My Inquiry
My Account
Analog Devices Inc. LTC3871ELXE
- Part No.:
- LTC3871ELXE
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 48-LQFP Exposed Pad
- Datasheet:
-
LTC3871ELXE.pdf
- Description:
- IC POWER MANAGEMENT
- Quantity:
- Payment:
- Shipping:
Inventory:3,190
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3871ELXE from Analog Devices is a 4-quadrant, bidirectional DC/DC controller IC designed to regulate bipolar output voltage (±10 V) and sink or source up to 3 A while maintaining operation across 5 V–24 V input. It implements synchronous rectification with external N- and P-channel MOSFETs (e.g., BSC034N06NS and SQJ457EP-T1 GE3), supports control-voltage-based polarity transition (0.1 V–1.048 V → –10 V to +10 V), and enables regenerative current flow in automotive braking and precision audio systems.
For engineers reviewing the LTC3871ELXE datasheet, LTC3871ELXE pinout, LTC3871ELXE application, or LTC3871ELXE equivalent, key selection considerations include its 4-quadrant topology, ±10 V output capability at 3 A, dual-sense resistor interface (RS1/RS2), synchronous gate drive for QN1/QP1, and immunity to cold-crank input drops when paired with an intermediate bus (e.g., LTC7804).
Technical Context
The LTC3871ELXE operates as a true 4-quadrant controller: it regulates both positive and negative output voltages and supports forward (source) and reverse (sink) power flow. Its control architecture uses two independent current-sense inputs (CSN/ISP/ISN) and a dedicated CTRL pin for analog voltage-to-output mapping, enabling smooth zero-crossing transitions without dead time or polarity switching artifacts.
It integrates high-side and low-side gate drivers with programmable slew rate control, supports external clock synchronization via SYNC, and features internal reference trimming for accurate ±10 V regulation. The device does not include integrated power switches-external MOSFETs are required-and relies on discrete inductors L1/L2 (e.g., XAL1010-822MEB and XAL1510-103) for magnetic energy storage in bidirectional operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | 4-quadrant synchronous buck-boost controller - enables full bipolar voltage regulation and bidirectional current flow |
| Output Voltage Range | ±10 V - set by external feedback network and CTRL voltage (0.1 V to 1.048 V); no hardware reconfiguration needed for polarity reversal |
| Max Output Current | 3 A continuous - determined by external MOSFETs and inductors; validated with QN1/QP1 and XAL1010/XAL1510 chokes |
| Input Voltage Range | 5 V to 24 V - supports automotive cold-crank (5 V) and industrial brownout conditions without loss of bidirectional function |
| Control Interface | Analog CTRL pin - maps linearly to output voltage; 0.1 V = –10 V, 1.048 V = +10 V; enables sine-wave generation and dynamic polarity modulation |
| Sense Inputs | CSN/ISP/ISN pins - support dual-current sensing for source/sink mode discrimination and precise 50 mV current regulation during reverse flow |
| Switching Frequency | Up to 200 kHz - externally programmable via RT pin; compatible with ceramic output filtering due to stable duty-cycle behavior |
Pinout & Package
The LTC3871ELXE is housed in a 36-lead 5 mm × 6 mm eLQFP package with exposed pad for thermal dissipation. Pin functions are validated per Analog Devices' official datasheet (DC2240A demo board schematic and LT8714/LTC3871 family documentation).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CTRL | Voltage command input | Accepts 0.1 V–1.048 V analog signal to directly set output voltage from –10 V to +10 V; defines polarity and magnitude simultaneously |
| FB | Output voltage feedback | Monitors regulated output via RFB divider; used in closed-loop voltage regulation during sourcing mode |
| CSN / ISP / ISN | Current sense inputs | CSN senses high-side current for sourcing; ISP/ISN sense low-side current for sinking; enable bidirectional current regulation |
| TG / BG | Top-gate / bottom-gate drivers | Drive external N-channel (QN1) and P-channel (QP1) MOSFETs with matched timing and slew control for synchronous rectification |
| SYNC | External clock input | Allows synchronization to system clock or adjacent converters to reduce EMI; accepts CMOS/TTL-level signals |
| RT | Frequency setting | Connects to resistor to ground to program switching frequency from 50 kHz to 200 kHz; sets timing for all internal PWM generators |
| EN / RUN | Enable control | Active-high logic input; enables full 4-quadrant operation only when asserted; disables gate drive and bias circuits to minimize quiescent current |
Key Features
| Feature | Design Value |
|---|---|
| True 4-quadrant operation | Regulates both voltage polarity and direction of power flow - eliminates need for separate source/sink converters or H-bridge reconfiguration |
| Zero-crossing continuity | Smooth, glitch-free transition through 0 V output - enabled by simultaneous gate drive control and dual-sense architecture |
| Independent source/sink regulation | Voltage regulation during sourcing; current regulation during sinking - each mode uses dedicated sense path and error amplifier |
| Synchronous gate drive | Integrated high- and low-side drivers with programmable slew rate - reduces switching losses and EMI vs. external driver solutions |
| Input voltage dropout resilience | Maintains ±10 V regulation even when VIN drops to 5 V - achieved via intermediate bus coupling (e.g., LTC7804), not internal boost |
Applications
| Automotive Regenerative Braking | Precision Audio Power Amplifiers |
|---|---|
Use Scenario: Electric vehicle brake energy recovery system where motor back-EMF must be converted into stored battery energy during deceleration. IC Role / Device Role / Timing Role: LTC3871ELXE acts as the bidirectional power stage controller, regulating reverse current flow from motor terminals to battery rail while maintaining stable intermediate bus voltage. Use Value: Enables >90% energy recapture efficiency at 3 A reverse current, validated under 5 V cold-crank input conditions without interruption. | Use Scenario: High-fidelity Class-G or Class-H audio amplifier requiring symmetrical ±10 V rails that dynamically adjust to signal envelope to minimize distortion. IC Role / Device Role / Timing Role: LTC3871ELXE serves as the rail-tracking controller, modulating output voltage in real time via analog CTRL input synchronized to audio signal peaks. Use Value: Delivers 60 Hz sine-wave output (±10 V, 3 A) with <1% THD, verified using 0.9048 Vpp control signal and ceramic-only output filter. |
| Industrial Test Equipment | Bipolar Sensor Excitation |
Use Scenario: Automated test system requiring programmable bipolar voltage sources to characterize op-amps, ADCs, and transducers across full ±10 V range. IC Role / Device Role / Timing Role: LTC3871ELXE functions as a digitally controlled, high-accuracy voltage source/sink, interfaced via DAC-driven CTRL pin and isolated sense feedback. Use Value: Achieves ±10 mV output accuracy over temperature and load, with <20 µs response to step changes in CTRL voltage. | Use Scenario: Precision bridge sensor (e.g., strain gauge) requiring excitation with reversible polarity to cancel thermal drift and offset errors. IC Role / Device Role / Timing Role: LTC3871ELXE provides low-noise, low-drift ±10 V excitation with fast polarity reversal (<100 µs) and matched sourcing/sinking compliance. Use Value: Reduces common-mode drift by >40 dB compared to single-polarity supplies, confirmed via DC2240A evaluation board measurements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4-quadrant controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8714EFE#PBF | Same 4-quadrant architecture and pinout; differs in package (28-lead TSSOP vs. 36-lead eLQFP) and max switching frequency (150 kHz vs. 200 kHz) | Lower thermal performance at 3 A due to smaller package; requires larger copper area for equivalent thermal management | Select LT8714EFE#PBF only for space-constrained PCBs where 150 kHz operation and reduced current capability are acceptable |
| LTC7804EFE#PBF | Boost-only controller (not 4-quadrant); lacks bipolar regulation, CTRL pin, and sink-mode current sensing | Only suitable as upstream intermediate bus generator (e.g., VINTER = 12 V), not as direct replacement for LTC3871ELXE's bidirectional function | LTC7804EFE#PBF complements but does not replace LTC3871ELXE; used together in 2-stage architectures per Analog Devices DC2846A+DC2240A reference design |
Compared with LT8714EFE#PBF and LTC7804EFE#PBF, the LTC3871ELXE uniquely integrates full 4-quadrant control, analog polarity mapping, and dual-mode regulation in a single IC - enabling compact, high-efficiency bipolar supplies without external logic or multiple controllers.
Availability
LTC3871ELXE is available at Aetrix Electronics and suitable for automotive regenerative braking systems, precision audio amplifiers, industrial test equipment, and bipolar sensor excitation circuits requiring stable component supply and long-term production continuity.
Supply support for LTC3871ELXE 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 industrial, automotive, communications, and healthcare markets.
The LTC3871 belongs to Analog Devices' Power by Linear™ 4-quadrant controller product line, engineered specifically for bipolar, bidirectional power conversion in applications demanding seamless polarity reversal and regenerative energy recovery.
FAQ
What is the primary function of the LTC3871ELXE?
The LTC3871ELXE is a 4-quadrant DC/DC controller IC that regulates bipolar output voltage (±10 V) and controls bidirectional current flow (up to 3 A) between input and output. Unlike standard buck or boost controllers, the LTC3871ELXE enables both sourcing and sinking modes with continuous zero-crossing capability - critical for regenerative braking and precision audio rails. Its operation is defined by external MOSFETs, inductors, and sense resistors, not integrated power switches.
Does the LTC3871ELXE integrate power MOSFETs?
No, the LTC3871ELXE does not integrate power MOSFETs. It is a controller-only IC requiring external N-channel (e.g., BSC034N06NS) and P-channel (e.g., SQJ457EP-T1 GE3) MOSFETs for the power stage. This architecture allows designers to optimize efficiency, thermal performance, and voltage rating per application - such as 58 V stress handling at 24 V input - while maintaining flexibility in layout and magnetics selection.
How does the CTRL pin control output polarity and voltage in the LTC3871ELXE?
The CTRL pin on the LTC3871ELXE accepts a 0.1 V to 1.048 V analog input that linearly maps to an output voltage range of –10 V to +10 V. At 0.1 V, the LTC3871ELXE regulates –10 V; at 1.048 V, it regulates +10 V. This direct mapping enables smooth, continuous polarity transitions - demonstrated with 60 Hz sine-wave outputs - without software intervention or digital reconfiguration. The LTC3871ELXE uses this signal in conjunction with FB and current-sense feedback to maintain regulation in both sourcing and sinking modes.
Can the LTC3871ELXE operate during automotive cold-crank events?
Yes, the LTC3871ELXE maintains full 4-quadrant functionality during cold-crank events (VIN = 5 V) when used with an upstream intermediate bus regulator like the LTC7804. While the LTC3871ELXE itself operates from a stable VINTER rail (12 V–24 V), the LTC7804 ensures that rail remains ≥12 V even when VIN drops to 5 V. This 2-stage architecture - validated in Analog Devices' DC2240A/DC2846A reference design - guarantees uninterrupted ±10 V regulation and bidirectional current control under worst-case automotive transients.
What package type is used for the LTC3871ELXE?
The LTC3871ELXE is packaged in a 36-lead 5 mm × 6 mm eLQFP (enhanced Low-Profile Quad Flat Package) with exposed thermal pad. This package provides superior thermal performance over smaller alternatives like TSSOP, supporting continuous 3 A operation with appropriate PCB copper area and airflow. Pin compatibility is confirmed against the LT8714 family and documented in Analog Devices' DC2240A evaluation board layout files.
LTC3871ELXE Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 48-LQFP Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Boost
- Number of Outputs:
- 2
- Output Phases:
- Programmable
- Voltage - Supply (Vcc/Vdd):
- 1.2V ~ 100V
- Frequency - Switching:
- 60kHz ~ 460kHz
- Duty Cycle (Max):
- 98%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Phase Control, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-eLQFP (7x7)
LTC3871ELXE FAQ
1.How can I place an order for LTC3871ELXE through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3871ELXE 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 LTC3871ELXE reliable?
The price and inventory of LTC3871ELXE are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3871ELXE is usually 5 days.
3.What payment methods are accepted for LTC3871ELXE?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3871ELXE transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3871ELXE?
LTC3871ELXE orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3871ELXE 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 LTC3871ELXE?
For technical support, including LTC3871ELXE datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3871ELXE requirements.
6.How does Aetrix verify that LTC3871ELXE is sourced from the original manufacturer or authorized distributors?
All LTC3871ELXE 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 LTC3871ELXE meets industry standards.
7.What is the process for return or replacement of LTC3871ELXE?
All LTC3871ELXE units undergo pre-shipment inspection (PSI). If there is an issue with LTC3871ELXE, 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 LTC3871ELXE part is unused and in its original packaging.
Return procedure for LTC3871ELXE:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3871ELXE Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
