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Analog Devices Inc. LTC1861CS8#PBF
- Part No.:
- LTC1861CS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1861CS8#PBF.pdf
- Description:
- IC ADC 12BIT SAR 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:140
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Product details
Overview
LTC1861CS8#PBF from Analog Devices (formerly Linear Technology) is a 12-bit, 250ksps, 2-channel software-selectable multiplexed successive approximation ADC in an 8-lead SOIC package, operating from a single 5V supply with 850µA typical supply current and auto-shutdown to 1nA between conversions. It features SPI/MICROWIRE-compatible serial I/O, true differential input capability per channel, and supports ratiometric or external reference operation - used in portable instrumentation for high-resolution, low-power analog-to-digital conversion.
For engineers reviewing the LTC1861CS8#PBF datasheet, LTC1861CS8#PBF pinout, LTC1861CS8#PBF application, or LTC1861CS8#PBF equivalent, key selection criteria include its 2-channel MUX configuration, SO-8 package compatibility, 0°C to 70°C temperature grade, VREF tied internally to VCC, and guaranteed 250ksps sampling at full 12-bit resolution without external reference buffering.
Technical Context
The LTC1861CS8#PBF implements a switched-capacitor SAR architecture with integrated sample-and-hold and a 2-bit software-configurable MUX that selects between single-ended or differential input modes across CH0 and CH1. Its serial interface operates in full-duplex mode: SDI accepts a 2-bit configuration word on CONV↓, while SDO outputs 12-bit conversion results synchronized to SCK falling edges.
This SO-8 variant fixes VREF = VCC internally, eliminating external reference routing but limiting full-scale span to 4.75V–5.25V. Unlike the MSOP version, it lacks a dedicated VREF pin and DGND/AGND separation - all ground connections share a single GND pin, simplifying layout at the cost of reduced noise immunity in mixed-signal systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 4096 discrete output codes with no missing codes over full temperature range. |
| Max Sampling Rate | 250ksps - supports real-time acquisition of signals up to 125kHz full-linear bandwidth (SINAD ≥ 68dB). |
| Supply Current | 850µA typ at 250ksps; drops to 1nA in auto-shutdown - enables battery life extension in intermittent-sampling systems. |
| INL Error | ±1 LSB max - ensures monotonicity and ≤0.024% full-scale absolute accuracy for precision measurement. |
| SNR | 72dB - corresponds to ~11.9 effective bits, suitable for medium-fidelity sensor digitization. |
| Reference Configuration | VREF internally tied to VCC - eliminates external reference component but requires stable 5V rail for <±0.5% full-scale error. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded systems, not extended industrial or automotive use. |
Pinout & Package
Package: 8-lead plastic SOIC (narrow, 0.150-inch width), JEDEC MS-012AC, 3.9mm × 4.9mm body, 1.27mm lead pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CONV (Pin 1) | Convert Control Input | Rising edge initiates conversion; held high after completion forces auto-shutdown; low enables SDO output. |
| CH0 (Pin 2) | Analog Input Channel 0 | Primary single-ended or differential "+" input; referenced to GND in SO-8 package. |
| CH1 (Pin 3) | Analog Input Channel 1 | Secondary single-ended or differential "–" input; shares same GND reference as CH0. |
| GND (Pin 4) | Analog/Digital Ground | Single shared ground plane connection - requires low-impedance PCB tie to minimize noise coupling. |
| SDI (Pin 5) | Serial Data Input | Accepts 2-bit MUX configuration word (SGL/DIFF + ODD/SIGN) on first SCK rising edge after CONV↓. |
| SDO (Pin 6) | Serial Data Output | Outputs 12-bit conversion result MSB-first on SCK falling edges; tri-stated when CONV is high. |
| SCK (Pin 7) | Serial Clock Input | Drives full-duplex data transfer; max frequency 16.7MHz (H-grade) or 20MHz (C/I-grade). |
| VCC (Pin 8) | Positive Supply | 5V ±5% supply; also serves as internal reference source - must be bypassed with ≥1µF tantalum to GND. |
Key Features
| Feature | Design Value |
|---|---|
| 2-Channel Software-Selectable MUX | Enables dynamic reconfiguration between CH0/CH1 single-ended or differential pairs without hardware change. |
| Auto Shutdown Between Conversions | Reduces average power to nanowatt levels during idle periods - critical for duty-cycled sensor nodes. |
| Internal VREF = VCC | Eliminates external reference IC and associated layout complexity, reducing BOM count and board area. |
| SPI/MICROWIRE-Compatible Interface | Ensures drop-in compatibility with common microcontroller peripherals, avoiding custom driver development. |
| Guaranteed Operation to 70°C | Validated performance across full commercial temperature range - suitable for enclosed industrial enclosures. |
Applications
| Portable Multimeter Front-End | Battery Management System Voltage Monitoring |
|---|---|
Use Scenario: Digitizing DC voltage ranges (200mV, 2V, 20V) from precision resistive dividers in handheld DMMs. IC Role / Device Role / Timing Role: Primary 12-bit sampling ADC with software-switched input scaling via CH0/CH1 MUX and internal VREF. Use Value: Eliminates need for external reference and level-shifting op-amps, reducing component count by ≥3 parts per channel. |
Use Scenario: Simultaneous monitoring of 4–6 Li-ion cell voltages in compact BMS modules. IC Role / Device Role / Timing Role: Dual-channel ADC scanning individual cell terminals using single-ended mode with GND-referenced inputs. Use Value: Enables 250ksps aggregate sampling across channels, supporting fast fault detection (<4µs response latency). |
| Industrial PLC Analog Input Module | Isolated Remote Sensor Node |
Use Scenario: Converting 4–20mA loop signals and thermocouple outputs in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: High-accuracy front-end ADC accepting ratiometric inputs from signal-conditioning stages. Use Value: ±1 LSB INL and 72dB SNR support 0.1% system-level measurement accuracy without calibration. |
Use Scenario: Low-power wireless node acquiring vibration or temperature data from piezoelectric/RTD sensors. IC Role / Device Role / Timing Role: Power-gated ADC activated only during scheduled wake-up intervals to minimize energy consumption. Use Value: 1nA shutdown current extends CR2032 battery life to >5 years in 1-sample-per-minute duty cycle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit, serial-output ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1861IMS8#PBF | 10-lead MSOP package with separate AGND/DGND pins and externally adjustable VREF (1V–VCC). | Supports higher noise immunity and flexible reference scaling - required for precision ratiometric sensing with variable gain stages. | Select when reference independence, ground separation, or extended –40°C to 85°C operation is mandatory. |
| LTC1864CS8#PBF | 16-bit resolution, same SO-8 package, 250ksps, pin-compatible with LTC1861CS8#PBF but higher power (4.25mW vs 4.25mW at 250ksps). | Delivers 16-bit accuracy for high-end instrumentation where 12-bit quantization noise is unacceptable. | Select when resolution upgrade is prioritized over power budget and existing layout reuse is desired. |
Compared with LTC1861CS8#PBF, the LTC1861IMS8#PBF trades SO-8 simplicity for enhanced analog integrity via dedicated grounds and reference flexibility, while the LTC1864CS8#PBF retains identical footprint and timing but doubles resolution at the cost of increased supply current and reduced dynamic range headroom.
Availability
LTC1861CS8#PBF is available at Aetrix Electronics and suitable for portable instrumentation, battery management systems, industrial PLC analog input modules, and isolated remote sensor nodes requiring stable component supply with commercial-temperature qualification.
Supply support for LTC1861CS8#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; Linear pioneered high-performance analog ICs including precision ADCs, references, and power management solutions.
The LTC1861CS8#PBF belongs to Linear's µPower SAR ADC family, designed specifically for space-constrained, battery-operated systems demanding high resolution without sacrificing speed or power efficiency.
FAQ
What is the maximum sampling rate of the LTC1861CS8#PBF while maintaining full 12-bit accuracy?
The LTC1861CS8#PBF guarantees 250ksps sampling with ±1 LSB INL and no missing codes across its 0°C to 70°C operating range. At this rate, it achieves 72dB SNR and 71dB SINAD, confirming full 12-bit effective resolution. Performance remains stable up to fSCK = 20MHz, with conversion time fixed at 3.2µs regardless of clock frequency.
Does the LTC1861CS8#PBF require an external reference voltage?
No - the LTC1861CS8#PBF internally ties VREF to VCC, making it self-referenced. This eliminates external reference components but requires the 5V supply to be stable within ±1% to maintain full-scale accuracy. External reference use is not supported in the SO-8 variant; only the MSOP versions (e.g., LTC1861IMS#PBF) provide a dedicated VREF pin.
How does the 2-channel MUX operate in the LTC1861CS8#PBF?
The LTC1861CS8#PBF uses a 2-bit configuration word shifted into SDI after CONV↓ to select among four input modes: CH0 single-ended, CH1 single-ended, CH0–CH1 differential, or CH1–CH0 differential. The MUX is software-controlled per conversion cycle, enabling dynamic channel selection without changing hardware connections or adding external switches.
What is the shutdown current of the LTC1861CS8#PBF and how is it activated?
The LTC1861CS8#PBF achieves 1nA typical shutdown current when CONV is held high after conversion completion. This auto-shutdown state disables internal bias circuits and places SDO in high-impedance mode. Recovery to active sampling takes <100ns, allowing rapid wake-up for burst-mode acquisition without startup delay penalties.
Can the LTC1861CS8#PBF interface directly with a 3.3V microcontroller SPI port?
Yes - the LTC1861CS8#PBF supports mixed-voltage operation: VCC = 5V powers the core ADC, while digital I/O (CONV, SDI, SDO, SCK) tolerate 3.3V logic levels. VIH is specified at 2.4V min and VIL at 0.8V max with VCC = 4.75V, ensuring reliable interfacing with 3.3V MCUs without level shifters, provided SDO output drive strength meets MCU input requirements.
LTC1861CS8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 250k
- Number of Inputs:
- 2
- Input Type:
- Differential, Single Ended
- Data Interface:
- SPI
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 8-SO
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
LTC1861CS8#PBF FAQ
1.How can I place an order for LTC1861CS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1861CS8#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 LTC1861CS8#PBF reliable?
The price and inventory of LTC1861CS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1861CS8#PBF is usually 5 days.
3.What payment methods are accepted for LTC1861CS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1861CS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1861CS8#PBF?
LTC1861CS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1861CS8#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 LTC1861CS8#PBF?
For technical support, including LTC1861CS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1861CS8#PBF requirements.
6.How does Aetrix verify that LTC1861CS8#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1861CS8#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 LTC1861CS8#PBF meets industry standards.
7.What is the process for return or replacement of LTC1861CS8#PBF?
All LTC1861CS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1861CS8#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 LTC1861CS8#PBF part is unused and in its original packaging.
Return procedure for LTC1861CS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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