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Analog Devices Inc. LTC3894IFE#PBF
- Part No.:
- LTC3894IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Datasheet:
-
LTC3894IFE#PBF.pdf
- Description:
- 150V LOW IQ STEP-DOWN DC/DC CONT
- Quantity:
- Payment:
- Shipping:
Inventory:368
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Product details
Overview
LTC3894IFE#PBF from Analog Devices is a high-voltage, 150V input, peak-current-mode synchronous step-down DC/DC controller driving an external P-channel MOSFET. It supports 100% duty cycle operation, regulates outputs from 0.8V to 60V, draws only 9µA quiescent current at 48VIN/3.3VOUT, and operates across –40°C to 125°C. It enables robust power conversion in automotive front-end and industrial 48V systems.
For engineers reviewing the LTC3894IFE#PBF datasheet, LTC3894IFE#PBF pinout, LTC3894IFE#PBF application, or LTC3894IFE#PBF equivalent, key selection criteria include its 150V max input rating, 9µA no-load IQ, programmable 50–850kHz switching frequency, 100% duty cycle capability, and P-channel gate drive architecture with VIN–CAP LDO biasing.
Technical Context
The LTC3894IFE#PBF implements a constant-frequency, peak-current-mode control loop with transconductance error amplifier (2mS), slope compensation, and internal 0.8V reference. Its ITH pin serves as both error amplifier output and current limit setpoint, directly modulating the peak inductor current threshold via VSENSE+–VSENSE–.
It features dual-mode light-load operation-Burst Mode® (9µA IQ) or pulse-skipping-with mode selected via PLLIN/MODE pin state. Gate drive is sourced from a thermally managed VIN–CAP LDO (regulated to 8V, ±0.5V), with UVLO thresholds configurable at 3.75V or 6V via DRVUV/EXTG pin, and includes integrated overvoltage, overcurrent, and overtemperature protection with PGOOD monitoring.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 150V - supports direct connection to unregulated 48V, 72V, or 110V industrial/automotive rails without pre-regulation. |
| Output Voltage Range | 0.8V to 60V - enables generation of core logic, analog, and intermediate bus voltages from single high-VIN source. |
| Quiescent Current | 9µA at 48VIN/3.3VOUT - ensures ultra-low standby power in always-on systems such as telematics or remote sensors. |
| Switching Frequency | 50kHz to 850kHz (resistor-programmable); 75–800kHz sync-capable - allows optimization of size vs. EMI in space-constrained designs. |
| Duty Cycle Capability | 100% - enables dropout operation down to VOUT + VF(diode), critical for low-VIN transient recovery in battery-fed systems. |
| Current Sensing | RSENSE or DCR - supports accurate, temperature-stable current limiting using either discrete shunt or inductor-based sensing. |
| Protection Features | OVP (via OVLO pin), OCP (via SENSE pins), OTP, PGOOD with adjustable UV/OV thresholds - provides system-level fault containment without external supervision ICs. |
Pinout & Package
The LTC3894IFE#PBF is housed in a thermally enhanced 20-lead TSSOP package (FE) with leads removed between pins 1–4 and 17–20 to meet high-voltage creepage/clearance requirements. The exposed pad (Pin 21) is GND and must be soldered to PCB for rated thermal performance (θJA = 38°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GATE (1) | P-channel MOSFET gate driver output | Swings between CAP and VIN; actively pulls low to turn on P-MOSFET, high to turn off - enables 100% duty cycle with no bootstrap complexity. |
| RUN (3) | Enable/disable control input | 1.24V enable threshold with 125mV hysteresis; <0.7V forces micropower shutdown (7µA), enabling precise system-level sequencing. |
| SENSE+ (5) / SENSE– (6) | Differential current sense inputs | Support Kelvin-connected RSENSE or DCR filter capacitor; SENSE– powers internal circuitry when >3.2V - improves accuracy and reduces layout sensitivity. |
| ITH (7) | Error amplifier output & current limit setpoint | Voltage directly sets peak inductor current threshold; used for compensation and current foldback - enables tight load transient response and programmable OCP. |
| PGUV (8) | PGOOD undervoltage monitor input | Adjustable trip point (default 720mV); asserts PGOOD low after 100µs delay if VFB drops below threshold - supports custom brown-out detection. |
| VFB (9) | Feedback voltage input | Regulated to 0.800V ±12mV; line/load regulation <0.015%/V and <0.15% - ensures stable output under wide input/output conditions. |
| TRACK/SS (10) | Soft-start and tracking control | Internal 10µA pull-up charges external capacitor; regulates VFB to smaller of 0.8V or TRACK/SS voltage - enables controlled startup and supply tracking. |
| PLLIN/MODE (11) | Sync clock input / light-load mode select | Floating = Burst Mode®; grounded = pulse-skipping; AC-coupled external clock synchronizes gate edge - eliminates beat frequencies in multi-rail systems. |
| PGOOD (12) | Open-drain power-good status output | Asserts low on VFB OV (>10%) or PGUV UV (<720mV); 100µs blanking - provides reliable system power sequencing signal. |
| FREQ (13) | Frequency programming input | 20µA current source develops voltage across RFREQ; ground = 350kHz, open = 535kHz - simplifies EMI tuning without trimming components. |
| OVLO (14) | Input overvoltage lockout input | 0.8V threshold; disables MOSFET and discharges TRACK/SS on overvoltage - protects downstream circuitry during load dump or surge events. |
| DRVUV/EXTG (16) | Gate driver UVLO select / NMOS gate | GND = 3.75V UVLO; floating = 6V UVLO; also connects to external NMOS gate for off-chip bias - enhances thermal management in high-power designs. |
| CAP (18) | Gate driver LDO return rail | Forms VIN–CAP bias supply; requires ≥0.47µF ceramic bypass (≥2.2µF if external NMOS used) - stabilizes gate drive under high dV/dt and heavy capacitive loads. |
| VIN (20) | Main supply input | Accepts up to 150V; requires ≥1µF low-ESR ceramic bypass near pin - handles wide-input industrial and automotive transients. |
| GND (21) | Power and signal ground (exposed pad) | Thermal and electrical reference; must be soldered to PCB copper pour - essential for achieving rated θJA and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| 100% duty cycle operation | Enables true dropout regulation down to VOUT + VF, eliminating need for linear post-regulators in battery backup or low-VIN scenarios. |
| 9µA quiescent current (Burst Mode®) | Extends battery life in always-on IoT nodes and telematics modules where standby power budget is sub-10µA. |
| Programmable 50–850kHz switching frequency | Allows trade-off between inductor size (higher f) and conduction loss (lower f), while avoiding AM radio band interference. |
| Adjustable PGOOD undervoltage threshold | Permits custom brown-out detection aligned with downstream IC requirements (e.g., 2.95V for 3.3V logic), improving system reliability. |
| External N-MOSFET gate driver bias option | Moves heat-generating LDO losses off-die, enabling higher power density and improved thermal margin in 48V/10A+ applications. |
| Integrated overvoltage, overcurrent, and overtemperature protection | Reduces BOM count by eliminating discrete supervisors and fault latches, while ensuring fail-safe behavior during fault conditions. |
Applications
| Automotive Front-End Power Supply | Industrial 48V Intermediate Bus Converter |
|---|---|
Use Scenario: Regulating 12V–60V battery or alternator input to stable 3.3V/5V for ADAS camera modules and domain controllers. IC Role / Device Role / Timing Role: High-voltage step-down controller managing P-channel MOSFET switch, providing 100% duty cycle for cold-crank support and Burst Mode® for parking-mode efficiency. Use Value: Eliminates need for pre-regulator + LDO cascade; 9µA IQ extends vehicle battery life during extended parking; 150V rating withstands ISO 7637-2 load dump pulses. | Use Scenario: Converting unregulated 48V telecom or factory automation rail to 12V/15V for PLC I/O modules and motor drivers. IC Role / Device Role / Timing Role: Primary controller for nonsynchronous buck stage, coordinating with external Schottky diode and supporting DCR current sensing for thermal stability. Use Value: Wide 4.5–150V input range accommodates brownout and overvoltage events; programmable frequency avoids EMI-sensitive bands; PGOOD enables safe hot-swap insertion. |
| Distributed Power Architecture (DPA) Brick | Telecom Rectifier Backup Stage |
Use Scenario: Secondary-side regulation in modular power supplies where main brick delivers 12V, and LTC3894IFE#PBF generates isolated 1.8V/2.5V for FPGA cores. IC Role / Device Role / Timing Role: Precision feedback-controlled buck controller with TRACK/SS pin enabling output voltage ramping synchronized to upstream supply. Use Value: External tracking capability ensures glitch-free power-up sequencing; 0.8V reference tolerance (±1.5%) guarantees tight output regulation across temperature. | Use Scenario: Standby converter powered from 48V telecom rectifier output, delivering 5V to keep real-time clocks and memory alive during AC failure. IC Role / Device Role / Timing Role: Ultra-low-IQ controller maintaining regulated output with no load, using RUN pin for graceful enable/disable during mains restoration. Use Value: 9µA IQ minimizes battery drain during extended outages; OVLO pin disables converter during rectifier overvoltage, protecting backup battery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3895IFE#PBF | Includes integrated N-channel MOSFET driver (replaces external P-MOSFET + diode); same 150V input, 9µA IQ, and feature set. | Reduces component count and board area but requires N-MOSFET high-side configuration; not drop-in compatible with P-MOSFET layouts. | Select LTC3895IFE#PBF when optimizing for footprint and efficiency in new designs; retain LTC3894IFE#PBF for legacy P-MOSFET compatibility or cost-sensitive BOMs. |
| LM5164QPWPRQ1 | 4.5–100V input, 100µA IQ, integrated 100V N-MOSFET, fixed 500kHz frequency - lacks programmable frequency, 100% duty cycle, and external current sense flexibility. | Suitable for lower-voltage automotive body electronics but cannot replace LTC3894IFE#PBF in 110V industrial or 150V surge-tolerant applications. | Choose LM5164QPWPRQ1 only for cost-driven 48V automotive modules where 100V max input and higher IQ are acceptable trade-offs. |
Compared with LTC3895IFE#PBF and LM5164QPWPRQ1, the LTC3894IFE#PBF uniquely combines 150V absolute maximum input, 100% duty cycle, and ultra-low 9µA Burst Mode® IQ - making it the sole choice for high-reliability, wide-input industrial and automotive front-end converters requiring P-MOSFET simplicity and minimal standby loss.
Availability
LTC3894IFE#PBF is available at Aetrix Electronics and suitable for automotive front-end power supplies, industrial 48V intermediate bus converters, and telecom rectifier backup stages requiring stable component supply, long-term lifecycle assurance, and guaranteed temperature-grade compliance.
Supply support for LTC3894IFE#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 is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets with precision, reliability, and innovation.
The LTC3894IFE#PBF belongs to Analog Devices' Power by Linear™ high-voltage DC/DC controller family, engineered specifically for rugged, wide-input industrial and automotive power conversion where input transients, low IQ, and 100% duty cycle are mandatory design requirements.
FAQ
What is the maximum input voltage rating for the LTC3894IFE#PBF?
The LTC3894IFE#PBF has an absolute maximum input voltage rating of 150V on the VIN pin, with operational input range specified from 4.5V to 150V. This rating enables direct interface with 48V, 72V, and 110V industrial rails and withstands ISO 7637-2 automotive load dump transients. Exceeding 150V may cause permanent damage per Absolute Maximum Ratings.
Does the LTC3894IFE#PBF support 100% duty cycle operation, and how is it implemented?
Yes, the LTC3894IFE#PBF supports true 100% duty cycle operation by driving an external P-channel MOSFET. When the gate is pulled to CAP (VIN–8V), the P-MOSFET remains fully enhanced, allowing continuous conduction even as input voltage approaches output voltage. This eliminates dropout voltage limitations inherent in N-MOSFET-based controllers and is confirmed in the Dropout Behavior typical curve (Figure G05) of the LTC3894IFE#PBF datasheet.
What is the quiescent current of the LTC3894IFE#PBF under no-load conditions?
The LTC3894IFE#PBF draws 9µA quiescent current in Burst Mode® operation at 48VIN/3.3VOUT with no load, as specified in the Electrical Characteristics table (IQ(VINR)). In pulse-skipping mode, it draws 1.5mA under the same conditions. These values are measured in the Typical Application circuit and are valid across the –40°C to 125°C operating junction temperature range.
Can the LTC3894IFE#PBF synchronize its switching frequency to an external clock?
Yes, the LTC3894IFE#PBF supports external clock synchronization via the PLLIN/MODE pin. When an AC-coupled clock signal (75kHz to 800kHz, VHIGH ≥2V, VLOW ≤0.5V) is applied, the internal phase-locked loop aligns the gate driver's turn-on edge to the rising edge of the external clock. This feature is explicitly documented in the "Switching Frequency and Clock Synchronization" section of the LTC3894IFE#PBF datasheet.
What package type and thermal specifications apply to the LTC3894IFE#PBF?
The LTC3894IFE#PBF uses a 20-lead plastic TSSOP package (FE) with an exposed GND pad (Pin 21). Its thermal resistance is θJA = 38°C/W when mounted on a 2-layer PCB with 2 in² of 2-oz copper connected to the exposed pad. The device is rated for operation from –40°C to 125°C junction temperature, and the exposed pad must be soldered to PCB for rated electrical and thermal performance.
LTC3894IFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 150V
- Frequency - Switching:
- 50kHz ~ 850kHz
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LTC3894IFE#PBF FAQ
1.How can I place an order for LTC3894IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3894IFE#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 LTC3894IFE#PBF reliable?
The price and inventory of LTC3894IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3894IFE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3894IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3894IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3894IFE#PBF?
LTC3894IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3894IFE#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 LTC3894IFE#PBF?
For technical support, including LTC3894IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3894IFE#PBF requirements.
6.How does Aetrix verify that LTC3894IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3894IFE#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 LTC3894IFE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3894IFE#PBF?
All LTC3894IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3894IFE#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 LTC3894IFE#PBF part is unused and in its original packaging.
Return procedure for LTC3894IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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