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Analog Devices Inc. LTC1540CS8#PBF
- Part No.:
- LTC1540CS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Comparators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1540CS8#PBF.pdf
- Description:
- IC COMPARATOR 1 W/VOLT REF 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,620
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Product details
Overview
LTC1540CS8#PBF from Analog Devices (formerly Linear Technology) is an ultralow-power nanopower comparator with integrated 1.182V ±2% voltage reference, TTL/CMOS-compatible output capable of sourcing up to 40mA, and programmable hysteresis via the HYST pin. It operates from a single 2V to 11V supply, draws only 0.3µA typical quiescent current at 25°C, and supports input common-mode range from V– to V+ – 1.3V - ideal for battery-powered threshold detection in portable instrumentation.
For engineers reviewing the LTC1540CS8#PBF datasheet, LTC1540CS8#PBF pinout, LTC1540CS8#PBF application, or LTC1540CS8#PBF equivalent, key selection considerations include its guaranteed 0.68µA max supply current over 0°C to 70°C, 60µs propagation delay with 10mV overdrive, ±12mV input offset voltage (C-grade), ability to drive 0.01µF reference bypass capacitors without oscillation, and SO-8 package compatibility with LTC1440/MAX921/MAX931.
Technical Context
The LTC1540CS8#PBF integrates a precision bandgap reference (1.182V ±2% over 0°C to 70°C) and rail-to-rail input comparator in a single SO-8 package. Its input stage accepts voltages from V– to within 1.3V of V+, and its CMOS output swings fully from GND to V+ while delivering 40mA source / 5mA sink capability without crowbar current during transitions.
Hysteresis is implemented externally using two resistors between REF and HYST pins, enabling adjustable hysteresis bands up to 100mV (±50mV around REF); the HYST pin voltage range is strictly limited to REF – 50mV to REF. The reference can source up to 1mA and sink up to 10µA while maintaining stability with up to 0.01µF capacitive loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2V to 11V single supply - enables operation from coin cells (e.g., 3V CR2032) up to industrial rails. |
| Quiescent Current (ICC) | 0.3µA typ / 0.71µA max at 0°C to 70°C - ensures multi-year battery life in always-on monitoring. |
| Reference Voltage (VREF) | 1.182V ±2% (0°C to 70°C) - provides stable, factory-trimmed threshold without external components. |
| Propagation Delay (tPD) | 60µs with 10mV overdrive - balances speed and ultra-low power for slow-varying signals like battery voltage decay. |
| Input Offset Voltage (VOS) | ±12mV max (C-grade) - sets minimum detectable differential voltage across IN+ and IN–. |
| Output Drive Capability | 40mA continuous source / 5mA sink - directly drives LEDs, small relays, or logic inputs without buffer stages. |
| Input Common-Mode Range | V– to V+ – 1.3V - supports ground-referenced sensing and high-side monitoring in single-supply systems. |
Pinout & Package
Package: 8-Lead Plastic Small Outline (SO-8, narrow 0.150-inch body), RoHS-compliant lead-free finish (PBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Connect to V– for single-supply operation; serves as output stage return path. |
| V– (Pin 2) | Negative supply | Can be tied to GND (single supply) or driven negative (±1V to ±5.5V dual supply). |
| IN+ (Pin 3) | Noninverting input | Accepts signals from V– to V+ – 1.3V; input leakage < ±0.01nA ensures minimal loading on high-Z sources. |
| IN– (Pin 4) | Inverting input | Same common-mode range as IN+; used with resistor dividers for precise threshold setting. |
| HYST (Pin 5) | Hysteresis control | Voltage must stay between REF – 50mV and REF; sets hysteresis band width via external resistors. |
| REF (Pin 6) | Reference output | 1.182V ±2% referenced to V–; drives 0.01µF bypass caps stably; sources up to 1mA. |
| V+ (Pin 7) | Positive supply | Primary power input; bypass with 0.1µF capacitor if output sourcing >1mA or supply impedance is high. |
| OUT (Pin 8) | Comparator output | CMOS rail-to-rail output swinging GND to V+; no crowbar current eliminates supply glitches. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow quiescent current | 0.3µA typical at 25°C - extends battery life in remote sensors and wearables beyond 10 years. |
| Integrated precision reference | 1.182V ±2% over 0°C to 70°C - eliminates need for external reference IC or resistor divider calibration. |
| Programmable hysteresis | Up to 100mV band via two external resistors - prevents chatter near threshold in noisy environments. |
| No crowbar current | Eliminates supply rail transients during output transitions - critical for mixed-signal systems sharing analog rails. |
| Capacitor-stable reference | Drives up to 0.01µF bypass cap without oscillation - simplifies layout and improves noise immunity. |
Applications
| Battery-Powered System Monitoring | Threshold Detectors |
|---|---|
Use Scenario: Monitoring lithium coin cell voltage (2.0V–3.0V) in medical patch sensors to trigger low-battery alerts before shutdown. IC Role / Device Role / Timing Role: Nanopower comparator compares divided battery voltage against internal 1.182V reference to generate digital alert signal. Use Value: 0.3µA supply current enables >5-year operation on CR2032; built-in reference avoids drift-prone external dividers. |
Use Scenario: Detecting when a 5V system rail drops below 4.65V to initiate graceful shutdown in IoT gateways. IC Role / Device Role / Timing Role: Configured with resistor divider and 15mV hysteresis to avoid false triggers during transient dips. Use Value: 60µs propagation delay allows fast response; 40mA output directly drives enable pin of backup LDO without buffer. |
| Window Comparators | Oscillator Circuits |
Use Scenario: Validating that photodiode amplifier output stays within 1.1V–1.3V range in optical smoke detectors. IC Role / Device Role / Timing Role: Paired LTC1540CS8#PBF units (one for upper, one for lower threshold) form window detector with shared REF. Use Value: Identical reference voltage across both comparators ensures matched thresholds; SO-8 footprint simplifies dual-channel PCB layout. |
Use Scenario: Building relaxation oscillator for LED blink timing in asset trackers using RC feedback to HYST pin. IC Role / Device Role / Timing Role: Comparator toggles OUT based on capacitor charging/discharging through resistor network tied to HYST and REF. Use Value: Programmable hysteresis defines precise timing window; 0.3µA ICC minimizes oscillator's contribution to total system current. |
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 HYST pin; fixed 10mV max input offset; 0.9µA max ICC (C-grade) | Lacks programmable hysteresis - requires external hysteresis circuitry for noise immunity | Select when tighter reference accuracy (±1%) is prioritized over hysteresis flexibility and lowest possible ICC. |
| MAX921ESA+ | 1.235V reference; 1.5µA max ICC (–40°C to 85°C); open-drain output; no internal hysteresis | Requires external pull-up and hysteresis network; higher supply current limits battery life vs LTC1540CS8#PBF | Select when open-drain interface is required for wired-OR bus configurations or level translation. |
Compared with LTC1440CS8#PBF and MAX921ESA+, the LTC1540CS8#PBF offers the lowest quiescent current (0.71µA max), integrated hysteresis control, and push-pull CMOS output - making it optimal for space-constrained, ultra-low-power threshold detection where board area and battery longevity are critical.
Availability
LTC1540CS8#PBF is available at Aetrix Electronics and suitable for battery-powered system monitoring, precision threshold detection, window comparator circuits, and nanopower oscillator designs requiring stable component supply and long-term lifecycle support.
Supply support for LTC1540CS8#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, formed through the acquisition of Linear Technology in 2017.
The LTC1540 belongs to ADI's legacy Linear Technology nanopower analog product line, designed specifically for energy-constrained applications including portable medical devices, wireless sensor nodes, and long-life industrial monitoring systems.
FAQ
What is the maximum hysteresis voltage band achievable with LTC1540CS8#PBF?
The LTC1540CS8#PBF supports a maximum hysteresis voltage band of 100mV, achieved when the HYST pin voltage is set to REF – 50mV (lower threshold) and REF (upper threshold). This 50mV differential at the HYST pin translates to a 100mV input hysteresis band due to internal gain. Exceeding REF – 50mV violates absolute maximum ratings and may cause malfunction. The LTC1540CS8#PBF datasheet confirms this limit in the HYST pin voltage range specification.
Can LTC1540CS8#PBF operate from a 1.8V supply?
The LTC1540CS8#PBF is not guaranteed to operate below 2V supply - its absolute minimum rated supply voltage is 2V (or ±1V for dual supply). While functional behavior may occur down to ~1.6V in some conditions, parameters degrade significantly: VREF accuracy worsens, propagation delay increases, and output drive capability falls. The LTC1540CS8#PBF datasheet explicitly states "operation below 2V is not recommended" and cautions that supply current rises below 1.5V. For 1.8V systems, consider alternatives like the LTC1541 or design margining with full temperature testing.
Does LTC1540CS8#PBF require an external bypass capacitor on the REF pin?
The LTC1540CS8#PBF does not require an external bypass capacitor on the REF pin for basic functionality, but adding one (up to 0.01µF) is strongly recommended to suppress noise and prevent false triggering from supply transients. The device is uniquely specified to remain stable with up to 0.01µF directly on REF - a key differentiator versus most comparators. Larger capacitors (up to 10µF) can be used with a series damping resistor per Figure 1 in the LTC1540CS8#PBF datasheet.
Is LTC1540CS8#PBF pin-compatible with LTC1440CS8#PBF?
Yes, the LTC1540CS8#PBF is pin-compatible with the LTC1440CS8#PBF in the SO-8 package: both share identical pin assignments for GND, V–, IN+, IN–, REF, V+, and OUT. However, the LTC1540CS8#PBF adds the HYST pin (Pin 5), which must be connected to REF if unused - unlike the LTC1440CS8#PBF, which has no HYST function. This makes LTC1540CS8#PBF a functional superset, enabling drop-in replacement where hysteresis is needed.
What is the output voltage swing range of LTC1540CS8#PBF?
The LTC1540CS8#PBF features a rail-to-rail CMOS output stage that swings from GND to V+ under load. Specifically, VOH is guaranteed ≥ V+ – 0.4V at –13mA sink (for C-grade), and VOL is ≤ GND + 0.4V at 1.8mA source. This ensures reliable TTL/CMOS logic-level compatibility across its full 2V–11V supply range. The output remains functional even with V+ as low as 2V, delivering usable logic-high and logic-low margins for interfacing with microcontrollers and digital logic.
LTC1540CS8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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):
- 680nA
- Current - Quiescent (Max):
- 80dB CMRR, 80dB PSRR
- CMRR, PSRR (Typ):
- 60µs
- Propagation Delay (Max):
- 50mV
- Hysteresis:
- 0°C ~ 70°C
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- Surface Mount
- :
- 8-SO
LTC1540CS8#PBF FAQ
1.How can I place an order for LTC1540CS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1540CS8#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 LTC1540CS8#PBF reliable?
The price and inventory of LTC1540CS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1540CS8#PBF is usually 5 days.
3.What payment methods are accepted for LTC1540CS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1540CS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1540CS8#PBF?
LTC1540CS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1540CS8#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 LTC1540CS8#PBF?
For technical support, including LTC1540CS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1540CS8#PBF requirements.
6.How does Aetrix verify that LTC1540CS8#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1540CS8#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 LTC1540CS8#PBF meets industry standards.
7.What is the process for return or replacement of LTC1540CS8#PBF?
All LTC1540CS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1540CS8#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 LTC1540CS8#PBF part is unused and in its original packaging.
Return procedure for LTC1540CS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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