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Analog Devices Inc. LTC3894HFE#TRPBF
- Part No.:
- LTC3894HFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Datasheet:
-
LTC3894HFE#TRPBF.pdf
- Description:
- 150V LOW IQ STEP-DWN DC/DC CTLR
- Quantity:
- Payment:
- Shipping:
Inventory:3,166
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Product details
Overview
LTC3894HFE#TRPBF from Analog Devices is a high-voltage, 150V input, P-channel synchronous step-down DC/DC controller with 100% duty cycle capability, 9μA quiescent current at 48VIN→3.3VOUT, and programmable 50kHz–850kHz switching frequency. It regulates outputs from 0.8V to 60V and delivers robust overvoltage, overcurrent, and overtemperature protection with adjustable PGOOD thresholds - deployed in automotive power systems requiring wide VIN tolerance and low-noise regulation.
For engineers reviewing the LTC3894HFE#TRPBF datasheet, LTC3894HFE#TRPBF pinout, LTC3894HFE#TRPBF application, or LTC3894HFE#TRPBF equivalent, key selection criteria include its –55°C to 150°C operating junction temperature range, 20-pin TSSOP package with exposed GND pad, RSENSE/DCR current sensing flexibility, and Burst Mode® operation for ultra-low IQ at light loads.
Technical Context
The LTC3894HFE#TRPBF implements peak-current-mode control with slope compensation and a transconductance error amplifier (2 mS) referenced to a precise 0.800 V feedback voltage. Its gate driver supports P-channel MOSFETs with programmable UVLO thresholds (3.75 V or 6 V) on the DRVUV/EXTG pin and delivers strong pull-up (2 Ω) and pull-down (0.9 Ω) drive strength.
It integrates a phase-locked loop for external clock synchronization (75 kHz–800 kHz), supports soft-start or voltage tracking via the TRACK/SS pin, and features dual current-sensing options: discrete sense resistors or inductor DCR with optional filtering. The internal VIN–CAP LDO regulates gate bias to 8.0 V ±0.5 V with ≤4.4 V dropout at 15 mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 150 V - enables direct connection to unregulated industrial or automotive battery rails without pre-regulation. |
| Output Voltage Range | 0.8 V to 60 V - supports both low-voltage logic supplies and intermediate bus voltages in distributed power architectures. |
| Quiescent Current | 9 μA at 48 VIN/3.3 VOUT - sustains regulation with near-zero standby power, critical for always-on automotive modules. |
| Switching Frequency | 50 kHz to 850 kHz (resistor-programmable) - allows optimization of size vs. EMI; synchronized externally from 75 kHz to 800 kHz. |
| Feedback Reference | 0.800 V ±12 mV - high-precision reference enables tight output regulation across temperature and load. |
| Operating Junction Temp | –55°C to +150°C - qualified for under-hood automotive and high-reliability industrial environments. |
| Current Sensing | RSENSE or DCR - eliminates need for dedicated current-sense ICs; supports cost-effective, low-loss inductor-based sensing. |
Pinout & Package
The LTC3894HFE#TRPBF is housed in a thermally enhanced 20-pin TSSOP (FE package) with leads removed for high-voltage creepage; 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 operation. |
| RUN (3) | Enable/disable control input | 1.24 V threshold enables operation; <0.7 V forces micropower shutdown (7 μA), supporting system-level power sequencing. |
| SENSE+ (5) / SENSE– (6) | Differential current sense inputs | Support Kelvin-connected RSENSE or DCR filter capacitor; SENSE– powers internal circuitry when >3.2 V - reduces external bias requirements. |
| ITH (7) | Error amplifier output & compensation node | Voltage sets peak inductor current limit; connects to external RC network for loop stability tuning. |
| PGUV (8) | PGOOD undervoltage monitor input | Adjustable trip point (default 720 mV); asserts PGOOD low after 100 μs delay if output falls below threshold. |
| VFB (9) | Output voltage feedback input | Regulated to 0.800 V; resistor divider from VOUT sets output - precision reference enables ±1% output accuracy. |
| TRACK/SS (10) | Soft-start and voltage tracking input | Internal 10 μA current source charges external capacitor for controlled ramp; also accepts external voltage for supply tracking. |
| PLLIN/MODE (11) | External clock sync / light-load mode select | Floating = Burst Mode®; grounded = pulse-skipping; AC-coupled clock = PLL synchronization - flexible efficiency optimization. |
| PGOOD (12) | Open-drain power-good status output | Asserts low on VFB overvoltage (>10%) or PGUV undervoltage; 100 μs blanking prevents false triggers during transients. |
| FREQ (13) | Switching frequency programming input | 20 μA current source develops voltage across RFREQ; grounding = 350 kHz, floating = 535 kHz - no external oscillator needed. |
| OVLO (14) | Input overvoltage lockout input | 0.8 V threshold; disconnects P-MOSFET and discharges TRACK/SS on overvoltage - protects downstream circuitry from surge events. |
| EXTS (15) | Source terminal for optional N-MOSFET bias | Used only with external N-MOSFET gate driver bias path; requires 0.1 μF local bypass - moves heat off-die for high-power designs. |
| DRVUV/EXTG (16) | Gate driver UVLO select & N-MOSFET gate drive | GND = 3.75 V UVLO; >400 mV = 6 V UVLO; also drives external N-MOSFET gate via 1 kΩ resistor - dual-function pin saves board space. |
| CAP (18) | Gate driver LDO return rail | VIN–CAP regulated to 8.0 V; requires ≥0.47 μF ceramic cap (≥2.2 μF if using external N-MOSFET) - ensures stable gate drive under dynamic load. |
| VIN (20) | Main power supply input | Accepts up to 150 V; requires ≥1 μF low-ESR ceramic bypass near pin - handles wide-input transient conditions without external TVS. |
| GND (21) | Exposed thermal pad / signal ground | Must be soldered to PCB plane; provides primary thermal path and low-impedance return - essential for 150°C junction rating. |
Key Features
| Feature | Design Value |
|---|---|
| 100% duty cycle operation | Enables dropout-free regulation down to VOUT ≈ VIN - critical for battery-powered systems during deep discharge or cold-crank scenarios. |
| Burst Mode® operation | Reduces IQ to 9 μA at no load while maintaining regulation - extends battery life in always-on telematics and ADAS modules. |
| Programmable PGOOD thresholds | Independent OV and UV monitoring (via VFB and PGUV pins) enables custom power-rail sequencing and fault isolation in multi-rail systems. |
| Thermally enhanced TSSOP-20 | Exposed GND pad and lead removal meet IPC-2221 creepage/clearance requirements for 150 V applications - simplifies safety-certified layout. |
| Flexible current sensing | Supports both RSENSE (high accuracy) and DCR (low loss) methods - eliminates BOM duplication and enables optimal trade-off between cost and efficiency. |
Applications
| Automotive Engine Control Unit (ECU) | Industrial Programmable Logic Controller (PLC) |
|---|---|
Use Scenario: Regulating 12 V–16 V battery input to stable 3.3 V for microcontroller and CAN transceiver in under-hood ECU. IC Role / Device Role / Timing Role: High-voltage step-down controller managing main power rail with cold-crank (4.5 V) and load-dump (150 V) immunity. Use Value: 9 μA IQ preserves battery during vehicle sleep; 150°C junction rating ensures reliability at elevated ambient temperatures. | Use Scenario: Converting 24 V DC industrial bus to isolated 5 V and 12 V rails for I/O modules and communication interfaces. IC Role / Device Role / Timing Role: Primary non-isolated buck controller delivering high-efficiency, low-noise power with programmable soft-start for inrush control. Use Value: Adjustable OVLO and PGOOD enable coordinated startup/shutdown with safety-rated PLC backplane logic. |
| Telecom Remote Radio Unit (RRU) | Avionics Power Distribution Unit (PDU) |
Use Scenario: Stepping down –48 V telecom supply to 5 V for FPGA and RF front-end ICs in outdoor base station equipment. IC Role / Device Role / Timing Role: Negative-input compatible buck controller (with level-shifting interface) providing high-reliability power in harsh environmental conditions. Use Value: Wide 4.5 V–150 V input range accommodates reverse-polarity protection circuits and brownout margins; Burst Mode® maintains efficiency at partial load. | Use Scenario: Generating 28 V to 5 V conversion for flight-control sensors and data acquisition systems in commercial aircraft. IC Role / Device Role / Timing Role: MIL-STD-704 compliant DC/DC controller meeting DO-160 lightning-induced transient immunity requirements. Use Value: 150 V absolute max rating and robust OVLO/UVLO protect against induced surges; –55°C start capability supports arctic operations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3895HFE#TRPBF | Includes integrated MOSFET drivers for *both* high-side and low-side N-channel FETs; supports synchronous rectification. | Enables higher efficiency at medium-to-heavy loads; requires external bootstrap circuitry and more complex layout. | Select when >95% full-load efficiency is required and board space permits added gate-drive complexity. |
| LM5164QPWPRQ1 | 65 V max input, 1.5 A integrated FET, lower IQ (15 μA), no PGOOD adjustability, automotive AEC-Q100 Grade 1. | Targeted at cost-sensitive, lower-power automotive body electronics; lacks 150 V rating and programmable PGOOD. | Select for sub-65 V, <1 A applications where AEC-Q100 qualification is mandatory but extended voltage range is unnecessary. |
Compared with LTC3895HFE#TRPBF, the LTC3894HFE#TRPBF offers simpler P-channel topology and superior 150 V tolerance but requires external Schottky catch diode; versus LM5164QPWPRQ1, it trades AEC-Q100 compliance for wider input range, lower IQ, and greater design flexibility in high-reliability industrial and aerospace use cases.
Availability
LTC3894HFE#TRPBF is available at Aetrix Electronics and suitable for automotive engine control units, industrial programmable logic controllers, and avionics power distribution units requiring stable component supply across extended temperature and high-voltage stress conditions.
Supply support for LTC3894HFE#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and aerospace markets.
The LTC3894 belongs to Analog Devices' Power by Linear™ high-voltage DC/DC controller family, engineered specifically for ruggedized power conversion in automotive, industrial, and telecom infrastructure where input transients, wide temperature ranges, and ultra-low standby power are critical.
FAQ
What is the maximum input voltage rating for the LTC3894HFE#TRPBF?
The LTC3894HFE#TRPBF has an absolute maximum input supply voltage (VIN) rating of 150 V, with a functional operating range from 4.5 V to 150 V. This rating is validated per Analog Devices' Absolute Maximum Ratings table and applies across its full –55°C to +150°C junction temperature range - making it suitable for automotive load-dump and industrial surge environments without external clamping.
Does the LTC3894HFE#TRPBF support synchronous rectification?
No, the LTC3894HFE#TRPBF does not support synchronous rectification. It is a nonsynchronous controller designed exclusively for driving an external P-channel MOSFET as the high-side switch, with freewheeling handled by an external Schottky diode. For synchronous operation, consider the pin-compatible LTC3895HFE#TRPBF, which adds integrated drivers for both high-side and low-side N-channel FETs.
How is the output voltage programmed on the LTC3894HFE#TRPBF?
The output voltage of the LTC3894HFE#TRPBF is programmed using a resistor divider from VOUT to the VFB pin, which regulates to a precise 0.800 V reference. For example, to set 5 V output, use R1 = 52.3 kΩ (top) and R2 = 10 kΩ (bottom). The VFB pin draws only ±50 nA bias current, ensuring minimal divider error and high accuracy across temperature and line conditions.
Can the LTC3894HFE#TRPBF operate with 100% duty cycle, and what design conditions enable it?
Yes, the LTC3894HFE#TRPBF supports true 100% duty cycle operation - essential for ultra-low dropout regulation. This is enabled by its P-channel MOSFET architecture and gate driver that pulls GATE to VIN to turn off and to CAP to turn on. To sustain 100% duty cycle, VIN–CAP must remain above the selected UVLO threshold (3.75 V or 6 V), and the ITH voltage must be sufficiently high to maintain continuous conduction mode.
What thermal considerations apply to the exposed pad (Pin 21) of the LTC3894HFE#TRPBF?
The exposed pad (Pin 21) of the LTC3894HFE#TRPBF is electrically GND and serves as the primary thermal path. It must be soldered to a minimum 200 mm² copper pour with ≥4 thermal vias (0.3 mm diameter) to an internal or bottom-layer ground plane. Failure to do so degrades θJA from the rated 38°C/W and risks exceeding the 150°C maximum junction temperature - especially under sustained 150 V input and full-load conditions.
LTC3894HFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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#TRPBF FAQ
1.How can I place an order for LTC3894HFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3894HFE#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 LTC3894HFE#TRPBF reliable?
The price and inventory of LTC3894HFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3894HFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3894HFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3894HFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3894HFE#TRPBF?
LTC3894HFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3894HFE#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 LTC3894HFE#TRPBF?
For technical support, including LTC3894HFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3894HFE#TRPBF requirements.
6.How does Aetrix verify that LTC3894HFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3894HFE#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 LTC3894HFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3894HFE#TRPBF?
All LTC3894HFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3894HFE#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 LTC3894HFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3894HFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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