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Analog Devices Inc. LTC1277ISW#TRPBF
- Part No.:
- LTC1277ISW#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LTC1277ISW#TRPBF.pdf
- Description:
- IC ADC 12BIT SAR 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,241
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Product details
Overview
LTC1277ISW#TRPBF from Analog Devices (formerly Linear Technology) is a 12-bit successive-approximation ADC with differential analog input, 2-byte parallel readout, and dual power-down modes (180µA Nap, 1µA Sleep). It operates from single 5V or ±5V supplies, delivers 100ksps sampling rate, 72dB S/(N+D) at 100kHz input, and supports unipolar (0V–4.096V) or bipolar (±2.048V) input ranges - used in high-speed portable data acquisition and DSP front-ends.
For engineers reviewing the LTC1277ISW#TRPBF datasheet, LTC1277ISW#TRPBF pinout, LTC1277ISW#TRPBF application, or LTC1277ISW#TRPBF equivalent, key selection criteria include its 24-pin SOIC-W package, 2.42V internal reference with overdrive capability, HBEN-controlled byte-read timing, VLOGIC-compatible 3V/5V digital interface, and verified 6–8µs conversion time under industrial temperature range (–40°C to +85°C).
Technical Context
The LTC1277ISW#TRPBF implements a capacitive DAC-based successive approximation architecture with integrated sample-and-hold, internal synchronized clock, and factory-trimmed 2.42V bandgap reference. Its differential input stage rejects common-mode noise, while offset-binary bipolar encoding ensures seamless sign-magnitude interpretation in measurement systems.
Power management includes two distinct low-power states: Nap mode (180µA, 620ns wake-up via NAP pin) for brief idle intervals, and Sleep mode (1µA, 3.3–4.2ms wake-up via REFRDY assertion after SLEEP deassertion). The 2-byte read format (D0/8–D3/11 for LSB, D4–D7 for MSB) reduces bus contention versus full 12-bit parallel output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit with no missing codes - guarantees monotonic transfer function for precision measurement. |
| Sampling Rate | 100ksps maximum - enables real-time capture of signals up to 350kHz full-linear bandwidth. |
| S/(N + D) | 72.5dB typical at 100kHz input - supports >11.7 ENOB for high-fidelity signal digitization. |
| Input Range | 0V to 4.096V (unipolar) or ±2.048V (bipolar) - matches 1mV/LSB step size for direct mV-scale sensor interfacing. |
| Supply Current | 2mA typ at 100ksps; 180µA in Nap mode; 1µA in Sleep mode - enables battery operation in portable instrumentation. |
| Reference Output | 2.420V ±20mV, ±10ppm/°C tempco - provides stable scaling without external reference ICs. |
| Conversion Time | 6–8µs - defines minimum inter-conversion interval and supports tight timing control in synchronous systems. |
Pinout & Package
Package: 24-lead plastic SO wide (SOIC-W), 0.300" body width, JEDEC MS-013AC, θJA = 130°C/W, TJMAX = 110°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN+ | Differential analog input (positive) | Accepts voltage relative to AIN–; must settle fully during 0.35–2µs acquisition window. |
| AIN– | Differential analog input (negative) | Reference node for differential pair; requires low-noise, low-impedance source during conversion. |
| VREF | 2.42V reference output / overdrive input | Provides internal reference; can be overdriven ≥2.45V to scale input range (e.g., ±4.23V bipolar). |
| REFRDY | Reference ready status indicator | Asserts high after Sleep wake-up when VREF has settled - required before initiating first conversion. |
| SLEEP | Deep power-down enable input | Active-low control; pulls supply current to 1µA; triggers REFRDY delay on exit. |
| NAP | Low-latency power-down enable (LTC1277 only) | Active-low control; reduces current to 180µA with 620ns wake-up - suitable for burst-mode sampling. |
| HBEN | High-byte enable for 2-byte read | When high, pins D0/8–D3/11 output MSB (D8–D11); when low, they output LSB (D0–D3). |
| VLOGIC | Digital I/O supply rail | Accepts 2.7V–5.25V; sets logic swing for BUSY, REFRDY, and data outputs - enables 3V µP interfacing. |
| CONVST | Conversion start trigger | Falling-edge initiated; requires CS low; starts SAR cycle and resets internal register. |
| BUSY | Conversion status flag | Active-low open-drain output; falls at CONVST edge, rises after conversion completes - used for latch timing. |
Key Features
| Feature | Design Value |
|---|---|
| Differential input architecture | Rejects common-mode noise up to full-scale amplitude - critical for ECG, strain gauge, and motor current sensing. |
| 2-byte parallel read format | Reduces bus loading and simplifies 8-bit µP interface by splitting 12-bit result across two 8-bit reads (MSB/LSB). |
| Offset-binary bipolar encoding | Maps –2.048V to 0x0000 and +2.048V to 0xFFFF - eliminates sign-extension logic in firmware processing. |
| Internal synchronized clock | Removes need for external clock generator or timing-critical routing - lowers BOM count and layout complexity. |
| VREF overdrive capability | Allows external precision reference (e.g., LT1019A-2.5) to replace internal 2.42V source - improves drift to ≤5ppm/°C. |
| Industrial temperature grade | Specified from –40°C to +85°C - qualified for deployment in embedded industrial controllers and field instruments. |
Applications
| Portable Battery-Powered DAQ | Motor Phase Current Monitoring |
|---|---|
Use Scenario: Handheld vibration analyzer acquiring acceleration waveforms from piezoelectric sensors in rotating equipment maintenance. IC Role / Device Role / Timing Role: Primary ADC capturing differential sensor outputs at 100ksps with Nap-mode power gating between bursts. Use Value: 180µA Nap current extends battery life; 2.42V reference enables direct mV-to-code mapping; differential input suppresses EMI from nearby drives. |
Use Scenario: Real-time monitoring of three-phase motor currents using shunt resistors and isolated amplifiers in variable-frequency drives. IC Role / Device Role / Timing Role: Bipolar-mode ADC digitizing ±200mV shunt voltage drops with offset-binary output for signed current calculation. Use Value: ±2.048V input range accommodates amplifier gain settings; 72dB S/(N+D) ensures accurate RMS current estimation below 1% error. |
| DSP-Based Audio Front-End | Multi-Channel Spectrum Analyzer |
Use Scenario: Low-power audio codec board sampling microphone preamp outputs for FFT-based acoustic event detection. IC Role / Device Role / Timing Role: Unipolar ADC feeding 12-bit samples to TI C55xx DSP via 8-bit data bus with HBEN-controlled byte sequencing. Use Value: VLOGIC pin allows direct 3.3V DSP interface; internal clock eliminates jitter-sensitive external oscillator; 1µA Sleep mode enables ultra-low standby. |
Use Scenario: 16-channel RF spectrum monitor capturing IF signals from downconverters for interference mapping in cellular base stations. IC Role / Device Role / Timing Role: High-linearity ADC digitizing 0–4.096V IF envelopes with 350kHz full-linear bandwidth to preserve modulation fidelity. Use Value: 82dB THD at 100kHz prevents harmonic aliasing into analysis band; 24-pin SOIC-W enables dense channel packing on PCB. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit, 100ksps ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | SPI interface, 2.7V–5.25V supply, no internal reference, 1µA shutdown, 200ksps max | Requires external reference and serial interface logic; higher speed but lower noise floor (70dB S/(N+D)) | Choose for space-constrained designs needing serial interface and higher throughput; avoid if parallel bus or internal reference required. |
| MAX1166BCAP+ | 16-pin QSOP, internal reference, 50ksps max, 2.5V–5.5V supply, 1µA shutdown | Lower sampling rate limits dynamic signal capture; smaller package reduces thermal mass but increases layout sensitivity | Choose for cost-sensitive, lower-bandwidth applications where 50ksps suffices and board area is premium; verify thermal derating in sealed enclosures. |
Compared with LTC1277ISW#TRPBF, ADS7822U offers faster sampling and serial simplicity but sacrifices integrated reference and differential input; MAX1166BCAP+ provides comparable integration in smaller footprint but trades 50% speed for reduced power density and bandwidth.
Availability
LTC1277ISW#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, motor control feedback loops, and DSP-based audio acquisition requiring stable component supply across industrial temperature grades and long-term production continuity.
Supply support for LTC1277ISW#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.
The LTC1277ISW#TRPBF belongs to ADI's legacy Linear Technology precision data converter family, designed specifically for low-power, high-accuracy measurement systems where differential input, internal reference, and flexible power management are essential.
FAQ
What is the operating temperature range for the LTC1277ISW#TRPBF?
The LTC1277ISW#TRPBF is specified for industrial operation from –40°C to +85°C. This rating applies to all key parameters including integral linearity (±1 LSB), S/(N+D) (72.5dB typ), and supply current (2mA typ at 100ksps). Thermal resistance is θJA = 130°C/W in the 24-lead SOIC-W package, with maximum junction temperature limited to 110°C.
How does the LTC1277ISW#TRPBF handle bipolar versus unipolar input modes?
The LTC1277ISW#TRPBF uses offset-binary encoding in bipolar mode (–2.048V = 0x0000, +2.048V = 0xFFFF) and straight binary in unipolar mode (0V = 0x0000, +4.096V = 0xFFF). Mode selection is determined by supply configuration: unipolar requires VSS tied to AGND; bipolar requires VSS = –5V. Input range and encoding are fixed per supply setup - no software register configures this behavior.
Can the internal reference of the LTC1277ISW#TRPBF be overdriven, and what are the limits?
Yes, the LTC1277ISW#TRPBF's VREF pin (Pin 3) accepts external reference voltages ≥2.45V to override the internal 2.42V source. Overdrive up to 5V is permitted in bipolar mode, enabling ±4.23V input spans. The pin sinks up to 1mA and must be decoupled with 10µF tantalum + 0.1µF ceramic. Driving below 2.45V risks conflict with internal reference and undefined behavior.
What is the purpose of the HBEN pin on the LTC1277ISW#TRPBF, and how is it used?
The HBEN (High Byte Enable) pin on the LTC1277ISW#TRPBF controls whether pins D0/8–D3/11 output the 12-bit result's most significant byte (D8–D11) or least significant byte (D0–D3). When HBEN is high, D0/8–D3/11 carry D8–D11; when low, they carry D0–D3. This enables clean 8-bit µP interfacing without multiplexing or external latches, and is synchronized to RD timing per Table 1 in the datasheet.
Does the LTC1277ISW#TRPBF require an external clock, or is timing internally generated?
The LTC1277ISW#TRPBF contains a fully integrated, factory-trimmed synchronized clock circuit - no external clock source is required. This clock drives the successive approximation register, sample-and-hold, and internal logic. Timing parameters such as tCONV (6–8µs) and tACQ (0.35–2µs) are guaranteed over temperature and supply voltage, eliminating clock jitter concerns and reducing system-level timing validation effort.
LTC1277ISW#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 100k
- Number of Inputs:
- 1
- Input Type:
- Differential, Single Ended
- Data Interface:
- Parallel
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 5V, -2.45V ~ 5.25
- Voltage - Supply, Digital:
- 2.7V ~ 5.25V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 24-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
LTC1277ISW#TRPBF FAQ
1.How can I place an order for LTC1277ISW#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1277ISW#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 LTC1277ISW#TRPBF reliable?
The price and inventory of LTC1277ISW#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1277ISW#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1277ISW#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1277ISW#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1277ISW#TRPBF?
LTC1277ISW#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1277ISW#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 LTC1277ISW#TRPBF?
For technical support, including LTC1277ISW#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1277ISW#TRPBF requirements.
6.How does Aetrix verify that LTC1277ISW#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1277ISW#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 LTC1277ISW#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1277ISW#TRPBF?
All LTC1277ISW#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1277ISW#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 LTC1277ISW#TRPBF part is unused and in its original packaging.
Return procedure for LTC1277ISW#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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