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Analog Devices Inc. LTC7871ELWE#PBF
- Part No.:
- LTC7871ELWE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 64-LQFP Exposed Pad
- Datasheet:
-
LTC7871ELWE#PBF.pdf
- Description:
- 6-PHASE BIDIRECTIONAL BUCK/BOOST
- Quantity:
- Payment:
- Shipping:
Inventory:112
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Product details
Overview
LTC7871ELWE#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 up to 180A output at 12V, supports 60kHz–750kHz programmable switching frequency, and features ±1% voltage regulation accuracy over temperature.
For engineers reviewing the LTC7871ELWE#PBF datasheet, LTC7871ELWE#PBF pinout, LTC7871ELWE#PBF application, or LTC7871ELWE#PBF equivalent, key selection considerations include bidirectional current programming accuracy, SPI-based real-time monitoring, phase-lockable multi-IC synchronization, and AEC-Q100 qualification status for automotive power conversion.
Technical Context
The LTC7871ELWE#PBF implements a proprietary constant-frequency current-mode architecture with independent buck and boost loop compensation, enabling precise bidirectional energy transfer while maintaining >98% efficiency via synchronous rectification. Its six-phase interleaved operation achieves tight current matching across phases using dedicated SNSA+/SNSD+/SNS− sensing paths per channel.
Control logic dynamically selects buck or boost mode based on the BUCK pin state and external voltage conditions, while the integrated SPI interface allows real-time readback of operating status, fault reports, and programmable margining of VHIGH/VLOW setpoints - all without interrupting regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VHIGH Range | 6V to 100V input - supports 48V battery rail with 20% transient headroom for automotive load dump. |
| VLOW Range | 1.2V to 60V regulated output - covers 12V system operation with extended range for hybrid architectures. |
| Regulation Accuracy | ±1% over –40°C to 125°C - ensures stable bus voltage under thermal stress in engine bay environments. |
| Switching Frequency | 60kHz to 750kHz, programmable via FREQ pin or external SYNC - enables EMI optimization and inductor size reduction. |
| Current Sensing | DCR or RSENSE-based bidirectional sensing with ±10% IMON accuracy - provides reliable average current monitoring for battery balancing. |
| Phase Count | Six interleaved PWM outputs (PWM1–PWM6) with 60° phase offset - reduces input/output ripple and thermal stress on MOSFETs. |
| Interface | SPI-compliant serial port (CSB/SCLK/SDI/SDO) with fault reporting and register-level control - enables closed-loop telemetry in vehicle ECUs. |
Pinout & Package
Package: 64-lead (10mm × 10mm) LQFP (LWE), thermally enhanced with exposed SGND pad soldered to PCB ground plane (θJA = 17°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VHIGH (Pin 48) | Main high-side supply input | Accepts 6–100V; powers internal circuitry and gate drivers when EXTVCC is inactive. |
| VFBHIGH (Pin 7) | VHIGH feedback sense input | Non-inverting input to error amplifier; used to regulate VHIGH during boost mode. |
| VFBLOW (Pin 3) | VLOW feedback sense input | Inverting input to error amplifier; used to regulate VLOW during buck mode. |
| ITHHIGH / ITHLOW (Pins 6, 4) | Buck/boost current threshold inputs | Set peak current limit per phase; enable independent loop compensation for each direction. |
| SETCUR (Pin 11) | Maximum average current programming | Sources 16µA; sets bidirectional current limit via resistor or SPI register MFR_IDAC_SETCUR. |
| BUCK (Pin 54) | Mode selection control | Ground = boost mode; float/V5 = buck mode - determines primary regulation target (VLOW or VHIGH). |
| SNSA1+ to SNSA6+ (Pins 17,22,23,58,59,64) | AC current sense inputs (per phase) | Amplify switching ripple component for accurate peak current detection in current-mode control. |
| SNSD1+ to SNSD6+ (Pins 19,20,25,56,61,62) | DC current sense inputs (per phase) | Amplify DC inductor current for average current regulation and bidirectional monitoring. |
| IMON (Pin 10) | Current monitor output | Analog voltage proportional to total average inductor current; 1.25V = zero current, scalable with SETCUR. |
| CSB/SCLK/SDI/SDO (Pins 37–40) | SPI interface signals | 4-wire serial interface for configuration, telemetry, and fault logging; SDO requires external pull-up. |
| PGOOD / FAULT (Pins 30, 35) | Status indicator outputs | Open-drain outputs signaling regulation compliance (±10%) or fault condition (OV/UV/OC) with 40µs/120µs delay. |
Key Features
| Feature | Design Value |
|---|---|
| Six-phase interleaved control | Reduces input/output ripple by >90% vs single-phase, lowering capacitor count and EMI filter size in 48V/12V converters. |
| Bidirectional current regulation | Accurate ±10% IMON reporting and programmable SETCUR enable active battery balancing and regenerative braking support. |
| Independent buck/boost compensation | Separate ITHHIGH/ITHLOW pins allow optimized loop stability for both power flow directions without compromise. |
| SPI telemetry and control | Real-time readback of VHIGH/VLOW, current, temperature, and fault flags eliminates need for external ADCs in ECU integration. |
| Spread spectrum modulation | Configurable via SYNC pin to reduce peak EMI emissions by up to 12%, easing automotive CISPR 25 Class 5 compliance. |
| AEC-Q100 qualification in progress | Qualified for automotive underhood use with guaranteed operation from –40°C to 125°C junction temperature. |
Applications
| Automotive Dual-Battery Systems | Backup Power Supplies |
|---|---|
Use Scenario: Seamless power transfer between 48V starter-generator and 12V auxiliary loads during engine start-stop cycles. IC Role / Device Role / Timing Role: Bidirectional controller managing energy flow direction, voltage regulation, and current limiting across two battery domains. Use Value: Enables fuel-efficient micro-hybrid architectures with <100µs mode transition and <±1% bus voltage deviation during transients. |
Use Scenario: Uninterruptible DC-DC conversion in telecom base stations where 48V backup must power 12V control circuits during AC failure. IC Role / Device Role / Timing Role: High-reliability bidirectional regulator ensuring continuous VLOW delivery even if VHIGH drops below nominal. Use Value: Maintains critical control power with <40µs PGOOD assertion delay and hardware-based OV/UV fault protection. |
| Energy Recovery Systems | Industrial Battery Management |
Use Scenario: Capturing braking energy in electric commercial vehicles and feeding it back into the 48V battery pack. IC Role / Device Role / Timing Role: Boost-mode controller regulating VHIGH during regenerative events while monitoring bidirectional current with 6-phase precision. Use Value: Achieves >95% boost efficiency at 100A with DCR-based sensing, minimizing heat generation in confined chassis spaces. |
Use Scenario: Active cell balancing and inter-bank charge equalization in 48V lithium-ion battery systems for material handling equipment. IC Role / Device Role / Timing Role: Programmable current-limited bidirectional stage enabling controlled charge/discharge between parallel battery strings. Use Value: Supports ±16µA SETCUR resolution for fine-grained current control and SPI-read IMON for SOC estimation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional DC-DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7872EFE#PBF | Eight-phase version with identical pinout, higher phase count, and same 60kHz–750kHz frequency range. | Supports >200A output with lower per-phase current stress; requires additional external gate drivers for full scalability. | Select when higher output current or improved thermal distribution is required without changing layout footprint. |
| MPQ8875A-AEC1 | Single-chip 48V/12V bidirectional converter (integrated MOSFETs); no external driver support; max 60A output. | Lacks SPI telemetry, phase synchronization, and programmable current limits; limited to fixed-frequency operation. | Choose for cost-sensitive, lower-current applications where integration outweighs configurability and monitoring needs. |
Compared with LTC7871ELWE#PBF, LTC7872EFE#PBF offers greater current capacity through added phases but shares identical control architecture and automotive qualification path, whereas MPQ8875A-AEC1 trades flexibility and diagnostics for monolithic simplicity and lower BOM count.
Availability
LTC7871ELWE#PBF is available at Aetrix Electronics and suitable for automotive dual-battery systems, backup power supplies, and industrial battery management requiring stable component supply with long-term lifecycle assurance.
Supply support for LTC7871ELWE#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, and communications markets since 1965.
The LTC7871ELWE#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 supported VHIGH voltage for the LTC7871ELWE#PBF?
The LTC7871ELWE#PBF supports VHIGH input voltages from 6V to 100V, with absolute maximum rating of 100V. This allows robust operation in 48V automotive systems subject to ISO 7637-2 load dump transients. Operation above 80V requires careful attention to DRVCC biasing and thermal management due to increased power dissipation in internal regulators.
How does the LTC7871ELWE#PBF handle bidirectional mode switching?
The LTC7871ELWE#PBF switches between buck and boost modes based on the BUCK pin state and real-time voltage conditions. When BUCK is grounded, it operates in boost mode (VLOW-to-VHIGH); when floated or tied to V5, it operates in buck mode (VHIGH-to-VLOW). The transition is seamless and does not require reinitialization or software intervention.
Can the LTC7871ELWE#PBF be synchronized with other controllers?
Yes, the LTC7871ELWE#PBF supports multi-IC synchronization via its SYNC and CLKOUT pins. Driving SYNC with an external clock (60kHz–750kHz) locks all phases to that source, while CLKOUT provides a buffered phase-locked output to daisy-chain additional LTC7871ELWE#PBF or compatible controllers for up to 24-phase systems.
What current sensing methods does the LTC7871ELWE#PBF support?
The LTC7871ELWE#PBF supports both DCR and RSENSE current sensing. SNSD+ pins process the DC component for average current regulation, while SNSA+ pins amplify the AC component for peak current-mode control. ILIM pin selects gain scaling, and SETCUR sets the maximum average current limit with ±10% accuracy.
Is the LTC7871ELWE#PBF qualified for automotive applications?
The LTC7871ELWE#PBF is specified for –40°C to 125°C operation and is undergoing AEC-Q100 qualification. Its LWE package features an exposed thermal pad, robust ESD protection, and built-in OV/UV/OC fault detection - all aligned with automotive reliability requirements. Automotive-grade variants (e.g., LTC7871ELWE#WPBF) are available with full qualification documentation.
LTC7871ELWE#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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-LQFP-EP (10x10)
LTC7871ELWE#PBF FAQ
1.How can I place an order for LTC7871ELWE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7871ELWE#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 LTC7871ELWE#PBF reliable?
The price and inventory of LTC7871ELWE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7871ELWE#PBF is usually 5 days.
3.What payment methods are accepted for LTC7871ELWE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7871ELWE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7871ELWE#PBF?
LTC7871ELWE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7871ELWE#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 LTC7871ELWE#PBF?
For technical support, including LTC7871ELWE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7871ELWE#PBF requirements.
6.How does Aetrix verify that LTC7871ELWE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7871ELWE#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 LTC7871ELWE#PBF meets industry standards.
7.What is the process for return or replacement of LTC7871ELWE#PBF?
All LTC7871ELWE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7871ELWE#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 LTC7871ELWE#PBF part is unused and in its original packaging.
Return procedure for LTC7871ELWE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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