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Analog Devices Inc. LTC2445IUHF#PBF
- Part No.:
- LTC2445IUHF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC2445IUHF#PBF.pdf
- Description:
- IC ADC 24BIT SIGMA-DELTA 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:392
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Product details
Overview
LTC2445IUHF#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 4.5 V to 5.5 V and is used in high-precision weight scales and auto-ranging 6-digit DVMs.
For engineers reviewing the LTC2445IUHF#PBF datasheet, LTC2445IUHF#PBF pinout, LTC2445IUHF#PBF application, or LTC2445IUHF#PBF equivalent, key selection criteria include guaranteed modulator stability under all input/reference conditions, simultaneous 50 Hz/60 Hz rejection at 6.9 Hz, autosleep mode enabling 20 µA operation, and MUXOUT/ADCIN pins for external buffering.
Technical Context
The LTC2445IUHF#PBF employs a proprietary 3rd-order delta-sigma modulator with decimating FIR filter and continuous internal offset/full-scale calibration per conversion cycle. It supports both internal oscillator (no external components) and external fO up to 12 MHz for timing control.
Its 4-wire SPI-compatible interface uses SDI for channel/speed/resolution selection and SDO for 32-bit output (24-bit result + status bits), with BUSY indicating conversion completion. The device features no latency mode: first conversion after channel/speed change is fully accurate, and multiplexing across all 8 differential channels achieves 500 Hz scan rate.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 24-bit with no missing codes - guarantees monotonicity and full dynamic range utilization. |
| INL | ±0.0005% of full scale - ensures linearity error ≤ ±3 ppm of VREF, critical for metrology-grade measurements. |
| RMS Noise | 2 µV at 1.76 kHz output rate - enables high-speed precision without sacrificing signal-to-noise ratio. |
| Offset Error | <5 µV over –40°C to 85°C - minimizes zero-point drift in temperature-varying industrial environments. |
| Common Mode Range | GND to VCC on inputs and reference - allows direct interfacing with sensors operating at rail-to-rail common-mode voltages. |
| Output Rate | Up to 4 kHz multiplexing rate with external fO - supports rapid scanning of multiple sensor channels without settling delay. |
| Supply Current | 8–11 mA active, 20 µA in autosleep at 6.9 Hz - balances performance and power for battery-backed instrumentation. |
Pinout & Package
Package: 38-lead (5 mm × 7 mm) plastic QFN (UHF), exposed pad (Pin 39) soldered to PCB ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1,4,5,6,31,32,33) | Ground reference | Seven dedicated ground pins ensure low-impedance return paths for analog/digital currents and optimal VCC decoupling. |
| BUSY (Pin 2) | Conversion status indicator | Active-HIGH during conversion; transitions LOW when 32-bit result is ready for readout - eliminates polling overhead. |
| EXT (Pin 3) | SCK mode select | Logic HIGH enables internal SCK generation on Pin 38; logic LOW configures SCK as external clock input. |
| COM (Pin 7) | Single-ended negative input common | Shared IN– for all single-ended channels; supports bipolar input range from –0.5·VREF to +0.5·VREF. |
| CH0–CH7 (Pins 9,10,13,14,17,18,21,22) | Analog input channels | Configurable as 8 single-ended or 4 differential pairs; input voltage range: GND–0.3 V to VCC+0.3 V. |
| MUXOUTP/N (Pins 24,27) | Multiplexer output (±) | Provides buffered post-mux analog signal for external amplification - isolates ADC front-end from gain-stage nonlinearity. |
| ADCINP/N (Pins 25,26) | ADC input (±) | Accepts conditioned signal from external buffer; enables transparent calibration to cancel buffer offset errors. |
| VCC (Pin 28) | Positive supply | 4.5 V to 5.5 V operation; requires 10 µF tantalum + 0.1 µF ceramic bypass close to pin. |
| REF+/REF– (Pins 29,30) | Differential reference inputs | Accept 0.1 V to VCC differential reference; common-mode range: GND to VCC - supports ratiometric sensor interfaces. |
| SDI (Pin 34) | Serial data input | 3-bit channel address + 4-bit OSR + 2-bit mode control (1X/2X, single/diff); updated during data output phase. |
| FO (Pin 35) | Frequency control | Tie to GND or VCC to enable internal oscillator; connect external clock (0.1–12 MHz) for precise timing control. |
| CS (Pin 36) | Chip select | Active-LOW enables SDO and wakes ADC from sleep; HIGH forces autosleep & holds conversion result indefinitely. |
| SDO (Pin 37) | Serial data output | 32-bit frame (EOC/DMY/SIG/MSB/24-bit result/5 sub-LSBs); tri-state when CS = HIGH. |
| SCK (Pin 38) | Serial clock | Bidirectional: output in internal mode, input in external mode; duty cycle 45–55% with 20 pF load. |
| Exposed Pad (Pin 39) | Thermal & electrical ground | Must be soldered to PCB ground plane for thermal dissipation (θJA = 34°C/W) and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| No latency delta-sigma architecture | First conversion after channel/speed change is fully accurate - eliminates settling delay in multiplexed systems. |
| Simultaneous 50 Hz/60 Hz rejection | Guaranteed at 6.9 Hz output rate without external notch filters - simplifies EMI mitigation in AC-powered equipment. |
| Continuous internal calibration | Per-conversion offset and full-scale correction - maintains stability against temperature, supply, and time drift without user intervention. |
| MUXOUT/ADCIN interface | Enables external gain/buffer between multiplexer and ADC core - preserves SNR while extending input range or driving long traces. |
| Autosleep mode | Reduces current to 20 µA at 6.9 Hz output rate - extends battery life in portable test equipment and IoT edge sensors. |
Applications
| Weight Scales | Auto-Ranging 6-Digit DVMs |
|---|---|
Use Scenario: High-resolution load cell measurement in commercial/industrial weighing systems requiring NTEP or OIML certification. IC Role / Device Role / Timing Role: Primary 24-bit ADC capturing differential bridge outputs with simultaneous 50/60 Hz rejection and <5 µV offset drift over temperature. Use Value: Eliminates need for external digital filtering or zero-calibration routines, reducing firmware complexity and improving repeatability. | Use Scenario: Precision benchtop multimeter supporting autoranging across µV to 10 V full-scale ranges with >100 dB CMRR. IC Role / Device Role / Timing Role: Core metrology ADC providing 24-bit no-latency conversions with programmable OSR (256–32768) and integrated reference buffering via MUXOUT/ADCIN. Use Value: Enables seamless range switching without dead time or accuracy loss - critical for fast, high-accuracy automated test systems. |
| Direct Temperature Measurement | High-Speed Data Acquisition |
Use Scenario: Cold-junction compensation and thermocouple linearization in industrial process controllers with wide ambient temperature range. IC Role / Device Role / Timing Role: Differential ADC digitizing thermocouple voltage referenced to RTD-based cold-junction sensor, leveraging GND-to-VCC common-mode range. Use Value: Supports direct connection to unbuffered thermocouples without level-shifting circuitry, reducing BOM cost and board space. | Use Scenario: Multi-channel sensor monitoring in predictive maintenance gateways sampling vibration, pressure, and current simultaneously. IC Role / Device Role / Timing Role: 8-channel scan-capable ADC delivering 500 Hz per-channel throughput with guaranteed modulator lock-up immunity under transient input conditions. Use Value: Ensures data integrity during ESD events or power glitches - avoids corrupted readings that could trigger false fault alarms. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-precision delta-sigma ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS1258IRHBT | 24-bit, 8-channel, but uses internal clock only; no external fO option; higher typical noise (3.5 µVRMS at 1 kSPS). | Lacks simultaneous 50/60 Hz rejection at low rates; no MUXOUT/ADCIN pins for external gain staging. | Choose ADS1258IRHBT if internal clock suffices and external buffering is unnecessary. |
| LTC2449IUHF#PBF | 16-channel (8-differential) variant of same family; identical noise, INL, and MUXOUT/ADCIN architecture; same pinout except CH8–CH15 added. | Supports larger sensor arrays; requires additional PCB routing for extra channels but shares layout and firmware compatibility. | Choose LTC2449IUHF#PBF when system requires >8 input channels without redesigning signal chain. |
Compared with ADS1258IRHBT, LTC2445IUHF#PBF offers superior noise performance and built-in 50/60 Hz rejection, while LTC2449IUHF#PBF extends channel count with full pin and functional compatibility - making LTC2445IUHF#PBF optimal for compact, high-fidelity 8-channel systems where timing flexibility and external signal conditioning are critical.
Availability
LTC2445IUHF#PBF is available at Aetrix Electronics and suitable for weight scales, auto-ranging 6-digit DVMs, and direct temperature measurement systems requiring stable component supply, long-term calibration stability, and industrial temperature range support (–40°C to 85°C).
Supply support for LTC2445IUHF#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, formed through the acquisition of Linear Technology in 2017.
The LTC2445IUHF#PBF belongs to ADI's precision delta-sigma ADC product line, designed specifically for metrology-grade applications demanding ultra-low noise, guaranteed stability, and no-latency multiplexing in industrial, test & measurement, and scientific instrumentation.
FAQ
What is the maximum output data rate of the LTC2445IUHF#PBF with an external oscillator?
The LTC2445IUHF#PBF supports up to 8 kHz output rate when using an external oscillator (fEOSC ≤ 12 MHz) in 2X speed mode. In standard 1X mode with external clock, the maximum is 4 kHz multiplexing rate - sufficient for scanning all 8 differential channels at 500 Hz each without latency or settling penalties.
Does the LTC2445IUHF#PBF require external components for basic operation?
No, the LTC2445IUHF#PBF operates with no external components when using its internal oscillator. Only standard power supply decoupling (10 µF tantalum + 0.1 µF ceramic on VCC) is required. External components are optional - e.g., crystal for fO, op-amps for MUXOUT/ADCIN buffering, or RC filters for enhanced EMI immunity.
How does the MUXOUT/ADCIN feature improve system accuracy in the LTC2445IUHF#PBF?
The MUXOUT/ADCIN pins in the LTC2445IUHF#PBF allow insertion of an external amplifier between the multiplexer and ADC core. Because the LTC2445IUHF#PBF performs continuous internal calibration, it automatically cancels the offset and gain errors introduced by that external amplifier - preserving end-to-end accuracy without manual trimming or calibration tables.
What is the significance of "no latency" in the LTC2445IUHF#PBF's delta-sigma architecture?
"No latency" means the first conversion result after changing channel, speed, or resolution is fully accurate - no discarded samples or filter settling delay. This enables deterministic real-time control in applications like closed-loop sensor feedback, where every conversion must reflect the newly selected input without delay or error accumulation.
Can the LTC2445IUHF#PBF operate with a 2.5 V reference voltage?
Yes, the LTC2445IUHF#PBF accepts differential reference voltages from 0.1 V to VCC (4.5–5.5 V), so a 2.5 V reference is fully supported. With VREF = 2.5 V, the input range becomes ±1.25 V, and INL improves due to reduced reference-related nonlinearity - though RMS noise remains ~2 µVRMS independent of VREF.
LTC2445IUHF#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:
- -
LTC2445IUHF#PBF FAQ
1.How can I place an order for LTC2445IUHF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2445IUHF#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 LTC2445IUHF#PBF reliable?
The price and inventory of LTC2445IUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2445IUHF#PBF is usually 5 days.
3.What payment methods are accepted for LTC2445IUHF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2445IUHF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2445IUHF#PBF?
LTC2445IUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2445IUHF#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 LTC2445IUHF#PBF?
For technical support, including LTC2445IUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2445IUHF#PBF requirements.
6.How does Aetrix verify that LTC2445IUHF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC2445IUHF#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 LTC2445IUHF#PBF meets industry standards.
7.What is the process for return or replacement of LTC2445IUHF#PBF?
All LTC2445IUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2445IUHF#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 LTC2445IUHF#PBF part is unused and in its original packaging.
Return procedure for LTC2445IUHF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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