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Analog Devices Inc. LTC3894HFE#PBF
- Part No.:
- LTC3894HFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Datasheet:
-
LTC3894HFE#PBF.pdf
- Description:
- PWR MGMT SWITCHING REGULATOR
- Quantity:
- Payment:
- Shipping:
Inventory:194
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Product details
Overview
LTC3894HFE#PBF from Analog Devices is a high-voltage, low-quiescent-current step-down DC/DC controller driving an external P-channel MOSFET to enable 100% duty cycle operation. It supports 4.5V–150V input, regulates 0.8V–60V output, draws only 9µA IQ at 48VIN→3.3VOUT, and features programmable frequency (50kHz–850kHz), Burst Mode® for light-load efficiency, and overvoltage/overcurrent/overtemperature protection. It is used in automotive and industrial power systems requiring robust high-input-voltage regulation.
For engineers reviewing the LTC3894HFE#PBF datasheet, LTC3894HFE#PBF pinout, LTC3894HFE#PBF application, or LTC3894HFE#PBF equivalent, key selection considerations include its –55°C to 150°C operating junction temperature, 20-pin TSSOP package with exposed GND pad, 100% dropout capability, RSENSE/DCR current sensing flexibility, and dual-mode light-load control (Burst Mode® vs pulse-skipping).
Technical Context
The LTC3894HFE#PBF implements a constant-frequency peak current-mode control architecture with transconductance error amplifier (2mS gm) and slope compensation. Its gate driver delivers strong pull-up (2Ω) and pull-down (0.9Ω) strength to drive high-side P-MOSFETs, with VIN–CAP LDO regulated to 8.0V (±0.5V) and UVLO thresholds selectable between 3.75V and 6.0V via DRVUV/EXTG pin configuration.
It supports synchronous clock synchronization (75kHz–800kHz) via PLLIN/MODE, offers programmable soft-start or voltage tracking via TRACK/SS pin with internal 10µA charge current, and integrates safety logic including PGOOD with adjustable undervoltage threshold (PGUV), OVLO input for input overvoltage lockout, and thermal shutdown at TJ = 150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 150V - enables direct regulation from 48V telecom, 72V industrial, or 120V AC-derived rails without pre-regulation. |
| Output Voltage Range | 0.8V to 60V - supports wide-range loads including FPGA cores, analog sensors, and isolated bias supplies. |
| Quiescent Current | 9µA at 48VIN→3.3VOUT - ensures ultra-low standby power in always-on automotive or remote monitoring systems. |
| Switching Frequency | 50kHz to 850kHz (programmable) - allows optimization of size (higher f) vs EMI/noise (lower f) across diverse board layouts. |
| Operating Temperature | –55°C to +150°C (junction) - qualified for under-hood automotive, downhole, and high-reliability industrial environments. |
| Current Sensing | RSENSE or DCR - provides design flexibility: precision shunt-based sensing or cost-optimized inductor DCR sensing with minimal BOM impact. |
| Protection Features | OVP, OCP, OTP, PGOOD, adjustable PGUV/OVLO - enables self-contained fault management without external supervisors. |
Pinout & Package
The LTC3894HFE#PBF is housed in a thermally enhanced 20-pin (16-lead) plastic TSSOP package with exposed GND pad (Pin 21), rated for θJA = 38°C/W. High-voltage creepage is ensured by lead removal on Pins 2, 4, 17, 19.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GATE (1) | P-channel MOSFET gate driver output | Swings between CAP and VIN to turn MOSFET on/off; 2Ω pull-up / 0.9Ω pull-down ensures fast switching with high gate capacitance devices. |
| RUN (3) | Enable/shutdown control input | 1.24V enable threshold with 125mV hysteresis; <0.7V forces micropower shutdown (7µA IQ), enabling system-level power sequencing. |
| SENSE+ (5) / SENSE– (6) | Differential current sense inputs | Support Kelvin-connected shunt or DCR filter; SENSE– powers internal circuitry when >3.2V, reducing external bias requirements. |
| ITH (7) | Error amplifier output & current limit setpoint | Voltage directly sets peak inductor current threshold; interfaces with compensation network (RITH/CITH1) for loop stability. |
| PGUV (8) | PGOOD undervoltage monitor input | Adjustable trip point (default 0.72V); when pulled below threshold, asserts PGOOD low after 100µs blanking for reliable rail monitoring. |
| VFB (9) | Feedback voltage input | Regulated to 0.800V ±12mV; resistor divider from VOUT sets output; line/load regulation <0.015%/V and <0.15% ensures tight accuracy. |
| TRACK/SS (10) | Soft-start and tracking control | Internal 10µA current source charges external capacitor for controlled ramp; also accepts external voltage for supply tracking during startup. |
| PLLIN/MODE (11) | Sync clock input / light-load mode select | Floating = Burst Mode®; grounded = pulse-skipping; external clock input enables phase-locked operation across multiple converters. |
| PGOOD (12) | Open-drain power-good status output | Asserts low on VFB overvoltage (>10%) or PGUV undervoltage; 100µs delay prevents false triggering during transients. |
| FREQ (13) | Frequency programming input | 20µA current source develops voltage across RFREQ; 25kΩ → 375kHz, 64.9kΩ → 100kHz; ground = 350kHz, open = 535kHz. |
| OVLO (14) | Input overvoltage lockout input | 0.8V threshold; when exceeded, immediately disables GATE and discharges TRACK/SS for safe recovery - critical for unregulated HV inputs. |
| EXTS (15) | External N-MOSFET source connection | Used with optional external NMOS to offload gate driver heat; requires 0.1µF local bypass and grounding when unused. |
| DRVUV/EXTG (16) | Driver UVLO select / external NMOS gate | Ground = 3.75V UVLO; floating ≥400mV = 6.0V UVLO; also connects to NMOS gate via 1kΩ resistor when bias path is implemented. |
| CAP (18) | Gate driver LDO return rail | VIN–CAP regulated to 8.0V; requires ≥0.47µF ceramic (≥2.2µF if external NMOS used); placement adjacent to VIN minimizes noise and instability. |
| VIN (20) | Main supply input | Accepts up to 150V; requires ≥1µF low-ESR ceramic bypass near pin to suppress high di/dt transients and ensure stable start-up. |
| GND (21) | Exposed thermal pad / signal ground | Must be soldered to PCB plane for rated thermal performance (θJA = 38°C/W) and electrical integrity; serves as primary return for all internal circuits. |
Key Features
| Feature | Design Value |
|---|---|
| 100% duty cycle operation | Enables true dropout regulation down to VOUT ≈ VIN - essential for battery backup, cold-cranking, and brownout resilience in automotive systems. |
| 9µA quiescent current at no load | Extends battery life in always-on telematics, ADAS sensors, and remote IoT nodes where standby power is constrained. |
| Selectably programmable light-load modes | Burst Mode® (floating PLLIN/MODE) maximizes efficiency at µA loads; pulse-skipping (grounded PLLIN/MODE) reduces output ripple for noise-sensitive analog rails. |
| Configurable UVLO thresholds (3.75V or 6.0V) | Allows optimization for low-VIN applications (e.g., 5V systems) or high-reliability HV bias paths - avoids spurious shutdown during transient dips. |
| Integrated PGOOD with adjustable UV/OV thresholds | Eliminates need for external supervisors; PGUV and OVLO pins enable fully customizable power-rail monitoring with hysteresis and blanking. |
| Thermally enhanced TSSOP with exposed pad | Delivers 38°C/W junction-to-ambient thermal resistance - supports continuous 3A+ output in compact layouts without heatsinks. |
Applications
| Automotive Power Management | Industrial HV DC Distribution |
|---|---|
Use Scenario: Regulating 12V–48V battery-supplied power to 3.3V/5V for infotainment ECUs and camera modules under cold-crank (4.5V) and load-dump (120V) conditions. IC Role / Device Role / Timing Role: High-voltage step-down controller managing P-MOSFET switch; provides 100% duty cycle during cranking and fast transient response to load dumps. Use Value: Eliminates need for pre-regulator stages; 9µA IQ extends battery runtime in parked mode; –55°C to 150°C rating ensures operation across full vehicle thermal envelope. | Use Scenario: Converting 72V or 96V DC bus in factory automation equipment to stable 12V/24V for PLC I/O and motor drivers. IC Role / Device Role / Timing Role: Primary DC/DC controller implementing peak-current-mode regulation with programmable 100–850kHz switching to balance efficiency and EMI compliance. Use Value: 150V absolute max rating accommodates worst-case bus transients; RSENSE/DCR flexibility lowers BOM cost; OVLO/PGUV enable autonomous fault containment. |
| Telecom Rectified Supply | Downhole Oil & Gas Instrumentation |
Use Scenario: Post-regulation of –48V telecom rectifier outputs (up to +150V transient) to generate isolated 5V/12V bias for optical transceivers and management ASICs. IC Role / Device Role / Timing Role: High-reliability buck controller with Burst Mode® for low-idle power and synchronized FREQ input for multi-rail EMI reduction. Use Value: 150V input rating withstands lightning-induced surges; 100% duty cycle maintains output during brownouts; PGOOD enables hot-swap sequencing. | Use Scenario: Power conversion in borehole logging tools exposed to extreme temperatures (–55°C to +150°C) and high-voltage transients from motor drives. IC Role / Device Role / Timing Role: Radiation-tolerant (by design) step-down controller regulating 120V DC string to 3.3V for sensor front-ends and telemetry radios. Use Value: Extended temperature grade eliminates derating; exposed-pad TSSOP sustains thermal performance in sealed enclosures; integrated protections reduce failure risk in inaccessible deployments. |
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 |
|---|---|---|---|
| LTC3895HFE#PBF | Includes integrated 5V bias LDO for gate driver; higher IQ (12µA); same 150V/150°C rating and pinout. | Reduces external components for gate bias but increases idle power; preferred when external NMOS bias path is undesirable. | Select LTC3895HFE#PBF when simplifying layout outweighs 3µA IQ penalty; verify thermal margin with integrated LDO dissipation. |
| LM5164HWRX/NOPB | 65V max input; 150°C temp grade; integrated N-MOSFET driver; lower IQ (6.5µA); different 16-pin WQFN package. | Not suitable for >65V inputs; lacks 100% duty cycle; better for space-constrained designs where HV tolerance is secondary. | Choose LM5164HWRX/NOPB only if input stays ≤65V and board area is critical; cannot replace LTC3894HFE#PBF in 120V+ systems. |
Compared with LTC3895HFE#PBF, the LTC3894HFE#PBF trades integrated bias LDO for lower quiescent current and greater flexibility in gate driver thermal management; versus LM5164HWRX/NOPB, it delivers unique 150V input and 100% dropout capability essential for harsh-environment HV regulation.
Availability
LTC3894HFE#PBF is available at Aetrix Electronics and suitable for automotive power management, industrial HV DC distribution, and telecom rectified supply applications requiring stable component supply across extended temperature and high-voltage operating conditions.
Supply support for LTC3894HFE#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 digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.
The LTC3894HFE#PBF belongs to Analog Devices' Power by Linear™ high-voltage DC/DC controller family, engineered specifically for reliability-critical applications demanding wide input range, ultra-low IQ, and robust fault protection in extreme thermal environments.
FAQ
What is the maximum input voltage rating for the LTC3894HFE#PBF?
The LTC3894HFE#PBF has an absolute maximum input supply voltage (VIN) rating of 150V, with guaranteed operation from 4.5V to 150V. This rating is validated across its full –55°C to +150°C junction temperature range and enables direct interface with unregulated 48V, 72V, and rectified AC-derived rails without external clamping or pre-regulation stages.
Does the LTC3894HFE#PBF support 100% duty cycle operation, and how is it implemented?
Yes, the LTC3894HFE#PBF supports true 100% duty cycle operation by driving an external high-side P-channel MOSFET. When the control signal commands continuous conduction, the GATE pin is held at VCAP (≈VIN–8V), maintaining the P-MOSFET in full enhancement - enabling VOUT to track VIN down to millivolt-level dropout, critical for cold-crank and brownout resilience.
How does the LTC3894HFE#PBF achieve ultra-low quiescent current, and what is its typical value?
The LTC3894HFE#PBF achieves 9µA typical quiescent current (IQ) in Burst Mode® at 48VIN→3.3VOUT by dynamically disabling non-essential circuitry during light-load intervals while maintaining regulation via periodic wake-up bursts. This is measured with no output load and confirmed in the Typical Application circuit (Figure 14) per the official datasheet Rev. A.
What package type and thermal characteristics does the LTC3894HFE#PBF use?
The LTC3894HFE#PBF uses a 20-pin (16-lead) plastic TSSOP package with exposed GND pad (Pin 21). Its thermal resistance is θJA = 38°C/W when properly soldered to a 2-in² 2-oz copper plane, supporting continuous operation at full load in high-temperature environments up to +150°C junction temperature.
Can the LTC3894HFE#PBF synchronize its switching frequency to an external clock, and what is the supported range?
Yes, the LTC3894HFE#PBF can synchronize to an external clock applied to the PLLIN/MODE pin across a 75kHz to 800kHz range. The internal PLL locks to the rising edge of the external clock, enabling precise phase alignment across multiple converters to reduce EMI peaks and simplify filtering in multi-rail power systems.
LTC3894HFE#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
LTC3894HFE#PBF FAQ
1.How can I place an order for LTC3894HFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3894HFE#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 LTC3894HFE#PBF reliable?
The price and inventory of LTC3894HFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3894HFE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3894HFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3894HFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3894HFE#PBF?
LTC3894HFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3894HFE#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 LTC3894HFE#PBF?
For technical support, including LTC3894HFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3894HFE#PBF requirements.
6.How does Aetrix verify that LTC3894HFE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3894HFE#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 LTC3894HFE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3894HFE#PBF?
All LTC3894HFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3894HFE#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 LTC3894HFE#PBF part is unused and in its original packaging.
Return procedure for LTC3894HFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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