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Analog Devices Inc. LTC2446CUHF#PBF
- Part No.:
- LTC2446CUHF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC2446CUHF#PBF.pdf
- Description:
- IC ADC 24BIT SIGMA-DELTA 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,154
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Product details
Overview
LTC2446CUHF#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 15ppm absolute accuracy, 200nVRMS noise at 13.8Hz, and up to 8kHz output rate in 2× mode-enabling high-precision sensor digitization in industrial weight scales and pressure transducers.
For engineers reviewing the LTC2446CUHF#PBF datasheet, LTC2446CUHF#PBF pinout, LTC2446CUHF#PBF application, or LTC2446CUHF#PBF equivalent, key selection criteria include guaranteed no-latency conversion after channel/reference changes, internal oscillator operation (no external crystal required), 38-pin QFN package with exposed thermal pad, and support for multiplexed RTD/bridge measurements using four dedicated reference input pairs.
Technical Context
The LTC2446CUHF#PBF implements a proprietary third-order delta-sigma modulator with on-the-fly offset and full-scale calibration every conversion cycle-ensuring stability over temperature, supply voltage, and time without user intervention. Its 4-wire serial interface supports both internal SCK (SCK as output) and external SCK (SCK as input) modes via the EXT pin, with BUSY indicating real-time conversion status.
It features a 19-input/4-output analog multiplexer enabling simultaneous selection of differential input channels (CH0–CH7) and corresponding differential reference pairs (VREF01, VREF23, VREF45, VREF67, or global VREFG). Input common-mode range extends from GND – 0.3V to VCC + 0.3V, and reference differential range spans 0.1V to VCC with ±100mV minimum differential.
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% (±5ppm of VREF)-enables direct high-accuracy bridge/RTD readout without post-calibration linearization. |
| Offset Error | <5µV (4.5V ≤ VCC ≤ 5.5V, –40°C to 85°C)-minimizes zero-point drift in precision weigh scale and pressure sensor front ends. |
| RMS Noise | 200nV at 13.8Hz with 50/60Hz rejection-supports high-resolution thermocouple or low-level strain gauge measurements. |
| Output Rate | Up to 8kHz in 2× mode-allows real-time monitoring of fast-varying physical parameters such as flow dynamics. |
| Supply Current | 8mA typical in conversion mode; 20µA in autosleep at 6.9Hz-reduces power in battery-operated portable instrumentation. |
| Reference Inputs | Five selectable differential reference pairs-enables true ratiometric digitization of multiple sensors sharing one ADC. |
Pinout & Package
Package: 38-lead (5mm × 7mm) plastic QFN with exposed thermal pad (Pin 39 = GND). Requires soldering exposed pad to PCB ground plane for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1,4,5,6,31,32,33) | Power and signal ground | Seven dedicated ground pins minimize ground bounce and improve PSRR in high-resolution measurement systems. |
| BUSY (Pin 2) | Conversion status indicator | Active-HIGH during conversion; transitions LOW immediately upon completion-enables interrupt-driven microcontroller data capture. |
| EXT (Pin 3) | SCK mode select | Logic HIGH selects internal SCK generation; LOW enables external clock control-eliminates need for configuration registers. |
| COM (Pin 7) | Single-ended negative input common | Serves as shared IN– for all single-ended channel configurations-simplifies wiring in multi-sensor systems. |
| CH0–CH7 (Pins 8,9,12,13,16,17,20,21) | Analog input channels | Configurable as differential pairs or single-ended inputs relative to COM-supports flexible sensor interfacing without external mux ICs. |
| VREF01± to VREF67± (Pins 10,11,14,15,18,19,22,23) | Differential reference inputs | Four independent reference pairs enable simultaneous ratiometric measurement of four distinct sensor types (e.g., RTD, load cell, thermocouple, current sense). |
| VREFG± (Pins 29,30) | Global reference input | Single additional reference pair usable with any channel-provides fallback reference for non-ratiometric measurements like thermocouples. |
| CS (Pin 36) | Chip select / wake-up | Active-LOW enables SDO and exits sleep mode; rising edge aborts data transfer and initiates new conversion-simplifies timing-critical host control. |
| SDO (Pin 37) | 3-state serial data output | Outputs 32-bit frame (status + 24-bit result + 5 sub-LSBs); tri-states when CS HIGH-prevents bus contention in multi-device SPI systems. |
| SCK (Pin 38) | Bidirectional serial clock | Functions as output (internal mode) or input (external mode)-adapts to host controller capabilities without hardware change. |
Key Features
| Feature | Design Value |
|---|---|
| No-latency conversion | First result after channel/reference/speed change is valid-enables deterministic scan rates up to 4kHz without settling delay. |
| Autocalibration per cycle | Continuous offset and full-scale correction eliminates drift-induced errors in long-duration industrial monitoring. |
| Multiplexed ratiometric architecture | Four dedicated reference input sets allow independent scaling for each sensor type-removes need for external reference switching. |
| Internal oscillator | Eliminates external crystal or clock source-reduces BOM count and layout complexity in space-constrained designs. |
| 50/60Hz rejection | Integrated digital filtering rejects line-frequency interference without external notch filters-critical for lab-grade instrumentation. |
Applications
| Weight Scales | Pressure Transducers |
|---|---|
Use Scenario: High-accuracy digital weighing systems for commercial and industrial applications requiring NTEP or OIML certification. IC Role / Device Role / Timing Role: Primary ADC digitizing mV/V output from load cell bridges with ratiometric reference to eliminate excitation voltage drift. Use Value: 15ppm INL and <5µV offset ensure repeatability within ±0.001% of full scale-meeting Class III and Class IIIB metrology requirements. | Use Scenario: Industrial pressure sensing in hydraulic/pneumatic control systems where long-term stability and temperature immunity are critical. IC Role / Device Role / Timing Role: Signal conditioner converting differential output from silicon piezoresistive sensors with programmable gain and reference selection. Use Value: Autosleep mode reduces average current to 20µA at 6.9Hz-enabling multi-year battery life in wireless pressure nodes. |
| Direct Temperature Measurement | Gas Chromatography Detectors |
Use Scenario: Precision RTD-based temperature monitoring in HVAC, medical equipment, and environmental chambers. IC Role / Device Role / Timing Role: Delta-sigma ADC performing 4-wire RTD measurements using dedicated VREF01± pair for true ratiometric excitation and sensing. Use Value: 200nVRMS noise at 13.8Hz enables 0.005°C resolution with PT100 sensors-exceeding ASTM E1137 Class A tolerance. | Use Scenario: Signal acquisition from thermal conductivity (TCD) or flame ionization (FID) detectors in portable GC analyzers. IC Role / Device Role / Timing Role: High-speed, low-noise digitizer capturing transient detector peaks with simultaneous 50/60Hz line rejection. Use Value: 8kHz output rate in 2× mode resolves peak widths down to 125µs-supporting chromatographic separation of complex hydrocarbon mixtures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 24-bit multichannel delta-sigma ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS1256IPW | 24-bit, 8-channel, but only one differential reference input; no built-in ratiometric multiplexing for multiple references. | Requires external analog switches to support multiple reference sources-increases component count and layout complexity. | Select when system uses single-reference architecture and cost sensitivity outweighs ratiometric flexibility. |
| LTC2449CUHF#PBF | Pin-compatible upgrade with improved 100nVRMS noise at 13.8Hz and enhanced 50/60Hz rejection algorithm. | Same footprint and interface-direct drop-in replacement for higher SNR in demanding metrology applications. | Select when upgrading existing LTC2446 designs for improved noise floor without PCB revision. |
Compared with ADS1256IPW, LTC2446CUHF#PBF provides native support for five independent differential reference inputs-enabling true ratiometric measurement of diverse sensors without external muxes. Compared with LTC2449CUHF#PBF, it offers identical functionality at a lower noise specification ceiling, making it optimal for cost-sensitive industrial instrumentation where 200nVRMS meets system requirements.
Availability
LTC2446CUHF#PBF is available at Aetrix Electronics and suitable for industrial weight scales, pressure transducers, direct temperature measurement systems, and gas chromatography detectors requiring stable component supply across extended production lifecycles.
Supply support for LTC2446CUHF#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC2446CUHF#PBF belongs to ADI's precision delta-sigma ADC product line, designed specifically for high-accuracy, low-drift sensor signal conditioning in industrial process control and test equipment.
FAQ
What is the operating temperature range for the LTC2446CUHF#PBF?
The LTC2446CUHF#PBF is rated for 0°C to 70°C ambient operation (Commercial grade). This is confirmed by the "C" suffix in the part number and the ordering information table specifying "0°C to 70°C" for the CUHF#PBF variant. The device maintains specified performance-including 15ppm INL and <5µV offset-across this full range when powered from 4.5V to 5.5V.
Does the LTC2446CUHF#PBF require an external oscillator?
No, the LTC2446CUHF#PBF does not require an external oscillator. It integrates a fully functional internal oscillator that enables operation with no external timing components. The FO pin may be tied to GND or VCC to select internal clock mode, and the device achieves stable conversion timing across its full speed/resolution range without external crystals or oscillators.
How many differential reference inputs does the LTC2446CUHF#PBF support?
The LTC2446CUHF#PBF supports five selectable differential reference inputs: four dedicated pairs (VREF01±, VREF23±, VREF45±, VREF67±) plus one global pair (VREFG±). Each pair can be independently assigned to any input channel via the serial interface, enabling true ratiometric digitization of up to four distinct sensor types simultaneously-such as RTDs, load cells, and thermocouples-without external reference switching circuitry.
What is the function of the EXT pin on the LTC2446CUHF#PBF?
The EXT pin on the LTC2446CUHF#PBF selects the serial clock source mode: logic HIGH configures SCK as an output (internal clock mode), while logic LOW configures SCK as an input (external clock mode). This dual-mode capability allows seamless integration with host controllers that either generate the serial clock externally or rely on the ADC to drive the interface timing-no register programming or firmware changes are needed to switch modes.
Can the LTC2446CUHF#PBF perform conversions without latency after changing channels?
Yes, the LTC2446CUHF#PBF operates in no-latency mode: the first conversion result after any channel, reference, or speed change is fully accurate and valid. This is achieved through proprietary architecture that eliminates filter settling delays-enabling deterministic multiplexing rates up to 4kHz and supporting real-time scanning of multiple sensors in dynamic measurement systems.
LTC2446CUHF#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:
- 0°C ~ 70°C
- Supplier Device Package:
- 38-QFN (5x7)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
LTC2446CUHF#PBF FAQ
1.How can I place an order for LTC2446CUHF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2446CUHF#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 LTC2446CUHF#PBF reliable?
The price and inventory of LTC2446CUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2446CUHF#PBF is usually 5 days.
3.What payment methods are accepted for LTC2446CUHF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2446CUHF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2446CUHF#PBF?
LTC2446CUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2446CUHF#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 LTC2446CUHF#PBF?
For technical support, including LTC2446CUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2446CUHF#PBF requirements.
6.How does Aetrix verify that LTC2446CUHF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC2446CUHF#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 LTC2446CUHF#PBF meets industry standards.
7.What is the process for return or replacement of LTC2446CUHF#PBF?
All LTC2446CUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2446CUHF#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 LTC2446CUHF#PBF part is unused and in its original packaging.
Return procedure for LTC2446CUHF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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