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Analog Devices Inc. LTC1277ISW#PBF
- Part No.:
- LTC1277ISW#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LTC1277ISW#PBF.pdf
- Description:
- IC ADC 12BIT SAR 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,016
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Product details
Overview
LTC1277ISW#PBF from Analog Devices (formerly Linear Technology) is a 12-bit, 100ksps successive-approximation ADC with differential analog input, 2-byte parallel read interface, and dual power-down modes (180µA Nap, 1µA Sleep). It operates from single 5V or ±5V supplies, features an internal 2.42V reference, synchronized clock, and supports unipolar (0V–4.096V) or bipolar (±2.048V) input ranges - used in high-speed data acquisition systems requiring low-power precision sampling.
For engineers reviewing the LTC1277ISW#PBF datasheet, LTC1277ISW#PBF pinout, LTC1277ISW#PBF application, or LTC1277ISW#PBF equivalent, key selection considerations include its 24-pin SO wide package, differential input architecture, offset-binary bipolar output format, REFRDY wake-up signaling, and VLOGIC-compatible 3V/5V digital interface for mixed-voltage microprocessor interfacing.
Technical Context
The LTC1277ISW#PBF implements a capacitive DAC-based successive approximation register (SAR) architecture with integrated sample-and-hold, delivering 8µs conversion time and 0.35µs acquisition time. Its internal 2.42V bandgap reference is factory-trimmed and overdrivable, supporting external reference injection for span adjustment.
Digital control uses active-low CONVST to initiate conversion, CS/RD for bus management, HBEN for high-byte enable, and NAP/SLEEP for hierarchical power management. Output data is delivered in two 8-bit bytes (D7–D4 + D3/11–D0/8), formatted as straight binary (unipolar) or offset binary (bipolar), with BUSY indicating conversion status and REFRDY confirming reference stabilization after Sleep wake-up.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit with no missing codes - guarantees monotonic transfer function and full-scale linearity for precision measurement. |
| Sampling Rate | 100ksps maximum - enables real-time capture of signals up to 350kHz full-linear bandwidth (S/(N+D) ≥ 68dB). |
| Power Dissipation | 10mW at 100ksps - supports battery-powered portable instrumentation without thermal derating. |
| Input Range | 0V to 4.096V (unipolar) or ±2.048V (bipolar) - provides 1mV/LSB quantization step for direct mV-level signal digitization. |
| Dynamic Performance | 72.5dB S/(N+D) and –82dB THD at 100kHz input - meets requirements for audio-band and telecom spectral analysis. |
| Wake-Up Latency | 620ns from Nap mode, 3.3–4.2ms from Sleep mode - enables rapid duty-cycled operation in burst-sampling applications. |
| Reference Output | 2.42V ±20mV, ±10ppm/°C tempco - stable internal reference eliminates need for external precision voltage source in most designs. |
Pinout & Package
Package: 24-lead plastic SO wide (SW), 0.300" body width, JEDEC MS-013AC compliant, θJA = 130°C/W, TJMAX = 110°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN+ | Differential analog input (+) | Primary analog signal path; must settle fully during 0.35–2µs acquisition window before conversion start. |
| AIN– | Differential analog input (–) | Reference node for differential measurement; requires low-noise, low-impedance drive during conversion phase. |
| VREF | 2.42V reference output | Internally trimmed bandgap reference; bypassed with 10µF tantalum + 0.1µF ceramic; overdrivable for span calibration. |
| REFRDY | Reference ready indicator | Open-drain output goes high when internal reference stabilizes post-Sleep - required before initiating first conversion. |
| NAP | Nap mode control input | Active-low entry into 180µA low-power state with instant (620ns) wake-up - ideal for microsecond-scale idle periods. |
| SLEEP | Sleep mode control input | Active-low entry into 1µA ultra-low-power state; REFRDY goes low and requires 3.3–4.2ms recovery before sampling. |
| HBEN | High-byte enable | When high, pins D3/11–D0/8 output MSBs (DB11–DB8); enables byte-wise read for 8-bit bus interfaces. |
| VLOGIC | Digital I/O supply | Accepts 2.7V–5.25V to set logic swing - allows direct interfacing with 3V or 5V microcontrollers without level shifters. |
| CONVST | Conversion start trigger | Falling-edge initiated; must be asserted with CS low; initiates SAR cycle and sample-to-hold transition. |
| BUSY | Conversion status flag | Active-low open-drain output; goes low at CONVST edge and rises when 12-bit result is latched and ready. |
Key Features
| Feature | Design Value |
|---|---|
| Differential input architecture | Rejects common-mode noise on AIN+/AIN– pair - improves SNR in noisy industrial or motor-control environments. |
| Two-stage power management | 180µA Nap mode (instant wake-up) + 1µA Sleep mode (reference re-stabilization) - enables adaptive power scaling across varying activity windows. |
| Offset-binary bipolar output | Eliminates sign-extension logic in DSP firmware - simplifies arithmetic for signed signal processing in spectrum analyzers and digital oscilloscopes. |
| VLOGIC-compatible I/O | Independent 2.7V–5.25V digital supply - permits seamless integration with modern 3V SoCs or legacy 5V controllers without external level translation. |
| Internal synchronized clock | Removes need for external crystal or clock generator - reduces BOM count and layout complexity in space-constrained portable systems. |
Applications
| Battery-Powered Portable Systems | High-Speed Data Acquisition for PCs |
|---|---|
Use Scenario: Handheld multimeters and portable oscilloscopes operating from coin-cell or Li-ion batteries with strict 10mW average power budget. IC Role / Device Role / Timing Role: Primary 12-bit sampling front-end converting sensor or probe signals at 100ksps with Nap/Sleep cycling between measurements. Use Value: 1µA Sleep current extends battery life by >10× versus continuous operation; differential input rejects EMI from switching power supplies. | Use Scenario: USB-connected DAQ modules adding real-time waveform capture to desktop PCs for lab testing and education. IC Role / Device Role / Timing Role: High-fidelity analog digitizer interfaced via parallel bus to FPGA or microcontroller, synchronized to host-triggered acquisition bursts. Use Value: 72.5dB S/(N+D) at 100kHz ensures clean FFT analysis of audio and RF signals; 24-pin SO package enables compact PCB design. |
| Digital Signal Processing Front-End | Multiplexed Data Acquisition Systems |
Use Scenario: Embedded DSP boards performing real-time filtering, spectral analysis, or modulation/demodulation on analog sensor streams. IC Role / Device Role / Timing Role: Precision ADC feeding fixed-point or floating-point processor; offset-binary output aligns directly with DSP arithmetic units. Use Value: Straight-binary (unipolar) and offset-binary (bipolar) formats eliminate software sign-conversion overhead; 350kHz full-linear bandwidth supports undersampling. | Use Scenario: Industrial PLC analog input modules scanning multiple RTD, thermocouple, or current-loop channels via multiplexer. IC Role / Device Role / Timing Role: Shared ADC core serving 8–16 channels through analog MUX; Nap mode minimizes power between channel switches. Use Value: 620ns Nap wake-up latency enables sub-microsecond channel switching; internal reference ensures consistent gain across all channels. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7822U | 8-bit, 200ksps, SPI interface, no internal reference - requires external REF and level-shifting for 3V logic. | Lower resolution and serial interface limit use in precision 12-bit parallel-bus systems. | Select only if 8-bit resolution suffices and board space constraints favor SPI over parallel bus. |
| MAX1166BCPP+ | 12-bit, 100ksps, internal reference, but single-ended input and no Nap mode - Sleep current is 2µA vs 1µA. | Lacks differential input and fast Nap wake-up, reducing noise immunity and dynamic power efficiency. | Prefer LTC1277ISW#PBF where common-mode rejection or microsecond-scale duty cycling is required. |
Compared with ADS7822U and MAX1166BCPP+, the LTC1277ISW#PBF uniquely combines differential input, 1µA Sleep current, 620ns Nap wake-up, and VLOGIC flexibility - making it optimal for portable, noise-sensitive, and dynamically powered 12-bit acquisition systems.
Availability
LTC1277ISW#PBF is available at Aetrix Electronics and suitable for battery-powered portable systems, high-speed PC-based data acquisition, digital signal processing front-ends, and multiplexed industrial data loggers requiring stable component supply across extended temperature ranges (–40°C to +85°C).
Supply support for LTC1277ISW#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, serving industrial, automotive, communications, and healthcare markets.
The LTC1277ISW#PBF belongs to ADI's legacy Linear Technology precision data converter product line, designed specifically for low-power, high-speed 12-bit sampling in portable instrumentation, test equipment, and embedded control systems.
FAQ
What is the operating temperature range for the LTC1277ISW#PBF?
The LTC1277ISW#PBF is rated for industrial operation from –40°C to +85°C. This extended range ensures reliable performance in harsh environments such as factory automation, outdoor instrumentation, and automotive under-hood monitoring systems where thermal stability is critical. The device's internal reference tempco of ±10ppm/°C supports consistent accuracy across this full range.
How does the LTC1277ISW#PBF handle bipolar input signals?
The LTC1277ISW#PBF supports bipolar operation with ±2.048V input range when powered from ±5V supplies. In this mode, it outputs data in offset-binary format - where 0000 0000 0000 = –2.048V and 1111 1111 1111 = +2.047V - eliminating sign-extension logic in downstream processors. The AIN+ and AIN– inputs maintain true differential behavior, rejecting common-mode noise while preserving signal integrity.
Can the internal reference of the LTC1277ISW#PBF be overdriven?
Yes, the LTC1277ISW#PBF's VREF pin (Pin 3) can be overdriven with an external reference voltage ≥2.45V. This allows precise input span calibration - e.g., driving VREF to 2.95V yields a 0V–5V unipolar range, or to 5.0V yields ±4.23V bipolar range. The internal 2.42V reference is disabled when an external source exceeds its threshold, and the part maintains ±10ppm/°C tempco when driven by a stable external reference.
What is the purpose of the HBEN pin on the LTC1277ISW#PBF?
The HBEN (High Byte Enable) pin on the LTC1277ISW#PBF controls output multiplexing of the 12-bit result across two 8-bit data buses. When HBEN is high, pins D3/11–D0/8 deliver the four most significant bits (DB11–DB8); when low, they deliver the four least significant bits (DB3–DB0). This enables efficient interfacing with 8-bit microcontrollers or FPGAs using time-multiplexed byte reads instead of requiring a full 12-bit bus.
Does the LTC1277ISW#PBF require external clock circuitry?
No, the LTC1277ISW#PBF includes an internally synchronized clock that eliminates the need for external crystals, oscillators, or clock generators. This integrated timing resource drives the SAR conversion sequence and sample-and-hold control, reducing system component count, PCB area, and potential clock jitter sources - particularly beneficial in compact portable and battery-operated designs where layout simplicity and power efficiency are paramount.
LTC1277ISW#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LTC1277ISW#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1277ISW#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 LTC1277ISW#PBF reliable?
The price and inventory of LTC1277ISW#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1277ISW#PBF is usually 5 days.
3.What payment methods are accepted for LTC1277ISW#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1277ISW#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1277ISW#PBF?
LTC1277ISW#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1277ISW#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 LTC1277ISW#PBF?
For technical support, including LTC1277ISW#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1277ISW#PBF requirements.
6.How does Aetrix verify that LTC1277ISW#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1277ISW#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 LTC1277ISW#PBF meets industry standards.
7.What is the process for return or replacement of LTC1277ISW#PBF?
All LTC1277ISW#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1277ISW#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 LTC1277ISW#PBF part is unused and in its original packaging.
Return procedure for LTC1277ISW#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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