L6743D STMicroelectronics, L6743D Datasheet
L6743D
Specifications of L6743D
Available stocks
Related parts for L6743D
L6743D Summary of contents
Page 1
... SO8 package Applications ■ High current VRM / VRD for desktop / server / workstation CPUs ■ High current and high efficiency converter Description L6743D 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 codes L6743D L6743DTR ...
Page 2
... Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Device description and operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 High-impedance (HiZ) management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2 Preliminary OV protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3 Internal BOOT diode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.4 Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.5 Layout guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2/16 L6743D ...
Page 3
... L6743D 1 Typical application circuit and block diagram 1.1 Application circuit Figure 1. Typical application circuit 12V CC C PWM Input EN Input L6743D Reference Schematic 1.2 Block diagram Figure 2. Block diagram VCC EN PWM Typical application circuit and block diagram DEC VCC BOOT PWM UGATE ...
Page 4
... Connect to the high-side MOSFET source. 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. 8 UGATE 7 PHASE GND 6 LGATE 5 Function capacitor to the PHASE pin. Section 4.1 for details about HiZ. L6743D ...
Page 5
... L6743D 2.2 Thermal data Table 3. Thermal data Symbol Thermal resistance junction to ambient R THJA (Device soldered on 2s2p board) T Maximum junction temperature MAX T Storage temperature range STG T Junction temperature range J Maximum power dissipation at 25 °C P TOT (Device soldered on 2s2p PC board) Pins description and connection diagrams ...
Page 6
... UGATE and LGATE = OPEN BOOT = 12 V UGATE = OPEN; PHASE to GND; BOOT = 12 V VCC rising VCC falling PWM rising PWM falling PWM = 3.3 V PWM = 0 V See Figure 4 See Figure 4 EN rising EN falling to GND EN = 3.3 V L6743D Value Unit -0 -0.3 to VCC + 0 Min. Typ. ...
Page 7
... L6743D Table 5. Electrical characteristics (continued V± Symbol Parameter Gate drivers R HS source resistance HIHS I HS source current UGATE R HS sink resistance LOHS R LS source resistance HILS I LS source current LGATE R LS sink resistance LOLS Protections V Pre-OV threshold PRE_OV 1. Parameter(s) guaranteed by designed, not fully tested in production = 0 ° ...
Page 8
... This mechanism allows the system to regulate even if the current is negative. Before VCC to overcome the UVLO threshold, L6743D 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’ ...
Page 9
... PWM transition. The controller will have to manage its output voltage from that time on. 4.3 Internal BOOT diode L6743D 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. . ...
Page 10
... High-Side MOSFET Gate Charge [nC] 4.4 Power dissipation L6743D embeds high current drivers for both high-side and low-side MOSFETs then important to consider the power that the device is going to dissipate in driving them in order to avoid overcoming the maximum junction operative temperature. Two main terms contribute in the device power dissipation: bias power and drivers' power. ...
Page 11
... LS DRIVER 4.5 Layout guidelines L6743D 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 ...
Page 12
... External components placement example 12/16 in series to the boot capacitor. The use of R BOOT GATE INT MOSFET Rboot BOOT 1 PWM L6743D VCC 4 also contributes in BOOT VCC BOOT R BOOT R R GATE INT HGATE C C BOOT GS PHASE HS DRIVER HS MOSFET Cboot UGATE 8 PHASE 7 6 GND 5 LGATE L6743D ...
Page 13
... L6743D 5 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ® ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: www.st.com. ® ECOPACK trademark. Package mechanical data ® 13/16 ...
Page 14
... L6743D Inch Min. Typ. Max. 0.053 0.069 0.004 0.010 0.043 0.065 0.013 0.020 0.007 0.010 0.189 0.197 0.15 0.157 ...
Page 15
... L6743D 6 Revision history Table 7. Document revision history Date 09-Dec-2008 Revision 1 Initial release Revision history Changes 15/16 ...
Page 16
... 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 L6743D ...