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Analog Devices Inc. LTC2446IUHF#PBF
- Part No.:
- LTC2446IUHF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC2446IUHF#PBF.pdf
- Description:
- IC ADC 24BIT SIGMA-DELTA 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,817
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Product details
Overview
LTC2446IUHF#PBF from Analog Devices (formerly Linear Technology) is a 24-bit, 8-channel delta-sigma ADC with selectable differential reference inputs and ratiometric measurement capability. It delivers 15 ppm absolute accuracy, 200 nVRMS noise at 13.8 Hz, and up to 8 kHz output rate in 2× mode. Designed for high-precision sensor digitization-including RTDs, strain gauges, and thermocouples-it operates over –40°C to +85°C in a 38-lead QFN package.
For engineers reviewing the LTC2446IUHF#PBF datasheet, LTC2446IUHF#PBF pinout, LTC2446IUHF#PBF application, or LTC2446IUHF#PBF equivalent, this page provides verified technical context, validated pin functions, confirmed ratiometric multiplexing architecture, real-world noise vs. speed trade-offs, and two rigorously cross-checked alternative parts for industrial sensor interface design.
Technical Context
The LTC2446IUHF#PBF implements a proprietary 3rd-order delta-sigma modulator with on-the-fly offset and full-scale calibration every conversion cycle-ensuring stability against temperature drift, supply variation, and time. Its 19-input/4-output analog multiplexer supports four independent differential input/reference pairs plus a global reference (VREFG±), enabling true ratiometric digitization of multiple bridges or RTDs without external switching.
It uses a flexible 4-wire serial interface (CS/SDI/SDO/SCK) with dual clock modes: internal oscillator (no external components) or external fO up to 12 MHz. Conversion latency is zero in 1× mode-each output corresponds precisely to its preceding conversion-even after channel, reference, or speed changes-enabling reliable 4 kHz multiplexing rates.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 24-bit with no missing codes; guarantees monotonicity and unambiguous digital representation across full input range. |
| INL | 0.0005% (5 ppm of VREF); ensures sub-LSB linearity error for precision metrology-grade measurements. |
| Offset Error | <5 µV (–40°C to +85°C); eliminates need for system-level offset trimming in low-drift applications. |
| RMS Noise | 200 nV at 13.8 Hz with simultaneous 50/60 Hz rejection; enables clean DC measurements in electrically noisy environments. |
| Max Output Rate | 8 kHz in 2× mode (external fO); doubles throughput without sacrificing latency-critical for dynamic sensor scanning. |
| Input Configuration | Four differential or eight single-ended channels + five differential reference inputs; supports mixed ratiometric/non-ratiometric sensors on one chip. |
| Supply Current | 8 mA active, 20 µA autosleep at 6.9 Hz; balances performance and power for battery-backed or energy-conscious systems. |
Pinout & Package
38-lead (5 mm × 7 mm) plastic QFN package with exposed thermal pad (Pin 39 = GND). All seven ground pins (1, 4, 5, 6, 31, 32, 33) must be soldered to PCB ground plane for proper operation and thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 4, 5, 6, 31, 32, 33) | Power and signal reference ground | Multiple dedicated GND pins minimize ground bounce and improve PSRR during high-speed conversions. |
| BUSY (Pin 2) | Conversion status indicator | Active-HIGH signal confirms ongoing conversion; transitions LOW immediately upon result readiness-usable as hardware interrupt. |
| EXT (Pin 3) | SCK mode selection control | Logic HIGH enables internal SCK generation on Pin 38; logic LOW configures SCK as external clock input-no register programming required. |
| COM (Pin 7) | Common negative input for single-ended mode | Shared IN– node for CH0–CH7 in single-ended configuration; supports rail-to-rail common-mode voltage (GND – 0.3V to VCC + 0.3V). |
| CH0–CH7 (Pins 8, 9, 12, 13, 16, 17, 20, 21) | Analog input channels | Programmable as differential pairs (e.g., CH0+/CH1–) or single-ended vs. COM; each pair supports ±0.5·VREF differential range. |
| VREF01± to VREF67± (Pins 10–11, 14–15, 18–19, 22–23) | Differential reference inputs | Four independent reference sets-each accepts 0.1 V to VCC differential voltage with GND-to-VCC common-mode range. |
| VREFG± (Pins 29–30) | Global reference input | Fifth reference pair usable with any channel via single-bit command; eliminates need for per-channel reference routing. |
| CS (Pin 36) | Active-low chip select | Wakes device from autosleep and enables SDO; HIGH maintains ultra-low 20 µA sleep current-ideal for duty-cycled sensing. |
| SDI/SDO/SCK (Pins 34, 37, 38) | 3-wire serial interface | Full-duplex SPI-compatible interface; 32-bit frame includes sign, status, 24-bit result, and 5 sub-LSBs-no post-processing needed. |
Key Features
| Feature | Design Value |
|---|---|
| No-latency conversion | Each output corresponds exactly to its preceding conversion-even after channel, reference, or speed change-eliminating filter settling delays in multiplexed systems. |
| Per-conversion auto-calibration | Continuous offset and full-scale correction removes drift due to temperature, aging, and supply variation-no manual recalibration required. |
| True ratiometric multiplexing | Four independent differential input/reference pairs enable simultaneous digitization of multiple RTDs or bridges using shared ADC resources. |
| 50/60 Hz rejection at 13.8 Hz | Integrated notch filtering rejects mains interference without external components-critical for weigh scales and industrial transmitters. |
| Internal oscillator | Eliminates external crystal or clock source; simplifies BOM and layout while maintaining timing integrity across temperature and voltage. |
Applications
| Flow Measurement | Weight Scales |
|---|---|
|
Use Scenario: High-accuracy mass flow meter using differential pressure sensor and temperature-compensated RTD array. IC Role / Device Role / Timing Role: Digitizes four bridge outputs (flow, temp, ambient, reference) with independent ratiometric references to reject excitation drift. Use Value: 15 ppm INL and 200 nVRMS noise ensure ±0.05% full-scale repeatability across –40°C to +85°C without recalibration. |
Use Scenario: Legal-for-trade platform scale with load cell array and temperature compensation. IC Role / Device Role / Timing Role: Simultaneously samples eight single-ended load cell outputs referenced to individual stable references to cancel wire resistance errors. Use Value: Zero-latency mode enables 4 kHz scan rate across all channels-supporting real-time vibration compensation and fast settling. |
| Pressure Transmitters | Gas Chromatography Detectors |
|
Use Scenario: Industrial pressure transmitter with HART interface requiring high-resolution analog front-end. IC Role / Device Role / Timing Role: Converts differential bridge output and on-chip temperature sensor using VREFG± for universal reference routing. Use Value: <5 µV offset and 0.2 ppm/°C full-scale drift guarantee long-term stability in field-deployed instrumentation. |
Use Scenario: Lab-grade GC detector requiring low-noise, multi-sensor digitization with 50/60 Hz rejection. IC Role / Device Role / Timing Role: Digitizes thermocouple (non-ratiometric) and thermal conductivity cell (ratiometric) on same device using VREF67± and VREFG±. Use Value: 13.8 Hz mode delivers 200 nVRMS noise with simultaneous 50/60 Hz rejection-enabling sub-part-per-trillion detection limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-precision multichannel ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7177-2BRUZ | 32-bit ΣΔ ADC, 10 kSPS max, integrated PGA, no built-in multiplexer for multiple reference inputs. | Requires external analog switches for ratiometric multi-sensor support; better suited for single-channel high-dynamic-range applications. | Select when higher resolution (32-bit) and integrated gain are prioritized over native ratiometric multiplexing and zero-latency scanning. |
| LTC2449CUHF#PBF | Same architecture and pinout, but commercial-grade (0°C to 70°C) and lower guaranteed INL (15 ppm vs. 5 ppm typical for LTC2446I). | Valid drop-in replacement only in non-industrial temperature environments; not rated for –40°C operation. | Select only for cost-sensitive, non-extended-temperature applications where full industrial grade is unnecessary. |
Compared with AD7177-2BRUZ and LTC2449CUHF#PBF, the LTC2446IUHF#PBF uniquely combines industrial temperature rating, native 4-reference ratiometric multiplexing, zero-latency conversion, and guaranteed 5 ppm INL-making it the only choice for embedded, multi-sensor industrial transmitters requiring long-term stability without recalibration.
Availability
LTC2446IUHF#PBF is available at Aetrix Electronics and suitable for industrial pressure transmitters, legal-for-trade weight scales, flow meters, and gas chromatography detectors requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC2446IUHF#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.
The LTC2446IUHF#PBF belongs to Linear's precision delta-sigma ADC family, engineered specifically for industrial sensor interfaces demanding ratiometric accuracy, zero-latency multiplexing, and guaranteed performance across –40°C to +85°C.
FAQ
What is the operating temperature range of the LTC2446IUHF#PBF?
The LTC2446IUHF#PBF is specified for operation from –40°C to +85°C. This industrial-grade temperature range is explicitly defined in the Absolute Maximum Ratings table and confirmed across all electrical characteristics-including offset error, INL, and noise-making it suitable for harsh-environment applications such as factory automation and outdoor instrumentation where thermal stability is critical.
Does the LTC2446IUHF#PBF require an external oscillator?
No, the LTC2446IUHF#PBF includes an internal oscillator and operates fully autonomously without external timing components. The FO pin can be tied to GND or VCC to enable internal clocking; external fO (0.1–12 MHz) is optional and used only when higher output rates or synchronization to system clocks is required-no crystal, capacitor, or resistor is needed for basic operation.
How does the LTC2446IUHF#PBF achieve ratiometric measurements across multiple sensors?
The LTC2446IUHF#PBF achieves true ratiometric measurement via four independent differential reference input pairs (VREF01± through VREF67±) and a global reference (VREFG±). Each analog input channel (CH0–CH7) can be assigned to any reference pair-enabling simultaneous digitization of multiple RTDs or bridges while rejecting excitation voltage drift, without external analog switches or calibration routines.
What is the meaning of "no latency mode" in the LTC2446IUHF#PBF?
"No latency mode" means that every 32-bit output word from the LTC2446IUHF#PBF corresponds precisely to the immediately preceding conversion-even after changing channel, reference, speed, or resolution. There is no filter settling delay or invalid data cycles, enabling deterministic 4 kHz multiplexing rates and real-time response in closed-loop control or dynamic scanning systems.
Can the LTC2446IUHF#PBF interface directly with a microcontroller SPI port?
Yes, the LTC2446IUHF#PBF uses a standard 3-wire SPI-compatible interface (CS/SDI/SDO/SCK) with MSB-first 32-bit frames. It supports both internal SCK generation (EXT = HIGH) and external SCK clocking (EXT = LOW), and its timing complies with common MCU SPI peripherals-requiring only GPIO-controlled CS and standard clock/data handling without custom protocol translation.
LTC2446IUHF#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:
- -
LTC2446IUHF#PBF FAQ
1.How can I place an order for LTC2446IUHF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2446IUHF#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 LTC2446IUHF#PBF reliable?
The price and inventory of LTC2446IUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2446IUHF#PBF is usually 5 days.
3.What payment methods are accepted for LTC2446IUHF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2446IUHF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2446IUHF#PBF?
LTC2446IUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2446IUHF#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 LTC2446IUHF#PBF?
For technical support, including LTC2446IUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2446IUHF#PBF requirements.
6.How does Aetrix verify that LTC2446IUHF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC2446IUHF#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 LTC2446IUHF#PBF meets industry standards.
7.What is the process for return or replacement of LTC2446IUHF#PBF?
All LTC2446IUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2446IUHF#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 LTC2446IUHF#PBF part is unused and in its original packaging.
Return procedure for LTC2446IUHF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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