L7986 3 A step-down switching regulator Datasheet - production data Applications Consumer: STB, DVD, DVD recorder, car audio, LCD TV and monitors Industrial: PLD, PLA, FPGA, chargers HSOP8 exp. pad VFDFPN10 3 x 3 mm Networking: XDSL, modems, DC-DC modules Computer: optical storage, hard disk drive, printers, audio/graphic cards Features LED driving 3 A DC output current Description 4.5 V to 38 V input voltage The L7986/A is a step-down switching regulator Output voltage adjustable from 0.6 V with a 3.7 A (minimum) current limited embedded 250 kHz switching frequency, programmable power MOSFET, so it is able to deliver up to 3 A up to 1 MHz current to the load depending on the application Internal soft-start and enable conditions. The input voltage can range from 4.5 V to 38 V, while the output voltage can be set Low dropout operation: 100% duty cycle starting from 0.6 V to V . Requiring a minimum IN Voltage feed-forward set of external components, the device includes Zero load current operation an internal 250 kHz switching frequency oscillator that can be externally adjusted up to 1 MHz. The Overcurrent and thermal protection DFN and the HSOP packages with exposed pad VFDFPN 3 x 3 - 10L and HSOP8 package allow reducing the R down to 60 C/W and 40 thJA C/W respectively. Figure 1. Application circuit / L 9 Q 9 9 9287 IURP 9 WR L 9Q 9& & 28 7 *1 6<1&+ / )6: (1 )% &203 & 5 & & 5 5 & 5 *1 *1 0 October 2021 DocID022450 Rev 8 1/47 This is information on a product in full production. www.st.comContents L7986 Contents 1 Pin settings 6 1.1 Pin connection 6 1.2 Pin description 6 2 Maximum ratings 7 3 Thermal data . 7 4 Electrical characteristics . 8 5 Functional description 10 5.1 Oscillator and synchronization 11 5.2 Soft-start 13 5.3 Error amplifier and compensation 14 5.4 Overcurrent protection . 14 5.5 Enable function 16 5.6 Hysteretic thermal shutdown 16 6 Application information . 17 6.1 Input capacitor selection 17 6.2 Inductor selection . 18 6.3 Output capacitor selection 19 6.4 Compensation network . 20 6.4.1 Type III compensation network . 22 6.4.2 Type II compensation network 26 6.5 Thermal considerations 29 6.6 Layout considerations . 30 6.7 Application circuit . 32 7 Application ideas . 36 7.1 Positive buck-boost . 36 7.2 Inverting buck-boost . 38 2/47 DocID022450 Rev 8