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Analog Devices Inc. LTC1540IDD#PBF
- Part No.:
- LTC1540IDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Comparators
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC1540IDD#PBF.pdf
- Description:
- IC COMPARATOR 1 W/VOLT REF 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,127
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Product details
Overview
LTC1540IDD#PBF from Analog Devices (formerly Linear Technology) is an ultralow-power nanopower comparator with integrated 1.182V ±2% voltage reference, designed for battery-critical monitoring in single-supply systems. It delivers 0.68µA typical supply current at –40°C to +85°C, supports 2V–11V supply range, features TTL/CMOS-compatible output capable of 40mA continuous sourcing, and enables programmable hysteresis via the HYST pin - used in low-battery detection, threshold sensing, and oscillator circuits.
For engineers reviewing the LTC1540IDD#PBF datasheet, LTC1540IDD#PBF pinout, LTC1540IDD#PBF application, or LTC1540IDD#PBF equivalent, key selection criteria include guaranteed sub-1µA quiescent current over industrial temperature, reference load regulation ≤3.5mV (source), input common-mode range extending to V–, propagation delay of 60µs at 10mV overdrive, and DFN package compatibility with space-constrained portable designs.
Technical Context
The LTC1540IDD#PBF integrates a rail-to-rail input comparator stage with a precision bandgap reference and dedicated hysteresis control circuitry. Its input stage operates from V– to V+ – 1.3V, with ±15mV max input offset voltage (I-grade), while the reference output drives up to 0.01µF capacitance without oscillation and sustains ±10µA sink / 1mA source capability.
The output stage uses crowbar-free CMOS logic to eliminate supply glitches during transitions, enabling stable operation in noise-sensitive applications. Hysteresis is implemented externally using two resistors between REF and HYST pins, supporting adjustable voltage bands up to 100mV with ±15% tolerance - independent of supply voltage and temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Current (ICC) | 0.68µA typ at –40°C to +85°C - enables multi-year battery life in coin-cell-powered devices |
| Reference Voltage (VREF) | 1.182V ±2% over temperature - provides stable trip point for precision threshold detection |
| Input Offset Voltage (VOS) | ±15mV max (I-grade) - ensures reliable decision margin in low-overdrive signal conditions |
| Propagation Delay (tPD) | 60µs at 10mV overdrive - balances speed and ultra-low power for nanopower timing functions |
| Output Drive Capability | 40mA continuous source / 5mA sink - directly interfaces with LEDs, MOSFET gates, or logic inputs without buffering |
| Input Common-Mode Range | V– to V+ – 1.3V - supports ground-referenced sensing and wide dynamic range in single-supply systems |
| Hysteresis Control Range | 0–100mV programmable band - prevents chatter near threshold without external op-amps or comparators |
Pinout & Package
Package: 8-lead (3mm × 3mm × 0.8mm) plastic DFN with underside metal pad connected to V–; RoHS-compliant, lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference for comparator output stage | Connect to V– for single-supply operation; decouples output switching noise from reference and input stages |
| V– (Pin 2) | Negative supply terminal | Accepts voltages more negative than GND; sets reference and input common-mode baseline |
| IN+ (Pin 3) | Noninverting comparator input | Supports input down to V– with ±10pA leakage - ideal for high-impedance sensor interfaces |
| IN– (Pin 4) | Inverting comparator input | Matches IN+ performance; used with resistor dividers for precise threshold setting |
| HYST (Pin 5) | Hysteresis control input | Accepts voltage from REF – 50mV to REF; enables user-defined hysteresis via external resistors |
| REF (Pin 6) | 1.182V reference output | Sources up to 1mA; drives 0.01µF bypass cap stably - eliminates need for external reference IC |
| V+ (Pin 7) | Positive supply input | Operates from 2V to 11V; requires 0.1µF bypass if output sourcing >1mA or supply impedance is high |
| OUT (Pin 8) | CMOS-compatible comparator output | Swings rail-to-rail (GND to V+); no crowbar current - avoids supply rail disturbance during transitions |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow quiescent current | 0.68µA typ over –40°C to +85°C - extends battery life in always-on monitoring nodes |
| Integrated reference with capacitor drive | Stable 1.182V ±2% output driving up to 0.01µF - removes external reference and bypass components |
| Programmable hysteresis | 0–100mV band set by two external resistors - eliminates need for secondary comparator or feedback network |
| Rail-to-rail input range | V– to V+ – 1.3V - enables direct sensing of signals referenced to ground or negative rails |
| Crowbar-free output stage | No cross-conducting current during logic transitions - prevents supply glitches that corrupt adjacent analog circuitry |
Applications
| Battery Voltage Monitoring | Threshold Detection in Portable Sensors |
|---|---|
Use Scenario: Detecting end-of-life voltage in 2-cell NiCd batteries (1.6V–2.5V range) for automatic shutdown in handheld medical devices. IC Role / Device Role / Timing Role: Comparator compares scaled battery voltage against internal 1.182V reference; hysteresis prevents false triggers during load transients. Use Value: Draws only 1.4µA at 2V supply - preserves battery capacity while ensuring reliable low-voltage warning before system failure. |
Use Scenario: Triggering data logging when temperature sensor output crosses 2.9V threshold in wireless environmental monitors. IC Role / Device Role / Timing Role: LTC1540IDD#PBF acts as a nanopower level detector; REF pin supplies reference to resistive divider on IN+. Use Value: Eliminates need for external reference and biasing circuitry - reduces BOM count and PCB area in compact IoT endpoints. |
| Oscillator Circuits | Auto Power-Off Switching |
Use Scenario: Building relaxation oscillator for LED blink timing in emergency beacons powered by CR2032 cells. IC Role / Device Role / Timing Role: Comparator configured with RC feedback and hysteresis generates precise square wave; REF stabilizes timing node. Use Value: Achieves 60µs propagation delay with <0.7µA supply current - enables predictable frequency stability across temperature and battery discharge. |
Use Scenario: Enabling timed power delivery to peripheral modules (e.g., GPS receiver) in asset trackers to minimize idle current. IC Role / Device Role / Timing Role: LTC1540IDD#PBF controls MOSFET gate via OUT; RC network on IN+ sets auto-shutdown timeout (~4.6RC). Use Value: Total circuit quiescent current = 0.8µA - extends operational window between wake cycles without compromising responsiveness. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nanopower comparator with reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1440CS8#PBF | 1.182V ±1% reference; no programmable hysteresis; 0.3µA supply current (C-grade only) | Fixed hysteresis limits noise immunity in noisy environments; not rated for industrial temperature range | Select when tighter reference accuracy is prioritized over hysteresis flexibility and extended temperature operation |
| MAX921ESA+ | 1.235V reference; 1.5µA supply current; open-drain output; no internal hysteresis | Requires external pull-up and hysteresis network; higher current draw reduces battery lifetime in long-duration deployments | Choose only if legacy MAX921 footprint compatibility is mandatory and reference voltage tolerance >1.2V is acceptable |
Compared with LTC1440CS8#PBF and MAX921ESA+, the LTC1540IDD#PBF uniquely combines industrial-temperature-rated programmable hysteresis, sub-1µA quiescent current, and integrated reference drive capability - making it optimal for next-generation ultra-low-power sensing and battery management where design margin and component count are critical.
Availability
LTC1540IDD#PBF is available at Aetrix Electronics and suitable for battery-powered system monitoring, threshold detectors, and oscillator circuits requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for LTC1540IDD#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 semiconductors for precision instrumentation, power management, and signal conditioning.
The LTC1540 belongs to Linear's nanopower analog product line, engineered specifically for energy-constrained applications including portable medical devices, remote sensors, and battery-backed security systems where µA-level supply current and integrated functionality are essential.
FAQ
What is the operating temperature range for the LTC1540IDD#PBF?
The LTC1540IDD#PBF is specified for industrial temperature operation from –40°C to +85°C. This rating is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics section of the official datasheet, where all I-grade parameters (including supply current, reference voltage, and input offset) are guaranteed across this full range. The "I" suffix in the part number explicitly denotes this industrial grade.
Does the LTC1540IDD#PBF require external components to use its internal reference?
No, the LTC1540IDD#PBF reference output (Pin 6) can drive up to 0.01µF bypass capacitance without oscillation, eliminating the need for external compensation. However, for larger capacitors (up to 10µF), a series damping resistor is required per Figure 1 in the datasheet. The reference is fully functional with no external parts for basic threshold detection using the built-in 1.182V ±2% reference.
Can the LTC1540IDD#PBF operate from a 1.8V supply?
The LTC1540IDD#PBF is not guaranteed to operate below 2V supply. While functional behavior may occur down to ~1.6V (as noted in Figure 4 and Low Voltage Operation section), parameters including VREF, VOS, propagation delay, and output drive degrade significantly. The datasheet specifies 2V as the minimum guaranteed operating voltage; operation below this violates absolute maximum ratings and is not recommended for production designs.
How is hysteresis programmed on the LTC1540IDD#PBF?
Hysteresis is programmed by connecting two external resistors: one between REF (Pin 6) and HYST (Pin 5), and another between HYST and V– (Pin 2). The resulting hysteresis voltage band equals twice the voltage difference between REF and HYST, with a maximum of 100mV. The datasheet provides design equations and example values (e.g., R2 = 2.4MΩ, R1 = 15kΩ for 15mV band) in the Applications Information section.
Is the LTC1540IDD#PBF pin-compatible with other comparators?
Yes, the LTC1540IDD#PBF is explicitly stated as pin-compatible with LTC1440, MAX921, and MAX931 in the Features section of the datasheet. This applies to the DFN (DD), SO (S8), and MSOP (MS8) packages. Pin mapping matches functionally: GND, V–, IN+, IN–, HYST, REF, V+, OUT align identically across these parts, enabling drop-in replacement where hysteresis and temperature requirements align.
LTC1540IDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Package/Case:
- 8-WFDFN Exposed Pad
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- with Voltage Reference
- Number of Elements:
- 1
- Output Type:
- CMOS, TTL
- Voltage - Supply, Single/Dual (±):
- 2V ~ 11V, ±1V ~ 5.5V
- :
- 12mV @ 5V
- Voltage - Input Offset (Max):
- -
- Current - Input Bias (Max):
- -
- Current - Output (Typ):
- 710nA
- Current - Quiescent (Max):
- 80dB CMRR, 80dB PSRR
- CMRR, PSRR (Typ):
- 60µs
- Propagation Delay (Max):
- 50mV
- Hysteresis:
- -40°C ~ 85°C
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- Surface Mount
- :
- 8-DFN (3x3)
LTC1540IDD#PBF FAQ
1.How can I place an order for LTC1540IDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1540IDD#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 LTC1540IDD#PBF reliable?
The price and inventory of LTC1540IDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1540IDD#PBF is usually 5 days.
3.What payment methods are accepted for LTC1540IDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1540IDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1540IDD#PBF?
LTC1540IDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1540IDD#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 LTC1540IDD#PBF?
For technical support, including LTC1540IDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1540IDD#PBF requirements.
6.How does Aetrix verify that LTC1540IDD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1540IDD#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 LTC1540IDD#PBF meets industry standards.
7.What is the process for return or replacement of LTC1540IDD#PBF?
All LTC1540IDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1540IDD#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 LTC1540IDD#PBF part is unused and in its original packaging.
Return procedure for LTC1540IDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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