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Analog Devices Inc. LTC2446IUHF#TRPBF
- Part No.:
- LTC2446IUHF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC2446IUHF#TRPBF.pdf
- Description:
- IC ADC 24BIT SIGMA-DELTA 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,343
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Product details
Overview
LTC2446IUHF#TRPBF from Analog Devices (formerly Linear Technology) is a 24-bit, 8-channel delta-sigma ADC with selectable differential reference inputs and no-latency multiplexing. It delivers 15 ppm absolute accuracy, 200 nVRMS noise at 13.8 Hz (with 50/60 Hz rejection), and up to 8 kHz output rate in 2× mode-enabling high-precision ratiometric measurements of RTDs, strain bridges, and thermocouples in industrial sensor front-ends.
For engineers reviewing the LTC2446IUHF#TRPBF datasheet, LTC2446IUHF#TRPBF pinout, LTC2446IUHF#TRPBF application, or LTC2446IUHF#TRPBF equivalent, this device supports seamless channel/reference switching without settling delay, internal oscillator operation (no external components), and guaranteed modulator stability across full input/reference common-mode ranges-critical for multi-sensor systems requiring traceable calibration and long-term drift immunity.
Technical Context
The LTC2446IUHF#TRPBF implements a proprietary 3rd-order delta-sigma modulator with decimating FIR filter and on-the-fly auto-calibration of offset and full-scale every conversion cycle. Its 19-input/4-output analog multiplexer enables independent selection of four differential input pairs plus one global reference (VREFG±), supporting true ratiometric digitization of up to eight sensors using only five reference paths.
It operates via a 4-wire SPI-compatible interface (CS, SDO, SDI, SCK) with dual clock modes: internal oscillator (no external crystal) or external fO up to 12 MHz. The EXT pin selects SCK direction (input/output), and BUSY provides real-time conversion status-eliminating polling overhead in microcontroller-based data acquisition.
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% (±15 ppm of VREF)-ensures linearity error remains below 1 LSB over temperature and supply variation. |
| Offset Error | ≤5 µV (–40°C to 85°C)-minimizes zero-point drift in precision weigh scales and pressure transducers. |
| RMS Noise | 200 nV at 13.8 Hz with simultaneous 50/60 Hz rejection-enables direct thermocouple digitization without external notch filtering. |
| Conversion Rate | Up to 8 kHz in 2× mode (external fO)-supports real-time monitoring of fast-changing bridge outputs in dynamic load cells. |
| Supply Current | 8–11 mA in conversion mode; 20 µA at 6.9 Hz autosleep-reduces power in battery-operated gas chromatography analyzers. |
| Input Range | Differential ±0.5 × VREF; common-mode GND – 0.3 V to VCC + 0.3 V-allows direct interfacing to unbuffered RTDs and Wheatstone bridges. |
| Reference Inputs | Five selectable differential references (four channel-paired + one global)-enables mixed-sensor systems (e.g., RTD + thermocouple + voltage) on single ADC. |
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 optimal noise immunity and thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (1, 4, 5, 6, 31, 32, 33) | Power and signal ground | Multiple low-impedance return paths minimize ground bounce and improve PSRR in high-resolution measurement. |
| BUSY (2) | Conversion status indicator | Active-HIGH signal confirms ongoing conversion; transitions LOW when 32-bit result is ready-enables interrupt-driven firmware. |
| EXT (3) | SCK direction control | Logic HIGH configures SCK as internal clock output; LOW configures it as external clock input-no register programming required. |
| COM (7) | Single-ended negative input common | Shared IN– node for all 8 single-ended channels-simplifies wiring in weight scale applications with multiple load cells. |
| CH0–CH7 (8, 9, 12, 13, 16, 17, 20, 21) | Analog input channels | Configurable as differential pairs (e.g., CH0+/CH1–) or single-ended vs COM-supports flexible sensor mapping without external mux ICs. |
| VREF01± to VREF67± (10–11, 14–15, 18–19, 22–23) | Differential reference inputs | Four dedicated reference pairs per two input channels-enables true ratiometric measurement of four independent bridges or RTDs. |
| VREFG± (29–30) | Global reference input | One additional differential reference usable by any channel-allows thermocouple digitization alongside ratiometric sensors. |
| CS (36) | Active-low chip select | Wakes ADC from sleep (20 µA) and enables SDO; rising edge aborts data transfer and initiates new conversion-simplifies timing-critical firmware. |
| SDO (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 systems. |
| FO (35) | Frequency control | Tied to GND/VCC to enable internal oscillator; connects to external clock source up to 12 MHz-removes need for crystal or oscillator IC. |
Key Features
| Feature | Design Value |
|---|---|
| No-latency multiplexing | First conversion after channel/reference change is valid-enables 4 kHz scan rate across 8 channels without dead time or settling delay. |
| Per-conversion auto-calibration | Continuous offset and full-scale correction eliminates drift-induced errors in long-duration industrial monitoring (e.g., pipeline pressure). |
| True differential reference support | Each reference pair accepts common-mode voltage from GND to VCC-allows direct connection to isolated bridge supplies without level-shifting. |
| 50/60 Hz simultaneous rejection | Embedded digital filter rejects both line frequencies in single acquisition-removes need for external synchronous sampling or software averaging. |
| Internal oscillator | Eliminates external crystal, capacitors, and layout sensitivity-reduces BOM count and improves reliability in harsh environments. |
| Autosleep at 6.9 Hz | Reduces current to 20 µA while maintaining full resolution-extends battery life in portable gas chromatography field instruments. |
Applications
| Flow Measurement | Weight Scales |
|---|---|
|
Use Scenario: High-accuracy mass flow meter using thermal dispersion or Coriolis principle with multiple temperature-compensated sensors. IC Role / Device Role / Timing Role: Primary ADC digitizing differential bridge outputs from flow tube strain gauges and RTD temperature references. Use Value: 15 ppm INL and per-conversion calibration ensure <±0.1% full-scale repeatability across ambient temperature swings (–40°C to 85°C). |
Use Scenario: Multi-load-cell platform scale with automatic tare, overload detection, and temperature compensation. IC Role / Device Role / Timing Role: Central 24-bit ADC acquiring ratiometric readings from four 350 Ω load cells and integrated temperature sensor. Use Value: Four dedicated VREF± pairs eliminate reference crosstalk; COM pin simplifies single-ended wiring; 200 nVRMS noise enables 1:1,000,000 dynamic range. |
| Pressure Transducers | Gas Chromatography |
|
Use Scenario: Industrial pressure transmitter with HART interface, compensating for nonlinearity and thermal drift in silicon piezoresistive sensors. IC Role / Device Role / Timing Role: Precision ADC capturing bridge output and on-chip temperature diode voltage for real-time linearization. Use Value: Differential input range ±0.5 × VREF matches typical bridge excitation; 5 µV offset ensures <0.01%FS zero error over lifetime. |
Use Scenario: Portable GC analyzer detecting trace VOCs using micro-thermal conductivity detectors (µTCD) with ultra-low signal levels. IC Role / Device Role / Timing Role: Low-noise ADC digitizing µV-level detector outputs while rejecting 50/60 Hz EMI in lab and field environments. Use Value: 200 nVRMS noise at 13.8 Hz with built-in line-frequency rejection enables sub-ppm detection limits without external analog filters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-precision multichannel delta-sigma ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS1258IRTCR | 24-bit, 8-channel, but uses internal PGA (1–128×) and fixed 4.096 V reference; no selectable differential references. | Best for single-reference systems with gain flexibility; lacks LTC2446IUHF#TRPBF's ratiometric multiplexing architecture. | Select ADS1258IRTCR when sensor signals require programmable gain before digitization and reference stability is less critical than channel count. |
| LTC2449CUHF#TRPBF | Same architecture and pinout, but commercial-grade (0°C to 70°C); identical electrical specs except wider temp drift on offset (±10 µV max). | Suitable for lab equipment or consumer devices where extended temperature range is unnecessary. | Choose LTC2449CUHF#TRPBF for cost-sensitive designs operating strictly within 0°C to 70°C with no requirement for industrial-grade thermal stability. |
Compared with ADS1258IRTCR and LTC2449CUHF#TRPBF, the LTC2446IUHF#TRPBF uniquely combines industrial temperature range, five independent differential reference inputs, and no-latency channel switching-making it irreplaceable in mixed-sensor industrial field instruments requiring traceable ratiometric accuracy.
Availability
LTC2446IUHF#TRPBF is available at Aetrix Electronics and suitable for industrial sensor front-ends, precision weigh scales, and portable gas chromatography analyzers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC2446IUHF#TRPBF 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#TRPBF belongs to the LTC244x family of high-speed delta-sigma ADCs designed specifically for industrial process control, test equipment, and sensor signal conditioning where ratiometric accuracy, low noise, and multiplexing flexibility are mandatory.
FAQ
What is the maximum output data rate of the LTC2446IUHF#TRPBF?
The LTC2446IUHF#TRPBF achieves up to 8 kHz output rate in 2× mode using an external oscillator (fO ≤ 12 MHz). In standard 1× mode, maximum rate is 4 kHz for multiplexed operation. The first conversion after any speed, channel, or reference change is valid-no settling delay affects throughput.
Does the LTC2446IUHF#TRPBF require external components for basic operation?
No. The LTC2446IUHF#TRPBF includes an internal oscillator and requires only bypass capacitors (10 µF tantalum + 0.1 µF ceramic on VCC) for full functionality. External crystal, reference ICs, or anti-aliasing filters are optional-enabling minimal footprint in space-constrained sensor modules.
How does the LTC2446IUHF#TRPBF handle ratiometric measurements across multiple sensors?
The LTC2446IUHF#TRPBF integrates a 19-input/4-output analog multiplexer with four dedicated differential reference pairs (VREF01± to VREF67±) plus one global reference (VREFG±). This allows independent ratiometric digitization of up to four bridges or RTDs-each with its own reference-without external mux or reference switching.
What is the guaranteed integral nonlinearity (INL) specification for the LTC2446IUHF#TRPBF over temperature?
The LTC2446IUHF#TRPBF guarantees ±15 ppm of VREF INL (±0.0005%) over its full operating range of –40°C to 85°C. This corresponds to less than ±1 LSB error in 24-bit representation, ensuring monotonicity and precision in closed-loop control systems.
Can the LTC2446IUHF#TRPBF interface directly with thermocouples?
Yes. The LTC2446IUHF#TRPBF supports thermocouple digitization using its fifth differential reference input (VREFG±) while simultaneously measuring ratiometric sensors on other channels. Its differential input range (±0.5 × VREF) and 200 nVRMS noise at 13.8 Hz-with simultaneous 50/60 Hz rejection-enable direct cold-junction-compensated thermocouple readings.
LTC2446IUHF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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#TRPBF FAQ
1.How can I place an order for LTC2446IUHF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2446IUHF#TRPBF 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#TRPBF reliable?
The price and inventory of LTC2446IUHF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2446IUHF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC2446IUHF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2446IUHF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2446IUHF#TRPBF?
LTC2446IUHF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2446IUHF#TRPBF 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#TRPBF?
For technical support, including LTC2446IUHF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2446IUHF#TRPBF requirements.
6.How does Aetrix verify that LTC2446IUHF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC2446IUHF#TRPBF 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#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC2446IUHF#TRPBF?
All LTC2446IUHF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2446IUHF#TRPBF, 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#TRPBF part is unused and in its original packaging.
Return procedure for LTC2446IUHF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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