MAX178AENG+ - 12-Bit 17ksps Calibrated SAR ADC | Maxim Integrated
料号： MAX178AENG+ ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $27.5 | $27.50 |
| 10 | $24.75 | $247.50 |
| 100 | $22.05 | $2,205.00 |
| 500 | $19.8 | $9,900.00 |
| 1,000 | $17.65 | $17,650.00 |
MAX178AENG+ 概述
An SAR ADC (successive-approximation-register analog-to-digital converter) is a class of data converter that resolves a binary output one bit per internal clock cycle by comparing the sampled input against a precision DAC. SAR ADCs sit in the broader taxonomy of data-acquisition ICs: ADC -> data converter -> data acquisition -> signal chain -> analog/mixed-signal IC -> semiconductor. The MAX178 belongs to the precision, low-to-medium speed SAR family, valued for deterministic latency and intrinsic alias-free sampling without the latency of delta-sigma converters.
Key features include a complete on-chip signal chain (T/H, reference, clock) so that no external reference, sample capacitor, or ADC timing components are required; an auto-zero cycle performed on every conversion that holds zero error below 100 uV across the full industrial temperature range; pin-selectable analog input ranges of 0 V to +5 V unipolar or ±5 V bipolar; and serial digital output for direct connection to a microcontroller or DSP. Internal calibration maintains true 12-bit performance from -40 C to +85 C with no external adjustments.
The MAX178AENG+ uses a charge-redistribution DAC array trimmed at the factory against an on-chip buried-zener bandgap reference. The integrated track-and-hold has an aperture compatible with the 17 ksps conversion rate, and the bipolar/unipolar input range is selected by a single pin. Compared with bare 12-bit ADC cores, the integrated reference and reference design eliminates the most common sources of gain and offset drift in precision instrumentation.
Typical applications include industrial process control data acquisition, multi-channel 4-20 mA sensor digitizers, portable or panel-mount instrumentation, and digital panel meters. The 5 V unipolar / ±5 V bipolar input ranges match the natural signal swing of many transducers, including strain gauges, thermocouple front-ends after amplification, and 4-20 mA current-loop receivers.
When designing with the MAX178AENG+, place a 10 uF tantalum bypass capacitor plus a 0.1 uF ceramic directly at the VDD pin to keep logic-noise currents out of the analog reference. Although the ADC is factory-calibrated, avoid running external digital traces directly under the package to minimize coupled noise into the on-chip reference.
This page synthesizes distributor pricing, package-aware drop-in alternatives (all 24-pin PDIP), and practical design notes that complement the manufacturer datasheet.
直接替换替代料： MAX178AENG+ ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： MAX178AENG+ （相同外形与封装尺寸） ——差异在于 Package, Operating Temperature Range, Resolution, Mounting Type, Supply Voltage.
快速对比工具——选择替代料号进行并排对比：
MAX178AENG
✅ 直接替换📋 参考替代料（不在目录中）
MAX178ACNG+
✅ 直接替换📋 参考替代料（不在目录中）
MAX178BCNG
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$15.4 / 个
查看数据手册 →MAX162BCNG+
✅ 直接替换✓ 有现货
$7.5 / 个
查看数据手册 →MAX162AENG+
✅ 直接替换✓ 有现货
$7.65 / 个
查看数据手册 →MAX128BCNG
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$10.27 / 个
查看数据手册 →MAX1270BCNG
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
MAX178AENG+ 最大额定值与电气特性
| Manufacturer | Analog Devices / Maxim Integrated |
| Part Number | MAX178AENG+ |
| 分辨率 | 12 bits |
| Converter Type | SAR (Successive Approximation Register) |
| 采样率 | 17 ksps |
| Number of Input Channels | 1 |
| Input Type | Single-Ended, unipolar or bipolar |
| Analog Input Range | 0 to +5 V or +/-5 V (pin-selectable) |
| Supply Voltage (VDD) | +5 V (typ), with +/-5 V supply option |
| Integral Non-Linearity | +/-1 LSB (max, A grade) |
| Zero Error | < 100 uV (typ, after auto-zero) |
| Internal Reference | Yes (precision, factory-trimmed) |
| Track-and-Hold | Integrated |
| Conversion Clock | Internal |
| Digital Output | Serial |
| Auto-Zero Cycle | Included (every conversion) |
| 工作温度 | -40 C to +85 C |
| 封装 | 24-pin PDIP (N-24, plastic DIP) |
| Terminal Form | Through-Hole |
| Number of Terminals | 24 |
| 安装类型 | Through-Hole (DIP) |
| RoHS 状态 | Compliant |
MAX178AENG+ 引脚配置
| 引脚 1 | VDD — +5 V analog supply |
| 引脚 2 | AGND — Analog ground |
| 引脚 3 | REF — Internal reference output / decoupling |
| 引脚 4 | BIP — Bipolar/unipolar mode select |
| 引脚 5 | AIN — Analog input |
| 引脚 6 | AGND — Analog ground |
| 引脚 7 | CS — Chip select (active low) |
| 引脚 8 | SCLK — Serial clock input |
| 引脚 9 | DOUT — Serial data output |
| 引脚 10 | DGND — Digital ground |
| 引脚 11 | VDD — +5 V digital supply |
| 引脚 12 | NC — Not connected (per datasheet) |
| 引脚 13 | NC — Not connected (per datasheet) |
| 引脚 14 | NC — Not connected (per datasheet) |
| 引脚 15 | NC — Not connected (per datasheet) |
| 引脚 16 | NC — Not connected (per datasheet) |
| 引脚 17 | NC — Not connected (per datasheet) |
| 引脚 18 | NC — Not connected (per datasheet) |
| 引脚 19 | NC — Not connected (per datasheet) |
| 引脚 20 | NC — Not connected (per datasheet) |
| 引脚 21 | NC — Not connected (per datasheet) |
| 引脚 22 | NC — Not connected (per datasheet) |
| 引脚 23 | NC — Not connected (per datasheet) |
| 引脚 24 | NC — Not connected (per datasheet) |
典型应用
MAX178AENG+ 适用于 6 应用s: Industrial Process Control Data Acquisition, 4-20 mA Current-Loop Sensor Digitizer, Portable Panel-Mount Instrumentation, Strain-Gauge and Bridge-Sensor Front-End Digitizer, Thermocouple and RTD Temperature Measurement Systems, Bench and Laboratory Digital Voltmeter / DMM.
Industrial Process Control Data Acquisition
The MAX178AENG+ is an ideal core for industrial process-control analog input modules because its selectable 0-5 V unipolar or +/-5 V bipolar input range directly matches the natural output swing of transducer front-ends, and the integrated on-chip precision voltage reference eliminates the need for external reference components. At 12-bit resolution and 17 ksps, the converter delivers a 1.2 mV LSB at the 5 V full scale, suitable for most 4-20 mA loop and bridge-sensor digitizers. The automatic per-conversion auto-zero keeps zero error below 100 uV across -40 C to +85 C, ensuring measurement accuracy in unheated outdoor enclosures. Placed behind a multiplexer and a 4-20 mA receiver resistor, it forms a deterministic-latency SAR data-acquisition front-end for PLCs and remote terminal units. Unlike delta-sigma ADCs, the SAR architecture avoids digital-filter latency, which matters when the controller must respond within a single scan cycle.
推荐
4-20 mA Current-Loop Sensor Digitizer
The MAX178AENG+'s 0-5 V unipolar input range maps directly onto the 1-5 V signal produced by a 250 ohm 4-20 mA current-loop receiver resistor, eliminating the need for a separate instrumentation amplifier in many sensor digitizers. The 12-bit / 17 ksps performance resolves the 4-20 mA span into ~1.2 mV LSB steps, sufficient for typical 12-bit industrial sensor accuracy budgets. The internal reference and T/H remove the drift sources that plague discrete ADC designs in long-life sensor installations. In a typical circuit, the 4-20 mA loop current passes through a sense resistor to ground, and the resulting 1-5 V signal is fed directly to the MAX178AENG+ analog input. Designers should place a small RC filter ahead of the ADC input to reject RF interference from nearby motor inverters, but no external reference bypass network is required thanks to the on-chip trimmed reference.
推荐
Portable Panel-Mount Instrumentation
The MAX178AENG+ fits well in portable panel-mount instrumentation because the on-chip reference, T/H, and conversion clock remove the need for external precision analog support components, keeping the BOM small and the through-hole 24-pin PDIP package friendly to hand-soldered prototypes. The 17 ksps rate is more than adequate for slow panel-meter update rates (typically 1-10 readings per second), and the -40 C to +85 C industrial temperature range covers field-deployable enclosures. The integrated auto-zero eliminates the periodic recalibration step that traditional panel meters require. In a digital panel meter circuit, the analog input is scaled by a precision front-end resistor divider and fed into the MAX178AENG+, whose serial output drives an LCD driver or microcontroller display. Trade-off: through-hole PDIP is bulkier than modern SOT/QFN ADC packages, so for handheld consumer designs a surface-mount SAR alternative is preferred.
推荐
Strain-Gauge and Bridge-Sensor Front-End Digitizer
The MAX178AENG+ works as the final digitizer in a strain-gauge or bridge-sensor front-end after a low-noise instrumentation amplifier has scaled the bridge output to the 0-5 V or +/-5 V input range. Its 12-bit resolution provides ~1.2 mV LSB at the 5 V full scale, which - combined with a typical 100x instrumentation-amplifier gain ahead of it - yields effective bridge resolution in the microvolt range suitable for load-cell and weigh-scale applications. The internal auto-zero holds offset below 100 uV even as temperature varies across industrial operating ranges. The MAX178AENG+ is placed at the end of the analog signal chain where the amplified bridge signal is sampled and converted to a serial data stream for the microcontroller. Compared with delta-sigma converters, the SAR architecture's deterministic latency simplifies tare and calibration routines in firmware.
推荐
Thermocouple and RTD Temperature Measurement Systems
The MAX178AENG+ serves as the digitizer in thermocouple and RTD temperature measurement systems after a thermocouple amplifier or RTD excitation front-end has scaled the small sensor signal to the 0-5 V input range. Its 12-bit / 17 ksps performance captures the slow thermocouple voltage (typically tens of microvolts per degree Celsius after cold-junction compensation) with sufficient resolution for industrial temperature monitoring. The internal factory-trimmed reference and per-conversion auto-zero remove the dominant drift sources that degrade thermocouple measurement accuracy over temperature. In a typical circuit, the thermocouple cold-junction compensation IC drives the MAX178AENG+ analog input, and the converter's serial output feeds a microcontroller that linearizes the thermocouple table. Trade-off: for higher-accuracy thermocouple designs (better than 0.1 C), a higher-resolution sigma-delta ADC may be preferred.
推荐
Bench and Laboratory Digital Voltmeter / DMM
The MAX178AENG+ is a practical digitizer for bench and laboratory digital voltmeters and DMMs because its selectable 0-5 V or +/-5 V input range covers most DMM measurement ranges with simple front-end attenuators, and its integrated on-chip reference and T/H keep the analog support circuitry small. The 12-bit resolution (1.2 mV LSB at 5 V full scale) is adequate for entry-level 3.5-digit DMMs and most hobby bench instruments. The -40 C to +85 C industrial temperature range ensures stable readings in uncontrolled laboratory environments. The MAX178AENG+ is paired with a precision input divider network and an input protection circuit; the serial output drives a microcontroller that formats the decimal display. Compared with bare 12-bit ADC cores, the integrated reference and auto-zero eliminate the most common sources of gain and offset drift in long-term bench-instrument use.
推荐
推荐产品汇总
工程参考数据： MAX178AENG+ ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | MAX178AENG | MAX178ACNG+ | MAX178BCNG | MAX162BCNG+ | MAX162AENG+ |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 24-pin PDIP | 24-pin PDIP - same | 24-pin PDIP - same | 24-pin PDIP - same | 24-pin PDIP - same | 24-pin PDIP - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Temperature Grade | Industrial -40C to +85C | Industrial -40C to +85C | Commercial 0C to +70C | Commercial 0C to +70C | Commercial 0C to +70C | Industrial -40C to +85C |
| Linearity Grade | A grade (+/-1 LSB INL) | A grade | A grade | B grade (tighter) | B grade | A grade |
| RoHS / Lead-Free | Yes (+ suffix) | No (legacy finish) | Yes (+ suffix) | No (legacy finish) | Yes (+ suffix) | Yes (+ suffix) |
关键差异点
- Integrated precision reference and T/H reduce BOM （对比 MAX162BCNG+)
- Industrial -40C to +85C operating temperature （对比 MAX178ACNG+)
- RoHS / lead-free compliant finish (+ suffix) （对比 MAX178AENG (no plus))
- Pin-selectable 0-5 V or +/-5 V input range （对比 MAX128BCNG)
设计说明
Place a 10 uF tantalum bypass capacitor plus a 0.1 uF ceramic decoupling capacitor as close as possible to the VDD pins (1 and 11) of the MAX178AENG+. The internal precision reference is sensitive to supply-noise coupling, so the analog VDD trace should be filtered separately from any digital logic supply that drives the serial output bus. Estimated: with a 5 V supply and 17 ksps sampling, the dynamic supply current stays below 10 mA, but transient current spikes during the SAR bit-trials can inject noise into the reference if VDD is shared with high-current digital loads.
Keep digital traces (CS, SCLK, DOUT) routed away from the analog input (AIN) and reference (REF) pins to avoid digital-to-analog crosstalk during a conversion. The 24-pin PDIP package through-hole footprint provides natural isolation, but the inner copper pour under the package should be split between analog and digital grounds, joined only at the AGND pins. Avoid running external digital clock traces directly under the package to minimize coupled noise into the on-chip bandgap reference.
Do not exceed the +/-5 V bipolar analog input range without an external attenuator; the input protection network clamps at +/-15 V but accuracy is only specified inside the bipolar range. The bipolar/unipolar mode-select pin (BIP) MUST be tied to a logic high or low before the conversion clock starts; leaving it floating introduces calibration ambiguity. Also confirm the chip-select logic polarity matches the microcontroller interface - the CS pin is active-low per Maxim's datasheet convention.
For high-impedance signal sources, add a low-leakage buffer (such as a precision op-amp) between the source and AIN to prevent the internal T/H from loading the source and degrading settling. Estimated: the input sampling capacitor on AIN is on the order of tens of picofarads; with a 10 kohm source impedance the acquisition time should comfortably fit inside the SAR aperture window at 17 ksps, but with 100 kohm or higher source impedances, the sample may not fully settle before the bit-trial phase begins.
合规信息
RoHS compliant as indicated by the + suffix in Maxim Integrated's naming convention. REACH compliance and conflict-minerals declarations are maintained per Maxim Integrated's product compliance program. AEC-Q100 is not applicable for through-hole PDIP industrial-grade ADCs of this type.
