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Analog Devices Inc. LTC1861IMS#PBF
- Part No.:
- LTC1861IMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LTC1861IMS#PBF.pdf
- Description:
- IC ADC 12BIT SAR 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,757
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Product details
Overview
LTC1861IMS#PBF from Analog Devices (formerly Linear Technology) is a 12-bit, 250ksps, 2-channel software-selectable multiplexed successive-approximation ADC in a 10-lead MSOP package, operating from a single 5V supply with 850µA typical supply current at full speed and auto-shutdown to 1nA between conversions. It features SPI/MICROWIRE-compatible serial I/O, adjustable reference input (1V to VCC), and high-impedance analog inputs enabling direct sensor interfacing in portable instrumentation.
For engineers reviewing the LTC1861IMS#PBF datasheet, LTC1861IMS#PBF pinout, LTC1861IMS#PBF application, or LTC1861IMS#PBF equivalent, key selection considerations include its 2-channel MUX configuration via SDI, guaranteed operation from –40°C to +85°C, differential or single-ended input modes, and compatibility with low-noise external references for ratiometric or precision measurement systems.
Technical Context
The LTC1861IMS#PBF implements a switched-capacitor SAR architecture with integrated sample-and-hold, supporting true differential or single-ended measurements across two analog inputs (CH0/CH1) selected by a 2-bit configuration word clocked into SDI. Its conversion timing is deterministic: tCONV = 2.75–3.3µs (H-grade), with data output synchronized on SCK falling edges and capture on rising edges in full-duplex mode.
It uses separate AGND and DGND pins for analog/digital domain isolation, requires 1µF tantalum bypassing on VCC and VREF, and supports reduced full-scale spans down to 1V - enabling direct connection to low-voltage sensors without gain stages. Reference voltage range is 1V to VCC, and absolute input range extends from –0.05V to VCC + 0.05V per input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 4096 discrete output codes with no missing codes over full temperature range. |
| Sampling Rate | 250ksps maximum - supports real-time acquisition of signals up to 125kHz full linear bandwidth. |
| Supply Current | 850µA typical at 250ksps; drops to 1nA in auto-shutdown - enables multi-year battery life in low-duty-cycle sensing. |
| INL Error | ±1 LSB max - ensures monotonicity and <0.025% end-point linearity error for precision measurement. |
| SNR | 72dB - provides >11.9 effective number of bits (ENOB) for clean signal digitization. |
| Reference Range | 1V to VCC - allows flexible scaling from low-power 1.8V systems to standard 5V rails without external dividers. |
| Operating Temp | –40°C to +85°C - qualified for industrial environments with guaranteed performance across full range. |
Pinout & Package
Package: 10-lead plastic MSOP (MS package), 3.0mm × 3.0mm body, 0.5mm lead pitch, exposed pad not present, RoHS-compliant lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CONV | Convert control input | Active-high edge-triggered start signal; high after conversion initiates auto-shutdown; low enables SDO output. |
| CH0 | Analog input channel 0 | High-impedance (+) or (–) terminal depending on MUX configuration; supports differential or single-ended sensing. |
| CH1 | Analog input channel 1 | High-impedance (+) or (–) terminal depending on MUX configuration; shares same sampling aperture as CH0. |
| AGND | Analog ground reference | Must be tied directly to analog ground plane with minimal trace length to minimize noise coupling into conversion. |
| DGND | Digital ground reference | Internally isolated from AGND; should be connected to AGND at single point near device to prevent ground loops. |
| SDI | Serial data input | Receives 2-bit MUX configuration word on rising SCK edges prior to conversion; ignored once CONV goes high. |
| SDO | Serial data output | Outputs 12-bit conversion result MSB-first on falling SCK edges; tri-stated when CONV is high. |
| SCK | Serial clock input | Master-controlled clock up to 20MHz (H-grade); synchronizes both SDI write and SDO read in full-duplex mode. |
| VCC | Positive supply | Single 4.75V–5.25V rail; requires local 1µF tantalum bypass to AGND for stable conversion performance. |
| VREF | Reference voltage input | Defines full-scale span (1V to VCC); must be low-noise and bypassed; not internally tied to VCC (unlike SO-8 version). |
Key Features
| Feature | Design Value |
|---|---|
| Software-selectable 2-channel MUX | Configurable via 2-bit SDI word for four input combinations (SGL/DIFF, ODD/SIGN), enabling flexible sensor routing without external switches. |
| Auto-shutdown between conversions | Reduces ICC to 1nA typical - eliminates need for external power gating in burst-mode acquisition systems. |
| Adjustable reference input (1V–VCC) | Supports direct interface to low-voltage references (e.g., LT1460, LT1790) or ratiometric operation with bridge sensors. |
| True differential input capability | Rejects common-mode noise on CH0/CH1 pairs - critical for noisy industrial or motor-control feedback applications. |
| Guaranteed operation to 85°C | Specified performance across full industrial temperature range - no derating required for embedded thermal environments. |
Applications
| Portable Data Loggers | Industrial Sensor Interfaces |
|---|---|
Use Scenario: Battery-powered environmental monitors acquiring temperature, humidity, and pressure at 100Hz intervals. IC Role / Device Role / Timing Role: Dual-channel ADC digitizing analog outputs from two isolated sensors with shared reference and automatic power cycling. Use Value: 850µA active current and 1nA shutdown enable >5-year battery life using CR2032 cells in intermittent-sampling mode. |
Use Scenario: PLC analog input module conditioning 4–20mA loop signals and thermocouple outputs in factory automation. IC Role / Device Role / Timing Role: Precision front-end converter with differential CH0/CH1 inputs rejecting EMI from adjacent motor drives. Use Value: ±1 LSB INL and 72dB SNR ensure <0.025% measurement accuracy across –40°C to +85°C ambient. |
| Isolated Remote Monitoring | Low-Power Medical Sensors |
Use Scenario: Wireless node measuring strain gauge bridges and RTD resistance via external excitation in hazardous locations. IC Role / Device Role / Timing Role: Ratiometric ADC using same reference for excitation and conversion, minimizing drift sensitivity. Use Value: 1V–VCC reference flexibility allows use of ultra-low-quiescent LDOs (e.g., LT3009) to extend isolation barrier runtime. |
Use Scenario: Wearable ECG patch digitizing amplified biopotential signals with minimal size and heat generation. IC Role / Device Role / Timing Role: Low-noise, low-power ADC sampling at 250ksps with internal sample-and-hold eliminating external hold capacitor. Use Value: 12-bit resolution and 125kHz full linear bandwidth support diagnostic-quality waveform capture without aliasing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit, serial-interface ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1864CMS8#PBF | 16-bit resolution, 250ksps, 8-lead MSOP, single-channel, pin-compatible with LTC1860 but not LTC1861; no MUX. | Higher resolution needed for precision metrology; lacks dual-input flexibility for multi-sensor systems. | Select when ENOB >12 bits is mandatory and channel count is fixed at one; avoid if 2-channel routing is required. |
| ADS7822U | 12-bit, 250ksps, 8-lead SOIC, single-supply 2.7–5.25V, SPI interface, no auto-shutdown (1.2mA active), no adjustable reference (VREF = VCC). | Lower cost for non-critical applications; unsuitable for battery life-sensitive or low-reference-voltage designs. | Choose for cost-driven consumer applications where 1nA shutdown and 1V reference are unnecessary. |
Compared with LTC1864CMS8#PBF and ADS7822U, the LTC1861IMS#PBF uniquely balances dual-channel configurability, ultra-low standby current, and wide reference voltage range - making it optimal for compact, battery-constrained industrial sensors requiring flexible analog input routing.
Availability
LTC1861IMS#PBF is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor interfaces, and isolated remote monitoring requiring stable component supply with guaranteed long-term availability and consistent parametric performance.
Supply support for LTC1861IMS#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 ICs, serving industrial, automotive, communications, and healthcare markets.
The LTC1861IMS#PBF belongs to Linear's µPower precision ADC family, designed specifically for space-constrained, battery-operated systems demanding high resolution, low quiescent current, and robust noise immunity in harsh environments.
FAQ
What is the maximum sampling frequency of the LTC1861IMS#PBF?
The LTC1861IMS#PBF achieves a maximum sampling frequency of 250ksps under recommended operating conditions (VCC = 4.75V–5.25V, TA = –40°C to +85°C). This is supported by a guaranteed conversion time of 2.75–3.3µs and SCK clock tolerance up to 20MHz for H-grade devices. At this rate, the device maintains full 12-bit accuracy with ±1 LSB INL and 72dB SNR.
Does the LTC1861IMS#PBF support differential input mode?
Yes, the LTC1861IMS#PBF supports true differential input mode via its software-configurable 2-channel MUX. When configured for differential operation (SGL/DIFF = 0, ODD/SIGN = 0 or 1), it measures the voltage difference between CH0 and CH1 with common-mode noise rejection. The full-scale range is defined by VREF, and the absolute input range is –0.05V to VCC + 0.05V per pin.
What is the reference voltage range supported by the LTC1861IMS#PBF?
The LTC1861IMS#PBF supports an externally applied reference voltage from 1V to VCC (4.75V–5.25V) on the VREF pin. Unlike the SO-8 variant, the MSOP version does not tie VREF internally to VCC - enabling ratiometric operation with low-voltage references or precision external sources such as the LT1460 (10ppm/°C, 130µA).
How does the auto-shutdown feature work on the LTC1861IMS#PBF?
The LTC1861IMS#PBF automatically enters ultra-low-power shutdown mode (ICC ≈ 1nA) when the CONV pin remains high after conversion completes. Driving CONV low re-enables the serial interface and prepares the ADC for the next sample. This eliminates external power control circuitry and reduces average system current in burst-mode applications.
What are the grounding requirements for optimal performance of the LTC1861IMS#PBF?
The LTC1861IMS#PBF requires separate AGND and DGND connections, both tied directly to a clean analog ground plane with minimal trace length. AGND handles analog return currents; DGND carries digital switching currents. These grounds should join at a single point near the device to prevent noise coupling - especially critical for achieving ±1 LSB INL and 72dB SNR performance.
LTC1861IMS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm 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:
- -40°C ~ 85°C
- Supplier Device Package:
- 10-MSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
LTC1861IMS#PBF FAQ
1.How can I place an order for LTC1861IMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1861IMS#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 LTC1861IMS#PBF reliable?
The price and inventory of LTC1861IMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1861IMS#PBF is usually 5 days.
3.What payment methods are accepted for LTC1861IMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1861IMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1861IMS#PBF?
LTC1861IMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1861IMS#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 LTC1861IMS#PBF?
For technical support, including LTC1861IMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1861IMS#PBF requirements.
6.How does Aetrix verify that LTC1861IMS#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1861IMS#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 LTC1861IMS#PBF meets industry standards.
7.What is the process for return or replacement of LTC1861IMS#PBF?
All LTC1861IMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1861IMS#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 LTC1861IMS#PBF part is unused and in its original packaging.
Return procedure for LTC1861IMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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