L5986 ,2.5 A step-down switching regulatorFunctional description . . . . . . . 85.1 Oscillator and synchronization . . 95.2 Soft-sta ..
L5987 ,3 A step-down switching regulatorFeaturesThe L5987 is a step-down switching regulator 3 A DC output currentwith a 3.5 A (minimum) ..
L5987A ,3 A step-down switching regulatorApplicationsthJA60 °C/W and 40 °C/W respectively. Consumer: STB, DVD, DVD recorder, car a ..
L5987ATR ,3 A step-down switching regulatorFunctional description . . . . . . 145.1 Oscillator and synchronization . 165.2 Soft-start ..
L5988 , 4A step-down switching regulator with synchronous rectification
L5988D ,4 A continuous (more than 5 A pulsed) step-down switching regulator with synchronous rectificationFunctional description . . . . . . 125.1 Multifunction pin . . . . 135.2 Oscillator and s ..
LC04-6 , Dual Low Capacitance TVS Array for Telecom LineCard Applications
LC05-6 , Dual Low Capacitance TVS Array for Telecom Line-Card Applications
LC05-6 , Dual Low Capacitance TVS Array for Telecom Line-Card Applications
LC05-6 , Dual Low Capacitance TVS Array for Telecom Line-Card Applications
LC05-6 , Dual Low Capacitance TVS Array for Telecom Line-Card Applications
LC05-6.TB , Dual Low Capacitance TVS Array for Telecom Line-Card Applications
L5986
2.5 A step-down switching regulator
May 2014 DocID14971 Rev 5 1/42
L59862.5 A step-down switching regulator
Datasheet - production data
Features 2.5 A DC output current 2.9 V to 18 V input voltage Output voltage adjustable from 0.6 V 250 kHz switching frequency, programmable
up to 1 MHz Internal soft-start and inhibit Low dropout operation: 100% duty cycle Voltage feedforward Zero load current operation Overcurrent and thermal protection VFQFPN 3 x 3 mm -8L and HSOP8 package
Applications Consumer: STB, DVD, DVD recorder, car
audio, LCD TV and monitors Industrial: chargers, PLD, PLA, FPGA Networking: XDSL, modems, DC-DC modules Computer: optical storage, hard disk drive,
printers, audio/graphic cards LED driving
DescriptionThe L5986 is a step-down switching regulator
with a 3.0 A (min.) current limited embedded
Power MOSFET, so it is able to deliver up to 2.5 A
current to the load depending on the application
conditions.
The input voltage can range from 2.9 V to 18 V,
while the output voltage can be set starting from
0.6 V to VIN. Having a minimum input voltage of
2.9 V, the device is suitable also for a 3.3 V bus.
Requiring a minimum set of external components,
the device includes an internal 250 kHz switching
frequency oscillator that can be externally
adjusted up to 1 MHz.
The QFN and the HSOP packages with an
exposed pad allow reducing the RthJA down to
60 °C/W and 40 °C/W respectively.
Figure 1. Application circuit
Contents L59862/42 DocID14971 Rev 5
Contents Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.1 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85.1 Oscillator and synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.2 Soft-start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
5.3 Error amplifier and compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4 Overcurrent protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.5 Inhibit function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.6 Hysteretic thermal shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156.1 Input capacitor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.2 Inductor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.3 Output capacitor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.4 Compensation network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.4.1 Type III compensation network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.4.2 Type II compensation network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.5 Thermal considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.6 Layout considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.7 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Application ideas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347.1 Positive buck-boost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7.2 Inverting buck-boost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
DocID14971 Rev 5 3/42
L5986 Contents Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Pin settings L59864/42 DocID14971 Rev 5
1 Pin settings
1.1 Pin connection
1.2 Pin description
Table 1. Pin description
DocID14971 Rev 5 5/42
L5986 Maximum ratings
2 Maximum ratings
3 Thermal data
Table 2. Absolute maximum ratings
Table 3. Thermal data Package mounted on demonstration board.