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Analog Devices Inc. LT8494IUF#TRPBF
- Part No.:
- LT8494IUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LT8494IUF#TRPBF.pdf
- Description:
- IC REG BST CHARGE PUMP ADJ 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,155
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Product details
Overview
LT8494IUF#TRPBF from Analog Devices is a monolithic SEPIC/boost/flyback DC/DC controller IC featuring a 2A/70V NPN power switch, adjustable switching frequency (250kHz–1.5MHz), and ultra-low 7µA quiescent current in active operation. It supports dual supply inputs (VIN and BIAS) for automatic efficiency optimization and enables battery-powered systems to operate down to ~1V after startup. Used in automotive ECU power supplies and portable industrial converters.
For engineers reviewing the LT8494IUF#TRPBF datasheet, LT8494IUF#TRPBF pinout, LT8494IUF#TRPBF application, or LT8494IUF#TRPBF equivalent, key selection criteria include its 70V switch rating, 7µA IQ, programmable UVLO via SWEN, low-ripple Burst Mode operation (<10mV ripple with 47µF output cap), and fault-tolerant TSSOP/QFN packaging with exposed thermal pad.
Technical Context
The LT8494IUF#TRPBF implements constant-frequency current-mode control with internal slope compensation, supporting stable operation up to 90% duty cycle in SEPIC/boost topologies. Its dual-supply architecture (VIN/BIAS) dynamically selects the lower-voltage rail to drive the NPN base, enabling operation below 2.5V after startup while maintaining regulation.
Burst Mode activation reduces VIN/BIAS supply current to <3µA at light loads, with seamless transition to full-frequency PWM under higher load. Integrated features include programmable soft-start (via SS pin), frequency foldback during startup (FB <1V), and open-drain power-good flag signaling when VOUT reaches 92% of regulation voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Rating | 2A continuous, 70V collector-emitter - supports 60V SEPIC input and 32V boost input with 60V ride-through. |
| Quiescent Current | 7µA typical at 12VIN→5VOUT; 0.3µA shutdown - extends battery life in always-on systems. |
| Feedback Voltage | 1.202V ±24mV - sets precise output regulation; enables accurate resistor-divider programming of VOUT. |
| Switching Frequency | 250kHz to 1.5MHz (RT-programmable) - allows optimization of size, efficiency, and EMI across wide load ranges. |
| Output Ripple | <10mVP-P typical in Burst Mode with 47µF output capacitance - meets low-noise analog supply requirements. |
| Operating Temp Range | –40°C to +125°C junction - qualified for automotive and industrial environments per LT8494I grade. |
| Package | 20-lead 4mm × 4mm QFN (UF) with exposed GND pad - θJA = 47°C/W; enables high-power density thermal design. |
Pinout & Package
LT8494IUF#TRPBF is housed in a 20-lead plastic QFN (4mm × 4mm) with exposed thermal pad (Pin 21 = GND). All GND pins (3, 4, 9, 11, 13, 14, 15) and the exposed pad must be soldered to a solid PCB ground plane for optimal thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 12) | Internal NPN collector node | High-voltage switching node; requires minimal trace area to reduce EMI and parasitic inductance. |
| VIN (Pin 10) | Main input supply connection | Accepts 1V–60V input; local bypassing required; powers control circuitry when BIAS is unavailable. |
| BIAS (Pin 16) | Secondary supply input | Enables operation below 2.5V after startup; automatically selected over VIN when lower and ≥2.4V. |
| FB (Pin 17) | Output voltage feedback input | Sensed at 1.202V reference; connects to resistor divider to program regulated VOUT. |
| SWEN (Pin 6) | Enable/UVLO control input | Resistor-divider programmable undervoltage lockout; 1.0V threshold with 30mV hysteresis. |
| PG (Pin 20) | Open-drain power-good flag | Asserts high when VOUT ≥92% of regulation voltage; requires external pull-up for system monitoring. |
| SS (Pin 1) | Soft-start timing node | Charged by internal 256kΩ resistor to ~2.1V; external capacitor sets ramp time for controlled startup. |
| RT (Pin 2) | Oscillator frequency set | Resistor-to-GND sets switching frequency from 250kHz to 1.5MHz; low capacitance critical. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Ripple Burst Mode | Maintains <10mV output ripple at light loads while reducing IQ to <3µA - eliminates need for post-regulation LDOs in noise-sensitive rails. |
| Dual-Supply Auto-Selection | VIN/BIAS logic selects most efficient supply in real time - enables >20% efficiency gain at partial load vs single-supply controllers. |
| FMEA-Fault-Tolerant Design | TSSOP variant guarantees no overvoltage on adjacent pin shorts or opens; QFN shares same functional safety architecture. |
| Programmable UVLO & Soft-Start | SWEN pin supports resistor-divider UVLO; SS pin uses single capacitor for adjustable startup ramp - simplifies system-level sequencing. |
| Frequency Foldback | Reduces max switching frequency when FB <1V - prevents subharmonic instability and improves current control during cold-start conditions. |
Applications
| Automotive ECU Power Supply | Portable Medical Device Rail |
|---|---|
|
Use Scenario: 12V vehicle battery powers isolated 5V/3.3V rails for microcontroller, CAN transceiver, and sensor interface in engine control unit. IC Role / Device Role / Timing Role: Primary SEPIC controller regulating stable output despite cold-crank (4.5V) and load-dump (60V) transients. Use Value: 70V switch rating and 60V input tolerance eliminate need for front-end TVS clamping; 7µA IQ preserves battery during extended key-off periods. |
Use Scenario: Battery-powered handheld diagnostic device requires quiet, long-life 3.3V rail for ADC, display, and Bluetooth LE radio. IC Role / Device Role / Timing Role: Boost converter generating regulated 3.3V from single-cell Li-ion (2.7V–4.2V). Use Value: Low-ripple Burst Mode delivers <10mV noise without external LDO; dual-supply operation extends runtime by enabling discharge to 1V. |
| Industrial Sensor Node Supply | Smart Meter Auxiliary Power |
|
Use Scenario: Remote wireless sensor node powered by primary alkaline cells must operate for 10+ years with periodic RF transmission bursts. IC Role / Device Role / Timing Role: SEPIC regulator delivering 3.3V from 1.5V–3.0V input range, accommodating deep battery discharge. Use Value: 0.3µA shutdown current and programmable UVLO prevent brownout resets; 20-lead QFN enables compact, thermally robust layout. |
Use Scenario: Utility smart meter derives auxiliary 5V rail from 120/240VAC line via flyback transformer, requiring high-reliability regulation. IC Role / Device Role / Timing Role: Flyback controller managing isolation, regulation, and power-good signaling for meter MCU and RTC. Use Value: PG flag provides deterministic power sequencing; –40°C to +125°C rating ensures operation in outdoor enclosures; fault-tolerant design meets IEC 62053 reliability requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SEPIC/boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EFE#PBF | Higher 4A switch rating, wider 4–36V input, but 25µA IQ - lacks sub-1V operation and dual-supply auto-selection. | Preferred for high-current industrial supplies; unsuitable for ultra-low-IQ battery backup or sub-2.5V start-up. | Select LTC3789EFE#PBF only when >2A output current or >36V input is required; LT8494IUF#TRPBF remains superior for low-IQ, wide-VIN, and battery longevity. |
| LT3958EFE#PBF | 75V switch, 5A rating, but fixed 100kHz/200kHz options and 30µA IQ - no Burst Mode, no programmable UVLO, no BIAS pin. | Used in LED driver and high-power boost applications; not optimized for low-noise, low-IQ, or multi-rail systems. | Choose LT3958EFE#PBF for high-current LED or HV boost where efficiency at full load dominates; LT8494IUF#TRPBF is better for mixed-load, noise-sensitive, or battery-constrained designs. |
Compared with LTC3789EFE#PBF and LT3958EFE#PBF, the LT8494IUF#TRPBF uniquely combines 70V/2A capability with 7µA IQ, dual-supply operation, and low-ripple Burst Mode - making it the only option capable of sustaining >10-year battery life while meeting stringent analog noise budgets in portable and automotive edge nodes.
Availability
LT8494IUF#TRPBF is available at Aetrix Electronics and suitable for automotive ECU power, portable medical device rails, and industrial sensor node supplies requiring stable component supply across extended temperature and lifecycle requirements.
Supply support for LT8494IUF#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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, automotive, and industrial markets.
The LT8494IUF#TRPBF belongs to Linear's high-voltage monolithic DC/DC controller product line, designed specifically for reliable, low-quiescent-power conversion in battery-backed, automotive, and harsh-environment applications where input voltage extremes and long service life are critical.
FAQ
What is the minimum input voltage required for LT8494IUF#TRPBF to start up and regulate?
The LT8494IUF#TRPBF requires a minimum of 2.5V on either VIN or BIAS to initiate startup and regulation. After startup, it can sustain operation with VIN as low as ~1V by drawing bias current from the output rail via the BIAS pin - a key enabler for deep battery discharge in portable systems. This behavior is confirmed in the Electrical Characteristics table under "Minimum VIN Operating Voltages" and "Minimum BIAS Operating Voltages".
Does LT8494IUF#TRPBF support SEPIC, boost, and flyback topologies simultaneously in one design?
No - the LT8494IUF#TRPBF supports SEPIC, boost, or flyback topologies individually, depending on external component configuration and transformer/inductor selection. Its internal NPN switch and control architecture are compatible with all three, but each application requires dedicated layout and component values. The datasheet provides distinct reference designs for each topology, and mixing configurations risks instability or failure to regulate.
How does the LT8494IUF#TRPBF achieve 7µA quiescent current, and is this value guaranteed over temperature?
The LT8494IUF#TRPBF achieves 7µA typical quiescent current through optimized biasing of internal references and clock circuitry, combined with aggressive sleep-state gating in Burst Mode. This value is specified at TA = 25°C and VIN = 12V; over the full –40°C to +125°C operating range, quiescent current remains ≤8.0µA for the LT8494I grade, as documented in the Electrical Characteristics table under "Quiescent Current from VIN".
Can the LT8494IUF#TRPBF's PG (Power Good) pin drive an LED directly?
No - the PG pin is an open-drain NMOS output rated for 1.25mA sink current at 33mV drop. Driving an LED typically requires 5–20mA and forward voltage >1.8V, exceeding PG's capabilities. Instead, use the PG signal to enable a dedicated LED driver or level-shifting buffer. The datasheet specifies PG leakage <0.3µA and output low voltage ≤150mV at 100µA sink, confirming it is intended for logic-level signaling, not direct LED biasing.
What is the purpose of the NC pins on the LT8494IUF#TRPBF QFN package, and can they be tied to GND?
The NC (No Connect) pins on the LT8494IUF#TRPBF QFN package - Pins 5, 7, 8, 18, and 19 - are unconnected internally and serve no electrical function. They must remain floating per the datasheet; tying them to GND or any other potential may compromise thermal performance or introduce parasitic coupling. Unlike the TSSOP variant, the QFN NC pins do not contribute to FMEA fault tolerance - that feature applies only to the TSSOP package's specific pinout and layout rules.
LT8494IUF#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:
- 2A
- Frequency - Switching:
- 250kHz ~ 1.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x4)
LT8494IUF#TRPBF FAQ
1.How can I place an order for LT8494IUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8494IUF#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 LT8494IUF#TRPBF reliable?
The price and inventory of LT8494IUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8494IUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8494IUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8494IUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8494IUF#TRPBF?
LT8494IUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8494IUF#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 LT8494IUF#TRPBF?
For technical support, including LT8494IUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8494IUF#TRPBF requirements.
6.How does Aetrix verify that LT8494IUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8494IUF#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 LT8494IUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8494IUF#TRPBF?
All LT8494IUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8494IUF#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 LT8494IUF#TRPBF part is unused and in its original packaging.
Return procedure for LT8494IUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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