MAX131ACQH+TD - 3.5 Digit ADC Dual-Slope, PLCC-44 | Maxim Integrated
MPN: MAX131ACQH+TD ✗ Cuối đờiMAX131ACQH+TD Tóm tắt
An ADC (analog-to-digital converter) is a semiconductor device that converts continuous analog signals into discrete digital codes; the dual-slope architecture is one of the oldest and most robust integrating-converter topologies, prized for excellent normal-mode and common-mode noise rejection because the integrator averages the input over a fixed integration window. Dual-slope ADCs sit within the data-converter family, which itself is a sub-category of data acquisition ICs under mixed-signal and power-management-adjacent signal-chain semiconductors.
Key features of the MAX131ACQH+TD include a single differential input channel, an on-chip bandgap voltage reference for measurement precision, and external reference support for system-level calibration. The integration architecture provides inherent 50 Hz / 60 Hz line-noise rejection. The serial data interface simplifies microcontroller read-back, and the device operates from a single supply rail.
From a technical depth perspective, the dual-slope conversion cycle consists of a defined integration phase (run-up) followed by a de-integration phase (run-down) against the reference; the count accumulated during run-down is proportional to the input voltage. This inherent averaging makes the architecture highly immune to periodic noise, especially at power-line frequencies, but limits throughput to a few conversions per second.
Typical applications include digital panel meters, handheld multimeters, industrial process monitors, weighing scales, and any precision low-frequency measurement front-end where line-noise rejection and absolute accuracy outweigh conversion speed.
When designing with this part, observe the integration timing capacitor and reference bypass capacitor recommendations in the datasheet, as they directly affect conversion linearity and noise performance. The PLCC-44 footprint simplifies PCB integration but requires a socket or careful reflow profiling.
Bộ thay thế dễ dàng lắp đặt cho MAX131ACQH+TD — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với MAX131ACQH+TD (cùng hình factor và footprint) — khác nhau ở Input Voltage Range, Resolution, Architecture, Package, Number of Channels.
MAX131ACQH+
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX131ACQH+
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX128BCNG
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →MAX1270BENG
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →MAX1162ACUB+T
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →MAX131ACQH+TD Tỷ lệ tối đa & tính chất điện
| Architecture | Dual-Slope Integrating ADC |
| Độ phân giải | 3.5 digits |
| Number of Channels | 1 differential input |
| Input Type | Differential |
| Reference Type | External (bandgap on-die) |
| Data Interface | Serial |
| Configuration | Single ADC |
| Phạm vi điện áp đầu vào | 0.2 V to 2 V |
| Số lượng chân | 44 |
| Package Type | PLCC-44 (QCCJ) |
| Terminal Form | J-Bend |
| Package Code | QCCJ |
| Nhiệt độ hoạt động | 0 C to 70 C |
| Temperature Grade | Industrial |
| Display Type | LCD driver output |
| Part Status | Obsolete |
Cấu hình chân MAX131ACQH+TD
| Chân 1 | INT — Integrator output |
| Chân 2 | AZ — Auto-zero compensation |
| Chân 3 | BUF — Buffer output |
| Chân 4 | INHI — Differential input high |
| Chân 5 | INLO — Differential input low |
| Chân 6 | COMMON — Common-mode reference |
| Chân 7 | REF+ — Reference positive input |
| Chân 8 | REF- — Reference negative input |
| Chân 9 | V+ — Positive supply |
| Chân 10 | GND — Ground |
| Chân 11 | OSC1 — Oscillator input |
| Chân 12 | OSC2 — Oscillator output |
| Chân 13 | SCLK — Serial clock |
| Chân 14 | SDO — Serial data output |
| Chân 15 | CS — Chip select |
| Chân 16 | BP — Backplane driver |
| Chân 17 | SEG1 — LCD segment 1 |
| Chân 18 | SEG2 — LCD segment 2 |
| Chân 19 | SEG3 — LCD segment 3 |
| Chân 20 | SEG4 — LCD segment 4 |
| Chân 21 | SEG5 — LCD segment 5 |
| Chân 22 | SEG6 — LCD segment 6 |
| Chân 23 | SEG7 — LCD segment 7 |
| Chân 24 | SEG8 — LCD segment 8 |
| Chân 25 | SEG9 — LCD segment 9 |
| Chân 26 | SEG10 — LCD segment 10 |
| Chân 27 | SEG11 — LCD segment 11 |
| Chân 28 | SEG12 — LCD segment 12 |
| Chân 29 | SEG13 — LCD segment 13 |
| Chân 30 | SEG14 — LCD segment 14 |
| Chân 31 | SEG15 — LCD segment 15 |
| Chân 32 | SEG16 — LCD segment 16 |
| Chân 33 | SEG17 — LCD segment 17 |
| Chân 34 | SEG18 — LCD segment 18 |
| Chân 35 | SEG19 — LCD segment 19 |
| Chân 36 | SEG20 — LCD segment 20 |
| Chân 37 | SEG21 — LCD segment 21 |
| Chân 38 | SEG22 — LCD segment 22 |
| Chân 39 | SEG23 — LCD segment 23 |
| Chân 40 | SEG24 — LCD segment 24 |
| Chân 41 | TEST — Factory test pin (no-connect in application) |
| Chân 42 | POL — Polarity indicator |
| Chân 43 | BP2 — Backplane 2 driver |
| Chân 44 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
MAX131ACQH+TD phù hợp cho 6 Áp dụngs: Digital Panel Meters, Handheld Digital Multimeters, Industrial Weighing Scales, Process Control Monitor Front-Ends, Battery-Powered Field Measurement, Automotive Battery / Sensor Test Equipment.
Digital Panel Meters
The MAX131ACQH+TD's 3.5-digit dual-slope conversion and integrated LCD drivers make it a drop-in solution for digital panel meters. With 0.2 V to 2 V differential input range and on-die bandgap reference, it directly drives LCD displays showing DC voltage, current, temperature (via RTD), or pressure (via strain gauge) without external ADC stages. Compared to SAR ADCs of similar bit count, it provides inherently superior 50 Hz/60 Hz line-noise rejection averaging over one full integration window - critical in factory and process-control panels where mains-borne interference is unavoidable. Place 0.1uF ceramic bypass caps on supply and reference pins per datasheet for optimum performance.
Được đề xuất
Handheld Digital Multimeters
The MAX131ACQH+TD is well-suited for handheld digital multimeter (DMM) front-ends because its dual-slope architecture provides automatic 60 dB+ normal-mode rejection at 50 Hz/60 Hz mains frequency, eliminating measurement errors from pick-up on test leads. The serial interface allows the main MCU to read conversion results efficiently while the LCD segment drivers directly drive the meter display. The PLCC-44 package enables compact PCB layouts suitable for portable form factors. Power consumption is low enough for battery-powered operation when paired with a low-quiescent regulator; the on-chip bandgap reference eliminates external precision components.
Được đề xuất
Industrial Weighing Scales
Industrial bench and floor scales benefit from the MAX131ACQH+TD's low-noise integrating conversion that resolves microvolt-level load-cell signals reliably over full bridge excitation. The differential input accepts a 0.2 V to 2 V signal range directly from a load cell bridge with 5 V or 10 V excitation, while the on-chip bandgap reference provides stable scaling for calibration. Unlike sigma-delta converters, the dual-slope approach is highly robust to periodic mains pick-up from nearby motor drives and inverter equipment in factory environments. The PLCC-44 (QCCJ) package and 0-70 C industrial temperature grade suit sealed scale enclosures deployed in harsh production environments.
Được đề xuất
Process Control Monitor Front-Ends
Process-control monitoring equipment uses the MAX131ACQH+TD as a precision DC measurement stage reading 4-20 mA loops, thermocouple/RTD signals, and strain-gauge bridges. The dual-slope architecture's inherent averaging over the integration window rejects 50 Hz/60 Hz mains interference common in industrial cabinets, providing accurate readings without complex digital filtering. The serial data interface allows connection to industrial microcontrollers and PLCs for downstream display and alarming. The 0-70 C industrial temperature range suits control-panel environments, and the PLCC-44 package supports dense PCB layouts.
Được đề xuất
Battery-Powered Field Measurement
The MAX131ACQH+TD operates at low quiescent current suitable for battery-powered field measurement instruments including portable pH meters, conductivity meters, and environmental loggers. The dual-slope conversion provides excellent immunity to electromagnetic interference from nearby switching regulators and battery-charging circuits, while the on-chip reference eliminates power-hungry external reference ICs. Low conversion rate (a few conversions per second) suits slowly-changing physical measurements. Combined with a low-Iq LDO, the part supports months of battery life in intermittent-sampling applications.
Được đề xuất
Automotive Battery / Sensor Test Equipment
Service-grade automotive diagnostic stations use the MAX131ACQH+TD to measure battery voltage, alternator output, and DC sensor signals with strong immunity to the noisy electrical systems of running engines. The dual-slope integration rejects cranking transients and alternator ripple, providing stable readings without complex filtering. The 0-70 C industrial temperature range suits service-environment operation; the PLCC-44 footprint allows dense bench-instrument PCB layouts. The serial interface enables easy connection to diagnostic-station displays and processors.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MAX131ACQH+TD — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | MAX131ACQH+ | MAX131ACQH | MAX128BCNG | MAX1270BENG | MAX1162ACUB+T |
|---|---|---|---|---|---|---|
| Package | PLCC-44 (QCCJ) | PLCC-44 (QCCJ) - same | PLCC-44 (QCCJ) - same | DIP-24 | DIP-24 | uMAX-10 |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Architecture | Dual-Slope Integrating | Dual-Slope Integrating | Dual-Slope Integrating | SAR (12-bit) | SAR (12-bit) | SAR (14-bit) |
| Resolution | 3.5 digits (~12 bit) | 3.5 digits | 3.5 digits | 12-bit+sign | 12-bit | 14-bit |
| Input Channels | 1 differential | 1 differential | 1 differential | 1 single-ended | 8 single-ended | 1 single-ended |
| Interface | Serial | Serial | Serial | Parallel | Serial | Serial SPI |
| Operating Temperature | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Active | Obsolete | Active |
| Number of Pins | 44 | 44 | 44 | 24 | 24 | 10 |
Bảo phân biệt quan trọng
- Integrated LCD segment drivers (vsMAX1270BENG (SAR, no LCD drivers))
- On-chip bandgap reference (vsMAX128BCNG (external reference required))
- Superior 50 Hz/60 Hz line-noise rejection (vsMAX1162ACUB+T (SAR, no inherent averaging))
Ghi chú thiết kế
Place the integrator capacitor (CINT) and auto-zero capacitor (CAZ) as close as possible to their respective pins to minimize leakage paths and pin-to-pin coupling. Use a low-leakage film or ceramic capacitor with NP0/C0G dielectric for CAZ; polyester or polypropylene is suitable for CINT. Reference bypass: place a 0.1uF ceramic cap on REF+ to REF- within 5 mm of the pins to prevent reference noise from degrading linearity.
Oscillator frequency directly sets the integration period and therefore the conversion rate and 50 Hz/60 Hz noise rejection. Crystal oscillator is recommended over RC for production designs to maintain calibration accuracy across temperature. The differential input range (0.2 V to 2 V) must be respected; signals outside this range saturate the integrator and produce non-linear results. Use input-protection resistors and TVS diodes when measuring signals that may exceed the input range.
The MAX131ACQH+TD requires a clean single-supply rail with low ripple; place a 10uF tantalum or ceramic bulk cap plus 0.1uF ceramic decoupling cap directly at the V+ pin. For battery-powered designs, a low-dropout regulator with <30 uVrms noise prevents power-rail noise from coupling into the integrator. When switching regulators are used elsewhere on the board, separate the analog ground return path from noisy digital grounds using a ground-plane cut or stitching strategy.
Thông tin tuân thủ
Lead-free PLCC package per Maxim product marking. RoHS compliant per distributor listings; REACH compliance inferred from Maxim corporate policy. Not AEC-Q100 qualified - this is an industrial-grade part intended for non-automotive applications. Conflict-minerals status not explicitly stated by Maxim/ADI for this obsolete product.
