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Analog Devices Inc. LTC1285IS8#TRPBF
- Part No.:
- LTC1285IS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1285IS8#TRPBF.pdf
- Description:
- IC ADC 12BIT SAR 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,671
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Product details
Overview
LTC1285IS8#TRPBF from Analog Devices (formerly Linear Technology) is a micropower 12-bit successive approximation ADC with differential analog input, single-supply operation (2.7V–6V), 160µA typical supply current at 7.5ksps, auto-shutdown to 1nA, and on-chip sample-and-hold - designed for battery-powered sensor interfaces and isolated data acquisition systems.
For engineers reviewing the LTC1285IS8#TRPBF datasheet, LTC1285IS8#TRPBF pinout, LTC1285IS8#TRPBF application, or LTC1285IS8#TRPBF equivalent, this page delivers verified specifications, SO-8 package terminal mapping, real-world use cases in remote monitoring and low-power instrumentation, and two validated alternative parts with documented functional and interface differences.
Technical Context
The LTC1285IS8#TRPBF implements a switched-capacitor SAR architecture with internal reference buffering and rail-to-rail compatible digital I/O. Its differential input supports ratiometric measurement against an external VREF (2.7V–6V range), enabling direct connection to transducers without gain stages.
It uses a 3-wire SPI/Microwire-compatible serial interface (CS/CLK/DOUT) with MSB-first output, 100µs conversion time, and automatic power-down between conversions - eliminating need for software-controlled sleep modes while maintaining ±3/4 LSB max DNL and 67dB SNR.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit with no missing codes - guarantees monotonic transfer function for precision control loops. |
| Supply Current | 160µA typ at 7.5ksps; drops to 1nA typ in shutdown - enables multi-year battery life in wireless sensors. |
| Input Type | Differential analog input (IN+, IN−) - rejects common-mode noise and supports floating signal sources. |
| Reference Support | External VREF pin (0.1V–VCC+0.05V) - allows flexible full-scale adjustment down to 1.5V span for high-resolution low-voltage sensing. |
| Conversion Time | 100µs (12 clock cycles @ 120kHz) - enables deterministic timing for synchronized sampling in embedded systems. |
| Dynamic Performance | 67dB SNR, 88dB SFDR at 1kHz - sufficient for 10+ ENOB in industrial temperature measurement and battery monitoring. |
| Operating Temp | 0°C to 70°C - qualified for commercial-grade embedded applications including portable medical devices and IoT edge nodes. |
Pinout & Package
Package: 8-lead plastic SO (SO-8), 150°C max junction temperature, θJA = 175°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VREF (Pin 1) | Reference Input | Defines full-scale voltage range; high-impedance node during conversion; supports external references from 1.5V to VCC. |
| +IN (Pin 2) | Positive Analog Input | Differential input terminal; 20pF input capacitance; accepts signals up to VCC + 0.05V. |
| −IN (Pin 3) | Negative Analog Input | Differential input terminal; matches +IN for common-mode rejection; same voltage limits as +IN. |
| GND (Pin 4) | Analog Ground | Must connect directly to analog ground plane; separates analog and digital return paths. |
| CS/SHDN (Pin 5) | Chip Select / Shutdown Control | Active-low enable; logic high forces 1nA shutdown regardless of CLK activity - critical for ultra-low-power scheduling. |
| DOUT (Pin 6) | Digital Data Output | 3-state serial output; MSB-first format; Hi-Z when CS high; drives standard CMOS loads. |
| CLK (Pin 7) | Serial Clock Input | Synchronizes data transfer; falling edge clocks data out; supports up to 120kHz at 2.7V. |
| VCC (Pin 8) | Power Supply | Single 2.7V–6V supply; requires local 10µF tantalum bypass to GND; sensitive to ripple due to SAR architecture. |
Key Features
| Feature | Design Value |
|---|---|
| Micropower Operation | 160µA active current at 7.5ksps enables >5-year operation on a CR2032 coin cell in duty-cycled sensor nodes. |
| Auto Shutdown | 1nA typical quiescent current when CS = VCC - eliminates need for external power gating circuitry. |
| Differential Input Architecture | Rejects common-mode noise up to 100mV; supports direct connection to bridge sensors and thermocouples without op-amp front-end. |
| Reduced Span Support | Full-scale range configurable down to 1.5V - achieves 366µV LSB resolution for sub-millivolt signal digitization. |
| 3-Wire Serial Interface | Compatible with SPI, Microwire, and generic GPIO bit-banging - simplifies integration into resource-constrained MCUs like Cortex-M0+. |
Applications
| Pen Screen Digitizing | Battery Monitoring |
|---|---|
Use Scenario: Analog stylus position detection in handheld PDAs using resistive touch overlay. IC Role / Device Role / Timing Role: Differential ADC captures voltage divider ratio across X/Y electrodes; 100µs conversion aligns with touch scan rate. Use Value: 12-bit resolution resolves <1mm positional error; micropower mode extends PDA runtime between charges. |
Use Scenario: Real-time cell voltage tracking in multi-cell Li-ion battery packs for portable tools. IC Role / Device Role / Timing Role: Measures individual cell voltages differentially against pack reference; 7.5ksps sampling captures transient load events. Use Value: ±3/4 LSB DNL ensures accurate state-of-charge estimation; 2.7V min supply supports operation down to deeply discharged states. |
| Remote Data Acquisition | Isolated Data Acquisition |
Use Scenario: Wireless environmental sensor node measuring temperature/humidity via analog outputs. IC Role / Device Role / Timing Role: Digitizes conditioned sensor outputs; auto-shutdown synchronizes with RF transmit intervals. Use Value: 1nA shutdown current minimizes leakage in sleep mode; differential input rejects EMI from long sensor cables. |
Use Scenario: High-voltage motor drive feedback where ADC must float at bus potential. IC Role / Device Role / Timing Role: Isolated-side ADC digitizing current shunt or DC-link voltage; powered locally from isolated supply. Use Value: No external reference needed - VREF tied to local VCC enables simple isolated supply design; 3-wire interface reduces isolation channel count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit micropower ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 8-pin SO, 12-bit, 200ksps, 1.2mA active current, internal reference only, no differential input. | Higher speed but 7.5× higher supply current; unsuitable for multi-year battery life; requires external op-amp for differential signals. | Select when sampling rate >10ksps is required and power budget allows >1mA average current. |
| MAX11131ASA+ | 8-pin SO, 12-bit, 100ksps, 190µA active current, pseudo-differential input (single-ended with shared REF), internal reference option. | Lower DNL (±0.5 LSB), but lacks true differential input; REF pin not independently configurable - limits ratiometric flexibility. | Select when cost sensitivity outweighs need for true differential input and external reference control. |
Compared with ADS7822U and MAX11131ASA+, the LTC1285IS8#TRPBF uniquely combines true differential input, external VREF support, and sub-200µA active current - making it the only choice for ultra-low-power, ratiometric, floating-signal applications in space-constrained SO-8 layouts.
Availability
LTC1285IS8#TRPBF is available at Aetrix Electronics and suitable for battery-operated systems, remote data acquisition, and isolated data acquisition requiring stable component supply and long-term production continuity.
Supply support for LTC1285IS8#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 acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for legacy Linear precision analog products.
The LTC1285IS8#TRPBF belongs to Linear's micropower precision ADC family, engineered specifically for energy-constrained instrumentation where accuracy, low supply current, and small footprint are co-primary requirements.
FAQ
What is the maximum clock frequency supported by the LTC1285IS8#TRPBF?
The LTC1285IS8#TRPBF supports up to 120kHz clock frequency at VCC = 2.7V. At higher supply voltages (e.g., 5V), maximum clock frequency increases - reaching ~300kHz at 6V per the "Maximum Clock Frequency vs Supply Voltage" curve in the datasheet. Exceeding recommended fCLK degrades DNL and increases supply current.
Does the LTC1285IS8#TRPBF require an external reference voltage?
Yes, the LTC1285IS8#TRPBF requires an external reference connected to the VREF pin (Pin 1). It does not include an internal reference. The reference can be as low as 1.5V for reduced spans, enabling 366µV LSB resolution, and must remain within –0.3V to VCC + 0.3V per absolute maximum ratings.
Can the LTC1285IS8#TRPBF operate from a 5V supply?
Yes, the LTC1285IS8#TRPBF operates over 2.7V to 6V. At 5V, supply current remains ~160µA at 7.5ksps, but logic thresholds scale with VCC - VIH minimum becomes ~3.5V and VIL maximum ~1.5V. Digital interface must comply with these adjusted thresholds for reliable communication.
How does the auto-shutdown feature work on the LTC1285IS8#TRPBF?
The LTC1285IS8#TRPBF automatically enters shutdown (1nA typical ICC) whenever CS/SHDN (Pin 5) is driven high to VCC. This occurs independently of CLK or DOUT activity. During shutdown, the reference input becomes high-impedance, bias circuits power off, and DOUT goes Hi-Z - no software intervention is required.
What is the purpose of the CS/SHDN pin on the LTC1285IS8#TRPBF?
The CS/SHDN pin (Pin 5) serves dual functions: when pulled low, it enables conversion and data transfer; when pulled high to VCC, it forces full shutdown with 1nA typical supply current. Unlike conventional chip select, its high state actively gates internal bias - making it the primary hardware-controlled power management signal for the LTC1285IS8#TRPBF.
LTC1285IS8#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 7.5k
- Number of Inputs:
- 1
- Input Type:
- Differential
- 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:
- 2.7V ~ 6V
- Voltage - Supply, Digital:
- 2.7V ~ 6V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 8-SO
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
LTC1285IS8#TRPBF FAQ
1.How can I place an order for LTC1285IS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1285IS8#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 LTC1285IS8#TRPBF reliable?
The price and inventory of LTC1285IS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1285IS8#TRPBF is usually 5 days.
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LTC1285IS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1285IS8#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 LTC1285IS8#TRPBF?
For technical support, including LTC1285IS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1285IS8#TRPBF requirements.
6.How does Aetrix verify that LTC1285IS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1285IS8#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 LTC1285IS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1285IS8#TRPBF?
All LTC1285IS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1285IS8#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 LTC1285IS8#TRPBF part is unused and in its original packaging.
Return procedure for LTC1285IS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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