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Analog Devices Inc. LTC3891EFE#TRPBF
- Part No.:
- LTC3891EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3891EFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:985
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Product details
Overview
LTC3891EFE#TRPBF from Analog Devices (formerly Linear Technology) is a high-performance, low-quiescent-current 60V synchronous step-down DC/DC controller driving all-N-channel MOSFETs. It delivers 0.8V–24V programmable output voltage, operates from 4V–60V input, supports phase-lockable switching up to 750kHz, and enables Burst Mode operation for battery-powered systems requiring ultra-low standby power.
For engineers reviewing the LTC3891EFE#TRPBF datasheet, LTC3891EFE#TRPBF pinout, LTC3891EFE#TRPBF application, or LTC3891EFE#TRPBF equivalent, key selection criteria include its 50μA no-load IQ, selectable light-load modes (Burst/Pulse-Skipping/Continuous), RSENSE or DCR current sensing, 0.8V precision reference, and integrated power-good monitoring with overvoltage protection.
Technical Context
The LTC3891EFE#TRPBF implements a constant-frequency current-mode control architecture with OPTI-LOOP® compensation, enabling stable loop response across wide output capacitance and ESR variations. Its error amplifier output (ITH) directly sets peak inductor current, while the VFB pin compares feedback against a trimmed 0.800V reference with ±12mV accuracy over temperature.
It integrates dual gate drivers (TG/BG) with sub-30ns transition times, internal 5.1V LDO (INTVCC) powered from VIN or EXTVCC ≥4.7V, and a dedicated dropout detector that forces periodic top-FET off-time to recharge the bootstrap capacitor during 99% duty-cycle operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 60V - supports wide intermediate bus and battery chemistries including 12V, 24V, and 48V systems. |
| Output Voltage Range | 0.8V to 24V - programmable via external resistor divider; 0.8V reference tolerance ±1.0% (±8mV) over full temp range. |
| No-Load Quiescent Current | 50μA - extends runtime in always-on automotive or portable applications without compromising startup behavior. |
| Switching Frequency Range | 75kHz to 750kHz - phase-lockable to external clock or programmable via FREQ pin resistor (50–900kHz). |
| Current Sense Threshold | 22mV to 85mV - selectable via ILIM pin (GND/FLOAT/INTVCC) to match sense resistor or DCR values. |
| Power-Good Accuracy | ±10% VOUT trip threshold with 2.5% hysteresis - ensures reliable system sequencing and fault reporting. |
| Max Duty Cycle | 99% - enables ultra-low dropout operation down to VIN – VOUT ≈ 0.3V at high load. |
Pinout & Package
Package: 20-lead plastic TSSOP (FE package), 0.65mm pitch, exposed pad (Pin 21 = SGND) soldered to PCB ground for thermal performance (θJA = 38°C/W). RoHS-compliant, lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| TRACK/SS (Pin 1) | Soft-start & tracking input | Internal 10µA pull-up charges external capacitor for linear VOUT ramp; accepts external voltage for supply tracking. |
| FREQ (Pin 2) | Oscillator frequency control | 20µA pull-up current develops voltage for VCO; GND = 350kHz, INTVCC = 535kHz, resistor-to-GND sets 50–900kHz. |
| PLLIN/MODE (Pin 3) | Light-load mode & sync input | GND = Burst Mode; INTVCC = forced continuous; 1.2V–(INTVCC−1.3V) = pulse-skipping; external clock = PLL sync. |
| RUN (Pin 6) | Enable/shutdown control | 1.16V threshold for soft shutdown; 0.7V for deep shutdown (<14µA IQ); internal 7µA pull-up enables float-to-enable. |
| SENSE– / SENSE+ (Pins 7/8) | Differential current sense inputs | Measure voltage across RSENSE or DCR; common-mode range up to 28V; bias current <±2µA ensures accuracy. |
| VFB (Pin 9) | Feedback input | Compares resistive divider output to 0.800V reference; ±5nA input current minimizes divider error. |
| ITH (Pin 10) | Error amplifier output | Directly controls peak inductor current; used for loop compensation and current limit programming. |
| PGOOD (Pin 11) | Open-drain status output | Pulled low when VFB deviates >±10% from setpoint; 2mA sink capability drives logic or enable signals. |
| TG (Pin 12) | Top N-MOSFET gate driver | Floating driver with 2.5Ω pull-up / 1.5Ω pull-down; swing = INTVCC + SW node voltage. |
| SW (Pin 13) | Switch node connection | Connects to inductor and source of bottom MOSFET; handles high dV/dt and 65V abs max rating. |
| BOOST (Pin 14) | Bootstrap supply | Charges external capacitor between BOOST and SW; diode-connected to INTVCC for charge replenishment. |
| BG (Pin 15) | Bottom N-MOSFET gate driver | Ground-referenced driver with 2.4Ω pull-up / 1.1Ω pull-down; 0–5.1V swing drives synchronous rectifier. |
| INTVCC (Pin 16) | Internal LDO output | 5.1V ±3%, supplies gate drivers and control circuits; requires ≥2.2µF ceramic decoupling to PGND. |
| EXTVCC (Pin 17) | External LDO input | Enables bypass of VIN-based LDO when >4.7V applied; reduces power loss and heat in high-VIN applications. |
| PGND (Pin 18) | Power ground return | Low-impedance return path for bottom MOSFET source and CIN negative terminal; separate from SGND. |
| VIN (Pin 19) | Main input supply | Accepts 4V–60V; requires local ceramic bypass to SGND pins; absolute max 65V. |
| ILIM (Pin 20) | Current limit select | GND/FLOAT/INTVCC selects max sense threshold: 22/43/64mV (typ), enabling flexible current-sense design. |
| SGND (Pins 4,5,21) | Small-signal ground | Mandatory separate routing from PGND; exposed pad (Pin 21) must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® compensation | Allows single-pole compensation network to stabilize loops across wide output capacitor types (ceramic, polymer, electrolytic) and ESR ranges without re-tuning. |
| Selectably optimized light-load efficiency | Burst Mode (50μA IQ), pulse-skipping, or forced continuous conduction - user-selectable per application noise/ripple/efficiency trade-off. |
| Robust current sensing | Differential SENSE+/– inputs with ±1µA bias, 28V common-mode range, and foldback protection during short-circuit conditions. |
| Integrated power management | Dual LDO architecture (VIN- and EXTVCC-powered) plus dropout detector ensures reliable bootstrapping and gate drive under extreme duty cycles. |
| Programmable soft-start/tracking | TRACK/SS pin supports both capacitor-ramped soft-start and precise voltage tracking of auxiliary rails during system power-up. |
| High-accuracy monitoring | 0.800V reference trimmed to ±1.0%, PGOOD with ±10% trip window and 2.5% hysteresis, and UVLO with 50mV hysteresis. |
Applications
| Automotive Always-On Systems | Battery-Powered Digital Devices |
|---|---|
Use Scenario: Powering infotainment head units, telematics modules, and ADAS sensors from 12V vehicle battery with cold-crank tolerance. IC Role / Device Role / Timing Role: Primary 3.3V/5V buck controller managing always-on domain; monitors VIN for undervoltage lockout and provides PGOOD for MCU reset sequencing. Use Value: 50μA quiescent current prevents battery drain during weeks of vehicle inactivity; 60V abs max withstands load-dump transients. |
Use Scenario: Regulating processor core voltage in handheld medical instruments or portable test equipment operating from Li-ion packs. IC Role / Device Role / Timing Role: High-efficiency synchronous buck controller delivering 1.2V @ 3A with dynamic voltage scaling support via ITH interface. Use Value: Burst Mode extends battery life >3× vs continuous mode at microamp loads; TRACK/SS enables clean power-up with FPGA or ASIC. |
| Distributed DC Power Systems | Industrial Control & PLC Modules |
Use Scenario: Intermediate bus conversion in 48V datacom or telecom systems feeding point-of-load regulators. IC Role / Device Role / Timing Role: Wide-input (36–60V) front-end controller generating 12V/5V rails; synchronized via PLLIN to avoid beat frequencies. Use Value: Phase-lockable 75–750kHz operation eliminates EMI peaks; RSENSE/DCR flexibility simplifies layout across multiple output currents. |
Use Scenario: Powering isolated I/O modules, analog sensor interfaces, and real-time controllers in factory automation cabinets. IC Role / Device Role / Timing Role: Robust 24V-to-5V/3.3V conversion with overvoltage protection and PGOOD signaling to PLC backplane supervisor. Use Value: Output overvoltage protection (VOVL) limits fault propagation; 150°C junction rating supports operation in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3892EFE#TRPBF | Dual-output version with independent channel control, higher max frequency (850kHz), and enhanced current sharing capability. | Required for dual-rail systems (e.g., ±12V, 5V+3.3V) where channel interleaving or phase offset is needed. | Choose LTC3892EFE#TRPBF only when dual outputs or tighter cross-regulation are mandatory; not drop-in compatible. |
| MP2451DT-LF-Z | Monolithic 60V buck converter (integrated MOSFETs), fixed 3.3V/5V options, 150μA IQ, no PLL or TRACK/SS. | Suitable for cost-sensitive, space-constrained designs where 2A output and simplified BOM outweigh programmability needs. | Choose MP2451DT-LF-Z for lower component count and footprint; avoid if adjustable VOUT, Burst Mode, or sync capability is required. |
Compared with LTC3892EFE#TRPBF and MP2451DT-LF-Z, the LTC3891EFE#TRPBF uniquely balances wide input range, ultra-low IQ, full programmability (VOUT, frequency, light-load mode), and robust protection - making it optimal for high-reliability, battery-aware, or thermally constrained industrial and automotive applications.
Availability
LTC3891EFE#TRPBF is available at Aetrix Electronics and suitable for automotive always-on systems, battery-powered digital devices, and distributed DC power systems requiring stable component supply, long-term lifecycle assurance, and guaranteed RoHS-compliant sourcing.
Supply support for LTC3891EFE#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. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC3891EFE#TRPBF belongs to ADI's Power by Linear™ high-voltage controller family, designed specifically for demanding industrial, automotive, and telecom applications where wide VIN, low IQ, and robust protection are critical.
FAQ
What is the maximum input voltage rating for the LTC3891EFE#TRPBF?
The LTC3891EFE#TRPBF has an absolute maximum input voltage (VIN) rating of 65V, with a recommended operating range of 4V to 60V. This allows safe operation across automotive cold-crank (down to ~4V) and load-dump (up to 60V transient) conditions. Exceeding 65V may cause permanent damage per Absolute Maximum Ratings.
How does the LTC3891EFE#TRPBF achieve 50μA quiescent current?
The LTC3891EFE#TRPBF achieves 50μA no-load IQ primarily through Burst Mode operation: when load current drops below threshold, the controller disables gate drivers and disconnects the error amplifier, reducing internal circuit activity. The RUN pin deep-shutdown mode further lowers IQ to <14μA. This behavior is verified across –40°C to 125°C.
Can the LTC3891EFE#TRPBF synchronize to an external clock?
Yes, the LTC3891EFE#TRPBF can synchronize to an external clock via the PLLIN/MODE pin. When an external square wave (75kHz–750kHz) is applied, the internal phase-locked loop aligns the rising edge of TG to the external clock's rising edge, eliminating beat frequencies in multi-rail systems. This is confirmed in the Functional Diagram and PLL section of the datasheet.
What package type and thermal performance does the LTC3891EFE#TRPBF use?
The LTC3891EFE#TRPBF uses a 20-lead plastic TSSOP (FE package) with exposed thermal pad (Pin 21 = SGND). Its thermal resistance is θJA = 38°C/W when mounted on a standard 2-layer PCB with 1in² copper pour. The exposed pad must be soldered to PCB ground for rated performance, as specified in the Absolute Maximum Ratings table.
Does the LTC3891EFE#TRPBF support output voltage tracking during startup?
Yes, the LTC3891EFE#TRPBF supports precise output voltage tracking via the TRACK/SS pin. By connecting a resistor divider from another supply rail to TRACK/SS, the LTC3891EFE#TRPBF regulates VFB to match that voltage during startup - ensuring controlled sequencing in multi-rail systems such as FPGAs or processors with strict power-up order requirements.
LTC3891EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width) 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):
- 4V ~ 60V
- Frequency - Switching:
- 105kHz ~ 835kHz, 350kHz ~ 535kHz
- Duty Cycle (Max):
- 99%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LTC3891EFE#TRPBF FAQ
1.How can I place an order for LTC3891EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3891EFE#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 LTC3891EFE#TRPBF reliable?
The price and inventory of LTC3891EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3891EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3891EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3891EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3891EFE#TRPBF?
LTC3891EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3891EFE#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 LTC3891EFE#TRPBF?
For technical support, including LTC3891EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3891EFE#TRPBF requirements.
6.How does Aetrix verify that LTC3891EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3891EFE#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 LTC3891EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3891EFE#TRPBF?
All LTC3891EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3891EFE#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 LTC3891EFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3891EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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