LTC7871ILWE
Synchronous Bidirectional Buck or Boost ControllerThe LTC7871ILWE is a synchronous bidirectional buck or boost controller from Analog Devices. View the full LTC7871ILWE datasheet below including pinout, electrical characteristics.
Manufacturer
Analog Devices
Category
Switching Regulators (Buck)Overview
Part: LTC7871 — Analog Devices
Type: Six-Phase, Synchronous Bidirectional Buck or Boost Controller
Description: The LTC7871 is a high performance six-phase bidirectional buck or boost switching regulator controller that operates from V HIGH voltages up to 100V and V LOW voltages up to 60V, featuring ±1% voltage regulation accuracy and an SPI compliant serial interface. It allows dynamic regulation of input voltage, output voltage, or current.
Operating Conditions:
- Supply voltage: V HIGH: 6–100 V, V LOW: 1.2–60 V
- Operating temperature: -40 to 150 °C
- Switching frequency: 60 kHz to 750 kHz
Absolute Maximum Ratings:
- Max supply voltage: V HIGH: 100 V
- Max continuous current: DRV CC /EXTV CC Peak Current: 150 mA
- Max junction/storage temperature: 150 °C
Key Specs:
- V HIGH Supply Voltage Range: 6 V to 100 V
- V LOW Supply Voltage Range: 1.2 V to 60 V
- V LOW Regulated Feedback Voltage: 1.188 V to 1.212 V (l, ITH LOW Voltage = 1.5V)
- V HIGH Regulated Feedback Voltage: 1.188 V to 1.212 V (l, ITH HIGH Voltage = 0.5V)
- Synchronous Rectification Efficiency: Up to 98%
- Synchronizable Frequency: 60 kHz to 750 kHz (l, SYNC = External Clock)
- Maximum Current Sense Threshold (R SENSE Configuration): 12.5 mV (Typ, V ILIM = 0V)
- Buck Mode Maximum Duty Cycle: 98%
Features:
- Unique Architecture Allows Dynamic Regulation of Input Voltage, Output Voltage or Current
- Operates with External Gate Drivers and MOSFETs
- Synchronous Rectification: Up to 98% Efficiency
- ±1% Voltage Regulation Accuracy Overtemperature
- SPI Compliant Serial Interface
- Multiphase/Multi-ICs Operation Up to 24 Phases
Applications:
- Automotive 48V/12V Dual Battery Systems
- Backup Power Systems
Package:
- 64-Lead (10mm × 10mm) Plastic LQFP
Features
- n Unique Architecture Allows Dynamic Regulation of Input Voltage, Output Voltage or Current
- n Operates with External Gate Drivers and MOSFETs
- n VHIGH Voltages Up to 100V; V LOW Voltages Up to 60V
- n Synchronous Rectification: Up to 98% Efficiency
- n ADI-Proprietary Advanced Current Mode Control
- n ±1% Voltage Regulation Accuracy Overtemperature
- n Accurate, Programmable Inductor Current Monitoring and Bidirectional Regulation
- n SPI Compliant Serial Interface
- n Operation Status and Fault Report
- n Programmable V HIGH , V LOW Margining
- n Phase-Lockable Frequency: 60kHz to 750kHz
- n Optional Spread Spectrum Modulation
- n Multiphase/Multi-ICs Operation Up to 24 Phases
- n Selectable CCM/DCM/Burst Mode Operation
- n Thermally Enhanced 64-Lead LQFP Package
- n AEC-Q100 Qualification in Progress
Applications
- n Automotive 48V/12V Dual Battery Systems
- n Backup Power Systems
Pin Configuration
LTC7871ILWE Pinout
Package: 64-Lead (10mm × 10mm) Plastic LQFP (LWE)
| Pin | Name | Type | Description |
|---|---|---|---|
| 1 | SS | I | Soft-Start |
| 2 | NC | — | No Connect |
| 3 | VFB_LOW | I | V_LOW Feedback |
| 4 | ITH_LOW | I | V_LOW Error Amplifier Output |
| 5 | SGND | P | Signal Ground |
| 6 | ITH_HIGH | I | V_HIGH Error Amplifier Output |
| 7 | VFB_HIGH | I | V_HIGH Feedback |
| 8 | NC | — | No Connect |
| 9 | V5 | P | 5V Supply Output |
| 10 | IMON | O | Current Monitor Output |
| 11 | SETCUR | I | Set Current DAC Input |
| 12 | NC | — | No Connect |
| 13 | OV_HIGH | I | V_HIGH Overvoltage Threshold |
| 14 | UV_HIGH | I | V_HIGH Undervoltage Threshold |
| 15 | OV_LOW | I | V_LOW Overvoltage Threshold |
| 16 | SGND | P | Signal Ground |
| 17 | SNSA- | I | V_LOW Current Sense Minus |
| 18 | SNSA+ | I | V_LOW Current Sense Plus |
| 19 | SNSD- | I | V_HIGH Current Sense Minus |
| 20 | SNSD+ | I | V_HIGH Current Sense Plus |
| 21 | SNSC- | I | Auxiliary Current Sense Minus |
| 22 | SNSC+ | I | Auxiliary Current Sense Plus |
| 23 | SNSB- | I | Auxiliary Current Sense Minus |
| 24 | SNSB+ | I | Auxiliary Current Sense Plus |
| 25 | ILIM | I | Current Limit Threshold |
| 26 | RUN | I | Enable/Run Control |
| 27 | BUCK | I | Buck/Boost Mode Select |
| 28 | NC | — | No Connect |
| 29 | PGND | P | Power Ground |
| 30 | PWM1 | O | PWM Driver Output 1 |
| 31 | PWM2 | O | PWM Driver Output 2 |
| 32 | PWM3 | O | PWM Driver Output 3 |
| 33 | PWM4 | O | PWM Driver Output 4 |
| 34 | PWM5 | O | PWM Driver Output 5 |
| 35 | FAULT | O | Fault Output |
| 36 | PWM6 | O | PWM Driver Output 6 |
| 37 | CSB | I | Chip Select / SPI Control |
| 38 | SDO | O | Serial Data Output |
| 39 | SDI | I | Serial Data Input |
| 40 | SCLK | I | Serial Clock |
| 41 | NC | — | No Connect |
| 42 | EXT_VCC | P | External VCC Supply |
| 43 | NC | — | No Connect |
| 44 | DRVSET | I | Driver Supply Voltage Set |
| 45 | SGND | P | Signal Ground |
| 46 | DRV_CC | P | Driver Supply Voltage |
| 47 | NC | — | No Connect |
| 48 | V_HIGH | P | V_HIGH Supply Input |
| 49–64 | (Bottom row, left to right) | — | See diagram |
| 49 | SNSK+ | I | Auxiliary Current Sense Plus |
| 50 | SNSK- | I | Auxiliary Current Sense Minus |
| 51 | SNSJ+ | I | Auxiliary Current Sense Plus |
| 52 | SNSJ- | I | Auxiliary Current Sense Minus |
| 53 | SNSI+ | I | Auxiliary Current Sense Plus |
| 54 | SNSI- | I | Auxiliary Current Sense Minus |
| 55 | SNSH+ | I | Auxiliary Current Sense Plus |
| 56 | SNSH- | I | Auxiliary Current Sense Minus |
| 57 | SNSG+ | I | Auxiliary Current Sense Plus |
| 58 | SNSG- | I | Auxiliary Current Sense Minus |
| 59 | SNSF+ | I | Auxiliary Current Sense Plus |
| 60 | SNSF- | I | Auxiliary Current Sense Minus |
| 61 | SNSE+ | I | Auxiliary Current Sense Plus |
| 62 | SNSE- | I | Auxiliary Current Sense Minus |
| 63 | SNSD+ | I | V_HIGH Current Sense Plus |
| 64 | SNSD- | I | V_HIGH Current Sense Minus |
| EP | SGND (Exposed Pad) | P | Signal Ground — must be soldered to PCB |
Notes
- Package: 64-Lead LQFP (LWE suffix), 10mm × 10mm plastic LQFP with exposed pad (Pin 65, center).
- Exposed Pad (EP): Connected to SGND; must be soldered to PCB for proper thermal and electrical performance.
- Multiple Current Sense Pairs: The LTC7871ILWE includes six independent current-sense input pairs (SNSA±, SNSB±, SNSC±, SNSD±, SNSE±, SNSF±, SNSG±, SNSH±, SNSI±, SNSJ±, SNSK±) for multi-phase or multi-output monitoring.
- PWM Outputs: Six PWM driver outputs (PWM1–PWM6) for controlling power switches.
- SPI Interface: SDI, SDO, SCLK, CSB pins provide serial communication for configuration and monitoring.
- Supply Pins: V_HIGH (primary input), V5 (regulated 5V output), DRV_CC (driver supply), EXT_VCC (external supply option).
- Ground Pins: Multiple SGND pins (5, 16, 45) and PGND (29) for low-impedance return paths.
Electrical Characteristics
| SYMBOL | PARAMETER | CONDITIONS | MIN | TYP | MAX | UNITS | |
|---|---|---|---|---|---|---|---|
| Current Sense Pin Voltage (V SNSD + - V SNS - ) to IMON Gain | V ILIM = 0V, 1/4 V V5 V ILIM = Float, 3/4 V V5 , V V5 | 40 20 | V/V V/V | ||||
| Total DC Sense Signal Gain | DCR Configuration | 5 | V/V | ||||
| Total DC Sense Signal Gain | R SENSE Configuration | 4 | V/V | ||||
| V SENSE(MAX) (DCR Configuration) | Maximum Current Sense Threshold (Buck and Boost Mode) | V ILIM = 0V V ILIM = 1/4 V V5 V ILIM = Float V ILIM = 3/4 V V5 V ILIM = V V5 | l l l l l | 6.5 17.0 27.0 36.0 44.0 | 10.0 20.0 30.0 40.0 50.0 | 13.5 23.0 33.0 44.0 56.0 | mV mV mV mV mV |
| V SENSE(MAX) (R SENSE Configuration) | Maximum Current Sense Threshold (Buck and Boost Mode) | V ILIM = 0V V ILIM = 1/4 V V5 V ILIM = Float V ILIM = 3/4 V V5 V ILIM = V V5 | l l l l l | 8.1 21.2 33.7 45.0 55.0 | 12.5 25.0 37.5 50.0 62.5 | 16.9 28.8 41.3 55.0 70.0 | mV mV mV mV mV |
| V OCFT | Overcurrent Fault Threshold, V SNSD + - V SNS - | V ILIM = 0V V ILIM = 1/4 V V5 V ILIM = Float V ILIM = 3/4 V V5 V ILIM = V V5 | l l l l l | 31.0 43.0 54.0 65.0 76.0 | 37.5 50.0 62.5 75.0 87.5 | 44.0 57.0 71.0 85.0 99.0 | mV mV mV mV mV |
| V NOCFT | Negative Overcurrent Fault Threshold, V SNSD + - V SNS - | V ILIM = 0V V ILIM = 1/4 V V5 V ILIM = Float V ILIM = 3/4 V V5 V ILIM = V V5 | l l l l l | -45.0 -58.0 -72.0 -86.0 -100.0 | -37.5 -50.0 -62.5 -75.0 -87.5 | -30.0 -42.0 -53.0 -64.0 -75.0 | mV mV mV mV mV |
| Overcurrent Fault Threshold Hysteresis, \ | V SNSD + - V SNS - \ | V ILIM = 0V V ILIM = 1/4 V V5 , Float, 3/4 V V5 , V V5 | 25 31 | ||||
| DRV CC and V5 Linear Regulators | DRV CC and V5 Linear Regulators | DRV CC and V5 Linear Regulators | DRV CC and V5 Linear Regulators | DRV CC and V5 Linear Regulators | DRV CC and V5 Linear Regulators | DRV CC and V5 Linear Regulators | DRV CC and V5 Linear Regulators |
| V DRVCC | DRV CC Regulation Voltage | 12V < V EXTVCC < 60V, V DRVSET = V V5 12V < V EXTVCC < 60V, V DRVSET = Float 12V < V EXTVCC < 60V, V DRVSET = 0V | 9.5 7.6 4.8 | 10 8 5 | 10.5 8.4 5.2 | V V V | |
| DRV CC Load Regulation | I DRVCC = 0mA to 100mA, V EXTVCC = 14V | 1.6 | 3.0 | % | |||
| EXTV CC Switchover Voltage EXTV CC Hysteresis | EXTV CC Ramping Positive, V DRVSET = V V5 EXTV CC Ramping Positive, V DRVSET = Float EXTV CC Ramping Positive, V DRVSET = 0V | 10.7 8.5 6.9 12 | V V V % | ||||
| V5 | V5 Regulation Voltage | 6V < V DRVCC < 10V | 4.8 | 5.0 | 5.2 | V | |
| V5 Load Regulation | I V5 = 0mA to 20mA | 0.5 | 1 | % | |||
| Current DACs (IDAC) | Current DACs (IDAC) | Current DACs (IDAC) | Current DACs (IDAC) | Current DACs (IDAC) | Current DACs (IDAC) | Current DACs (IDAC) | Current DACs (IDAC) |
| V HIGH /V LOW IDAC Accuracy | MFR_IDAC_V LOW/HIGH = 0x40 or 0x7F | -1 | 1 | % | |||
| V HIGH /V LOW IDAC Program Range | -64 | 63 | μA | ||||
| SETCUR IDAC Program Range | 0 | 31 | μA | ||||
| LSB | V HIGH /V LOW IDAC LSB SETCUR IDAC LSB | 1 1 | μA μA | ||||
| Oscillator and Phase-Locked Loop | Oscillator and Phase-Locked Loop | Oscillator and Phase-Locked Loop | Oscillator and Phase-Locked Loop | Oscillator and Phase-Locked Loop | Oscillator and Phase-Locked Loop | Oscillator and Phase-Locked Loop | Oscillator and Phase-Locked Loop |
| I FREQ | FREQ Pin Output Current | l | 19 | 20 | 21 | μA | |
| Nominal Frequency | V SYNC = 0V, R FREQ = 51.1k | 230 | 250 | 270 | kHz | ||
| f LOW | Low Fixed Frequency | V SYNC = 0V, R FREQ = 27.4k | 55 | 70 | 85 | kHz | |
| f HIGH | High Fixed Frequency | V SYNC = 0V, R FREQ = 105k | 640 | 710 | 780 | kHz |
Rev. B
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T A = 25°C, V HIGH = 48V, V RUN = 5V unless otherwise noted. (Note 2)
V
| SYMBOL | PARAMETER | CONDITIONS | MIN | TYP | MAX | UNITS | |
|---|---|---|---|---|---|---|---|
| Synchronizable Frequency | SYNC = External Clock | l | 60 | 750 | kHz | ||
| Spread Spectrum Frequency Modulation Range | V SYNC = 5V, R FREQ = 51.1k, MFR_SSFM = 0x00 | -12 | 12 | % | |||
| θ 2 - θ 1 | Phase 2 Relative to Phase 1 | 180 | Deg | ||||
| θ 3 - θ 1 | Phase 3 Relative to Phase 1 | 60 | Deg | ||||
| θ 4 - θ 1 | Phase 4 Relative to Phase 1 | 240 | Deg | ||||
| θ 5 - θ 1 | Phase 5 Relative to Phase 1 | 120 | Deg | ||||
| θ 6 - θ 1 | Phase 6 Relative to Phase 1 | 300 | Deg | ||||
| θ CLKOUT - θ 1 | CLKOUT Phase to Phase 1 | 30 | Deg | ||||
| Clock Output High Voltage | I LOAD = 0.5mA | V5 - 0.2 | V5 | V | |||
| Clock Output Low Voltage | I LOAD = -0.5mA | 0.2 | V | ||||
| SYNC Pin Input Threshold SYNC Pin Input Resistance | SYNC Pin Rising SYNC Pin Falling | 2 | 100 | 0.8 | V V kΩ | ||
| Power Good and FAULT | Power Good and FAULT | Power Good and FAULT | Power Good and FAULT | Power Good and FAULT | Power Good and FAULT | Power Good and FAULT | Power Good and FAULT |
| PGOOD Voltage Low | I PGOOD = 2mA | 0.1 | 0.3 | V | |||
| PGOOD Leakage Current | V PGOOD = 5V | ±1 | μA | ||||
| PGOOD Trip Level, VFB HIGH /VFB LOW With Respect to the Regulated Voltage | VFB HIGH /VFB LOW Ramping Negative VFB HIGH /VFB LOW Ramping Positive | -10 10 | % % | ||||
| PGOOD Delay | PGOOD Pin High to Low | 40 | μs | ||||
| FAULT Voltage Low | I FAULT = 2mA | 0.1 | 0.3 | V | |||
| FAULT Voltage Leakage Current | V FAULT = 5V | ±1 | μA | ||||
| FAULT Delay | FAULT Pin High to Low | 120 | μs | ||||
| V LOW OV Comparator Threshold | 1.15 | 1.2 | 1.25 | V | |||
| V LOW OV Comparator Hysteresis | V OVLOW > 1.2V | 5 | μA | ||||
| V HIGH OV Comparator Threshold | 1.15 | 1.2 | 1.25 | V | |||
| V HIGH OV Comparator Hysteresis | V OVHIGH > 1.2V | 5 | μA | ||||
| V HIGH UV Comparator Threshold | 1.15 | 1.2 | 1.25 | V | |||
| V HIGH UV Comparator Hysteresis | V UVHIGH < 1.2V | 5 | μA | ||||
| PWM Outputs | PWM Outputs | PWM Outputs | PWM Outputs | PWM Outputs | PWM Outputs | PWM Outputs | PWM Outputs |
| PWM Output High Voltage | I LOAD = 0.5mA | l | V5 - 0.5 | V | |||
| PWM Output Low Voltage PWM Output Current in Hi-Z State | I LOAD = -0.5mA | l | 0.5 ±5 | V μA | |||
| DIGITAL I/O: CSB, SCLK, SDI, SDO | DIGITAL I/O: CSB, SCLK, SDI, SDO | DIGITAL I/O: CSB, SCLK, SDI, SDO | DIGITAL I/O: CSB, SCLK, SDI, SDO | DIGITAL I/O: CSB, SCLK, SDI, SDO | DIGITAL I/O: CSB, SCLK, SDI, SDO | DIGITAL I/O: CSB, SCLK, SDI, SDO | DIGITAL I/O: CSB, SCLK, SDI, SDO |
| V IL | Digital Input Low Voltage | Pins CSB, SCLK, SDI | 0.5 | V | |||
| V IH | Digital Input High Voltage | Pins CSB, SCLK, SDI | 1.8 | V | |||
| V OL | Digital Output Voltage Low | Pin SDO, Sinking 1mA | 0.3 | V | |||
| R CSB | CSB Pin Pull-Up Resistor | 300 | kΩ | ||||
| R SCLK | SCLK Pin Pull-Down Resistor | 300 | kΩ | ||||
| R SDI | SDI Pin Pull-Down Resistor | 300 | kΩ |
Thermal Information
The LTC7871 has a temperature sensor integrated on the IC, to sense the die temperature. When the die temperature exceeds 180°C, all switching actions stop, and all PWM pins become Hi-Z, thus turning off all external MOSFETs. At the same time, all the channels are disconnected from the IMON pins, and the SS and ITH HIGH / ITH LOW pins continue to function normally, so as not to interfere with other LTC7871 chips that may reference the common pins. When the temperature drops 15°C below the trip threshold, normal operation resumes.
The Typical Application on the first page of this data sheet is a basic LTC7871 application circuit. In general, external component selection is driven by the load requirements, and begins with the DCR or R SENSE and inductor value. Next, power MOSFETs are selected. Finally, V HIGH and VLOW capacitors are selected.
Typical Application
High Voltage Bidirectional Controller with Programming and Monitoring Functions
Related Variants
The following components are covered by the same datasheet.
| Part Number | Manufacturer | Package |
|---|---|---|
| LTC7871 | Analog Devices | 64-Lead (10mm × 10mm) Plastic LQFP |
| LTC7871E | Analog Devices | — |
| LTC7871ELWE | Analog Devices | — |
| LTC7871H | Analog Devices | — |
| LTC7871HLWE | Analog Devices | — |
| LTC7871HLWE#PBF | Analog Devices Inc. | 64-LQFP Exposed Pad |
| LTC7871I | Analog Devices | — |
| LTC7871J | Analog Devices | — |
| LTC7871JLWE | Analog Devices | — |
| LTC7871S | Analog Devices | — |
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