ST1S10 STMicroelectronics, ST1S10 Datasheet - Page 14

• Manufacturer Part Number: ST1S10
• Description: Monolithic synchronous step-down regulator
• Manufacturer: STMicroelectronics

Specifications of ST1S10

• Input Voltage Range: 2.5 V to 18 V
• Max Iout: 3 A
• High Internal Switching Frequency: 900 kHz
• Quiescent Current: < 6 μA in inhibit state

Layout considerations
6
Figure 6.
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Layout considerations
Layout is an important step in design for all switching power supplies.
High-speed operation (900 kHz) of the ST1S10 device demands careful attention to PCB
layout. Care must be taken in board layout to get device performance, otherwise the
regulator could show poor line and load regulation, stability issues as well as EMI problems.
It is critical to provide a low inductance, impedance ground path. Therefore, use wide and
short traces for the main current paths.
The input capacitor must be placed as close as possible to the IC pins as well as the
inductor and output capacitor. Use a common ground node for power ground and a different
one for control ground (AGND) to minimize the effects of ground noise. Connect these
ground nodes together underneath the device and make sure that small signal components
returning to the AGND pin and do not share the high current path of C
The feedback voltage sense line (V
routed away from noisy components and traces (e.g., SW line). Its trace should be
minimized and shielded by a guard-ring connected to the ground.
PCB layout suggestion
Doc ID 13844 Rev 4
FB
) should be connected right to the output capacitor and
CN1 = Input power supply
CN2 = Enable/Disable
CN3 = Input sync.
CN4 = V
Input capacitor C1 must be
placed as close as possible
to the IC pins as well as the
inductor L1 and output
capacitor C2
Via holes from thermal pad
to bottom layer
IN
OUT
and C
OUT
.
ST1S10