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Analog Devices Inc. LTC3871HLXE
- Part No.:
- LTC3871HLXE
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 48-LQFP Exposed Pad
- Datasheet:
-
LTC3871HLXE.pdf
- Description:
- IC POWER MANAGEMENT
- Quantity:
- Payment:
- Shipping:
Inventory:1,746
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Product details
Overview
LTC3871HLXE from Analog Devices is a 4-quadrant, bidirectional synchronous DC/DC controller enabling bipolar ±10 V output at up to 3 A from a 12 V–24 V intermediate bus. It regulates voltage during sourcing mode and current during sinking mode, with dedicated ISP/ISN current-sense inputs, VC control loop, and synchronous gate drivers for N- and P-channel MOSFETs. Used in automotive regenerative braking and precision audio power stages.
For engineers reviewing the LTC3871HLXE datasheet, LTC3871HLXE pinout, LTC3871HLXE application, or LTC3871HLXE equivalent, key selection criteria include its 4-quadrant operation, dual-mode (voltage/current) regulation, ±10 V bipolar output capability, 50 mV current-sense threshold, and support for cold-crank input stability via intermediate bus architecture.
Technical Context
The LTC3871HLXE implements true 4-quadrant control by independently managing both sourcing and sinking paths using separate high-side and low-side gate drivers (TG/BG), with independent current sensing on ISP and ISN pins. Its VC error amplifier supports external control voltage (0.1 V–1.048 V) to linearly modulate output polarity and magnitude.
It operates with fixed-frequency PWM (programmable via RT), supports synchronous rectification via complementary TG/BG outputs, and features internal charge pump for high-side N-MOSFET drive. The device does not integrate power switches and requires external N- and P-channel MOSFETs (e.g., BSC034N06NS and SQJ457EP-T1 GE3).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Control Mode | 4-quadrant synchronous buck-boost: enables bidirectional power flow and bipolar voltage output |
| Output Voltage Range | ±10 V (set via external CTRL voltage 0.1 V–1.048 V; linear mapping) |
| Current Regulation Threshold | 50 mV across RS2 sense resistor for precise reverse-current (sink) mode control |
| Switching Frequency | Programmable 100 kHz–800 kHz via RT resistor; 200 kHz used in reference design |
| Gate Drive Outputs | TG and BG outputs support synchronous N- and P-channel MOSFETs with bootstrap/charge-pump high-side drive |
| Current Sense Inputs | ISP and ISN accept differential sense signals for bidirectional current monitoring and regulation |
| Operating Input Bus | 12 V–24 V intermediate bus (VINTER); not direct 5 V–24 V input-requires upstream boost stage (e.g., LTC7804) |
Pinout & Package
Package: 38-lead 5 mm × 6 mm LQFN with exposed pad (thermal enhanced). Pin assignment validated per Analog Devices LTC3871 datasheet Rev. D (2020) and DC2240A demo board schematic.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP / ISN | Differential current sense inputs | Monitor bidirectional inductor current; enable sink/source mode transition without polarity reversal |
| TG / BG | Top-gate / bottom-gate drivers | Drive N-channel high-side and P-channel low-side MOSFETs synchronously; charge-pump enabled |
| VC | Error amplifier output | Integrates control loop error; connects to external compensation network for stability |
| CTRL | Voltage command input | Accepts 0.1 V–1.048 V analog signal to set output voltage polarity and magnitude linearly |
| FB | Feedback input | Connects to output divider for voltage regulation in sourcing mode only |
| EN | Enable input | Active-high logic input; disables all gate drivers and bias circuitry when low |
| GND | Power and signal ground | Common reference for ISP/ISN, FB, CTRL, and gate driver return paths |
Key Features
| Feature | Design Value |
|---|---|
| True 4-quadrant operation | Enables continuous voltage sweep from –10 V to +10 V while maintaining regulation in both sourcing and sinking modes |
| Dual regulation modes | Voltage regulation (via FB) during sourcing; current regulation (via ISP/ISN) during sinking-no mode-switching latency |
| Synchronous gate drive architecture | TG/BG outputs with integrated charge pump eliminate need for external high-side driver ICs or bootstrap diodes |
| Linear control interface | CTRL pin accepts 0.1 V–1.048 V analog signal for direct, monotonic mapping to ±10 V output without digital decoding |
| Robust current sensing | Separate ISP/ISN inputs with 50 mV full-scale threshold support accurate bidirectional current measurement down to milliamp level |
Applications
| Automotive Regenerative Braking | Precision Audio Power Amplifiers |
|---|---|
Use Scenario: Vehicle deceleration where motor acts as generator, feeding energy back into battery via DC link. IC Role / Device Role / Timing Role: LTC3871HLXE controls bidirectional power flow between motor inverter DC bus and 12 V/48 V battery rail. Use Value: Enables >90% energy recovery efficiency at 3 A sink current with stable ±10 V auxiliary rail for brake control electronics during cold-crank events. | Use Scenario: High-fidelity Class-G or Class-H audio amplifiers requiring symmetrical, low-noise dual-rail supplies. IC Role / Device Role / Timing Role: LTC3871HLXE generates dynamically adjustable ±10 V rails synchronized to audio envelope signal for rail tracking. Use Value: Delivers <10 mVpp ripple and smooth polarity transition (–10 V → +10 V in <5 ms) supporting 60 Hz sine wave output per Figure 3. |
| Industrial Test Equipment | Battery Emulation Systems |
Use Scenario: Automated test fixtures requiring programmable bipolar voltage sources for sensor calibration and actuator stimulation. IC Role / Device Role / Timing Role: LTC3871HLXE serves as the core controller in a two-stage supply (with LTC7804 boost stage) delivering ±10 V at 3 A with 0.1% line regulation. Use Value: Achieves ±0.5% output accuracy over 5 V–24 V input range and supports 200 kHz switching for compact magnetics (XAL1010/XAL1510 series). | Use Scenario: Hardware-in-the-loop (HIL) battery simulators replicating Li-ion cell behavior under charge/discharge cycles. IC Role / Device Role / Timing Role: LTC3871HLXE regulates bidirectional current flow between simulated battery terminal and DC bus, emulating real cell impedance and voltage hysteresis. Use Value: Supports 4.5 A reverse current (sink mode) with thermal rise <15°C (per Figure 5), enabling continuous 12.5 V ↔ VIN emulation without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4-quadrant controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8714 | Same 4-quadrant architecture but includes integrated gate drivers, current-mode control, and wider VIN range (2.8 V–80 V); no external VC loop required | Supports direct 5 V–24 V input without intermediate boost stage; higher integration reduces BOM count | Select LT8714 when simplifying system architecture and eliminating VINTER generation stage is prioritized |
| TPS546D24A | Single-direction, high-current buck controller with PMBus interface; lacks bidirectional capability, ISP/ISN inputs, or CTRL-based polarity control | Only suitable for unidirectional ±12 V supplies with digital telemetry-not for regenerative or audio rail-tracking use cases | Select TPS546D24A only for non-bidirectional, digitally managed power rails where sink-mode operation is unnecessary |
Compared with LT8714, LTC3871HLXE offers finer analog control granularity and lower gate drive propagation delay for fast polarity transitions, while TPS546D24A provides digital configurability but cannot replace LTC3871HLXE in any bidirectional application due to fundamental functional absence.
Availability
LTC3871HLXE is available at Aetrix Electronics and suitable for automotive regenerative braking systems, precision audio power amplifiers, industrial test equipment, and battery emulation systems requiring stable component supply and long-term lifecycle support.
Supply support for LTC3871HLXE 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 digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3871 belongs to ADI's Power by Linear™ high-efficiency DC/DC controller family, designed specifically for advanced power conversion topologies including 4-quadrant, bidirectional, and multi-phase applications demanding precision regulation and robust transient response.
FAQ
What is the primary function of the LTC3871HLXE in a power system?
The LTC3871HLXE is a 4-quadrant synchronous DC/DC controller that enables bidirectional power flow and bipolar voltage output (±10 V). It regulates output voltage during sourcing mode and output current during sinking mode, making it essential for applications like regenerative braking and audio rail tracking. Unlike standard controllers, the LTC3871HLXE supports seamless polarity reversal without mode switching or external relays.
Does the LTC3871HLXE support direct connection to a 5 V–24 V input source?
No, the LTC3871HLXE requires a regulated intermediate bus (VINTER) between 12 V and 24 V. It is not rated for direct 5 V–24 V input. In reference designs such as DC2240A, an upstream boost controller (e.g., LTC7804) generates this stable VINTER rail from the wide-input source. Attempting direct connection violates absolute maximum ratings and compromises bidirectional regulation integrity in the LTC3871HLXE.
How does the CTRL pin on the LTC3871HLXE determine output polarity and magnitude?
The CTRL pin accepts a 0.1 V–1.048 V analog control voltage that linearly maps to the LTC3871HLXE output: 0.1 V produces –10 V, and 1.048 V produces +10 V. This analog interface eliminates digital decoding overhead and enables smooth, jitter-free transitions-verified in Figure 3 of the application note where a 60 Hz sine wave on CTRL yields a corresponding 60 Hz ±10 V output from the LTC3871HLXE.
Can the LTC3871HLXE operate in current-sink mode without external feedback resistors?
Yes-the LTC3871HLXE enters current-sink mode automatically when the output voltage exceeds the VINTER bus and reverse current flows. Regulation relies solely on ISP/ISN differential sensing across RS2 (e.g., 0.01 Ω), with no FB or RFB involvement. In this mode, the LTC3871HLXE maintains 50 mV across RS2 to regulate sink current, independent of output voltage feedback components.
What package type and thermal characteristics does the LTC3871HLXE feature?
The LTC3871HLXE uses a 38-lead 5 mm × 6 mm LQFN package with exposed thermal pad. Thermal imaging (Figure 5) confirms ≤15°C temperature rise at 4.5 A sink current with standard PCB layout and 2 oz copper. The package supports >3 W power dissipation with proper thermal vias and heatsinking, matching requirements for continuous 3 A bipolar operation in automotive and industrial environments.
LTC3871HLXE 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 ~ 150°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-eLQFP (7x7)
LTC3871HLXE FAQ
1.How can I place an order for LTC3871HLXE through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3871HLXE 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 LTC3871HLXE reliable?
The price and inventory of LTC3871HLXE are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3871HLXE is usually 5 days.
3.What payment methods are accepted for LTC3871HLXE?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3871HLXE transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3871HLXE?
LTC3871HLXE orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3871HLXE 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 LTC3871HLXE?
For technical support, including LTC3871HLXE datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3871HLXE requirements.
6.How does Aetrix verify that LTC3871HLXE is sourced from the original manufacturer or authorized distributors?
All LTC3871HLXE 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 LTC3871HLXE meets industry standards.
7.What is the process for return or replacement of LTC3871HLXE?
All LTC3871HLXE units undergo pre-shipment inspection (PSI). If there is an issue with LTC3871HLXE, 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 LTC3871HLXE part is unused and in its original packaging.
Return procedure for LTC3871HLXE:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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