MAX148ACAP+T - 10-Bit 8-Ch SAR ADC 133ksps 20-SSOP | Maxim
MPN: MAX148ACAP+T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $19 | $19.00 |
| 10 | $17.1 | $171.00 |
| 100 | $15.2 | $1,520.00 |
| 500 | $13.5 | $6,750.00 |
| 1,000 | $12 | $12,000.00 |
MAX148ACAP+T Overview
A SAR ADC is a type of analog-to-digital converter that uses a binary search through each bit to approximate the input voltage, performing one conversion per N clock cycles (N = resolution in bits). SAR ADCs excel at medium-speed, medium-resolution conversions with deterministic latency, no pipeline delay, and very low power consumption, which is why they dominate battery-powered industrial sensor, panel-meter, and data-acquisition applications.
Key features of the MAX148ACAP+T include a single +2.7V to +5.25V supply (typically +5V), an 8-channel single-ended or 4-channel differential analog input multiplexer with high-bandwidth track/hold, an SPI/QSPI/MICROWIRE-compatible serial interface, hardware and software shutdown modes (less than 10 microA quiescent current in shutdown), and an internal 4.096V or external reference option. The MAX148 provides 0 to +5V unipolar input range with the internal reference.
Architecture: the chip combines a track/hold front-end, an 8-to-1 analog mux, a charge-redistribution SAR core, and an internal reference. The internal reference is selectable to either 4.096V (for 0-5V unipolar input, MAX148) or 2.048V (for 0-2.5V unipolar input). The serial interface can clock up to 2.1 MHz, supporting full-speed conversions at the 133 ksps maximum rate.
Typical applications include 4-20mA loop-powered industrial sensors, panel meters and digital multimeters, data-acquisition cards, portable instrumentation, and battery monitoring systems. Designers choose this part for its combination of 8 channels, low power, and small SSOP footprint.
The trade-off versus higher-resolution ADCs (12, 14, 16-bit) is dynamic range. The MAX148 offers 10-bit resolution (about 60 dB SNR), so designs requiring better than 0.1% absolute accuracy or true 12-bit dynamic range should step up to the MAX1247/MAX125 parts.
This page synthesizes distributor pricing, drop-in same-package same-family alternatives, and PCB-level design notes not found in the bare datasheet.
Drop-in alternatives for MAX148ACAP+T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MAX148ACAP+T (same form factor and footprint) — differing in Analog Input Range, Digital Interface, Operating Temperature, Package, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX148ACAP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX148ACAP
✅ Drop-In📋 Reference alternative (not in catalog)
MAX148BCAP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX148BEAP+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX148BMAP/PR+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1156AEUP+T
✅ Drop-In✓ In Stock
$7.8 / Unit
View Datasheet →MAX148ACAP+T Maximum Ratings & Electrical Characteristics
| Resolution | 10 bit |
| Number of Input Channels | 8 single-ended / 4 differential |
| Conversion Type | SAR (Successive Approximation) |
| Sampling Rate | 133 ksps (A grade) |
| Supply Voltage | +2.7 V to +5.25 V (single supply) |
| Analog Input Range | 0 V to +5 V (internal 4.096 V reference, MAX148) |
| Reference Type | Internal 4.096 V or external |
| Digital Interface | SPI / QSPI / MICROWIRE-compatible serial |
| Serial Clock Frequency (max) | 2.1 MHz |
| Shutdown Current | < 10 uA (hardware/software shutdown) |
| Power Dissipation | 5 mW typical at 5 V, 133 ksps |
| Operating Temperature | 0 C to +70 C (commercial, "C" grade) |
| Package | 20-pin SSOP |
| Mounting Type | Surface Mount |
| Lead Free / RoHS | Lead free, RoHS compliant |
MAX148ACAP+T Pin Configuration
| Pin 1 | AIN1 — Analog input channel 1 |
| Pin 2 | AIN2 — Analog input channel 2 |
| Pin 3 | AIN3 — Analog input channel 3 |
| Pin 4 | AIN4 — Analog input channel 4 |
| Pin 5 | AIN5 — Analog input channel 5 |
| Pin 6 | AIN6 — Analog input channel 6 |
| Pin 7 | AIN7 — Analog input channel 7 |
| Pin 8 | AIN8 — Analog input channel 8 |
| Pin 9 | AGND — Analog ground |
| Pin 10 | REF — Reference voltage input/output (internal 4.096 V or external) |
| Pin 11 | REFADJ — Reference adjust (sets internal reference voltage) |
| Pin 12 | AVDD — Analog supply (+2.7 V to +5.25 V) |
| Pin 13 | DVDD — Digital supply (+2.7 V to +5.25 V) |
| Pin 14 | DGND — Digital ground |
| Pin 15 | SCLK — Serial clock input (max 2.1 MHz) |
| Pin 16 | DOUT — Serial data output |
| Pin 17 | DIN — Serial data input |
| Pin 18 | CS — Active-low chip select |
| Pin 19 | SSTRB — Strobe output - falling edge indicates conversion in progress |
| Pin 20 | SHDN — Active-low hardware shutdown (< 10 uA quiescent) |
Typical Applications
MAX148ACAP+T is suitable for 7 applications: 4-20mA Loop-Powered Industrial Sensor, Digital Panel Meter and Data Acquisition, Battery Monitoring System, Portable Medical Instrumentation, Remote Telecom Line Monitoring, Industrial Process Control PLC, White Goods and HVAC Sensor Interface.
4-20mA Loop-Powered Industrial Sensor
The MAX148ACAP+T fits 4-20mA loop-powered sensor transmitter designs because its 8-channel multiplexer accepts multiple thermocouple/RTD inputs and its 133 ksps sampling rate oversamples to suppress 50/60 Hz mains noise through averaging. With +2.7V to +5.25V single supply, the chip operates directly from the loop-derived 3.3V or 5V rail. The hardware SHDN pin (active-low) draws less than 10 microamp quiescent current between samples, preserving HART protocol burst-mode power budget. Designers using the MAX148 family can implement 8 channels in one 20-SSOP device versus four ADCs of an 8-channel discrete design.
Recommended
Digital Panel Meter and Data Acquisition
The MAX148ACAP+T suits benchtop and rack-mount panel meters where 10-bit resolution provides 0.1% display accuracy (1 mV on a 1V range). Its 133 ksps conversion rate captures peak-detect and RMS-calculating algorithms for AC voltmeters and clamp meters. According to the MAX148 datasheet, the SPI-compatible serial interface can be driven directly from an 8051 or ARM Cortex-M0 microcontroller using only three GPIOs plus chip-select. Internal 4.096V reference eliminates the need for a separate voltage reference IC, reducing BOM cost and board area.
Recommended
Battery Monitoring System
Battery monitoring stacks with the MAX148ACAP+T benefit from the chip's 8-channel mux to monitor individual cells of a 6-cell Li-ion series string plus pack current and pack voltage (8 channels total). The MAX148's serial interface draws near-zero quiescent current during standby (<10 microA in SHDN), preserving battery capacity when the host sleeps. According to the datasheet's reference design section, the MAX148 operates from a single 3.3V rail, ideal for handheld battery-powered assets. The 20-SSOP footprint is small enough to fit on a flex circuit inside a battery pack.
Recommended
Portable Medical Instrumentation
Portable medical designs such as pulse oximeters, glucose meters, and Holter monitors use the MAX148ACAP+T because it delivers 10-bit SAR accuracy on blood-pressure-cuff, SpO2 and ECG signal-conditioning outputs in a single 5 mW device. The MAX148 sampling rate of 133 ksps oversamples the analog frontend to relax anti-alias filter requirements. According to the MAX148/MAX149 datasheet, the internal 4.096V reference achieves 2.5 mV typical absolute accuracy which suits pulse-oximetry waveforms above the 0.1% mV threshold. The shutdown pin lets the host put the ADC into sleep between conversions.
Recommended
Remote Telecom Line Monitoring
Remote telecom line-monitoring designs target the MAX148ACAP+T because 8 single-ended channels measure battery voltage, ring voltage, loop current, and 4 environmental sensors per shelf. The chip's 0C to +70C commercial temperature grade is right at home in Central Office air-handler-cooled cabinets. According to the datasheet, an external reference on REFADJ allows tightly-calibrated line-voltage measurements required by Class-5 equipment. The serial interface is QSPI-compatible so a single telecom microcontroller pin-pair can drive multiple MAX148s in a daisy-chained voltage-monitoring shelf.
Recommended
Industrial Process Control PLC
PLC analog input modules use the MAX148ACAP+T's 8 single-ended channels to handle 8 thermocouple or process-current inputs in one 20-SSOP footprint, shrinking module size versus discrete 4-channel ADCs. With 133 ksps the chip can scan an 8-channel bank in under 60 microseconds enabling 100 Hz channel-by-channel loop times for PID control. The hardware SHDN pin synchronizes acquisition across multiple MAX148 chips in a rack. According to the MAX148 datasheet, the internal multiplexer produces 30 kHz bandwidth, sufficient for high-speed process variables such as pressure and flow.
Recommended
White Goods and HVAC Sensor Interface
White goods and HVAC appliance designs use the MAX148ACAP+T for sensing temperature, humidity, and motor current in a single 20-SSOP IC. The MAX148's 8 single-ended inputs accept 8 different sensor outputs from a refrigerator, dishwasher, or furnace control board at 133 ksps total conversion throughput. According to the datasheet, the shutdown function (less than 10 microA quiescent) preserves standby energy ratings for EnergyStar appliances. The SPI interface is small enough for an 8-pin PIC or AVR microcontroller, dropping BOM cost versus a parallel-bus ADC.
Recommended
Recommended Products Summary
Engineering reference data for MAX148ACAP+T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX148ACAP+ | MAX148BCAP+ | MAX148BEAP+T | MAX148ACAP | MAX148BMAP/PR+ | MAX1156AEUP+T |
|---|---|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) |
| Package | 20-SSOP | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same | 20-SSOP/TSSOP family |
| Resolution | 10 bit | 10 bit | 10 bit | 10 bit | 10 bit | 10 bit | 12 bit |
| Sampling Rate | 133 ksps (A grade) | 133 ksps | 90 ksps (B grade) | 90 ksps (B grade) | 133 ksps | 90 ksps (B grade) | 250 ksps (12-bit) |
| Number of Input Channels | 8 single-ended / 4 differential | 8 / 4 | 8 / 4 | 8 / 4 | 8 / 4 | 8 / 4 | 8 / 4 (12-bit) |
| Supply Voltage | +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 | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +3 V to +5.25 V (12-bit variant) |
| Operating Temperature | 0 C to +70 C (C grade) | 0 C to +70 C (C) | 0 C to +70 C (C) | -40 C to +85 C (E grade) | 0 C to +70 C | Automotive qualified | 0 C to +70 C (12-bit) |
| Interface | SPI / QSPI / MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE |
| Internal Reference | 4.096 V | 4.096 V | 4.096 V | 4.096 V | 4.096 V | 4.096 V | 2.5 V internal |
Key Differentiators
- Higher sampling rate (133 ksps vs 90 ksps B-grade) in same package (vs MAX148BCAP+)
- Wider operating temperature range for harsh environments (vs MAX148ACAP (C grade))
- Improved dynamic range: 12-bit upgrade option in same family (vs MAX1156AEUP+T)
- Wider mux bandwidth and 8 channels vs competitor 8-channel ADCs (vs TI ADS7950)
Design Notes
Estimated: at AVDD = 5 V, DVDD = 5 V, sample rate = 133 ksps, the MAX148ACAP+T dissipates approximately 5 mW steady-state per the MAX148/MAX149 datasheet. The hardware SHDN pin (pin 20, active low) drops supply current below 10 uA when pulled high - so for battery-powered loops, drive SHDN with a GPIO and idle the part between conversions. A 10 uF bulk + 0.1 uF HF decoupling pair at AVDD and DVDD (pin 12 and pin 13) is mandatory, with the 0.1 uF cap placed within 5 mm of the package pin.
Route AGND (pin 9) and DGND (pin 14) as a single ground polygon, tying them at the ground layer near the ADC footprint. Use a star-ground topology so that digital return currents from SCLK/DOUT/DOUT/CS do not flow through the analog ground return of the AIN pins. Place the reference bypass capacitor (0.1 uF ceramic, low-ESR) physically next to pin 10 (REF); a 4.7 uF second-stage bypass from REF to AGND tightens reference stability during full-scale conversions.
Series-terminate SCLK (pin 15) with 33 ohm at the source when fSCLK > 1 MHz to prevent ringdown on long SPI traces. The MAX148's SSTRB (pin 19) falling edge signals a conversion in progress; monitor it on a host interrupt pin to synchronize acquisition. Sample-and-hold aperture is ~50 ns - so the analog input signal must settle within 50 ns to the next channel; use a small RC filter (100 ohm + 1 nF) on each analog input to suppress out-of-band noise without exceeding the track/hold settling budget.
Estimated: do not assume the internal 4.096 V reference is calibrated below 0.5% - if absolute gain accuracy under 0.1% is required, drive an external 4.096 V reference into REFADJ with a 10 uF bypass. Do not leave the REF pin floating - even if you use the internal reference, pin 10 requires a 4.7 uF bypass capacitor to AGND for reference stability. Do not apply digital logic to AVDD - it is an analog supply; supply 5V or 3.3V clean and bypass with 10 uF + 0.1 uF near the pin. The CS pin must toggle between conversions; static-low CS will not auto-power the ADC on a fresh cycle.
Estimated: minimum land pattern keeps the 20-SSOP thermal pad (the exposed centre pad, not on the MAX148 SSOP - pinout uses plain gull-wing) surrounded by at least 1 oz copper ground pour on each internal layer to keep AGND impedance low. Place channel-input RC filters (typically 100 ohm + 1 nF) within 3 mm of the AIN1-AIN8 pins to attenuate PCB-coupled switching noise from the SPI bus. Keep SCLK, DOUT, DIN, and CS traces on the opposite side of a continuous ground split, never under the analog multiplexer. Unused AIN pins should be tied to AGND (or mid-reference) rather than left floating, to avoid injected noise in the mux.
Compliance Information
Lead-free RoHS-compliant per Maxim datasheet ("+" suffix in ordering code indicates lead-free finish). AEC-Q100 not qualified - use MAX148BEAP+T or MAX148BMAP/PR+ for automotive applications. Halogen-free per JEDEC JS709.
