L5987 3 A step-down switching regulator Datasheet - production data Industrial: PLD, PLA, FPGA, chargers Networking: XDSL, modems, DC-DC modules Computer: optical storage, hard disk drive, printers, audio/graphic cards HSOP8 exposed pad VFQFPN8 3 x 3 mm LED driving Description Features The L5987 is a step-down switching regulator 3 A DC output current with a 3.5 A (minimum) current limited embedded 2.9 V to 18 V input voltage Power MOSFET, so it is able to deliver an up to Output voltage adjustable from 0.6 V 3 A current to the load depending on the application conditions. 250 kHz switching frequency, programmable up to 1 MHz The input voltage can range from 2.9 V to 18 V, Internal soft-start and inhibit while the output voltage can be set starting from 0.6 V to V . Having a minimum input voltage of IN Low dropout operation: 100% duty cycle 2.9 V, the device is suitable also for a 3.3 V bus. Voltage feedforward Requiring a minimum set of external components, Zero load current operation the device includes an internal 250 kHz switching Overcurrent and thermal protection frequency oscillator that can be externally adjusted up to 1 MHz. VFQFPN 3 x 3 -8L and HSOP8 package The VFQFPN8 and the HSOP packages with an exposed pad allow reducing the R down to Applications thJA 60 C/W and 40 C/W respectively. Consumer: STB, DVD, DVD recorder, car audio, LCD TV and monitors Figure 1. Application circuit May 2014 DocID14972 Rev 4 1/40 This is information on a product in full production. www.st.comContents L5987 Contents 1 Pin settings 6 1.1 Pin connection 6 1.2 Pin description 6 2 Maximum ratings 8 3 Thermal data . 8 4 Electrical characteristics 10 5 Functional description 14 5.1 Oscillator and synchronization . 16 5.2 Soft-start 20 5.3 Error amplifier and compensation 21 5.4 Overcurrent protection . 22 5.5 Inhibit function . 23 5.6 Hysteretic thermal shutdown 23 5.7 Maximum DC output current L5987A (HSOP8) 24 5.8 Maximum DC output current L5987 (VFQFPN) 24 6 Application information . 26 6.1 Input capacitor selection 26 6.2 Inductor selection . 27 6.3 Output capacitor selection 28 6.4 Compensation network . 29 6.4.1 Type III compensation network . 30 6.4.2 Type II compensation network 34 6.5 Thermal considerations 38 6.6 Layout considerations . 39 6.7 Application circuit . 41 7 Package information 45 2/40 DocID14972 Rev 4