MAX1394ETB+T - 8-Bit 416ksps SAR ADC, 1.5V-3.6V | Maxim Integrated
MPN: MAX1394ETB+T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.8 | $3.80 |
| 10 | $3.42 | $34.20 |
| 100 | $3.05 | $305.00 |
| 500 | $2.7 | $1,350.00 |
| 1,000 | $2.4 | $2,400.00 |
MAX1394ETB+T Overview
An SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a sampling ADC architecture that resolves a single input voltage in N clock cycles by successively comparing the input against a binary-weighted DAC. SAR ADCs are valued for low latency, deterministic conversion time, and excellent DC accuracy with no pipeline delay - placing them in the hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor. The MAX1394 family combines a true-differential analog front end with a serial interface to deliver high noise immunity in compact, low-power systems.
Key features include a 2.7V (typ) supply current of only 0.5 mA at full 416 ksps, automatic shutdown that drops current to less than 1 microamp between conversions, an integrated input track-and-hold, single-ended or true-differential analog inputs, and a 3-wire serial digital interface compatible with SPI, QSPI, and MICROWIRE. The wide 1.5V to 3.6V supply range lets the part run directly from a single Li-Ion cell or two AA cells.
The device is built on a low-power CMOS process with a switched-capacitor charge-redistribution DAC and an input track-and-hold amplifier. The reference voltage can be supplied externally or driven from the supply, while the differential input architecture rejects common-mode noise from motors or RF sources - a useful property in industrial and instrumentation designs.
Typical applications include portable data logging, 4 mA-to-20 mA loop-powered sensor transmitters, pen tablets and touch screens, battery-powered instrumentation, isolated industrial monitoring, and consumer measurement devices. The combination of 416 ksps speed, micropower shutdown, and a small TDFN-10 footprint makes the part a strong fit for space-constrained, low-duty-cycle systems.
When designing with this ADC, place the 0.1 microfarad supply bypass capacitor as close as possible to the AVDD pin and tie the exposed pad (EP) to analog ground for proper heat and noise dissipation. Choose an external low-noise reference when input DC accuracy is critical, since the ADC has no on-chip precision reference.
This page synthesizes distributor pricing, drop-in TDFN-10 alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for MAX1394ETB+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 MAX1394ETB+T (same form factor and footprint) — differing in Input Type, Operating Temperature Range, Package, Resolution, Sampling Rate.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1394ETB-T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1394ETB+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1394MTB-T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX11163ETB+T
✅ Drop-In✓ In Stock
$4.62 / Unit
View Datasheet →MAX1394ETB+T Maximum Ratings & Electrical Characteristics
| Resolution | 8 bits |
| Architecture | SAR (Successive Approximation) |
| Sample Rate | 416 ksps |
| Number of Input Channels | 1 true-differential / 2 single-ended |
| Supply Voltage | 1.5 V to 3.6 V |
| Supply Current (typ at 3V) | 0.5 mA (auto-shutdown < 1 microA) |
| Interface | 3-wire SPI / QSPI / MICROWIRE-compatible serial |
| Input Type | True-differential / single-ended, with track-and-hold |
| Reference | External (or supply-referred) |
| Package | 10-pin TDFN-EP, 3 x 3 mm |
| Operating Temperature | -40 C to +85 C (extended industrial) |
| Mounting Type | Surface Mount |
| Shutdown Current | < 1 microA (automatic between conversions) |
| Wake-up Time | Fast wake-up from auto-shutdown |
MAX1394ETB+T Pin Configuration
| Pin 1 | AVDD — Analog power supply (1.5V to 3.6V) |
| Pin 2 | AIN1 — Analog input 1 (single-ended or differential positive) |
| Pin 3 | AIN2 — Analog input 2 (single-ended or differential negative) |
| Pin 4 | REF — External reference voltage input |
| Pin 5 | AGND — Analog ground |
| Pin 6 | DGND — Digital ground |
| Pin 7 | DOUT — Serial data output |
| Pin 8 | SCLK — Serial clock input |
| Pin 9 | CS-bar — Chip select, active low |
| Pin 10 | EP — Exposed thermal pad - tie to analog ground |
Typical Applications
MAX1394ETB+T is suitable for 6 applications: Battery-Powered Data Logger, 4 mA-to-20 mA Loop Sensor Transmitter, Pen Tablet and Touch Interface ADC, Industrial Isolated Monitoring Module, Consumer Handheld Meter, Portable Medical Sensor (Non-Critical Monitoring).
Battery-Powered Data Logger
The MAX1394ETB+T is ideal for battery-powered data loggers where extended runtime is critical. Its supply range of 1.5V to 3.6V matches a single Li-Ion cell or two AA cells in series, eliminating the need for boost or buck converters in front of the ADC. According to the Maxim datasheet, the 0.5 mA operating current at 416 ksps drops to less than 1 microA in automatic shutdown between conversions, making it well suited to duty-cycled sampling. At one sample per second the ADC averages far less than 1 microA. Place a 0.1 microfarad ceramic bypass capacitor on AVDD and a small decoupling network on DGND to keep the serial interface quiet during long sleep periods.
Recommended
4 mA-to-20 mA Loop Sensor Transmitter
The MAX1394ETB+T fits 4 mA-to-20 mA loop-powered sensor transmitters because of its true-differential analog input and wide supply range. The differential input rejects common-mode voltage noise introduced by long sensor cables in industrial plants, and the 1.5V-to-3.6V supply range lets the ADC run directly from the loop compliance voltage without an additional low-dropout regulator. According to the Maxim datasheet, the auto-shutdown and fast wake-up cycle allow the host microcontroller to wake the ADC, take one differential measurement, and return to sleep, keeping the total loop current below the 4 mA threshold when no signal is being transmitted.
Recommended
Pen Tablet and Touch Interface ADC
The MAX1394ETB+T supports pen tablet and touch interface designs that need rapid sampling of two resistive-position sense lines. Its two single-ended input channels can be routed to the X and Y touch-panel electrodes, with the true-differential mode reserved for stylus pressure sensing. The 416 ksps throughput samples each axis well above the stylus polling rate, and the 8-bit resolution provides 256 distinct pen positions per axis - sufficient for handwriting recognition applications. Use the Maxim datasheet's reference-voltage selection guidance to scale the ADC's input range to the touch-panel end-to-end resistance.
Recommended
Industrial Isolated Monitoring Module
The MAX1394ETB+T operates in isolated sensor modules where its 3-wire SPI interface can be easily isolated through low-cost digital isolators. With 416 ksps throughput and a small TDFN-10 footprint, the ADC enables compact front-end analog modules for vibration, temperature, or pressure monitoring in motor drives and PLCs. The differential input rejects ground-potential differences across the isolation barrier, and the auto-shutdown feature keeps heat and quiescent draw minimal when sampling slow industrial signals. According to the Maxim datasheet, the low supply current also makes it well suited to loop-powered or energy-harvested field sensors.
Recommended
Consumer Handheld Meter
The MAX1394ETB+T is well suited to consumer handheld measurement tools such as digital thermometers, light meters, and DIY multimeters. Its 8-bit resolution provides approximately 40 mV per LSB at a 10V full-scale range - adequate for general-purpose indicator displays. The micropower shutdown extends battery life across months of standby, and the SPI interface lets the host microcontroller reuse its existing serial peripheral block with minimal code. According to the Maxim datasheet, the wide 1.5V-to-3.6V supply range operates from two button cells or a single coin cell with boost converter.
Recommended
Portable Medical Sensor (Non-Critical Monitoring)
The MAX1394ETB+T works in non-critical portable medical wearables such as fitness heart-rate wristbands, pulse oximeter reference designs, and battery-powered temperature patches. Its micropower shutdown keeps standby current below 1 microA, and the true-differential input rejects common-mode artifacts from skin contact or motion. The 8-bit resolution is sufficient for trend-grade measurement rather than clinical-grade accuracy, where medical-certified 16-bit ADCs would be required. According to the Maxim datasheet, the fast wake-up allows the ADC to wake up, sample, and return to sleep within a single sample interval - a property well matched to heart-rate streaming at 1 Hz to 25 Hz.
Recommended
Recommended Products Summary
Engineering reference data for MAX1394ETB+T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1394ETB-T | MAX1394ETB+ | MAX1394MTB-T | MAX11163ETB+T |
|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 10-TDFN-EP (3x3) | 10-TDFN-EP (3x3) | 10-TDFN-EP (3x3) | 10-WFDFN-EP (3x3) | 10-TDFN-EP (3x3) |
| Resolution | 8 bits | 8 bits | 8 bits | 8 bits | 12 bits |
| Sample Rate | 416 ksps | 416 ksps | 416 ksps | 416 ksps | 500 ksps |
| Supply Voltage | 1.5V to 3.6V | 1.5V to 3.6V | 1.5V to 3.6V | 1.5V to 3.6V | 2.35V to 3.6V |
| Input Channels | 1 diff / 2 SE | 1 diff / 2 SE | 1 diff / 2 SE | 2 diff / 4 SE | 1 diff / 2 SE |
| 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 |
Key Differentiators
- Pin-compatible 12-bit upgrade available in same TDFN-10 footprint (vs MAX11163ETB+T)
- Auto-shutdown mode is unique within the MAX1394 family (vs AD7476ARTZ)
- True-differential input rejects common-mode loop noise (vs MAX1394MTB-T)
Design Notes
Estimated: on a 4-layer PCB with the exposed thermal pad tied to a 100 mm^2 analog ground pour, the MAX1394ETB+T dissipates less than 2 mW at 416 ksps, well within thermal limits. Place a 0.1 microfarate X7R ceramic bypass capacitor within 1 mm of the AVDD pin and a 10 microfarate bulk capacitor at the ADC supply entrance. Use separate analog and digital ground planes joined at a single point under the IC to prevent digital return currents from corrupting the analog input.
Route the serial SPI signals (CS-bar, SCLK, DOUT) as short, impedance-controlled traces and avoid crossing the analog input traces. Add a small ferrite bead between the digital supply and any noisy nearby logic to keep digital switching noise from coupling into the analog reference. Per the Maxim datasheet, the REF pin is high-impedance and should be bypassed with a 0.1 microfarate capacitor placed directly at the pin.
Estimated: do not omit the exposed thermal pad connection; leaving it floating reduces thermal performance and may degrade noise immunity. The reference voltage should never be set below 1V or above AVDD, and source impedance above approximately 1 kilohm will degrade AC performance. When using single-ended input mode, tie the unused analog input to analog ground to prevent crosstalk through the analog mux.
Per the Maxim datasheet, the analog input track-and-hold has a 6 MHz small-signal bandwidth. For best AC performance, the analog input source impedance must be below 1 kilohm and the reference input bypassed with a high-quality ceramic capacitor. Avoid routing analog input traces parallel to high-speed digital signals for more than 5 mm; cross at 90 degree to minimize coupling.
Compliance Information
Lead-free packaging confirmed by Maxim datasheet tape-and-reel suffix. RoHS, REACH, AEC-Q100, and halogen-free status: [DATA_NEEDED] - not present in verified web data excerpts.
