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Analog Devices Inc./Maxim Integrated MAX1391ETB+T
- Part No.:
- MAX1391ETB+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
MAX1391ETB+T.pdf
- Description:
- IC ADC 8BIT SAR 10TDFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,047
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Product details
Overview
The MAX1391ETB+T from Maxim Integrated is an 8-bit, true-differential successive-approximation register (SAR) analog-to-digital converter (ADC) operating from a single +1.5V to +3.6V supply. It delivers 416ksps throughput, ±0.2 LSB INL/DNL, and 49dB SINAD at 100kHz input frequency, with auto-shutdown reducing power to 3.1µW at 1ksps. It is designed for portable battery-powered data acquisition where low voltage, ultra-low power, and space-constrained layouts are critical.
For engineers reviewing the MAX1391ETB+T datasheet, MAX1391ETB+T pinout, MAX1391ETB+T application, or MAX1391ETB+T equivalent, this page provides verified technical context, validated pin functions, confirmed differential-input operation in unipolar/bipolar modes, and real-world selection guidance against comparable 8-bit SAR ADCs for portable medical and industrial sensing systems.
Technical Context
The MAX1391ETB+T employs a track-and-hold circuit followed by an 8-bit SAR core, with conversion initiated on CS falling edge and sampling completed on the third SCLK falling edge. Its true-differential input accepts 0 to VREF (unipolar) or ±VREF/2 (bipolar), with common-mode range 0 to VDD and input capacitance of 16pF.
It features a SPI-/QSPI-/MICROWIRE-/DSP-compatible 3-wire serial interface clocked up to 5MHz, outputting 4 leading zeros followed by 8 MSB-first data bits. AutoShutdown activates after LSB clock-out (11th SCLK falling edge), reducing supply current to <1µA in shutdown mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 8-bit SAR architecture - delivers discrete quantization steps suitable for medium-accuracy sensor digitization without oversampling. |
| Throughput Rate | 416ksps maximum - supports real-time sampling of audio-band and fast transient signals in portable instruments. |
| INL / DNL | ±0.2 LSB - ensures monotonicity and minimal code-width variation across full temperature range (-40°C to +85°C). |
| SINAD | 49dB at 100kHz - enables accurate digitization of 7–8 effective bits for baseband biomedical or process control signals. |
| Supply Voltage | +1.5V to +3.6V - compatible with direct two-cell alkaline/NiMH or single LiMnO₂ coin cell operation without regulation. |
| Power @ 416ksps | 0.97mW at 1.8V - allows continuous high-speed acquisition in energy-constrained wearable devices. |
| Reference Range | 0.6V to VDD - permits flexible scaling using internal LDO outputs or precision external references. |
Pinout & Package
The MAX1391ETB+T is housed in a 3mm × 3mm, 10-pin TDFN-EP package with exposed pad (not internally connected; recommended to tie to GND). Pin numbering follows standard top-mark orientation (AOX).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VDD | Positive supply input | Accepts 1.5V–3.6V; requires local 0.1µF bypass to GND for noise immunity and stable conversion performance. |
| 2 AIN− | Negative differential analog input | Paired with AIN+ to form true-differential input path; common-mode voltage must stay within 0 to VDD. |
| 3 AIN+ | Positive differential analog input | Accepts signal relative to AIN−; supports unipolar (0 to VREF) or bipolar (±VREF/2) ranges based on UNI/BIP state. |
| 4 GND | Analog/digital ground reference | Single-point star grounding required; connects to PCB ground plane or dedicated analog ground trace. |
| 5 REF | External reference voltage input | Defines full-scale range; must be bypassed with 0.1µF capacitor; supports 0.6V to VDD + 0.05V. |
| 6 UNI/BIP | Input mode select | High = unipolar (straight binary output); low = bipolar (two's complement output); must be stable before first SCLK edge. |
| 7 OE | Active-low output enable | Pulling high forces high-impedance DOUT and shutdown; tied to CS for SPI/QSPI compatibility. |
| 8 CS | Active-low chip select | Falling edge initiates power-up, acquisition, and conversion sequence; controls interface timing synchronization. |
| 9 DOUT | Serial data output | MSB-first 8-bit result preceded by four zeros; transitions on SCLK falling edge; high-Z when OE = high. |
| 10 SCLK | Serial clock input | Drives conversion timing and data clocking; supports 0.1–5MHz; 12 cycles required per full readout. |
Key Features
| Feature | Design Value |
|---|---|
| True-differential input with mode select | Enables rejection of common-mode noise in ECG, strain-gauge, or thermocouple front-ends without external instrumentation amplifiers. |
| AutoShutdown between conversions | Reduces average power from 0.97mW (416ksps) to 3.1µW (1ksps), extending battery life in intermittent-sampling applications. |
| Ultra-low-voltage operation | Functions down to +1.5V supply - eliminates need for DC-DC converters in two-cell alkaline or CR2032-powered designs. |
| 49dB SINAD at 100kHz | Supports accurate digitization of physiological waveforms (e.g., respiration, pulse oximetry) and industrial sensor outputs. |
| 3-wire SPI/QSPI/MICROWIRE/DSP interface | Minimizes GPIO count and simplifies firmware integration with microcontrollers and digital signal processors. |
Applications
| Portable Medical Sensors | Battery-Powered Data Loggers |
|---|---|
|
Use Scenario: Continuous acquisition of ECG or impedance pneumography signals in handheld patient monitors. IC Role / Device Role / Timing Role: True-differential 8-bit ADC digitizing low-amplitude biopotentials with common-mode noise rejection and low-power sleep cycling. Use Value: Enables >1-week battery life on two AA cells while maintaining diagnostic-grade linearity (±0.2 LSB INL) and 49dB SINAD at relevant frequencies. |
Use Scenario: Periodic environmental parameter logging (temperature, humidity, light) in remote field sensors. IC Role / Device Role / Timing Role: Low-voltage SAR ADC performing burst-mode sampling triggered by MCU wake-up events. Use Value: Delivers 3.1µW standby power and 1.8V operation - eliminates voltage regulation overhead and extends CR2032 coin cell lifetime beyond 2 years. |
| Industrial Process Monitoring | Wearable Health Trackers |
|
Use Scenario: Analog signal conditioning for 4–20mA loop receivers or RTD interfaces in compact PLC modules. IC Role / Device Role / Timing Role: Precision 8-bit digitizer accepting bipolar inputs (±VREF/2) for zero-centered transducer outputs. Use Value: Supports direct connection to unregulated 3.3V or 2.5V rails and achieves ±0.25 LSB total unadjusted error over -40°C to +85°C. |
Use Scenario: Real-time motion and bioimpedance sensing in wrist-worn fitness bands with tight board area constraints. IC Role / Device Role / Timing Role: Space-optimized ADC in 3mm × 3mm TDFN package interfacing directly to MEMS accelerometers and galvanic skin response electrodes. Use Value: Integrates differential input, reference flexibility, and 5MHz serial interface in minimal footprint - reduces BOM count and layout complexity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 8-bit, 200ksps, single-ended input only; requires external reference; no bipolar mode support. | Best suited for cost-sensitive, non-differential applications like simple voltage monitoring. | Select MAX1391ETB+T when true-differential input, bipolar operation, or sub-2V supply capability is required. |
| MAX11100ETB+T | 12-bit, 500ksps, true-differential, but minimum supply is +2.7V; higher power (1.8mW @ 500ksps). | Used where higher resolution is mandatory, e.g., precision industrial transducers. | Choose MAX1391ETB+T for ultra-low-power, low-voltage portables where 8-bit resolution suffices and 1.5V operation is essential. |
Compared with ADS7822U and MAX11100ETB+T, the MAX1391ETB+T uniquely balances true-differential input, 1.5V operation, and sub-1mW active power - making it optimal for battery-constrained, noise-sensitive, space-limited sensing nodes where 8-bit fidelity meets system requirements.
Availability
The MAX1391ETB+T is available at Aetrix Electronics and suitable for portable datalogging, battery-powered medical instruments, and industrial process monitoring requiring stable component supply and long-term manufacturability.
Supply support for MAX1391ETB+T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications markets.
The MAX1391ETB+T belongs to Maxim's micropower SAR ADC product line, engineered specifically for ultra-low-voltage, low-power portable instrumentation where size, battery life, and differential noise immunity are primary design constraints.
FAQ
What is the input configuration supported by the MAX1391ETB+T?
The MAX1391ETB+T supports a single true-differential analog input channel (AIN+, AIN−) with selectable unipolar (0 to VREF) or bipolar (±VREF/2) operation via the UNI/BIP pin. It does not support single-ended or dual-channel configurations - those are exclusive to the MAX1394 variant. The MAX1391ETB+T's differential architecture enables robust noise rejection in portable medical and industrial sensor interfaces.
Does the MAX1391ETB+T require an external reference voltage?
Yes, the MAX1391ETB+T requires an external reference voltage applied to the REF pin, which must be between 0.6V and VDD + 0.05V. This reference defines the full-scale input range and must be bypassed with a 0.1µF capacitor to GND for optimal performance. No internal reference is provided - the device relies entirely on this externally supplied precision voltage.
What is the minimum supply voltage for reliable operation of the MAX1391ETB+T?
The MAX1391ETB+T operates reliably from +1.5V to +3.6V. At 1.5V, it maintains full specification compliance including 416ksps throughput, ±0.2 LSB INL/DNL, and 49dB SINAD at 100kHz. This enables direct use with two fresh alkaline cells (≈3.0V) or aging cells (≈1.6V), eliminating the need for voltage regulation in portable designs.
How does AutoShutdown work on the MAX1391ETB+T?
AutoShutdown on the MAX1391ETB+T activates automatically after the LSB is clocked out on the 11th SCLK falling edge, reducing supply current to <1µA. It can also be forced by driving OE high at any time. This feature cuts average power from 0.97mW (416ksps) to 3.1µW (1ksps), significantly extending battery life in duty-cycled sensing applications without firmware overhead.
Is the MAX1391ETB+T pin-compatible with other devices in the MAX139x family?
No, the MAX1391ETB+T is not pin-compatible with the MAX1394ETB+T despite sharing the same 10-pin TDFN package. Pin 2 is AIN− (differential) on the MAX1391ETB+T but AIN2 (single-ended) on the MAX1394ETB+T; Pin 3 is AIN+ on MAX1391ETB+T but AIN1 on MAX1394ETB+T; and Pin 6 is UNI/BIP on MAX1391ETB+T but CH1/CH2 on MAX1394ETB+T. Board-level substitution requires layout revision.
MAX1391ETB+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Number of Bits:
- 8
- Sampling Rate (Per Second):
- 416k
- Number of Inputs:
- 1
- Input Type:
- Differential
- Data Interface:
- SPI, DSP
- Configuration:
- MUX-S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External
- Voltage - Supply, Analog:
- 1.5V ~ 3.6V
- Voltage - Supply, Digital:
- 1.5V ~ 3.6V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 10-TDFN (3x3)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX1391ETB+T FAQ
1.How can I place an order for MAX1391ETB+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1391ETB+T on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX1391ETB+T reliable?
The price and inventory of MAX1391ETB+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1391ETB+T is usually 5 days.
3.What payment methods are accepted for MAX1391ETB+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1391ETB+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1391ETB+T?
MAX1391ETB+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1391ETB+T order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX1391ETB+T?
For technical support, including MAX1391ETB+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1391ETB+T requirements.
6.How does Aetrix verify that MAX1391ETB+T is sourced from the original manufacturer or authorized distributors?
All MAX1391ETB+T products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX1391ETB+T meets industry standards.
7.What is the process for return or replacement of MAX1391ETB+T?
All MAX1391ETB+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX1391ETB+T, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX1391ETB+T part is unused and in its original packaging.
Return procedure for MAX1391ETB+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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