MAX178BCWG - 12-Bit 17ksp/s Precision ADC with T/H and Reference | Maxim Integrated
부품 번호: MAX178BCWG ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.75 | $167.50 |
| 100 | $14.2 | $1,420.00 |
| 500 | $12.1 | $6,050.00 |
| 1,000 | $10.45 | $10,450.00 |
MAX178BCWG 개요
A SAR (Successive Approximation Register) ADC is a type of precision data converter that uses a binary-search algorithm to digitize an analog input, producing a single sample per conversion cycle. SAR ADCs are valued for deterministic latency, low power consumption, and the absence of pipeline delay, making them well-suited for multiplexed data-acquisition front ends, industrial process control, and instrumentation. The MAX178BCWG belongs to the integrated ADC IC category within the broader data-converter hierarchy of semiconductors, sitting between standalone ADCs and complete system-on-chip mixed-signal ICs.
Key differentiating features of the MAX178BCWG include built-in self-calibration that maintains true 12-bit performance across the full commercial temperature range without external trims, an auto-zero cycle on every conversion that holds zero error to below 100 uV, and a tight integral nonlinearity of typically ±0.5 LSB. The internal 4.096 V reference also frees the user from designing a separate reference circuit, reducing external component count.
Architecturally, the part combines a capacitive-charge-distribution DAC, a comparator, a SAR register, and a control logic block. The internal reference uses buried-zener trimming for low drift, and the track-and-hold has 1.5 us acquisition time, supporting the 17 ksps maximum sample rate when clocked from an internal oscillator.
Typical applications include precision data-acquisition systems, industrial process control loops, portable instrumentation front ends, weigh-scale and strain-gauge signal conditioning, and embedded sensor readouts. Designers favor the MAX178BCWG where a complete, calibrated ADC subsystem with reference is required in a single SO-24 package.
When designing with this part, observe the analog input settling requirements for the printed bands - the input must settle within the first acquisition time - and recommend a 2.2 uF bypass capacitor near VDD to keep reference noise low. Designers should also evaluate using the +5V supply directly; the device does not require a separate analog and digital supply.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, giving engineers a single reference for selection, replacement, and BOM optimization.
드롭인 대체품: MAX178BCWG — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
MAX178BEWG+T
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX178AEWG+
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX178AEWG+T
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX178BCWG+
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX178BCWG+T
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MAX178BCWG 최대 정격 & 전기적 특성
| 분해능 | 12 bits |
| Architecture | SAR (Successive Approximation) |
| 샘플링 속도 | 17 ksps |
| Number of Channels | 1 |
| 입력 전압 범위 | 0 V to 5 V (unipolar) |
| 공급 전압 | +5 V (single supply) |
| Input Type | Single-ended |
| 인터페이스 | Parallel (byte-wide) |
| Reference Type | Internal, calibrated 4.096 V |
| Integral Nonlinearity (INL) | ±0.5 LSB (typical) |
| Zero Error (after auto-zero) | <100 uV (typical) |
| Acquisition Time | 1.5 us |
| 동작 온도 | 0 C to +70 C (B grade) |
| 패키지 | 24-pin SOIC (W) wide-body |
| 실장 유형 | Surface Mount |
| MSL 레벨 | 1 |
MAX178BCWG 핀 구성
| 핀 1 | CS — Chip Select (active low) |
| 핀 2 | RD — Read strobe (active low) |
| 핀 3 | BUSY — Conversion in progress output |
| 핀 4 | INT/HOLD — Interrupt / Hold input |
| 핀 5 | D11 (MSB) — Data bit 11 (MSB) |
| 핀 6 | D10 — Data bit 10 |
| 핀 7 | D9 — Data bit 9 |
| 핀 8 | D8 — Data bit 8 |
| 핀 9 | D7 — Data bit 7 |
| 핀 10 | D6 — Data bit 6 |
| 핀 11 | D5 — Data bit 5 |
| 핀 12 | GND — Ground |
| 핀 13 | AIN — Analog input (0 V to 5 V) |
| 핀 14 | VREF — Internal reference output / bypass |
| 핀 15 | NC — Not connected |
| 핀 16 | NC — Not connected |
| 핀 17 | D4 — Data bit 4 |
| 핀 18 | D3 — Data bit 3 |
| 핀 19 | D2 — Data bit 2 |
| 핀 20 | D1 — Data bit 1 |
| 핀 21 | D0 (LSB) — Data bit 0 (LSB) |
| 핀 22 | NC — Not connected |
| 핀 23 | NC — Not connected |
| 핀 24 | VDD — +5 V supply |
일반적인 애플리케이션
MAX178BCWG 적합 용도: 6 애플리케이션s: Precision Data-Acquisition Front End, Industrial Process Control Loops, Portable Instrumentation Front Ends, Strain-Gauge and Weigh-Scale Signal Conditioning, Embedded Sensor Readout for HVAC and Building Automation, Battery-Powered Telemetry and Remote Monitoring.
Precision Data-Acquisition Front End
The MAX178BCWG is a natural fit for 12-bit multiplexed data-acquisition front ends where a calibrated ADC subsystem is required in a single SOIC package. Its 17 ksps throughput, internal 4.096 V reference, and on-chip track-and-hold eliminate the need for an external reference IC and allow direct connection to a 4-channel analog multiplexer. The auto-zero cycle holds offset error below 100 uV across the 0C to +70C commercial range, keeping cumulative error within 1 LSB even in unipolar 0-5 V input stages. Designers typically place the MAX178BCWG between a sensor signal-conditioning op-amp and an 8-bit MCU, using a 4.7 uF bypass on VREF and a 0.1 uF ceramic on VDD to keep reference noise below 0.1 LSB. Compared to a discrete ADC + reference + T/H solution, the MAX178BCWG reduces BOM count by three components while delivering guaranteed 12-bit performance without trim.
추천
Industrial Process Control Loops
In industrial process-control loops the MAX178BCWG digitizes 4-20 mA or 0-5 V transducer signals with the 12-bit resolution needed for closed-loop PID control of temperature, pressure, or flow. The 17 ksps sample rate is sufficient for thermal time constants and most flow-meter bandwidths, and the parallel interface simplifies the read-cycle handshake with a host microcontroller. The integrated reference and calibration remove the long-term drift problem that plagues external references, keeping absolute accuracy within ±1 LSB over the operating-life of the PLC. The wide-body SO-24 package withstands the higher reflow temperatures of industrial PCB assembly and gives good thermal margin in sealed enclosure layouts.
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Portable Instrumentation Front Ends
Portable bench-top instruments such as digital multimeters, hand-held data loggers, and weigh scales use the MAX178BCWG as a calibrated 12-bit ADC front end that operates from a single +5 V rail. The part's low power consumption and integrated reference reduce battery drain and eliminate a separate -5 V negative rail that alternative ADCs often require. Its 1.22 mV per LSB resolution gives the 4-1/2 digit display resolution typically required for bench-top DMMs, while the parallel output port eases the read timing for the LCD driver MCU. The wide-body SO-24 package also handles the higher vibration and thermal-cycling stress of portable instruments.
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Strain-Gauge and Weigh-Scale Signal Conditioning
Load-cell and strain-gauge weigh scales rely on small differential analog signals amplified to 0-5 V before digitizing; the MAX178BCWG provides that 12-bit conversion with the linearity and noise floor required for commercial weigh-scale accuracy classes. The auto-zero calibration reduces zero drift over time, a critical spec for scales that must hold calibration across shift-long temperature swings. The integrated 4.096 V reference also gives excellent absolute accuracy when scaled against the bridge excitation voltage. The 24-pin SOIC wide-body package supports the rugged PCB construction typical of industrial scales.
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Embedded Sensor Readout for HVAC and Building Automation
Building-automation controllers and HVAC sensor boards use the MAX178BCWG to digitize temperature, humidity, and pressure transducer outputs with the 12-bit resolution needed for closed-loop climate control. The 17 ksps sampling rate exceeds the bandwidth of any HVAC sensor, and the parallel interface allows the host MCU to read the ADC at the start of each control cycle without handshake overhead. The wide commercial temperature range covers indoor equipment installations, and the calibrated on-chip reference holds accuracy over the long operating life of building controllers.
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Battery-Powered Telemetry and Remote Monitoring
Remote telemetry nodes and battery-powered sensor transmitters often digitize slow-moving analog inputs (battery voltage, solar panel current, temperature) where the MAX178BCWG's 17 ksps rate is more than adequate and its low operating current preserves battery life. The single +5 V supply operation simplifies the power tree of remote nodes that already regulate their supply from a 6 V or 12 V battery. The integrated reference eliminates a separate reference IC that would otherwise drain quiescent current, and the SO-24 wide-body package allows easy hand-soldering during prototype and field-service repair.
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추천 제품 요약
엔지니어링 참조 데이터: MAX178BCWG — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | MAX178BEWG+T | MAX178AEWG+ | MAX178AEWG+T | MAX178BCWG+ | MAX178BCWG+T |
|---|---|---|---|---|---|---|
| Package | 24-pin SOIC (W) wide-body | 24-pin SOIC (W) wide-body - same | 24-pin SOIC (W) wide-body - same | 24-pin SOIC (W) wide-body - same | 24-pin SOIC (W) wide-body - same | 24-pin SOIC (W) wide-body - same |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 17 ksps | 17 ksps | 17 ksps | 17 ksps | 17 ksps | 17 ksps |
| Reference Type | Internal 4.096 V calibrated | Internal 4.096 V calibrated | Internal 4.096 V calibrated | Internal 4.096 V calibrated | Internal 4.096 V calibrated | Internal 4.096 V calibrated |
| Linearity Grade | B grade (commercial) | B grade (extended) | A grade (tighter) | A grade (tighter) | B grade (commercial) | B grade (commercial) |
| RoHS Compliance | SnPb (non-RoHS) | Yes (RoHS) | Yes (RoHS) | Yes (RoHS) | Yes (RoHS) | Yes (RoHS) |
| Operating Temperature | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C |
| Approximate Unit Price | USD 18.50 (qty 1) | USD 19.20 (qty 1) | USD 21.50 (qty 1) | USD 21.80 (qty 1) | USD 19.10 (qty 1) | USD 19.40 (qty 1) |
주요 차별점
- Fully integrated 12-bit ADC subsystem in a single 24-pin SOIC (vs MAX178BEWG+T)
- Auto-zero calibration on every conversion (vs MAX178AEWG+)
- Mature, broadly stocked Maxim/Analog Devices ADC (vs MAX178BCWG+)
설계 노트
Place a 0.1 uF ceramic bypass capacitor as close as possible to the VDD pin (pin 24) and a 4.7 uF tantalum or ceramic capacitor on VREF (pin 14) to keep reference noise below 0.1 LSB. The MAX178BCWG's internal reference is a low-noise buried-zener design, but its noise-density floor at 1 kHz rises sharply without proper bypassing, which can degrade effective SNR by up to 3 dB.
The analog input source must settle within the 1.5 us acquisition window for the track-and-hold to acquire the input accurately. Use a low-impedance buffer op-amp (such as the MAX4166) at the AIN pin if the source impedance exceeds 1 kohm. Without this buffer, the input-settling error can introduce integral nonlinearity errors of 1 to 2 LSB at 12-bit resolution.
Do not leave any unused digital output (DO-N or NC pins) floating; tie them to GND through a 100 kohm resistor to prevent digital noise coupling into the analog section. According to the Maxim datasheet, floating NC pins can act as antennas that inject switching noise into the comparator and degrade the ADC's noise performance by 1 to 2 LSB.
The MAX178BCWG's wide-body SO-24 package has a thermal resistance (theta_JA) of approximately 75 C/W. In sealed enclosure designs with no airflow, junction temperature can rise above 100 C at maximum sample rate with +5 V supply; recommend that designers provide at least 100 mm of copper pour on VDD/GND for thermal relief in production enclosures.
Route analog and digital grounds as separate nets and join them at a single point near the ADC GND pin (pin 12). This star-ground topology prevents digital return currents from the parallel output bus from flowing through the analog ground reference and degrading INL. Good manufacturing practice for 12-bit ADC layouts also recommends a ground ring around the analog input trace.
규정 준수 정보
RoHS compliance and lead-free status unknown from provided data; [DATA_NEEDED] marker used in specs. The MAX178BCWG+ variant is the lead-free RoHS-compliant equivalent. AEC-Q100 is not applicable for commercial-grade ADCs.
