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Analog Devices Inc. LTC2444IUHF#PBF
- Part No.:
- LTC2444IUHF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC2444IUHF#PBF.pdf
- Description:
- IC ADC 24BIT SIGMA-DELTA 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,087
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Product details
Overview
LTC2444IUHF#PBF from Analog Devices (formerly Linear Technology) is a 24-bit, 8-channel (4-differential) no-latency delta-sigma ADC with selectable speed/resolution, 2 µVRMS noise at 1.76 kHz output rate, 0.0005% INL, and differential input/reference support. It operates from 4.5V to 5.5V supply and is used in high-precision industrial data acquisition systems requiring simultaneous 50/60 Hz rejection and channel-scanning capability.
For engineers reviewing the LTC2444IUHF#PBF datasheet, LTC2444IUHF#PBF pinout, LTC2444IUHF#PBF application, or LTC2444IUHF#PBF equivalent, key selection criteria include guaranteed modulator stability under all input/reference conditions, autosleep mode enabling 20 µA operation at 6.9 Hz, and true no-latency behavior-ensuring first-conversion accuracy after channel/speed changes without settling delay.
Technical Context
The LTC2444IUHF#PBF employs a proprietary 3rd-order delta-sigma modulator with decimating FIR filter and continuous internal auto-calibration of offset and full-scale every conversion cycle. Its architecture supports ten discrete speed/resolution combinations-from 6.9 Hz/280 nVRMS to 3.5 kHz/25 µVRMS-with no latency or DC accuracy shift between modes.
It features a 4-wire SPI-compatible serial interface (SDI/SDO/SCK/CS), internal oscillator (no external components required), and flexible clocking via EXT pin for internal/external SCK selection. Input multiplexing supports any mix of single-ended or differential channels with GND-to-VCC common-mode range independent of VREF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 24-bit with no missing codes-guarantees monotonicity and unambiguous digital representation across full dynamic range. |
| INL | ±0.0005% of VREF (±12 ppm)-enables 6½-digit DVM-grade linearity without post-calibration. |
| RMS Noise | 2 µV at 1.76 kHz output rate-supports high-speed precision measurement without oversampling penalty. |
| Offset Error | <5 µV (–40°C to 85°C, 4.5V ≤ VCC ≤ 5.5V)-minimizes zero-point drift in weight scale or sensor front-end applications. |
| Common-Mode Rejection | 120 dB DC-rejects ground loop or supply-induced common-mode interference in noisy industrial environments. |
| Supply Current | 8–11 mA active, 20 µA in autosleep at 6.9 Hz-enables low-power portable instrumentation with burst-mode operation. |
| Input Range | ±0.5 × VREF differential, with GND–to–VCC common-mode on CHx/COM-allows direct thermocouple or bridge sensor interfacing without level-shifting. |
Pinout & Package
Package: 38-lead (5 mm × 7 mm) plastic QFN (UHF), exposed pad (Pin 39) soldered to PCB ground. Thermal resistance θJA = 34°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 4, 5, 6, 31, 32, 33) | Ground reference and power return | Seven dedicated ground pins ensure low-impedance return paths for analog/digital currents and optimal VCC decoupling-mandatory for noise-sensitive 24-bit performance. |
| BUSY (Pin 2) | Conversion status indicator | Active-HIGH signal indicates ongoing conversion; transitions LOW when result is valid and ready for readout-enables precise timing control without polling. |
| EXT (Pin 3) | SCK mode selection | Logic HIGH selects internal SCK generation (SCK becomes output); LOW enables external SCK (SCK becomes input)-determines serial interface clock source without register writes. |
| COM (Pin 7) | Single-ended negative input common | Shared IN– node for all single-ended configurations; voltage range extends from GND – 0.3 V to VCC + 0.3 V-supports rail-to-rail sensor biasing. |
| CH0–CH7 (Pins 9, 10, 13, 14, 17, 18, 21, 22) | Analog input channels | Eight configurable inputs supporting differential (CH0/CH1, etc.) or single-ended (vs. COM) operation-enables 4-differential or 8-single-ended scanning at up to 500 Hz per channel. |
| VCC (Pin 28) | Positive supply | 4.5 V to 5.5 V operation; requires local 10 µF tantalum + 0.1 µF ceramic bypass-ensures stable modulator clock and reference integrity. |
| REF+ / REF– (Pins 29, 30) | Differential reference inputs | Accept 0.1 V to VCC differential reference with GND-to-VCC common-mode range-permits ratiometric sensing with unregulated supplies or precision external references. |
| SDI / SDO / SCK / CS (Pins 34, 37, 38, 36) | 4-wire serial interface | Standard SPI-like protocol: SDI configures next conversion (channel/speed/2X mode); SDO outputs 32-bit result (including sign/status bits); CS enables wake-up and output drive. |
Key Features
| Feature | Design Value |
|---|---|
| No-latency conversion | First result after channel/speed change is fully accurate-eliminates dead time and settling uncertainty in multiplexed sensor arrays. |
| Simultaneous 50 Hz/60 Hz rejection | Guaranteed at 6.9 Hz output rate-enables clean AC-line-powered measurements without external notch filters or software correction. |
| Continuous auto-calibration | Per-conversion offset and full-scale calibration-maintains ±5 µV offset and ±12 ppm INL over temperature, supply, and time without user intervention. |
| Autosleep mode | 20 µA quiescent current at 6.9 Hz output rate-extends battery life in portable DMMs or handheld test equipment. |
| Stable modulator lock-up immunity | Guaranteed operation under any input voltage and reference condition-prevents catastrophic failure during overvoltage transients or open-reference faults. |
Applications
| Weight Scales | Auto-Ranging 6-Digit DVMs |
|---|---|
|
Use Scenario: High-resolution load cell readout in commercial/industrial weighing systems with AC mains noise. IC Role / Device Role / Timing Role: Primary 24-bit ADC acquiring differential bridge output; performs simultaneous 50/60 Hz rejection at 6.9 Hz to suppress line interference. Use Value: Delivers true 23.5-bit effective resolution (ENOB) without external filtering, enabling 1:1,000,000 dynamic range in compact form factor. |
Use Scenario: Precision benchtop digital multimeter with automatic range switching and sub-µV sensitivity. IC Role / Device Role / Timing Role: Core measurement engine handling multiple voltage/current/resistance ranges; uses selectable OSR to optimize speed vs. noise per function. Use Value: Achieves 6½-digit accuracy (0.0005% INL, <5 µV offset) with no calibration drift-reducing factory calibration burden and field recalibration frequency. |
| Direct Temperature Measurement | High-Speed Data Acquisition |
|
Use Scenario: Cold-junction compensation and thermocouple linearization in industrial process controllers. IC Role / Device Role / Timing Role: Simultaneously digitizes thermocouple (differential) and RTD (ratiometric) inputs using shared REF+ and COM nodes. Use Value: GND-to-VCC common-mode range allows direct connection to grounded thermocouples; 200 nVRMS noise at 13.8 Hz enables <0.01°C resolution. |
Use Scenario: Multi-channel vibration monitoring in predictive maintenance systems with real-time FFT analysis. IC Role / Device Role / Timing Role: 8-channel scanner acquiring synchronized samples at up to 500 Hz per channel (4 kHz aggregate mux rate with external fO). Use Value: No-latency architecture ensures phase coherence across channels-critical for accurate cross-channel spectral correlation and bearing fault detection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-resolution delta-sigma ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS1258IRHBT | 24-bit, 16-channel, but fixed 30 kSPS max rate; no selectable OSR; requires external reference and clock. | Optimized for high-throughput industrial PLC I/O modules-not suited for ultra-low-noise, variable-speed applications like DVMs. | Select when deterministic throughput >3 kSPS is required and simultaneous 50/60 Hz rejection is unnecessary. |
| LTC2448IUHF#PBF | 16-channel (8-differential) variant of same family; identical noise, INL, and timing specs-but adds CH8–CH15 pins and removes NC pins. | Used where higher channel count is needed without changing layout-pin-compatible except for added CHx pins (requires PCB revision). | Choose when expanding from 8 to 16 inputs while retaining identical performance, calibration, and firmware compatibility. |
Compared with ADS1258IRHBT and LTC2448IUHF#PBF, the LTC2444IUHF#PBF uniquely balances ultra-low noise at low speeds (200 nVRMS) with high-speed capability (up to 3.5 kHz), all within a single chip requiring no external oscillator or reference-making it optimal for portable, battery-powered, or space-constrained precision instruments.
Availability
LTC2444IUHF#PBF is available at Aetrix Electronics and suitable for weight scales, auto-ranging DVMs, and direct temperature measurement systems requiring stable component supply, long-term calibration consistency, and industrial temperature range (–40°C to +85°C) operation.
Supply support for LTC2444IUHF#PBF 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
Analog Devices acquired Linear Technology in 2017 and maintains its high-precision analog product lines, including delta-sigma ADCs, with focus on metrology-grade performance and robust industrial reliability.
The LTC2444IUHF#PBF belongs to Linear's No Latency Delta-Sigma ADC family, designed specifically for applications demanding both high resolution and high flexibility-such as portable test equipment, industrial process control, and precision sensor interfaces where traditional sigma-delta converters introduce unacceptable latency or settling delays.
FAQ
What is the maximum output data rate of the LTC2444IUHF#PBF?
The LTC2444IUHF#PBF achieves up to 3.5 kHz output rate in internal oscillator mode and up to 4 kHz with an external oscillator. In 2X speed mode, it reaches 7 kHz (8 kHz with external oscillator). These rates correspond to specific OSR settings and maintain full 24-bit resolution with guaranteed no-latency behavior-meaning each output sample reflects a complete, accurate conversion without pipeline delay.
Does the LTC2444IUHF#PBF require external components for basic operation?
No-the LTC2444IUHF#PBF integrates an internal oscillator and requires only standard power supply decoupling (10 µF tantalum + 0.1 µF ceramic on VCC) and optional external reference. Unlike many delta-sigma ADCs, it needs no external crystal, clock buffer, or reference buffer for default operation, simplifying BOM and layout while maintaining 2 µVRMS noise at 1.76 kHz.
How does the LTC2444IUHF#PBF handle channel switching without introducing error?
The LTC2444IUHF#PBF uses a no-latency delta-sigma architecture where the first conversion after any channel, speed, or resolution change is fully accurate-no settling time or dummy conversions are needed. This is achieved through internal modulator reset and per-cycle auto-calibration, ensuring that multiplexed measurements (e.g., scanning 8 thermocouples) retain full DC accuracy and timing coherence across channels.
What is the meaning of "SoftSpan" in relation to the LTC2444IUHF#PBF?
"SoftSpan" is a trademarked feature of the LTC2444IUHF#PBF indicating its ability to accept input differential voltages up to ±0.5 × VREF while supporting arbitrary common-mode voltages from GND to VCC on both IN+ and IN– pins. This enables direct interfacing with grounded sensors (e.g., thermocouples) or biased bridges without level-shifting circuitry-preserving SNR and reducing component count.
Can the LTC2444IUHF#PBF operate with a 3.3 V supply?
No-the LTC2444IUHF#PBF specifies a minimum supply voltage of 4.5 V and maximum of 5.5 V. Operation below 4.5 V violates Absolute Maximum Ratings and risks modulator instability, increased noise, or failure to meet guaranteed specifications such as 0.0005% INL or 2 µV offset. For 3.3 V systems, consider the pin-compatible LTC2440 series or consult Analog Devices' low-voltage ADC portfolio.
LTC2444IUHF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 24
- Sampling Rate (Per Second):
- 8k
- Number of Inputs:
- 4, 8
- Input Type:
- Differential, Single Ended
- Data Interface:
- SPI
- Configuration:
- MUX-ADC
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- Sigma-Delta
- Reference Type:
- External
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 38-QFN (5x7)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
LTC2444IUHF#PBF FAQ
1.How can I place an order for LTC2444IUHF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2444IUHF#PBF 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 LTC2444IUHF#PBF reliable?
The price and inventory of LTC2444IUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2444IUHF#PBF is usually 5 days.
3.What payment methods are accepted for LTC2444IUHF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2444IUHF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2444IUHF#PBF?
LTC2444IUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2444IUHF#PBF 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 LTC2444IUHF#PBF?
For technical support, including LTC2444IUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2444IUHF#PBF requirements.
6.How does Aetrix verify that LTC2444IUHF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC2444IUHF#PBF 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 LTC2444IUHF#PBF meets industry standards.
7.What is the process for return or replacement of LTC2444IUHF#PBF?
All LTC2444IUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2444IUHF#PBF, 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 LTC2444IUHF#PBF part is unused and in its original packaging.
Return procedure for LTC2444IUHF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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