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Analog Devices Inc. LTC3891MPUDC#TRPBF
- Part No.:
- LTC3891MPUDC#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC3891MPUDC#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,173
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Product details
Overview
LTC3891MPUDC#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, supports 75kHz–750kHz phase-lockable switching frequency, and operates with only 50µA no-load IQ across –55°C to 150°C. It enables automotive always-on systems requiring ultra-low standby power and wide-input battery or bus rail compatibility.
For engineers reviewing the LTC3891MPUDC#TRPBF datasheet, LTC3891MPUDC#TRPBF pinout, LTC3891MPUDC#TRPBF application, or LTC3891MPUDC#TRPBF equivalent, key selection criteria include its 60V max input rating, 50µA light-load IQ, 0.8V reference accuracy over temperature, selectable Burst Mode/pulse-skipping/CCM operation, and robust 150°C junction-rated QFN package for harsh-environment deployment.
Technical Context
The LTC3891MPUDC#TRPBF implements a constant-frequency current-mode control architecture with OPTI-LOOP® compensation, enabling stable loop response across diverse output capacitor ESR and capacitance values. Its dual LDO architecture-internally powered from VIN or externally via EXTVCC-ensures gate driver reliability under dropout conditions while maintaining 5.1V INTVCC regulation.
It integrates precision current sensing with three selectable current limit thresholds (22mV/43mV/64mV), reverse-current prevention during light-load operation, and output overvoltage protection triggered at ±10% VFB deviation. The PLLIN/MODE pin directly configures light-load behavior without external logic, and the TRACK/SS pin supports both soft-start ramping and supply tracking with internal 10µA pull-up.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 60V - supports 12V/24V/48V industrial buses and LiFePO₄/Li-ion battery stacks without pre-regulation. |
| No-Load Quiescent Current | 50µA - extends battery runtime in always-on automotive or IoT edge nodes by minimizing standby loss. |
| Output Voltage Range | 0.8V to 24V - programmable via external resistor divider; 0.8V ±1.2% reference ensures tight regulation at low voltages. |
| Switching Frequency | 75kHz to 750kHz - phase-lockable to external clock or set via FREQ pin resistor; enables EMI shaping and inductor size optimization. |
| Current Sense Threshold | 22mV / 43mV / 64mV - selectable via ILIM pin connection (GND/FLOAT/INTVCC); reduces RSENSE power loss and thermal stress. |
| Operating Temperature | –55°C to +150°C - qualified per MIL-STD-883 Class H; suitable for under-hood automotive, avionics, and downhole electronics. |
| Duty Cycle Max | 99% - enables ultra-low dropout operation (e.g., 12V→11.5V), critical for high-efficiency post-regulation in distributed power systems. |
Pinout & Package
Package: 20-lead 3mm × 4mm plastic QFN (UDC) with exposed thermal pad (Pin 21 = SGND). Requires soldering of exposed pad to PCB ground plane for θJA = 43°C/W thermal performance and reliable high-current operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (QFN) / 3 (TSSOP) | PLLIN/MODE | Selects light-load mode: GND = Burst Mode, INTVCC = forced CCM, 1.2V–(INTVCC–1.3V) = pulse-skipping. |
| 2,3 (QFN) / 4,5 (TSSOP) | SGND | Small-signal ground reference; must be routed separately from PGND to avoid noise coupling into error amplifier. |
| 4 (QFN) / 6 (TSSOP) | RUN | Digital enable: <1.16V disables control loop; <0.7V shuts down entire IC, reducing IQ to 14µA. |
| 5 (QFN) / 7 (TSSOP) | SENSE– | Inverting input of differential current comparator; supplies bias current when > INTVCC – 0.5V. |
| 6 (QFN) / 8 (TSSOP) | SENSE+ | Non-inverting input of current comparator; connects to RSENSE or DCR network for accurate peak-current sensing. |
| 7 (QFN) / 9 (TSSOP) | VFB | Feedback input referenced to 0.8V internal reference; monitors output via external resistive divider. |
| 8 (QFN) / 10 (TSSOP) | ITH | Error amplifier output and compensation node; sets peak inductor current threshold and loop stability. |
| 9 (QFN) / 11 (TSSOP) | PGOOD | Open-drain power-good indicator; asserts low when VFB deviates >±10% from regulated value. |
| 10 (QFN) / 12 (TSSOP) | TG | Top-gate driver output; floating N-channel driver with swing = INTVCC above SW node. |
| 11 (QFN) / 13 (TSSOP) | SW | Switch node connection to inductor; carries high di/dt; requires tight layout and Kelvin sensing for stability. |
| 12 (QFN) / 14 (TSSOP) | BOOST | Bootstrap supply for TG driver; capacitor between BOOST and SW sustains gate drive during high-duty cycles. |
| 13 (QFN) / 15 (TSSOP) | BG | Bottom-gate driver output; drives synchronous N-MOSFET from GND to INTVCC (5.1V). |
| 14 (QFN) / 16 (TSSOP) | INTVCC | Internal 5.1V LDO output; powers drivers and analog circuitry; requires ≥2.2µF ceramic decoupling to PGND. |
| 15 (QFN) / 17 (TSSOP) | EXTVCC | External supply input for INTVCC LDO; bypasses VIN LDO when >4.7V, improving efficiency in multi-rail systems. |
| 16 (QFN) / 18 (TSSOP) | PGND | Power ground return for BG driver and bottom MOSFET source; must connect to CIN(–) and low-impedance ground plane. |
| 17 (QFN) / 19 (TSSOP) | VIN | Main input supply; requires local ceramic bypass to SGND; supports up to 65V absolute max. |
| 18 (QFN) / 20 (TSSOP) | ILIM | Current limit range select: GND = 22mV, FLOAT = 43mV, INTVCC = 64mV - scales sense gain without changing RSENSE. |
| 19 (QFN) / 1 (TSSOP) | TRACK/SS | Soft-start/tracking input; internal 10µA pull-up charges external capacitor for linear VOUT ramp; accepts external divider for supply tracking. |
| 20 (QFN) / 2 (TSSOP) | FREQ | Oscillator frequency set point; GND = 350kHz, INTVCC = 535kHz, resistor-to-GND programs 50–900kHz. |
| 21 (QFN/TSSOP) | SGND (Exposed Pad) | Thermal and electrical ground; must be soldered to PCB ground plane for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Enables stable transient response across wide ranges of output capacitance (10µF–1000µF) and ESR (1mΩ–100mΩ) without loop re-tuning. |
| Three Light-Load Operating Modes | Configurable via single pin: Burst Mode (50µA IQ), pulse-skipping (low ripple), or forced CCM (fixed frequency, audio-friendly). |
| Programmable Current Limit Threshold | 22mV/43mV/64mV selection eliminates need for multiple RSENSE values; maintains accuracy across temperature and load. |
| 99% Maximum Duty Cycle | Supports ultra-low dropout conversion (e.g., 12V→11.8V) without external boost circuitry, preserving efficiency in margin-critical rails. |
| Robust Thermal Rating | –55°C to +150°C operating range with 150°C max junction temperature; qualified for extended-life automotive and aerospace applications. |
| Integrated EXTVCC Switchover | Automatically selects most efficient INTVCC source (VIN or external rail), reducing system-level power loss in multi-output converters. |
Applications
| Automotive ADAS Power Supply | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Powers radar sensor SoCs and camera ISPs in engine compartment environments where ambient temperatures exceed 105°C. IC Role / Device Role / Timing Role: Primary 5V/3.3V step-down controller delivering stable output from 12V/24V battery with cold-crank tolerance down to 4V. Use Value: 50µA quiescent current prevents battery drain during vehicle sleep mode; 150°C rating ensures reliability without derating. |
Use Scenario: Generates isolated 5V and 3.3V rails for digital I/O and microcontroller subsystems in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: High-efficiency synchronous buck controller supporting wide input (18–60V DC) from industrial power supplies. Use Value: 60V input capability eliminates need for front-end TVS/clamping; programmable frequency avoids EMI-sensitive bands in noisy factory settings. |
| Battery-Powered Test Equipment | Distributed Telecom Power System |
|
Use Scenario: Supplies FPGA, ADC, and RF front-end in portable handheld spectrum analyzers running on Li-ion packs (8.4V–12.6V). IC Role / Device Role / Timing Role: Adjustable-output buck controller with soft-start and tracking to coordinate power-up sequencing with auxiliary rails. Use Value: TRACK/SS pin enables precise output ramping and supply tracking, preventing latch-up during hot-plug or multi-rail startup. |
Use Scenario: Provides intermediate 5V/12V rails in 48V telecom rectifier systems feeding remote radio units and baseband processors. IC Role / Device Role / Timing Role: Synchronous step-down controller operating from 36–72V nominal input with high efficiency at partial load. Use Value: Selectable Burst Mode operation maintains >85% efficiency at 10mA load, extending backup battery runtime during grid outages. |
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 |
|---|---|---|---|
| LTC3892MPUDC#TRPBF | Dual-phase controller with current-sharing; identical 60V/150°C rating but adds phase interleaving and PMBus interface. | Required for >20A output or lower ripple/noise; not drop-in compatible due to doubled pin count and different control logic. | Choose LTC3892MPUDC#TRPBF only when higher output current, tighter ripple control, or digital monitoring is required. |
| LM5143APWPR | 60V, 50µA IQ, but rated only to 125°C; uses different current-sense architecture (high-side RSENSE only) and lacks TRACK/SS functionality. | Suitable for commercial/industrial ambient environments; cannot replace LTC3891MPUDC#TRPBF in automotive under-hood or extended-temp deployments. | Consider LM5143APWPR for cost-sensitive non-automotive designs where 125°C max junction temperature is acceptable. |
Compared with LTC3892MPUDC#TRPBF and LM5143APWPR, the LTC3891MPUDC#TRPBF uniquely balances ultra-wide temperature operation, flexible light-load modes, and analog programmability in a compact single-phase footprint-making it optimal for space-constrained, thermally aggressive, or analog-control-dominant designs.
Availability
LTC3891MPUDC#TRPBF is available at Aetrix Electronics and suitable for automotive ADAS modules, industrial PLCs, and battery-powered test equipment requiring stable component supply with guaranteed long-term availability and extended temperature support.
Supply support for LTC3891MPUDC#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 and maintains full product continuity, documentation, and qualification for all Linear power management ICs including the LTC3891 family.
The LTC3891MPUDC#TRPBF belongs to Linear's high-voltage synchronous controller product line, engineered specifically for demanding automotive, industrial, and aerospace applications requiring wide input range, ultra-low IQ, and extreme temperature resilience.
FAQ
What is the maximum input voltage rating for the LTC3891MPUDC#TRPBF?
The LTC3891MPUDC#TRPBF has an absolute maximum input voltage rating of 65V, with a recommended operating range of 4V to 60V. This allows direct interfacing with 48V battery systems, industrial 24V/36V buses, and automotive 12V/24V rails including cold-crank transients. Exceeding 65V risks permanent damage per Absolute Maximum Ratings.
How does the LTC3891MPUDC#TRPBF achieve 50µA quiescent current?
The LTC3891MPUDC#TRPBF achieves 50µA no-load IQ through integrated low-power circuit design, including optimized biasing of the error amplifier and current comparator, selective clock gating during light-load Burst Mode operation, and shutdown of non-essential analog blocks. This specification is verified across –55°C to 150°C and enables multi-year battery life in always-on systems.
Can the LTC3891MPUDC#TRPBF operate with only a single external MOSFET?
No-the LTC3891MPUDC#TRPBF is a synchronous step-down controller requiring two external N-channel MOSFETs: one high-side (driven by TG) and one low-side (driven by BG). It does not support asynchronous (diode-based) operation. Using only one MOSFET violates the functional architecture and will prevent proper regulation and cause device malfunction.
What is the purpose of the EXTVCC pin on the LTC3891MPUDC#TRPBF?
The EXTVCC pin on the LTC3891MPUDC#TRPBF provides an alternative input to the internal 5.1V LDO that powers gate drivers and analog circuitry. When EXTVCC exceeds 4.7V, the IC automatically switches from VIN-derived INTVCC to EXTVCC-derived INTVCC-improving overall system efficiency by avoiding losses in the VIN LDO, especially useful when powering INTVCC from a more efficient downstream converter rail.
Is the LTC3891MPUDC#TRPBF pin-compatible with other variants like LTC3891EUDC#TRPBF?
Yes-the LTC3891MPUDC#TRPBF shares identical pinout, package (20-lead 3mm×4mm QFN), and electrical interface with all UDC-package variants (E/I/H/MP grades). Differences are limited to temperature rating, screening, and parametric guarantees; no PCB layout changes are needed when upgrading from EUDC/IUDC/HUDC to MPUDC for extended-temperature operation.
LTC3891MPUDC#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN 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:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (3x4)
LTC3891MPUDC#TRPBF FAQ
1.How can I place an order for LTC3891MPUDC#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3891MPUDC#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 LTC3891MPUDC#TRPBF reliable?
The price and inventory of LTC3891MPUDC#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3891MPUDC#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3891MPUDC#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3891MPUDC#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3891MPUDC#TRPBF?
LTC3891MPUDC#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3891MPUDC#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 LTC3891MPUDC#TRPBF?
For technical support, including LTC3891MPUDC#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3891MPUDC#TRPBF requirements.
6.How does Aetrix verify that LTC3891MPUDC#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3891MPUDC#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 LTC3891MPUDC#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3891MPUDC#TRPBF?
All LTC3891MPUDC#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3891MPUDC#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 LTC3891MPUDC#TRPBF part is unused and in its original packaging.
Return procedure for LTC3891MPUDC#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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