LMG708B0RXR - 20A GaN Synchronous Buck 80VIN | Texas Instruments
MPN： LMG708B0RXR ✓ 啟用中LMG708B0RXR 概覽
A GaN synchronous buck converter is a step-down DC-DC switching regulator that uses gallium-nitride FETs as the power switches. In the power-management hierarchy it sits within the DC-DC converter subsystem, converting higher-voltage distribution rails to lower point-of-load voltages for processors, logic, and mixed-signal loads. GaN transistors exhibit very low gate charge and output capacitance, enabling faster switching transitions and dramatically lower switching losses than silicon MOSFETs, which is especially valuable at high step-down ratios such as 48V-to-12V and 48V-to-5V.
Key features include the fully integrated controller-plus-GaN power-stage architecture, 20A continuous output current, and near-zero deadtime that minimizes body-diode conduction loss. The integrated approach eliminates external high-side/low-side FET selection and simplifies gate-drive PCB layout. Low RDS(on) reduces conduction loss at full load, yielding high efficiency across a broad load range, while high-frequency capability permits smaller inductors and output capacitors for maximum power density.
The 80V maximum input rating provides substantial headroom for 48V industrial distribution buses, telecom -48V infrastructures, and automotive load-dump transients. Output configuration flexibility - resistor-divider adjustable or fixed 5V/12V - allows one footprint to serve multiple rail requirements.
Typical applications include 48V industrial bus converters, telecom line cards, server power shelves, 48V automotive subsystems, and high-current LED lighting drivers. The wide input and output ranges make it an effective front-end point-of-load solution for 12V, 5V, or lower core rails at currents up to 20A.
Design tip: place low-ESR ceramic input capacitors close to VIN and PGND to handle steep high-frequency current steps, and use thermal vias under the exposed pad to hold junction temperature below 125C. Follow the TI datasheet layout guidelines for optimum switching performance and EMI behavior.
直接替換替代品，適用於 LMG708B0RXR — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： LMG708B0RXR （相同外形與佔位） — 差異在於 Output Voltage Range, Topology.
LMG708B0QRXRQ1
✅ 直接替換聯絡詢價
查看資料表 →LMG708B0QRXRQ1
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →LMG5126QRXRQ1
⚡ 相同封裝聯絡詢價
查看資料表 →LMG708B0RXR 最大額定值與電氣特性
| 拓撲 | Synchronous Step-Down (Buck) |
| 輸入電壓範圍 | 5 V to 80 V |
| 最大輸出電流 | 20 A |
| 輸出電壓範圍 | 1 V to 55 V (adjustable) |
| Fixed Output Options | 5 V or 12 V |
| Power Switches | Integrated low RDS(on) GaN FETs |
| Switching Characteristic | Near-zero deadtime switching |
| Maximum Junction Temperature | 125 C |
| 封裝 | VQFN-28 (RXR) |
| 安裝類型 | Surface Mount |
| Product Family | High power density GaN synchronous buck |
| Key Benefit | Ultra-high current density and excellent power conversion efficiency |
| Typical Applications | 48V bus converters, telecom, server power |
LMG708B0RXR vqfn-28 (rxr) 腳位配置指南
LMG708B0RXR（vqfn-28 (rxr) 封裝）的腳位配置。 此功率元件具有閘極、汲極與源極端子。對於非極性封裝，請參閱製造商資料表以取得確切的第 1 腳方向與佈局詳細資訊。常見應用包括電源設計、馬達驅動與負載切換。
無詳細腳位定義資料： LMG708B0RXR.
請參閱 資料表 以查看完整腳位配置。
典型應用
LMG708B0RXR 適用於 6 應用s: 48V Industrial Bus Converters, Server Power Shelves, Telecom Line Cards, 48V Automotive Subsystems, High-Current LED Lighting Drivers, Point-of-Load Core Rails.
48V Industrial Bus Converters
The LMG708B0RXR converts 48V industrial distribution rails directly to 12V or 5V at up to 20A, with the 80V input rating supplying margin for bus transients. Integrated GaN FETs with near-zero deadtime reduce switching losses at high step-down ratios, improving efficiency and shrinking inductor size. Place ceramic input capacitors at VIN and use the exposed-pad thermal vias to keep the junction under 125C in sealed industrial enclosures.
推薦
Server Power Shelves
In datacenter power shelves, the LMG708B0 delivers dense 48V-to-12V intermediate-bus conversion at 20A per phase. GaN near-zero deadtime switching raises efficiency versus silicon, cutting thermal load per rack. TI's LMG708B0-EVM2PH (12V, 40A, 400kHz two-phase EVM) validates multiphase scaling; two LMG708B0 phases interleave to double output current while halving input/output ripple.
推薦
Telecom Line Cards
Telecom infrastructure distributes power at -48V nominal; the LMG708B0's 80V input tolerance covers surges on rectified telecom feeds. It steps down to 12V or 5V point-of-load rails at up to 20A per device. High efficiency at full load reduces heatsink needs on densely packed line cards, while the adjustable 1V to 55V output range accommodates custom ASIC and DSP core voltages.
推薦
48V Automotive Subsystems
For 48V automotive zonal loads (mild-hybrid belts, e-compressor auxiliaries), the Q1-qualified LMG708B0QRXRQ1 in the identical RXR package handles battery transients within its 80V input rating. GaN efficiency at 20A minimizes waste heat under the hood. Use the fixed 12V output option for legacy 12V accessory rails, and follow the datasheet layout guide for EMI compliance in vehicle environments.
推薦
High-Current LED Lighting Drivers
High-bay and stage lighting fixtures use 48V LED strings; the LMG708B0 supplies controlled high-current rails up to 20A with the efficiency advantage of integrated GaN FETs. Its adjustable output (1V to 55V) supports series LED stack voltages, and 80V input headroom absorbs AC-line-derived transients. Compact VQFN-28 integration allows the driver electronics to fit within slim luminaire housings.
推薦
Point-of-Load Core Rails
For processors, FPGAs, and DSPs fed from a 48V or 24V backplane, the LMG708B0 provides a single-chip front-end conversion to 5V or lower core rails at 20A. The fixed-output options simplify BOM for common rails, while adjustable mode supports custom core voltages down to 1V. Low output ripple from GaN fast switching eases downstream filtering for noise-sensitive analog and RF loads.
推薦
推薦產品摘要
工程參考資料，適用於 LMG708B0RXR — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | LMG708B0QRXRQ1 | LMG5126QRXRQ1 |
|---|---|---|---|
| Package | VQFN-28 (RXR) | VQFN-28 (RXR) - same | VQFN-28 (RXR) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Power Switches | Integrated GaN FETs | Integrated GaN FETs | GaN family device |
| Qualification | Industrial/consumer grade | Automotive Q1 | Automotive Q1 |
主要差異化特點
- Integrated GaN power stage with near-zero deadtime (對比LM70860RRXR (6A silicon-class 80V buck))
- Automotive Q1 same-package option (對比LMG708B0QRXRQ1)
- Wide adjustable output to 55V (對比LMG5126QRXRQ1)
設計說明
Place low-ESR ceramic input capacitors immediately adjacent to the VIN and PGND pins to source the steep high-frequency current steps created by GaN fast switching. Minimize the high-side switching loop area; the integrated GaN stage has much faster edge rates than silicon, so short, wide power traces and a solid ground plane are essential for low EMI and clean switching waveforms.
The maximum junction temperature is 125C. At 48V-to-12V, 20A operation, use an array of thermal vias under the VQFN-28 exposed pad connecting to internal and bottom-layer copper pours. Estimate dissipation from I2R of the GaN RDS(on) plus switching losses, and verify with the TI LMG708B0-EVM2PH two-phase EVM thermal measurements for high-current designs.
Do not exceed the 80V absolute input rating - 48V buses with load-dump or surge events require input transient suppression. For the adjustable output variant, use 1% or better feedback divider resistors. When paralleling phases for currents above 20A (as in the EVM2PH), follow the TI two-phase current-sharing guidance to prevent one phase from carrying disproportionate load.
合規資訊
Compliance details not captured in verified data; commercial LMG708B0RXR is not the Q1 automotive variant. Consult ti.com/product/LMG708B0 for certifications. AEC-Q100-qualified operation requires the LMG708B0QRXRQ1.
