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Analog Devices Inc. LT1721IGN#TRPBF
- Part No.:
- LT1721IGN#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Comparators
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LT1721IGN#TRPBF.pdf
- Description:
- IC COMPARATOR 4 GEN PUR 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,992
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Product details
Overview
LT1721IGN#TRPBF from Analog Devices (formerly Linear Technology) is a quad, ultrafast comparator optimized for single-supply 3V/5V operation with rail-to-rail outputs, 4.5ns propagation delay at 20mV overdrive, 4mA per comparator supply current, and input voltage range extending 100mV below ground to 1.2V below VCC. It is used in high-speed sampling circuits, window comparators, and crystal oscillator interfaces where low power and precise threshold detection are critical.
For engineers reviewing the LT1721IGN#TRPBF datasheet, LT1721IGN#TRPBF pinout, LT1721IGN#TRPBF application, or LT1721IGN#TRPBF equivalent, key selection considerations include guaranteed 4.5ns propagation delay at 20mV overdrive, internal 3.5mV hysteresis, rail-to-rail TTL/CMOS-compatible outputs, –40°C to +85°C industrial temperature grade, and 16-pin narrow SSOP package with dual ground and dual VCC pins.
Technical Context
The LT1721IGN#TRPBF implements four fully independent high-speed comparators using complementary bipolar process technology. Each channel features a differential PNP input stage, gain/hysteresis stage, and symmetric rail-to-rail output driver capable of sourcing/sinking ≥4mA while maintaining sub-5ns delay.
Its pinout places inverting inputs away from outputs and shields them with adjacent power and ground rails to minimize parasitic coupling. Dual VCC (pins 11 & 14) and dual GND (pins 3 & 6) are electrically shorted internally but must be externally tied together to function as high-frequency shields between input and output traces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Propagation Delay | 4.5ns typical at 20mV overdrive - enables reliable 220MHz+ toggle rate in high-speed digital sampling. |
| Supply Voltage Range | 2.7V to 6V - supports direct interface with 3V and 5V logic families without level translation. |
| Input Common Mode Range | –0.1V to VCC – 1.2V - allows detection of signals near ground or rail in single-supply systems. |
| Output Drive | Rail-to-rail, TTL/CMOS compatible - directly drives 74HC/LVC logic with VOH ≥ VCC – 0.4V and VOL ≤ 0.4V at load. |
| Internal Hysteresis | 3.5mV typical - prevents oscillation on slow-moving or noisy inputs without external components. |
| Quiescent Current | 4mA per comparator at 5V - enables low-power operation in battery-sensitive or thermally constrained designs. |
| Differential Propagation Delay | ≤1.0ns max between channels - ensures tight timing alignment across all four comparators in multi-channel systems. |
Pinout & Package
LT1721IGN#TRPBF is housed in a 16-lead narrow plastic SSOP (GN package), 5.3mm × 6.2mm × 1.75mm, with exposed pad not connected. Pin 1 is top-left corner, marked by notch or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (–IN A) | Inverting input of Comparator A | Most sensitive node; placed away from outputs and shielded by adjacent GND (pin 3) and VCC (pin 11) for minimal coupling. |
| 2 (+IN A) | Noninverting input of Comparator A | Paired with pin 1; differential pair forms high-gain, low-offset front end with PNP topology. |
| 3, 6 (GND) | Ground reference for all comparators | Dual pins required for low-inductance return path; must be externally shorted to support shielding function. |
| 4 (OUT A) | Output of Comparator A | Rail-to-rail CMOS/TTL-compatible output; capable of 4mA source/sink with <2.5ns rise/fall times. |
| 5 (OUT B) | Output of Comparator B | Electrically isolated from OUT A; shares no internal nodes - critical for noise-immune multi-channel timing. |
| 7 (+IN B) | Noninverting input of Comparator B | Positioned opposite OUT A/OUT B to minimize crosstalk; referenced to same GND/VCC network. |
| 8 (–IN B) | Inverting input of Comparator B | Complements pin 7; completes second independent comparator with identical specs to Channel A. |
| 9 (–IN C) | Inverting input of Comparator C | Third channel input; layout symmetry ensures matched delay and offset vs Channels A/B/D. |
| 10 (+IN C) | Noninverting input of Comparator C | Paired with pin 9; enables simultaneous threshold monitoring across three independent signal paths. |
| 11, 14 (VCC) | Positive supply for all comparators | Dual pins provide low-impedance power delivery; must be externally shorted and bypassed with 10nF + 2.2μF. |
| 12 (OUT C) | Output of Comparator C | Supports four-channel parallel decision logic; timing skew vs other outputs ≤1.5ns (tSKEW). |
| 13 (OUT D) | Output of Comparator D | Final channel output; enables full quad-window or multi-level detection without external fanout. |
| 15 (+IN D) | Noninverting input of Comparator D | Completes fourth independent comparator; pin 16 provides matching inverting input. |
| 16 (–IN D) | Inverting input of Comparator D | Enables true four-channel differential comparison with no shared bias or signal path. |
Key Features
| Feature | Design Value |
|---|---|
| UltraFast 4.5ns propagation delay | Enables real-time response to fast edges in sampling, pulse stretching, and zero-crossing detection. |
| Internal 3.5mV hysteresis | Eliminates need for external positive feedback resistors in most threshold-detection applications. |
| Rail-to-rail TTL/CMOS outputs | Direct interface to 74LVC, 74AHC, and microcontroller GPIO without level-shifting circuitry. |
| –40°C to +85°C operating range | Qualified for industrial environments including motor control, test equipment, and factory automation. |
| Dual VCC and dual GND pins | Provides dedicated low-inductance power/ground paths that double as EMI shields between inputs and outputs. |
Applications
| High-Speed Sampling Circuits | Crystal Oscillator Circuits |
|---|---|
Use Scenario: Digitizing analog waveforms at >100MSPS using flash ADC front-end with parallel comparator bank. IC Role / Device Role / Timing Role: Quad comparator acts as 4-bit flash ADC core, comparing input against 4 reference thresholds simultaneously. Use Value: 4.5ns propagation delay ensures <5ns aperture uncertainty across all channels, preserving signal integrity up to Nyquist frequency. | Use Scenario: Converting AT-cut crystal oscillator sine output into clean square wave for clock distribution. IC Role / Device Role / Timing Role: Comparator converts low-amplitude crystal signal into rail-to-rail logic-level clock with minimal jitter. Use Value: 15psRMS timing jitter and 2.2ns fall time maintain sub-10ps edge uncertainty for low-jitter clock trees. |
| Window Comparators | Threshold Detectors/Discriminators |
Use Scenario: Monitoring sensor output (e.g., temperature, pressure) to detect out-of-range conditions within defined upper/lower bounds. IC Role / Device Role / Timing Role: Two comparators form upper/lower thresholds; third and fourth enable latched alarm or hysteresis extension. Use Value: Matched propagation delay (<1ns skew) ensures simultaneous evaluation of both limits, eliminating false triggers during ramp transitions. | Use Scenario: Detecting presence of valid data pulses in serial communication lines or sensor event streams. IC Role / Device Role / Timing Role: Single comparator channel compares incoming signal against programmable reference voltage. Use Value: 100mV below ground input range allows detection of negative-going pulses without level-shifting circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX961ESA+ | 4.8ns propagation delay, 5.5mA supply current, single 5V supply only (not 2.7–6V), no internal hysteresis. | Requires external hysteresis resistor network; less suitable for low-voltage or battery-powered systems. | Choose MAX961ESA+ only if 5V-only operation and external hysteresis design are acceptable. |
| ADCMP572BCPZ-REEL7 | 2.5ns propagation delay, 12mA supply current, ECL/PECL outputs only, requires negative supply for full functionality. | Not pin-compatible; needs level translation for TTL/CMOS loads; higher power and board area. | Choose ADCMP572BCPZ-REEL7 only when sub-3ns delay and ECL interfacing are mandatory. |
Compared with MAX961ESA+ and ADCMP572BCPZ-REEL7, LT1721IGN#TRPBF delivers optimal balance of speed (4.5ns), low power (4mA), single-supply flexibility (2.7–6V), and integrated hysteresis - making it uniquely suited for space-constrained industrial and test equipment where reliability and design simplicity are prioritized.
Availability
LT1721IGN#TRPBF is available at Aetrix Electronics and suitable for high-speed sampling circuits, crystal oscillator interfaces, window comparators, and threshold detectors requiring stable component supply across industrial temperature ranges.
Supply support for LT1721IGN#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 semiconductors, formed through acquisition of Linear Technology in 2017.
The LT1721IGN#TRPBF belongs to ADI's UltraFast™ comparator product line, designed specifically for single-supply, high-speed threshold detection in test & measurement, communications infrastructure, and precision instrumentation.
FAQ
What is the maximum operating temperature range for LT1721IGN#TRPBF?
The LT1721IGN#TRPBF is rated for –40°C to +85°C operation (industrial I-grade). This is confirmed in the Order Information table and Absolute Maximum Ratings section of the official datasheet. The GN package has θJA = 135°C/W, and junction temperature must not exceed 125°C under continuous operation. Thermal derating is required above 85°C ambient.
Does LT1721IGN#TRPBF require external hysteresis for stable operation?
No, LT1721IGN#TRPBF includes internal hysteresis of 2.0mV minimum, 3.5mV typical, and 7.0mV maximum. This eliminates the need for external positive feedback in most applications involving slow-moving or noisy inputs. External hysteresis can be added via resistor networks if wider thresholds are required, as detailed in the Applications Information section.
Can LT1721IGN#TRPBF operate from a 3V supply?
Yes, LT1721IGN#TRPBF is fully specified for 2.7V to 6V single-supply operation. At 3V, it delivers 70MHz maximum toggle frequency, 4.5ns propagation delay (with appropriate overdrive), and rail-to-rail output swing from 0V to 3V. Input common mode extends from –0.1V to 1.8V, supporting ground-referenced signal detection.
What is the purpose of the dual VCC and dual GND pins on LT1721IGN#TRPBF?
The dual VCC (pins 11 & 14) and dual GND (pins 3 & 6) on LT1721IGN#TRPBF are electrically shorted internally but must be externally connected to serve as high-frequency shields between input and output traces. This layout minimizes parasitic coupling and improves noise immunity - a key requirement for stable 4.5ns operation in dense PCB layouts.
Is LT1721IGN#TRPBF pin-compatible with other LT172x family members?
No, LT1721IGN#TRPBF (16-pin SSOP) is not pin-compatible with LT1720 variants (8-pin SO/MSOP/DFN). While functional and electrical specs overlap, the LT1721IGN#TRPBF has unique 16-pin pinout with dual VCC/GND and four independent comparator channels arranged for optimal high-speed layout - distinct from the dual-comparator LT1720 footprint.
LT1721IGN#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Series:
- UltraFast™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- General Purpose
- Number of Elements:
- 4
- Output Type:
- CMOS, Rail-to-Rail, TTL
- Voltage - Supply, Single/Dual (±):
- 2.7V ~ 6V
- :
- 3mV @ 5V
- Voltage - Input Offset (Max):
- 6µA @ 5V
- Current - Input Bias (Max):
- 20mA
- Current - Output (Typ):
- 7mA
- Current - Quiescent (Max):
- 70dB CMRR, 80dB PSRR
- CMRR, PSRR (Typ):
- 10ns
- Propagation Delay (Max):
- 7mV
- Hysteresis:
- -40°C ~ 85°C
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- Surface Mount
- :
- 16-SSOP
LT1721IGN#TRPBF FAQ
1.How can I place an order for LT1721IGN#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1721IGN#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 LT1721IGN#TRPBF reliable?
The price and inventory of LT1721IGN#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1721IGN#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1721IGN#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1721IGN#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1721IGN#TRPBF?
LT1721IGN#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1721IGN#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 LT1721IGN#TRPBF?
For technical support, including LT1721IGN#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1721IGN#TRPBF requirements.
6.How does Aetrix verify that LT1721IGN#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1721IGN#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 LT1721IGN#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1721IGN#TRPBF?
All LT1721IGN#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1721IGN#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 LT1721IGN#TRPBF part is unused and in its original packaging.
Return procedure for LT1721IGN#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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