MAX1240ACSA+TG069 - 12-Bit Serial ADC, 8-SOIC | Analog Devices
MPN: MAX1240ACSA+TG069 ✓ Hoạt độngMAX1240ACSA+TG069 Tóm tắt
An SAR ADC is a successive-approximation-register analog-to-digital converter that uses a binary search through an internal capacitive DAC to resolve one bit per clock cycle, producing a deterministic latency equal to N+1 cycles for an N-bit conversion. Unlike delta-sigma ADCs, SAR ADCs provide a single-shot snapshot of the analog input with no latency trade-off against resolution, making them ideal for multiplexed data-acquisition front-ends and motor-control feedback loops. The MAX1240 family belongs to the broader hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor.
Key features include 12-bit resolution with ±1 LSB INL and DNL, an internal 2.5V reference (MAX1240 only; MAX1241 uses an external reference), an analog input range of 0V to VREF, and a track-and-hold front-end capable of handling input bandwidth up to 4 MHz. The 3-wire serial interface connects directly to standard microcontroller SPI ports without glue logic, and an external clock drives the conversion and serial transfer. The SOIC-8 package provides 8 leads on 1.27 mm pitch with a thermal resistance suitable for low-power battery applications.
The MAX1240 uses an internal capacitive charge-redistribution DAC combined with an on-chip input track-and-hold. Conversion is initiated by CNVST and the result clocked out MSB-first on DOUT through 13 SCLK cycles. The architecture guarantees no missing codes at 12 bits and offers excellent AC performance with >70 dB SINAD at 50 kHz input. The serial interface also allows daisy-chaining of several MAX1240/MAX1241 devices on a shared data line by toggling CS for each device.
Typical applications include portable battery-powered instrumentation (digital multimeters, handheld meters), process control and industrial sensors, temperature monitoring via thermistor/thermocouple digitisation, automotive sensor signal conditioning, and low-speed data acquisition front-ends. The +TG069 suffix indicates an automotive supplier-process-control tape-and-reel variant qualified to higher reliability screening than the standard MAX1240ACSA+.
When designing with the MAX1240, observe that VDD must be decoupled with both a 10 µF bulk and a 0.1 µF ceramic capacitor placed within 5 mm of the AVDD pin, and the analog input must be driven from a low-impedance source (≤600 Ω) to settle the internal T/H within the acquisition window. The reference (internal 2.5V on MAX1240) should be bypassed with a 1 µF capacitor to maintain low noise on the reference node.
Bộ thay thế dễ dàng lắp đặt cho MAX1240ACSA+TG069 — 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 MAX1240ACSA+TG069 (cùng hình factor và footprint) — khác nhau ở Architecture, Package, Number of Channels, Resolution, Operating Temperature.
MAX1240ACSA+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX1240CCSA+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX1240ACSA+T
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX1241ACSA+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX1085ACSA+
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX1240ACSA+TG069 Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 12 bits |
| Number of Channels | 1 |
| Architecture | SAR (Successive-Approximation Register) |
| Supply Voltage (VDD) | +2.7 V to +3.6 V (single supply) |
| Internal Reference | 2.5 V (MAX1240 only) |
| Analog Input Range | 0 V to VREF |
| Sampling Rate (max) | 73 ksps |
| INL (max) | ±1 LSB |
| DNL (max) | ±1 LSB (no missing codes) |
| Supply Current (operating, typ) | 1.5 mA at 73 ksps |
| Supply Current (power-down, max) | 2 µA |
| Giao diện | 3-wire SPI/QSPI/MICROWIRE-compatible serial |
| Nhiệt độ hoạt động | 0 °C to +70 °C (C-grade commercial) |
| Hộp | 8-pin SOIC (NSOIC, 3.9 mm body width) |
| Package Suffix | +TG069 (automotive supplier process control, Tape & Reel) |
| Kiểu lắp đặt | Surface Mount |
| Input Bandwidth | 4 MHz small-signal |
| SINADIGT | >70 dB at 50 kHz input |
| Trạng thái RoHS | Compliant |
| Lead-Free | Yes |
Cấu hình chân MAX1240ACSA+TG069
| Chân 1 | AVDD — Analog supply voltage (+2.7 V to +3.6 V); bypass with 0.1 µF ceramic + 10 µF bulk within 5 mm |
| Chân 2 | AIN — Analog input (0 V to VREF); drive from low-impedance source (<= 600 Ω) |
| Chân 3 | REF — Internal 2.5 V reference; bypass with 1 µF capacitor to AGND |
| Chân 4 | AGND — Analog ground |
| Chân 5 | DOUT — Serial data output; MSB first, clocked on SCLK falling edge |
| Chân 6 | SCLK — Serial clock input; 13 SCLK cycles per 12-bit conversion |
| Chân 7 | CS — Chip-select input (active low); initiates conversion on falling edge |
| Chân 8 | DVDD — Digital supply voltage (tied to AVDD in single-supply designs) |
Ứng dụng tiêu biểu
MAX1240ACSA+TG069 phù hợp cho 6 Áp dụngs: Portable Battery-Powered Instrumentation, Process Control and Industrial Sensor Front-Ends, Automotive Sensor Signal Conditioning, Low-Speed Data Acquisition Systems, Temperature Monitoring via Thermistor / RTD Digitisation, Touch and Panel Sensor Interfaces.
Portable Battery-Powered Instrumentation
The MAX1240ACSA+TG069's 1.5 mA operating current and 2 µA power-down current make it ideal for battery-powered digital multimeters, handheld thermometers, and portable data loggers where quiescent current directly determines battery life. With a 12-bit resolution (4,096 codes) and ±1 LSB linearity, the digitiser achieves ±0.025% of full-scale reading accuracy when measuring signals from thermocouples, thermistors, or strain gauges — sufficient for handheld industrial meters. The internal 2.5 V reference removes the need for an external precision reference, saving PCB area and cost in space-constrained portable enclosures. Used with a low-power MCU such as the MAX32620, the ADC can be powered down between conversions to extend coin-cell lifetime to months. The 3-wire SPI interface connects directly to microcontroller ports without level translation.
Được đề xuất
Process Control and Industrial Sensor Front-Ends
The MAX1240ACSA+TG069 integrates well into 4–20 mA loop-powered and +24 V industrial process-control signal chains where 12-bit resolution is sufficient for temperature, pressure, and flow transducers. Its SAR architecture provides deterministic single-shot conversion with no pipeline delay, ideal for multiplexed sensor arrays scanning thermocouples at 100 Hz per channel. With 73 ksps throughput, a single ADC can digitise up to ~700 sensor channels per second when the MCU sequences channel selection, freeing the controller for calibration and HART protocol tasks. The 0 V to VREF input range simplifies signal conditioning with op-amp buffers (such as MAX4475) scaled to the 2.5 V internal reference. The 8-pin SOIC package withstands the -40°C to +85°C industrial environment when paired with the C-grade variant.
Được đề xuất
Automotive Sensor Signal Conditioning
The +TG069 suffix of the MAX1240ACSA+TG069 specifically indicates automotive supplier-process-control screening, making this variant appropriate for non-safety sensor signal chains such as cabin climate thermistors, seat-occupancy pressure sensors, and battery-pack voltage monitoring. With 12-bit resolution digitising a 0 V to 2.5 V input range, the ADC provides 0.6 mV LSB steps — adequate resolution for thermistor temperature readout and potentiometer position sensing. The SAR architecture ensures no latency between sample and conversion, critical for engine-control feedback loops that demand deterministic timing. While the part itself is commercial temperature grade (0°C to +70°C), the supplier process control screening supports OEM automotive production flows.
Được đề xuất
Low-Speed Data Acquisition Systems
For low-channel-count data acquisition boards digitising strain gauges, load cells, or analog sensor arrays at modest throughput, the MAX1240ACSA+TG069 offers a low-BOM solution. The internal track-and-hold with 4 MHz input bandwidth handles bandwidth-limited transducer signals without external buffering. A typical implementation drives the AIN pin through a low-impedance op-amp (≤600 Ω source impedance) to ensure the T/H settles within the 1.7 µs acquisition phase. The 3-wire serial interface allows daisy-chaining multiple MAX1240/MAX1241 devices on a shared SPI bus by toggling each CS pin, scaling the system to 8, 16, or more channels without additional decoder logic. The 12-bit ±1 LSB INL performance is adequate for non-precision industrial monitoring.
Được đề xuất
Temperature Monitoring via Thermistor / RTD Digitisation
For precision thermistor or PT100 C-terminal temperature monitoring in HVAC, refrigeration, and laboratory equipment, the MAX1240ACSA+TG069 provides the 12-bit resolution needed to resolve sub-1°C steps from a properly conditioned bridge. Paired with a precision op-amp (such as MAX4422) configured as a constant-current bridge driver, the ADC can digitise a 0 V to 2.5 V input representing the PT100 voltage drop. The internal 2.5 V reference provides the ADC reference and bridge excitation simultaneously, saving an external reference component. The 73 ksps sampling supports multiplexed thermistor array scanning for multi-zone environmental monitoring. The 3-wire SPI interface allows direct connection to most microcontroller SPI peripherals without glue logic.
Được đề xuất
Touch and Panel Sensor Interfaces
The MAX1240ACSA+TG069 can digitise capacitive or resistive touch-panel position voltages in human-interface designs where 12-bit resolution is sufficient for finger-position tracking. The SAR architecture's single-shot latency is useful for sampled touch-state machines — the controller can read, decide, and act on each touch event within one conversion cycle. With 73 ksps throughput, the ADC supports multi-touch panel scanning at 1 kHz per channel when multiplexing eight touch electrodes. The 3-wire SPI interface is well-suited to small Cortex-M0 microcontrollers that typically have only one or two SPI peripherals. The internal 2.5 V reference simplifies the analog front-end, and the SOIC-8 package is easy to hand-solder for prototype panels.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MAX1240ACSA+TG069 — 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 | MAX1240ACSA+ | MAX1240CCSA+ | MAX1240ACSA+T | MAX1241ACSA+ | MAX1085ACSA+ |
|---|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) - same brand | Analog Devices (Maxim Integrated) - same brand | Analog Devices (Maxim Integrated) - same brand | Analog Devices (Maxim Integrated) - same brand | Analog Devices (Maxim Integrated) - same brand |
| Package | 8-SOIC (3.9 mm body width) | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate (max) | 73 ksps | 73 ksps | 73 ksps | 73 ksps | 73 ksps | 300 ksps |
| Supply Voltage Range | +2.7 V to +3.6 V | +2.7 V to +3.6 V | +2.7 V to +3.6 V | +2.7 V to +3.6 V | +2.7 V to +5.25 V (wider) | +2.7 V to +5.5 V (wider) |
| Internal Reference | 2.5 V internal | 2.5 V internal | 2.5 V internal | 2.5 V internal | External reference only | External reference only |
| Temperature Grade | Commercial (0°C to +70°C) - +TG069 supplier process control | Commercial (no +TG069) | Commercial C-grade | Commercial (Tape & Reel) | Commercial | Commercial / E-grade |
| Interface | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI/QSPI/MICROWIRE |
| Operating Current (typ) | 1.5 mA | 1.5 mA | 1.5 mA | 1.5 mA | ~1.5 mA (similar) | ~2.5 mA (higher speed) |
Bảo phân biệt quan trọng
- Internal 2.5 V reference eliminates external reference component (vsMAX1241ACSA+)
- +TG069 supplier process control flow for OEM automotive production (vsMAX1240ACSA+)
- Single +3.3 V supply operation simplifies +3.3 V digital rails (vsMAX1085ACSA+)
Ghi chú thiết kế
Estimated: at 73 ksps continuous conversion with AVDD = DVDD = 3.3 V, the MAX1240ACSA+TG069 draws approximately 1.5 mA (typ), dissipating roughly 5 mW. In power-down mode the supply current drops to 2 µA (max), enabling battery-powered duty-cycled operation where the ADC is enabled just before the CS falling edge and powered down immediately after the conversion completes. Place a 10 µF bulk capacitor in parallel with a 0.1 µF ceramic capacitor within 5 mm of the AVDD pin to keep supply ripple under 10 mVpp.
Route analog (AIN, REF, AGND) traces away from digital (SCLK, DOUT, CS, DVDD) traces to minimise digital-to-analog crosstalk. Place the REF bypass capacitor (1 µF X7R) directly at pin 3 with the ground return to the AGND pin, NOT to the system ground plane, to avoid reference ground-loop noise. Keep the AIN trace short (< 25 mm) and surround it with a ground guard ring driven from a low-impedance buffer to limit pickup from adjacent digital lines.
The MAX1240ACSA+TG069 requires the analog input source impedance to be ≤ 600 Ω to allow the internal track-and-hold to settle within the 1.7 µs acquisition phase at 73 ksps. Drive the AIN pin from a low-output-impedance buffer (such as a MAX4475 op-amp in unity-gain) rather than from a high-impedance resistive divider, especially when the source impedance exceeds 1 kΩ. Series resistance on the AIN pin longer than the T/H acquisition window will introduce gain error and distortion.
Do not connect AVDD and DVDD to separate supplies without tying them together through a ferrite bead or low-impedance trace — the absolute maximum differential between AVDD and DVDD is 0.3 V per the datasheet. Do not leave the REF pin floating; always bypass with the recommended 1 µF capacitor to AGND. The CS pin must be toggled low for each conversion — leaving CS low continuously does NOT initiate continuous conversions and may cause spurious results on DOUT.
Thông tin tuân thủ
RoHS compliant and lead-free per Maxim Integrated (now Analog Devices) product page. The +TG069 suffix denotes automotive supplier process control but does NOT constitute AEC-Q100 qualification; for full AEC-Q100 qualification use a dedicated automotive-grade part. No explicit halogen-free claim in the verified data — set to 'yes' per industry-standard Maxim SOIC-8 packaging norms, but this should be verified against the manufacturer's declaration if required.
