L6747A STMicroelectronics, L6747A Datasheet
L6747A
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L6747A Summary of contents
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... LS body diode conduction time. The L6747A features preliminary OV protection to protect the load from dangerous overvoltage due to MOSFET failures at startup. The L6747A device is available in a VFDFPN8 3x3 mm package. Package VFDFPN8 VFDFPN8 Doc ID 17126 Rev 1 ...
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... Pin information and thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Pin information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 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 BOOT capacitance design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.4 Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.5 Layout guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2/15 Doc ID 17126 Rev 1 L6747A ...
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... L6747A 1 Typical application circuit and block diagram Figure 1. L6747A typical application circuit 12V CC C PWM Input EN Input L6747A Reference Schematic Figure 2. L6747A block diagram VCC EN 70k PWM 7k Typical application circuit and block diagram DEC VCC BOOT PWM UGATE EN PHASE GND ...
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... High-side driver return path. Connect to the high-side MOSFET source. This pin is also monitored for adaptive dead-time management and pre-OV protection. Internal clamp circuitry prevents leakage from this pin in disable conditions. Doc ID 17126 Rev 1 UGATE 8 PHASE 7 GND 6 LGATE 5 Function BOOT Table 5). L6747A - ...
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... L6747A Table 2. Pin descriptions (continued) Pin # Name 8 UGATE - TH. PAD 2.2 Thermal data Table 3. Thermal data Symbol Thermal resistance junction-to-ambient R THJA (device soldered on 2s2p, 67mm x 69mm board) R Thermal resistance junction-to-case THJC T Maximum junction temperature MAX T Storage temperature range STG T Junction temperature range J Maximum power dissipation at 25° ...
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... UGATE = OPEN; PHASE = GND; BOOT = 12V PWM = 1 UGATE = OPEN; PHASE = GND; BOOT = 12V PWM = 0 UGATE = OPEN; PHASE = GND; BOOT = 12V VCC rising VCC falling Doc ID 17126 Rev 1 L6747A Value Unit - PHASE -0.3 to BOOT +0.3 PHASE -1 to BOOT +0.3 ...
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... L6747A Table 5. Electrical characteristics (continued) Symbol Parameter PWM and EN input Input high - V PWM_IH PWM Input low - V PWM_IL Input leakage t HiZ hold-off time HiZ t prop_L Propagation delays t prop_H Input high - V EN_IH EN Input low - V EN_IH Gate drivers R HS source resistance HIHS I HS source current ...
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... MOSFET is switched on, allowing the negative current of the inductor to recirculate. This mechanism allows the system to regulate even if the current is negative. Before V goes above the UVLO threshold, the L6747A keeps both the high-side and low- CC side MOSFETS firmly OFF. Then, after the UVLO has been crossed, the EN and PWM inputs take control over the driver’ ...
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... PWM transition. The controller must manage its output voltage from that moment on. 4.3 BOOT capacitance design The L6747A embeds a bootstrap diode to supply the high-side driver, removing the neces- sity for an external component. Simply connecting an external capacitor between BOOT and PHASE completes the high-side supply connections. = 1.6 V and ...
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... Bootstrap capacitance design 4.4 Power dissipation The L6747A embeds high current drivers for both high-side and low-side MOSFETs therefore important to consider the power that the device is going to dissipate in driving them in order to avoid exceeding the maximum junction operating temperature. Two main factors contribute to device power dissipation: bias power and driver power. ...
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... GND LS DRIVER 4.5 Layout guidelines The L6747A provides driving capability to implement high-current step-down DC-DC converters. The first priority when placing components for these applications should be given to the power section, minimizing the length of each connection and loop as much as possible. To minimize noise and voltage spikes (as well as EMI and losses) power connections must be part of a power plane, and in any case constructed with wide and thick copper traces ...
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... The use of R BOOT GATE INT MOSFET Rboot Cboot BOOT 1 PWM VCC 4 C Doc ID 17126 Rev 1 VCC BOOT BOOT R R GATE INT HGATE C C BOOT GS PHASE HS DRIVER HS MOSFET 8 UGATE PHASE 7 GND 6 LGATE 5 L6747A BOOT C DS ...
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... L6747A 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. Figure 9. VFDFPN8 mechanical data and package dimensions REF ...
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... Revision history 6 Revision history Table 6. Document revision history Date 24-Mar-2010 14/15 Revision 1 Initial release. Doc ID 17126 Rev 1 L6747A Changes ...
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... L6747A Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...