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Analog Devices Inc. LT8495IUF#TRPBF
- Part No.:
- LT8495IUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LT8495IUF#TRPBF.pdf
- Description:
- IC REG BST CHARGE PUMP ADJ 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,712
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Product details
Overview
LT8495IUF#TRPBF from Analog Devices is a monolithic SEPIC/boost/flyback DC/DC controller with integrated 2A/70V NPN power switch, programmable 250kHz–1.5MHz switching frequency, 9µA quiescent current in active operation, and independent power-on reset (tRST = 8.5–11.85ms) and watchdog timer (tWDL = 580–812µs, tWDU = 14.9–20.9ms). It enables battery-powered automotive ECU supplies with VIN down to 2.5V at startup and BIAS-powered operation below 1V after startup.
For engineers reviewing the LT8495IUF#TRPBF datasheet, LT8495IUF#TRPBF pinout, LT8495IUF#TRPBF application, or LT8495IUF#TRPBF equivalent, key selection criteria include its dual-supply (VIN/BIAS) architecture for extended battery life, FMEA-fault-tolerant TSSOP/QFN package, low-ripple Burst Mode® operation (<10mV output ripple), and independently programmable POR/watchdog timing via CPOR/CWDT capacitors.
Technical Context
The LT8495IUF#TRPBF implements constant-frequency current-mode control with adjustable oscillator (RT pin), quadratic ramp compensation, and active clamp-based current limiting. Its power switch driver dynamically selects between VIN and BIAS supplies based on real-time voltage comparison (threshold hysteresis 0.20V), enabling seamless transition to BIAS-only operation when VIN drops below 2.5V.
Burst Mode® operation reduces quiescent current to ≤3.1µA (VIN) / ≤6.0µA (BIAS) under light load by gating full switching cycles, while maintaining output ripple <10mV via controlled burst energy delivery. The integrated POR and watchdog use capacitor-programmed timing (CPOR sets tRST; CWDT sets tWDL/tWDU) with independent enable pins (SWEN, WDE, RSTIN) and fault-tolerant logic that prevents overvoltage during adjacent-pin shorts in QFN/TSSOP packages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | SEPIC, boost, or flyback - selectable via external component configuration without IC reconfiguration |
| Switch Rating | Integrated 2A/70V NPN transistor - eliminates need for external high-voltage switch in 60V-input SEPIC designs |
| Quiescent Current | 9µA at 12VIN→5VOUT - enables >10-year battery life in always-on automotive modules |
| Output Ripple | <10mV typical - achieved via low-ripple Burst Mode® and optimized control loop stability |
| Switching Frequency | 250kHz to 1.5MHz (RT-programmable) - allows optimization of size (high f) vs. efficiency (low f) in space-constrained designs |
| POR Timeout | 8.5–11.85ms (CPOR = 4.7nF) - ensures reliable microcontroller initialization before release of RST signal |
| Watchdog Window | tWDL = 580–812µs, tWDU = 14.9–20.9ms (CWDT = 1nF) - provides precise failure detection window for safety-critical MCU supervision |
Pinout & Package
LT8495IUF#TRPBF is housed in a 20-lead (4mm × 4mm) plastic QFN package with exposed thermal pad (Pin 21 = GND), rated for –40°C to 125°C junction temperature and θJA = 47°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SS (Pin 1) | Soft-start timing node | Charged by internal 256kΩ resistor to ~2.1V; external capacitor sets controlled output voltage ramp rate |
| RT (Pin 2) | Oscillator frequency set | Resistor-to-GND sets switching frequency (250kHz–1.5MHz); low capacitance required for stability |
| GND (Pins 3,4,11,13,14,15,21) | Power and signal reference | All GND pins and exposed pad must be soldered to PCB ground plane for thermal and EMI performance |
| RSTIN (Pin 5) | Reset input reference | Resistor divider sets UVLO threshold (~1.1V internal reference); asserts RST low if input falls below threshold |
| SWEN (Pin 6) | Switch enable detect | Enables/disables regulator and soft-start; 1V rising threshold with 30mV hysteresis enables programmable VIN UVLO |
| WDE (Pin 7) | Watchdog timer enable | Logic-high (>1.1V) activates watchdog; low disables WDO output (high-impedance state) |
| WDO (Pin 8) | Watchdog output | Active-low open-drain output pulses low on watchdog timeout; duration set by CPOR capacitor |
| VIN (Pin 10) | Main supply input | Accepts 2.5–60V for startup; supports SEPIC topologies up to 60V input |
| SW (Pin 12) | Internal switch collector | Connects to external inductor/diode; minimize trace area to reduce EMI and switching losses |
| BIAS (Pin 16) | Secondary supply input | Accepts 2.4–60V; enables operation when VIN drops below 2.5V (e.g., battery sag), extending runtime |
| FB (Pin 17) | Feedback voltage sense | Regulates to 1.202V ±24mV; resistor divider sets output voltage with line regulation ≤0.2%/V |
| CPOR (Pin 18) | POR/reset delay timing | Capacitor-to-GND programs RST assertion time (tRST = 8.5–11.85ms at 4.7nF) |
| CWDT (Pin 19) | Watchdog timing | Capacitor-to-GND sets watchdog window boundaries (tWDL/tWDU proportional to CWDT value) |
| RST (Pin 20) | Open-drain reset output | Asserts low during POR, RSTIN UVLO, or shutdown; sinks ≥1.25mA at ≤150mV drop |
Key Features
| Feature | Design Value |
|---|---|
| Dual-supply operation (VIN/BIAS) | Automatically selects most efficient supply; enables sub-1V BIAS-only operation after startup to extend battery life |
| Low-ripple Burst Mode® | Maintains <10mV output ripple at light loads while reducing quiescent current to ≤3.1µA (VIN) / ≤6.0µA (BIAS) |
| FMEA-fault-tolerant design | Adjacent-pin shorts or opens in QFN package cannot raise output above programmed value - critical for automotive ASIL-B systems |
| Programmable POR and watchdog | Independent CPOR/CWDT capacitors allow precise, application-specific timing without firmware dependency |
| UVLO on SWEN and RSTIN | Resistor dividers on SWEN/RSTIN enable user-defined undervoltage lockout thresholds for input monitoring and reset control |
Applications
| Automotive Engine Control Unit (ECU) Power | Portable Medical Device Supply |
|---|---|
Use Scenario: Powering 3.3V/5V microcontrollers and sensors in engine bay environments where battery voltage sags to 6V during cranking and ambient temperature reaches 125°C. IC Role / Device Role / Timing Role: Primary DC/DC controller providing regulated output with BIAS-powered operation during cold-crank events and POR supervision of MCU boot sequence. Use Value: Enables uninterrupted operation during 6V battery dips via BIAS rail, while 8.5–11.85ms POR ensures deterministic MCU initialization before code execution. | Use Scenario: Long-life battery-powered glucose monitors requiring multi-year operation with periodic sensor activation and low-noise analog front-end biasing. IC Role / Device Role / Timing Role: High-efficiency SEPIC converter delivering stable 3.3V from single Li-ion cell (2.7–4.2V), with watchdog supervision of sleep/wake MCU transitions. Use Value: 9µA quiescent current and low-ripple Burst Mode® extend battery life beyond 5 years; tWDL/tWDU window ensures timely MCU reset on firmware hang. |
| Industrial IoT Sensor Node | Railway Signaling Interface Supply |
Use Scenario: Remote vibration sensors deployed in unheated substations where input voltage varies from 12–60V DC and operating temperature spans –40°C to 85°C. IC Role / Device Role / Timing Role: Wide-input SEPIC controller powering 3.3V wireless transceivers and ADCs, with watchdog monitoring communication stack health. Use Value: 60V input capability eliminates need for pre-regulator; programmable CWDT allows tuning watchdog window to match LoRaWAN transmission intervals. | Use Scenario: Isolated 24V-to-5V supply for signaling logic in railway trackside cabinets exposed to 1500V surge transients and wide temperature swings. IC Role / Device Role / Timing Role: Flyback controller with reinforced insulation interface, providing fail-safe reset signaling to interlocking systems via RST output. Use Value: FMEA-fault-tolerant pinout prevents overvoltage during surge-induced PCB tracking failures; RST output meets EN 5012x safety timing requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3639EMSE#PBF | Integrated 1.5A MOSFET; fixed 2MHz frequency; no watchdog/POR; 3.1V–40V input | Lacks programmable reset/watchdog; suited for compact, high-frequency point-of-load but not safety-critical supervision | Select when board space is constrained and supervision functions are handled externally |
| MAX5033AASA+ | Fixed 500kHz frequency; 0.6A switch; no BIAS pin; 3.6V–76V input; no integrated watchdog | Higher input range but no dual-supply operation or fault-tolerant features; requires external reset IC | Select for cost-sensitive industrial supplies where BIAS operation and FMEA are not required |
Compared with LTC3639EMSE#PBF and MAX5033AASA+, the LT8495IUF#TRPBF uniquely integrates BIAS-powered operation below 1V, independent POR/watchdog timing, and FMEA-fault-tolerant layout - making it the only choice for automotive ECU and safety-monitored portable systems requiring guaranteed reset behavior and extended battery runtime.
Availability
LT8495IUF#TRPBF is available at Aetrix Electronics and suitable for automotive ECU power, portable medical device supplies, industrial IoT sensor nodes, and railway signaling interface designs requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT8495IUF#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, and automotive markets.
The LT8495 product line delivers highly integrated DC/DC controllers with embedded supervision functions (POR, watchdog) and dual-supply architectures specifically designed for battery-backed automotive and portable systems demanding ultra-low quiescent current and functional safety compliance.
FAQ
What is the maximum input voltage supported by the LT8495IUF#TRPBF in SEPIC topology?
The LT8495IUF#TRPBF supports up to 60V input voltage in SEPIC topology, as specified in the Absolute Maximum Ratings and confirmed in the Applications Information section. This rating applies when the device is configured as a SEPIC converter and is distinct from its 32V limit for boost/flyback topologies (with 60V ride-through capability). The 70V-rated internal switch ensures safe operation within this range.
How does the LT8495IUF#TRPBF achieve sub-1V operation after startup?
The LT8495IUF#TRPBF achieves sub-1V operation after startup by automatically switching to BIAS-supplied power when VIN drops below 2.5V. Its dual-supply architecture monitors both VIN and BIAS pins, and when VIN falls below the 2.4V minimum operating threshold, the internal power switch driver draws current exclusively from BIAS - enabling continued regulation even if BIAS remains as low as ~1V, thereby extending battery life in deep-discharge scenarios.
Can the LT8495IUF#TRPBF be used without an external RT resistor?
No, the LT8495IUF#TRPBF requires an external RT resistor connected from Pin 2 (RT) to GND to set the switching frequency. The datasheet specifies no default or internal oscillator; frequency is programmable from 250kHz to 1.5MHz solely via the RT resistor value (e.g., 68.1kΩ yields ~1MHz, 324kΩ yields ~250kHz). Omitting the RT resistor leaves the oscillator undefined and prevents proper regulation.
What is the purpose of the NC pins on the LT8495IUF#TRPBF QFN package?
The NC pins (Pins 4, 9, 17, 19) on the LT8495IUF#TRPBF QFN package are intentionally unconnected to internal circuitry and must be left floating. Their presence supports FMEA-fault-tolerant design: if a PCB short occurs between adjacent pins, leaving NC pins unconnected prevents unintended current paths that could cause overvoltage or latch-up - a critical reliability feature validated in automotive-grade applications.
How is the watchdog timeout period adjusted on the LT8495IUF#TRPBF?
The watchdog timeout period on the LT8495IUF#TRPBF is adjusted using an external capacitor (CWDT) connected from Pin 19 (CWDT) to GND. The lower boundary (tWDL) and upper boundary (tWDU) periods scale linearly with CWDT value - for example, 1nF yields tWDL = 580–812µs and tWDU = 14.9–20.9ms. The datasheet provides exact scaling curves (Figure 8495 G22/G20), and deviation from the listed capacitance causes proportional timing variation.
LT8495IUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Boost, Charge Pump, Flyback, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.202V
- Voltage - Output (Max):
- 70V (Switch)
- Current - Output:
- 2.1A (Switch)
- Frequency - Switching:
- 250kHz ~ 1MHz
- Synchronous Rectifier:
- Both
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x4)
LT8495IUF#TRPBF FAQ
1.How can I place an order for LT8495IUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8495IUF#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 LT8495IUF#TRPBF reliable?
The price and inventory of LT8495IUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8495IUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8495IUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8495IUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8495IUF#TRPBF?
LT8495IUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8495IUF#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 LT8495IUF#TRPBF?
For technical support, including LT8495IUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8495IUF#TRPBF requirements.
6.How does Aetrix verify that LT8495IUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8495IUF#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 LT8495IUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8495IUF#TRPBF?
All LT8495IUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8495IUF#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 LT8495IUF#TRPBF part is unused and in its original packaging.
Return procedure for LT8495IUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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