions on SCLK falling edge and enters high-impedance when CS/SHDN = VDD, enabling multi-device bus sharing without external tri-state logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = VREF/4096 quantization step; supports ≥70dB SINAD at 10kHz input. |
| Sampling Rate | 108ksps - enables full-bandwidth digitization of signals up to 54kHz (Nyquist), or undersampling of higher-frequency transients. |
| INL (Max) | ±1 LSB - ensures monotonicity and <0.025% full-scale linearity error across temperature (0°C to +70°C). |
| Power (108ksps) | 0.9mA at +3V - equates to 2.7mW, allowing continuous operation on coin-cell or energy-harvesting supplies. |
| Shutdown Current | 0.2µA - reduces system standby power by >4000×, enabling wake-on-event architectures with <3µs recovery. |
| Input Type | Pseudo-differential (CH+, CH−) - accepts true differential signals but requires CH− to remain stable within ±0.5LSB of GND. |
| Serial Interface | SPI/QSPI/MICROWIRE-compatible 3-wire - interoperates with standard microcontroller peripherals without protocol translation. |
Pinout & Package
MAX145BCUA is housed in an 8-pin µMAX package (U8-1), 3mm × 3mm body, 0.5mm pitch, exposed pad for thermal enhancement. Pin 1 is VDD; pin 4 is GND; pin 5 is REF; pin 6 is CS/SHDN; pin 7 is DOUT; pin 8 is SCLK; pins 2 and 3 are analog inputs CH0 (CH+) and CH1 (CH−), respectively.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 1) | Positive supply input | Accepts +2.7V to +5.25V; powers all analog and digital circuitry; bypass with 0.1µF near pin. |
| CH0 / CH+ (Pin 2) | Positive analog input | Sampled node in pseudo-differential mode; full-scale range = 0 to VREF; input capacitance = 16pF. |
| CH1 / CH− (Pin 3) | Negative reference input | Must remain stable within ±0.5LSB of GND during conversion; connect 0.1µF to GND for noise immunity. |
| GND (Pin 4) | Analog/digital ground | Single ground plane required; separates analog return path from noisy digital currents. |
| REF (Pin 5) | External reference voltage | Sets full-scale range; requires ≥18kΩ DC impedance and ≤10Ω source impedance; bypass with 0.1µF. |
| CS/SHDN (Pin 6) | Chip-select / shutdown control | Active-high shutdown (≤0.2µA); active-low enables conversion; rising edge disables DOUT (high-Z). |
| DOUT (Pin 7) | Serial data output | 3-wire interface output; MSB-first 16-bit frame; transitions on SCLK falling edge; high-impedance when CS/SHDN = VDD. |
| SCLK (Pin 8) | Serial clock input | Drives data shift-out and (in external mode) controls conversion timing; falling edge clocks DOUT valid data. |
Key Features
| Feature | Design Value |
|---|---|
| Single-supply operation | +2.7V to +5.25V - eliminates need for dual-rail supplies in battery-powered systems and simplifies LDO selection. |
| Automatic power-down | 0.2µA shutdown current - enables ultra-low-power sleep modes without external enable circuitry. |
| Fast wake-up | 2.5µs wake-up time - allows rapid response to external triggers while maintaining low average power. |
| On-chip track-and-hold | 7.4µs conversion time with built-in T/H - removes need for external sample-hold amplifier in most signal chains. |
| Space-saving package | 8-pin µMAX (3mm × 3mm) - reduces PCB area by >60% vs. SOIC-8, critical for portable medical and sensor modules. |
| 3-wire serial interface | SPI/QSPI/MICROWIRE-compatible - integrates directly with common MCU peripherals without glue logic or level shifters. |
Applications
| Battery-Powered Data Loggers | Isolated Industrial Sensors |
|---|---|
Use Scenario: Continuous voltage/current monitoring in remote environmental sensors powered by Li-SOCl₂ cells. IC Role / Device Role / Timing Role: Pseudo-differential ADC digitizing conditioned transducer outputs while rejecting common-mode noise from long cable runs. Use Value: 0.9mA active current and 0.2µA shutdown extend 10-year battery life; 12-bit resolution captures sub-mV changes in pressure or humidity signals. |
Use Scenario: Signal conditioning in DIN-rail mounted I/O modules with galvanic isolation between field-side analog inputs and controller-side digital bus. IC Role / Device Role / Timing Role: Isolated-side ADC converting 4–20mA loop signals or thermocouple outputs into serial digital data for optocoupler or transformer-coupled transmission. Use Value: Single +3.3V supply simplifies isolated DC-DC design; 108ksps supports fast loop updates; µMAX footprint minimizes creepage/clearance layout constraints. |
| Portable Medical Instruments | Process-Control Monitoring Systems |
Use Scenario: ECG front-end in handheld patient monitors where size, power, and noise immunity are critical. IC Role / Device Role / Timing Role: Digitizing amplified, filtered biopotential signals with pseudo-differential input rejecting 50/60Hz mains interference. Use Value: CH− stability requirement enables use of local RC filter to suppress CM noise; 70dB SINAD ensures diagnostic-grade signal fidelity at 10kHz bandwidth. |
Use Scenario: Real-time temperature and flow measurement in PLC analog input cards deployed in factory automation. IC Role / Device Role / Timing Role: High-accuracy ADC interfacing with RTDs or strain gauges in multi-channel scan architectures. Use Value: ±1 LSB INL guarantees repeatability across channels; SPI compatibility allows daisy-chaining multiple MAX145BCUA devices on one controller bus. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit serial ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7816U | 12-bit SAR, 200ksps, +5V only, no internal T/H, requires external reference buffer | Higher speed but lacks integrated track-and-hold and single-supply flexibility | Choose ADS7816U only if throughput >108ksps is mandatory and +5V rail is available. |
| AD7495ARMZ | 12-bit SAR, 1MSPS, +2.7V to +5.25V, SPI-only (no QSPI/MICROWIRE), 10-pin MSOP | Faster sampling but larger package and narrower serial protocol support | Prefer AD7495ARMZ when system demands >100ksps and board space permits 10-pin MSOP. |
Compared with MAX145BCUA, ADS7816U offers higher speed but requires external signal conditioning and lacks shutdown/wake-up optimization, while AD7495ARMZ provides faster conversion at the cost of reduced protocol flexibility and increased PCB footprint - making MAX145BCUA optimal for space-constrained, multi-protocol, ultra-low-power designs.
Availability
MAX145BCUA is available at Aetrix Electronics and suitable for battery-powered data loggers, isolated industrial sensors, portable medical instruments, and process-control monitoring systems requiring stable component supply across extended production lifecycles.
Supply support for MAX145BCUA includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications.
The MAX144/MAX145 product line was designed for low-power, space-constrained data acquisition systems requiring precision 12-bit conversion with minimal external components and robust serial interoperability.
FAQ
What is the maximum sampling rate of the MAX145BCUA, and under what conditions is it guaranteed?
The MAX145BCUA achieves a guaranteed 108ksps sampling rate when operating with VDD = +2.7V to +5.25V, VREF = 2.5V, fSCLK = 2.17MHz in external clock mode, and CH− held stable within ±0.5LSB. This rate corresponds to a 7.4µs conversion time and is fully characterized over the 0°C to +70°C temperature range specified for the MAX145BCUA grade.
Does the MAX145BCUA require an external reference, and what are its drive requirements?
Yes, the MAX145BCUA requires an external reference applied to the REF pin. The reference must deliver ≥250µA DC load current with ≤10Ω output impedance and be bypassed with a 0.1µF capacitor. The input resistance at REF is ≥18kΩ, and the acceptable voltage range is 0 to VDD + 50mV - ensuring compatibility with precision bandgap or buffered op-amp references.
How does the pseudo-differential input architecture of the MAX145BCUA differ from true differential operation?
The MAX145BCUA uses pseudo-differential input: only CH+ (Pin 2) is actively sampled, while CH− (Pin 3) serves as a stable reference node that must remain within ±0.5LSB of GND during conversion. Unlike true differential ADCs, it does not reject common-mode voltage swings on CH− - requiring local decoupling (e.g., 0.1µF to GND) to maintain accuracy.
What are the power consumption characteristics of the MAX145BCUA at different sampling rates?
At 108ksps and +3V supply, MAX145BCUA draws 0.9mA (2.7mW); at 10ksps, current drops to 100µA; at 1ksps, it falls to 10µA; and in shutdown (CS/SHDN = VDD), it consumes just 0.2µA. These stepped reductions are achieved via automatic power-down circuitry, enabling adaptive power management without software intervention.
Which microcontroller serial interfaces are natively compatible with the MAX145BCUA without protocol translation?
The MAX145BCUA's 3-wire serial interface is natively compatible with SPI (CPOL = 0, CPHA = 0), QSPI, and MICROWIRE standards. It requires no protocol translation when connected to MCUs such as STM32, PIC16/17, or NXP Kinetis families with hardware SPI peripherals configured for master mode and 0–5MHz SCLK support.
MAX145BCUA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 108k
- Number of Inputs:
- 1
- Input Type:
- Pseudo-Differential
- Data Interface:
- SPI
- Configuration:
- MUX-S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External
- Voltage - Supply, Analog:
- 2.7V ~ 5.25V
- Voltage - Supply, Digital:
- 2.7V ~ 5.25V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 8-uMAX/uSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX145BCUA FAQ
1.How can I place an order for MAX145BCUA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX145BCUA on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX145BCUA reliable?
The price and inventory of MAX145BCUA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX145BCUA is usually 5 days.
3.What payment methods are accepted for MAX145BCUA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX145BCUA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX145BCUA?
MAX145BCUA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX145BCUA order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX145BCUA?
For technical support, including MAX145BCUA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX145BCUA requirements.
6.How does Aetrix verify that MAX145BCUA is sourced from the original manufacturer or authorized distributors?
All MAX145BCUA products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX145BCUA meets industry standards.
7.What is the process for return or replacement of MAX145BCUA?
All MAX145BCUA units undergo pre-shipment inspection (PSI). If there is an issue with MAX145BCUA, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX145BCUA part is unused and in its original packaging.
Return procedure for MAX145BCUA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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