L6743B STMicroelectronics, L6743B Datasheet
L6743B
Specifications of L6743B
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L6743B Summary of contents
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... VFDFPN8 package Applications ■ High current VRM / VRD for desktop / server / workstation CPUs ■ High current and high efficiency converters Description L6743B is a flexible, high-frequency dual-driver specifically designed to drive N-channel MOSFETs connected in synchronous-rectified buck topology. Table 1. Device summary Order code L6743B L6743BTR ...
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... Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Device description and operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.1 High-impedance (HiZ) management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.2 Preliminary OV protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.3 Internal BOOT diode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.4 Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.5 Layout guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2/16 L6743B ...
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... L6743B 1 Typical application circuit and block diagram 1.1 Application circuit Figure 1. Typical application circuit 12V CC C PWM Input EN Input L6743B Reference Schematic 1.2 Block diagram Figure 2. Block diagram VCC EN PWM Typical application circuit and block diagram DEC VCC BOOT PWM UGATE ...
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... This pin is also monitored for the adaptive dead-time management and pre- OV protection. high-side driver output. Connect to high-side MOSFET gate. Thermal pad connects the silicon substrate and makes good thermal contact with the PCB. Connect to the PGND plane. Function Section 5.1 for details about HiZ. L6743B ...
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... L6743B 3 Maximum ratings 3.1 Absolute maximum ratings Table 2. Absolute maximum ratings Symbol GND CC, PVCC to GND BOOT UGATE to PHASE V to GND PHASE V to GND LGATE GND PWM GND CC, PVCC 3.2 Thermal data Table 3. Thermal data Symbol Thermal resistance junction to ambient R THJA (Device soldered on 2s2p board) ...
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... Figure 4 See Figure 4 EN rising EN falling to GND EN = 3.3 V BOOT - PHASE = 12 V; 100 mA BOOT - PHASE = PHASE = 3.3 nF UGATE BOOT - PHASE = 12 V; 100 mA 100 mA ( GND = 5.6 nF LGATE 100 mA PHASE rising L6743B Min. Typ. Max. Unit 4 0.8 V µA 270 µA -360 ...
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... This mechanism allows the system to regulate even if the current is negative. Before VCC to overcome the UVLO threshold, L6743B keeps firmly-OFF both high-side and low-side MOSFETS then, after the UVLO has been crossed, the EN and PWM inputs take the control over driver’ ...
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... Preliminary OV protection After VCC has overcome its UVLO threshold and while in HiZ, L6743B activates the prelimi- nary-OV protection. The intent of this protection is to protect the load especially from high-side MOSFET failures during the system start-up. In fact, VRM, and more in general PWM controllers, have bus compatible turn-on threshold and results to be non-operative if VCC is below that turn- on thresholds (that results being in the range of about 10 V) ...
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... L6743B 5.3 Internal BOOT diode L6743B embeds a boot diode to supply the high-side driver saving the use of an external component. Simply connecting an external capacitor between BOOT and PHASE complete the high-side supply connections. To prevent bootstrap capacitor to extra-charge as a consequence of large negative spikes, an external series resistance R BOOT pin ...
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... Device description and operation When designing an application based on L6743B it is recommended to take into consideration the effect of external gate resistors on the power dissipated by the driver. External gate resistors helps the device to dissipate the switching power since the same power P will be shared between the internal driver impedance and the external resistor SW resulting in a general cooling of the device ...
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... L6743B 5.5 Layout guidelines L6743B provides driving capability to implement high-current step-down DC-DC converters. The first priority when placing components for these applications has to be reserved to the power section, minimizing the length of each connection and loop as much as possible. To minimize noise and voltage spikes (also EMI and losses) power connections must be a part of a power plane and anyway realized by wide and thick copper traces: loop must be anyway minimized ...
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... Device description and operation Figure 8. External components placement example 12/16 Rboot Cboot BOOT 1 PWM VCC 4 UGATE 8 PHASE 7 GND 6 LGATE 5 L6743B ...
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... L6743B 6 Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label ...
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... PACKAGE AND PACKING INFORMATION Very thin Fine pitch Dual Flat Package no Lead Weight: not available VFDFPN8 (3x3) L6743B ...
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... L6743B 7 Revision history Table 5. Document revision history Date 17-Jun-2008 Revision 1 Initial release Revision history Changes 15/16 ...
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... Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America 16/16 Please Read Carefully: © 2008 STMicroelectronics - All rights reserved STMicroelectronics group of companies www.st.com L6743B ...