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Analog Devices Inc. LTC7871JLWE#PBF
- Part No.:
- LTC7871JLWE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 64-LQFP Exposed Pad
- Datasheet:
-
LTC7871JLWE#PBF.pdf
- Description:
- 6-PHASE BIDIRECTIONAL BUCK/BOOST
- Quantity:
- Payment:
- Shipping:
Inventory:145
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Product details
Overview
LTC7871JLWE#PBF from Analog Devices is a six-phase, synchronous bidirectional buck/boost controller designed for 48V/12V dual-battery automotive systems. It regulates bidirectionally between VHIGH (up to 100V) and VLOW (up to 60V), delivers ±1% voltage regulation accuracy over temperature, supports 60kHz–750kHz programmable switching frequency, and features SPI interface with phase-lockable operation across up to 24 phases.
For engineers reviewing the LTC7871JLWE#PBF datasheet, LTC7871JLWE#PBF pinout, LTC7871JLWE#PBF application, or LTC7871JLWE#PBF equivalent, key selection considerations include its AEC-Q100 qualification status (in progress), 64-pin LQFP thermal performance (θJA = 17°C/W), bidirectional current programming loop, and independent buck/boost loop compensation - all critical for high-reliability 48V mild-hybrid power conversion designs.
Technical Context
The LTC7871JLWE#PBF implements a proprietary constant-frequency current-mode architecture with six interleaved phases offset at 0°, 60°, 120°, 180°, 240°, and 300°, enabling low-noise operation and precise per-phase current matching. Its dual-loop control supports independent error amplifiers for VHIGH and VLOW regulation, with transconductance values of 2 mmho (buck) and 1 mmho (boost).
It integrates an SPI-compliant serial interface (5 MHz max SCLK, 4-wire) for real-time monitoring of operation status and faults, programmable margining of VHIGH/VLOW setpoints, and configuration of CCM/DCM/Burst mode. The device uses external gate drivers and MOSFETs, with DRVCC output programmable to 5V/8V/10V via DRVSET pin and EXTVCC switchover thresholds ranging from 6.9V to 10.7V depending on DRVSET state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VHIGH Range | 6V to 100V input - enables direct connection to 48V battery rails with 2× safety margin for transients. |
| VLOW Range | 1.2V to 60V output/input - supports 12V system regulation and bidirectional energy transfer in dual-battery architectures. |
| Regulation Accuracy | ±1% over temperature - ensures stable voltage setpoints without recalibration in under-hood environments. |
| Switching Frequency | 60kHz to 750kHz, synchronizable - allows EMI optimization and multi-IC phase alignment for scalable high-current designs. |
| Phase Count | Six-phase interleaved operation - reduces input/output ripple current by ~87% vs single-phase, easing filter design. |
| Current Sensing | Separate AC (SNSA) and DC (SNSD) sense inputs per phase - enables accurate peak and average current measurement for robust overcurrent protection. |
| Thermal Rating | J-grade: –40°C to +150°C junction - qualified for engine compartment placement with validated derating above 125°C. |
Pinout & Package
The LTC7871JLWE#PBF is housed in a thermally enhanced 64-lead (10mm × 10mm) plastic LQFP package (LWE) with exposed SGND pad (Pin 65) requiring PCB soldering for rated thermal performance (θJA = 17°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VHIGH (Pin 48) | Main high-side supply input | Accepts up to 100V; powers internal circuitry and gate drivers when EXTVCC is inactive. |
| VFBHIGH / VFBLOW (Pins 7, 3) | Voltage feedback inputs | Connect to resistor dividers from VHIGH/VLOW rails; enable ±1% regulation accuracy with ±40nA input bias. |
| ITHHIGH / ITHLOW (Pins 6, 4) | Current threshold control points | Set maximum inductor current via voltage; buck mode uses ITHLOW (1.5V ref), boost uses ITHHIGH (0.5V ref). |
| SNSA1+–SNSA6+, SNSD1+–SNSD6+, SNS1––SNS6– (Pins 17–25, 56–64, 18–24, 57–63) | Per-phase current sense terminals | SNSA+ captures AC ripple for peak current limiting; SNSD+ senses DC component for average current regulation. |
| PWM1–PWM6 (Pins 29, 31, 32, 33, 34, 36) | Gate drive outputs | Three-state compatible signals driving external high-side MOSFETs; timing synchronized across six phases. |
| BUCK (Pin 54) | Mode selection input | Ground = boost mode (VLOW→VHIGH); float or V5 = buck mode (VHIGH→VLOW); enables dynamic direction control. |
| SPI Interface (CSB, SCLK, SDI, SDO; Pins 37–40) | Digital configuration bus | Enables real-time readback of fault status, VHIGH/VLOW margining, and SETCUR current limit programming. |
Key Features
| Feature | Design Value |
|---|---|
| Six-phase interleaved control | Reduces RMS input/output capacitor ripple current by >85%, lowering thermal stress and enabling smaller passive components. |
| Independent buck/boost loop compensation | Allows optimized stability margins for both power flow directions without hardware rework or compensation network changes. |
| Programmable current limit via SETCUR pin | 16µA sourcing current with 1µA LSB enables precise, temperature-stable current setting across full operating range. |
| Spread spectrum modulation support | Reduces peak EMI amplitude by up to 12% when enabled via SYNC pin, easing compliance with CISPR 25 Class 5 requirements. |
| Thermally enhanced LQFP with exposed pad | Exterior ground pad (Pin 65) must be soldered to PCB plane to achieve specified θJA = 17°C/W and sustain 150°C junction operation. |
Applications
| Automotive 48V/12V Dual-Battery Systems | Backup Power Systems |
|---|---|
Use Scenario: Bidirectional power transfer between 48V starter-generator and 12V chassis battery during engine start-stop cycles and regenerative braking. IC Role / Device Role / Timing Role: Primary bidirectional controller managing energy flow direction, voltage regulation, and phase interleaving timing across six channels. Use Value: Enables >98% efficiency in both buck and boost modes, reducing thermal load in confined engine bay space while supporting AEC-Q100 reliability targets. | Use Scenario: Seamless transition between main AC supply and backup battery during grid failure in telecom or industrial UPS units. IC Role / Device Role / Timing Role: High-voltage bidirectional regulator maintaining stable 12V/48V rail integrity during source switching with sub-100µs fault response. Use Value: Independent OV/UV monitoring on both rails (OVHIGH, UVHIGH, OVLOW) ensures fail-safe shutdown before battery overcharge or deep discharge occurs. |
| High-Current DC-DC Conversion | Scalable Multi-Controller Power Architectures |
Use Scenario: 180A 12V output generation from 48V input in electric power steering or ADAS domain controllers. IC Role / Device Role / Timing Role: Six-phase controller delivering 30A per phase with 60° phase shift, minimizing input capacitor RMS current and EMI emissions. Use Value: Programmable soft-start (SS pin) and ramp-controlled PWMEN enable controlled inrush current limiting during cold crank conditions. | Use Scenario: Parallel operation of multiple LTC7871 controllers to scale output current beyond 360A in server rack PSUs or EV charging modules. IC Role / Device Role / Timing Role: Master-slave synchronization via CLKOUT/SYNC pins ensures deterministic phase alignment across up to 24 total phases. Use Value: SPI interface allows centralized firmware control of all units, including coordinated fault reporting and dynamic current sharing calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional buck/boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7872JLWE#PBF | Pin-compatible upgrade with integrated gate drivers (replaces external drivers), higher VHIGH rating (120V), and improved current sense accuracy (±5% vs ±10%). | Eliminates external driver ICs and associated layout complexity; suited for space-constrained designs where driver integration adds value. | Select LTC7872JLWE#PBF when board area reduction and simplified BOM outweigh need for discrete driver flexibility. |
| MPQ8645PGU-AEC1-Z | Single-phase, 48V-input, 12V-output synchronous buck controller with integrated MOSFETs; no boost capability; AEC-Q100 qualified. | Only supports unidirectional 48V→12V conversion; lacks bidirectional control, multi-phase interleaving, and SPI configurability. | Choose MPQ8645PGU-AEC1-Z only for cost-sensitive, lower-current (<40A), unidirectional 48V/12V applications without need for reverse power flow. |
Compared with LTC7872JLWE#PBF, the LTC7871JLWE#PBF retains external driver flexibility and offers finer-grained current monitoring via separate SNSA/SNSD inputs; versus MPQ8645PGU-AEC1-Z, it provides true bidirectional operation, six-phase scalability, and comprehensive digital supervision - making it uniquely suited for high-reliability, high-power automotive energy management.
Availability
LTC7871JLWE#PBF is available at Aetrix Electronics and suitable for automotive 48V/12V dual-battery systems, backup power systems, high-current DC-DC conversion, and scalable multi-controller power architectures requiring stable component supply and extended temperature operation.
Supply support for LTC7871JLWE#PBF 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LTC7871JLWE#PBF belongs to Analog Devices' Power by Linear™ controller family, engineered specifically for high-efficiency, high-reliability bidirectional DC-DC conversion in next-generation automotive electrification systems.
FAQ
What is the maximum operating junction temperature for the LTC7871JLWE#PBF?
The LTC7871JLWE#PBF is rated for a maximum junction temperature of +150°C, with guaranteed operation across –40°C to +150°C. Thermal derating is required above +125°C to maintain lifetime reliability, and the exposed SGND pad (Pin 65) must be soldered to the PCB ground plane to achieve the specified θJA = 17°C/W thermal resistance.
How does the LTC7871JLWE#PBF support bidirectional operation between VHIGH and VLOW rails?
The LTC7871JLWE#PBF supports bidirectional operation through its BUCK pin (Pin 54): grounding this pin configures boost mode (VLOW → VHIGH), while floating or tying it to V5 enables buck mode (VHIGH → VLOW). Internal dual-loop control with independent ITHHIGH and ITHLOW thresholds ensures stable regulation and current limiting in both directions.
Can the LTC7871JLWE#PBF synchronize with external clock sources?
Yes, the LTC7871JLWE#PBF supports external synchronization via the SYNC pin (Pin 52), accepting clock inputs from 60kHz to 750kHz. When driven by an external source, all six internal phases lock to the incoming clock edge, enabling deterministic timing alignment across multiple LTC7871JLWE#PBF devices in parallel configurations.
What is the purpose of the separate SNSA+ and SNSD+ pins on the LTC7871JLWE#PBF?
The LTC7871JLWE#PBF uses separate SNSA+ (AC sense) and SNSD+ (DC sense) inputs per phase to decouple peak current limiting from average current regulation. SNSA+ captures switching ripple for cycle-by-cycle overcurrent protection, while SNSD+ measures steady-state current for accurate bidirectional current programming and IMON monitoring.
Does the LTC7871JLWE#PBF include built-in overvoltage and undervoltage protection?
Yes, the LTC7871JLWE#PBF integrates dedicated OV/UV comparators for both VHIGH and VLOW rails. OVHIGH, UVHIGH, and OVLOW pins accept resistor dividers to set custom thresholds (trip point = 1.2V), with 5µA hysteresis current sourced or sunk to provide adjustable hysteresis - enabling robust fault detection without external circuitry.
LTC7871JLWE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 64-LQFP Exposed Pad
- Packaging:
- Tray
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Number of Outputs:
- 6
- Output Phases:
- 6
- Voltage - Supply (Vcc/Vdd):
- 6V ~ 100V
- Frequency - Switching:
- 60kHz ~ 750kHz
- Duty Cycle (Max):
- 98%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- SPI
- Control Features:
- Enable, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-LQFP-EP (10x10)
LTC7871JLWE#PBF FAQ
1.How can I place an order for LTC7871JLWE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7871JLWE#PBF 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 LTC7871JLWE#PBF reliable?
The price and inventory of LTC7871JLWE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7871JLWE#PBF is usually 5 days.
3.What payment methods are accepted for LTC7871JLWE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7871JLWE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7871JLWE#PBF?
LTC7871JLWE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7871JLWE#PBF 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 LTC7871JLWE#PBF?
For technical support, including LTC7871JLWE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7871JLWE#PBF requirements.
6.How does Aetrix verify that LTC7871JLWE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7871JLWE#PBF 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 LTC7871JLWE#PBF meets industry standards.
7.What is the process for return or replacement of LTC7871JLWE#PBF?
All LTC7871JLWE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7871JLWE#PBF, 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 LTC7871JLWE#PBF part is unused and in its original packaging.
Return procedure for LTC7871JLWE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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