MAX145ACPA - 12-Bit 108ksps 2-Ch Serial ADC | Maxim Integrated
MPN: MAX145ACPA ✓ Hoạt độngMAX145ACPA Tóm tắt
What is a low-power SAR ADC? A successive-approximation register ADC is a precision data converter type that resolves one bit per clock cycle using a binary search against an internal DAC; it sits in the taxonomy analog-to-digital converter -> data converter -> signal chain IC -> semiconductor. Compared with delta-sigma ADCs, SAR parts offer single-cycle latency and deterministic acquisition, which is why they dominate multiplexed multi-channel data-acquisition front ends, sensor readouts, and embedded instrumentation loops.
Key specifications include 108 ksps maximum sampling rate, +/-1 LSB INL (max), +/-1 LSB DNL (no missing codes guaranteed), an internal 2.5 V reference option plus external reference mode, single-ended analog inputs with channel 2 configurable as pseudo-differential, and 1.5 mA maximum supply current at 108 ksps dropping to under 1 microamp in power-down. The MAX145ACPA guarantees 0.1 LSB sample-to-sample crosstalk between its two input channels and provides a serial interface software-select.
Architecturally, the MAX145 combines an input track-and-hold, a capacitive-charge redistribution DAC, a comparator and SAR logic, plus the on-chip oscillator and reference buffer. The auto-power-down feature draws under 1 microamp between conversions, making it ideal for duty-cycled battery measurements. The MAX145ACPA is the pseudo-differential input variant of the family (max 127 distinguishes true-differential MAX144 versus pseudo-differential MAX145 versus single-channel MAX144).
Typical applications include portable data loggers, loop-powered 4-20 mA sensor transmitters, handheld multimeters, battery monitoring boards, thermistor/RTD signal conditioning, and industrial process-control front ends. The wide 2.7 V to 5.25 V supply range lets it share the same rails as the host microcontroller.
When designing with the MAX145ACPA, place a 0.1 microfarat decoupling capacitor close to the supply pin and respect the 8 microsecond acquisition-time minimum after channel switching. Drive CS low to initiate conversion and read the MSB-first data on the falling edge of SCLK per the SPI timing diagram in the datasheet.
This page consolidates distributor pricing for the MAX145ACPA in 8-pin PDIP, drop-in equivalents, comparison against the MAX144 family siblings, and practical design notes that are not aggregated on any single distributor listing.
Bộ thay thế dễ dàng lắp đặt cho MAX145ACPA — 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 MAX145ACPA (cùng hình factor và footprint) — khác nhau ở Package, Resolution, RoHS Status, Sampling Rate, Conversion Time.
MAX145ACPA+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX145BCPA
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
MAX144ACPA
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX144BEUA
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX1202ACAP
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX1243ACPA
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX145ACPA Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 12 bits |
| Number of Channels | 2 |
| Tỷ lệ lấy mẫu | 108 ksps |
| Supply Voltage Range | +2.7 V to +5.25 V |
| Supply Current (max, 108 ksps) | 1.5 mA |
| Power-Down Current | less than 1 microamp |
| Conversion Time | 7.4 microseconds |
| Wake-Up Time | 2.5 microseconds |
| Input Configuration | Pseudo-differential (CH1, CH2 with COM) |
| Điện áp tham chiếu | +2.5 V internal or external |
| INL (max) | +/-1 LSB |
| DNL (max) | +/-1 LSB (no missing codes) |
| Serial Interface | SPI/QSPI/MICROWIRE-compatible |
| Khoảng nhiệt độ hoạt động | 0 C to +70 C |
| Hộp | PDIP-8 |
| Kiểu lắp đặt | Through-Hole |
| Trạng thái RoHS | Compliant (Pb-free + suffix) |
| Architecture | SAR (Successive Approximation) |
Cấu hình chân MAX145ACPA
| Chân 1 | VDD — Positive supply voltage, +2.7 V to +5.25 V |
| Chân 2 | CH1 (AIN1) — Analog input channel 1 |
| Chân 3 | AGND — Analog ground |
| Chân 4 | COM — Common reference for pseudo-differential inputs |
| Chân 5 | CH0 (AIN0) — Analog input channel 0 |
| Chân 6 | REF — Reference voltage input/output (internal 2.5 V or external) |
| Chân 7 | DOUT — Serial data output, MSB first |
| Chân 8 | SCLK — Serial clock input (with CS tied low through hardware) |
Ứng dụng tiêu biểu
MAX145ACPA phù hợp cho 7 Áp dụngs: Portable Data Logger, 4-20 mA Loop-Powered Sensor Transmitter, Handheld Digital Multimeter, Battery Monitoring Board, Thermistor/RTD Signal Conditioning, Industrial Process-Control Front End, Touch Panel / Resistive Sensor Interface.
Portable Data Logger
The MAX145ACPA's 108 ksps sampling rate and 2-channel pseudo-differential inputs suit handheld data loggers measuring temperature, voltage, or process signals over battery life. According to the datasheet, the less than 1 microamp power-down current lets the part be duty-cycled, and the 7.4 microsecond conversion supports burst sampling at 10 ms intervals across two analog channels. With +2.7 V to +5.25 V supply range, it shares a lithium or 3 x AA battery stack, while the 12-bit resolution (+/-1 LSB INL) captures sensor transients with 0.024 percent FS precision. Place the IC near the analog inputs with a 0.1 microfarat decoupling capacitor on VDD, and use the 2.5 V internal reference for absolute measurements.
Được đề xuất
4-20 mA Loop-Powered Sensor Transmitter
The MAX145ACPA's +2.7 V minimum supply and less than 1 microamp power-down current make it ideal for 4-20 mA loop-powered sensor transmitters that must operate within a tight 3.5 mA budget. According to the datasheet, the pseudo-differential inputs accept a bridge sensor referenced to a common COM pin, while the 2.5 microsecond wake-up enables sub-millisecond conversion cycles between long sleeps. The 12-bit resolution provides 0.024 percent FS precision adequate for industrial sensor standards. The serial SPI/QSPI/MICROWIRE interface connects directly to a low-power microcontroller that modulates the loop current.
Được đề xuất
Handheld Digital Multimeter
The MAX145ACPA's 12-bit resolution, +/-1 LSB linearity, and 108 ksps sampling rate suit handheld digital multimeters measuring DC and AC signals across multiple ranges. According to the datasheet, the two pseudo-differential channels can be configured to measure voltage and current simultaneously, while the internal 2.5 V reference eliminates external precision components. The +2.7 V to +5.25 V supply range lets the part run from a 9 V battery regulated down to 5 V or 3.3 V, and the small 8-pin PDIP/μMAX package fits in compact meter housings.
Được đề xuất
Battery Monitoring Board
The MAX145ACPA's low supply current (1.5 mA at 108 ksps, less than 1 microamp in power-down) and wide +2.7 V to +5.25 V supply range make it ideal for battery monitoring boards in UPS, e-bike, and portable medical devices. According to the datasheet, the two pseudo-differential channels can monitor individual cell voltages in a stacked battery pack, while the 12-bit resolution captures cell imbalance with millivolt precision. The serial 3-wire interface connects directly to a battery-management microcontroller without external glue logic.
Được đề xuất
Thermistor/RTD Signal Conditioning
The MAX145ACPA's pseudo-differential inputs are well suited to thermistor and RTD signal conditioning where ratiometric measurements reject lead-resistance errors. According to the datasheet, the two channels can be configured to measure a thermistor divider and a reference voltage simultaneously, enabling ratiometric temperature conversion. The internal 2.5 V reference can be used to drive the reference resistor, while the 12-bit resolution provides 0.1 degree Celsius precision for industrial temperature sensing. The wide supply range supports both 3.3 V and 5 V host microcontrollers.
Được đề xuất
Industrial Process-Control Front End
The MAX145ACPA's industrial temperature grade (0 C to +70 C commercial) and pseudo-differential inputs make it a fit for industrial process-control front ends measuring 0-10 V or 4-20 mA signals. According to the datasheet, the 108 ksps sampling rate supports multiplexed multi-channel measurements, while the 12-bit resolution provides 0.024 percent FS precision. The 3-wire SPI/QSPI/MICROWIRE interface connects directly to industrial PLC or microcontroller peripherals, and the small 8-pin PDIP/μMAX package enables compact DIN-rail module designs.
Được đề xuất
Touch Panel / Resistive Sensor Interface
The MAX145ACPA's pseudo-differential input architecture and 108 ksps sampling rate suit resistive touch-panel or position-sensor interfaces where two channels must be read ratiometrically. According to the datasheet, the less than 1 microamp power-down current enables aggressive duty cycling to extend battery life in handheld instruments. The 12-bit resolution provides 0.024 percent FS position precision, and the wide supply range supports 3.3 V and 5 V system rails. The 3-wire SPI interface requires only three microcontroller pins.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MAX145ACPA — 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 | MAX145ACPA+ | MAX144ACPA | MAX144BEUA | MAX1202ACAP | MAX1243ACPA |
|---|---|---|---|---|---|---|
| Package | PDIP-8 | PDIP-8 (same) | PDIP-8 (same) | μMAX-8 (SMD variant) | PDIP-8 (same) | PDIP-8 (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 |
| Number of Channels | 2 (pseudo-differential) | 2 (pseudo-differential) | 2 (true differential) | 2 (true differential) | 1 (differential) | 1 (single-ended) |
| Supply Voltage Range | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +/-5 V bipolar | +2.7 V to +5.25 V |
| Internal Reference | 2.5 V | 2.5 V | 2.5 V | 2.5 V | External only | External only |
| Serial Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI | SPI/QSPI/MICROWIRE |
Bảo phân biệt quan trọng
- Pseudo-differential input configuration with internal 2.5 V reference (vsMAX144ACPA)
- 2-channel multiplexed input in 8-pin PDIP (vsMAX1243ACPA)
- Less than 1 microamp power-down current (vsMAX1202ACAP)
Ghi chú thiết kế
The MAX145ACPA's automatic power-down reduces quiescent current to less than 1 microamp between conversions, with a 2.5 microsecond wake-up time per the datasheet. For battery-powered designs, duty-cycle conversions to a 1-10 Hz effective sample rate rather than running continuously. Place a 0.1 microfarat decoupling capacitor within 5 mm of the VDD pin to suppress digital noise coupling into the analog front end.
Do not leave the REF pin floating when using the internal reference - the datasheet requires a 0.1 microfarat bypass capacitor on REF for stability. When using an external reference, ensure the reference source can source/sink the dynamic current drawn during conversion. The pseudo-differential inputs require the COM pin to be driven to within +/-0.1 V of analog ground to maintain linearity at the input common-mode range.
For 108 ksps full-rate operation, route the SPI clock (SCLK) and data (DOUT) traces over a continuous ground plane and keep trace lengths under 50 mm to avoid ringing. According to the datasheet timing diagram, hold CS low for the entire conversion-and-readout cycle, and ensure SCLK rise/fall times are under 20 ns to meet setup/hold timing at 108 ksps.
Estimated: At continuous 108 ksps with 3.3 V supply, the MAX145ACPA draws 1.5 mA typical, dissipating roughly 5 mW - well within the PDIP-8 thermal limit. However, in sealed enclosures at +70 C ambient, verify with a thermocouple measurement that junction temperature stays below +150 C, especially when sampling multiple channels at maximum rate.
Thông tin tuân thủ
MAX145ACPA+ ordering code is Pb-free/RoHS compliant per Maxim product page. Legacy MAX145ACPA (no + suffix) uses SnPb finish. AEC-Q100 not applicable for this commercial-grade part. Refer to MAX145AEPA for extended temperature grade.
