XC9511A1434 TOREX [Torex Semiconductor], XC9511A1434 Datasheet - Page 13

• Manufacturer Part Number: XC9511A1434
• Description: Synchronous Step-Down DC/DC Converter with built-in LDO Regulator in parallel plus Voltage Detector
• Manufacturer: TOREX [Torex Semiconductor]

■NOTES ON USE (Continued)
●Application Information (Continued)
●Instructions on Pattern Layout
14. Should the bi-directional load current of the synchronous DC/DC converter and the regulator become large, please
15. The voltage detector circuit built-in the XC9511 series internally monitor the V
1. In order to stabilize V
2. Please mount each external component as close to the IC as possible.
3. Wire external components as close to the IC as possible and use thick, short connecting traces to reduce the circuit
4. Make sure that the PCB GND traces are as thick as possible, as variations in ground potential caused by high
5. If using a Schottky diode, please connect the anode side to the A
6. Please use the A
<SOP-8 Reference pattern layout>
possible to the A
output level may increase because of the switching noise of the DC/DC converter.
impedance.
ground currents at the time of switching may result in instability of the DC/DC converter and have adverse influence
on the regulator output.
caused by the noise may occur depending on the arrangement of the Schottky diode.
DC/DC power dissipation (when in synchronous operation): PdDC/DC = I
be careful of the power dissipation when in use. Please calculate power dissipation by using the following formula.
Pd=PdDC/DC + PdVR
VR power dissipation: PdVR=(V
voltage and VR output pin voltage. For the XC9511B/C/E/F series, which voltage detector circuit monitors the
DC/DC output pin voltage and the VR output pin voltage, please determine the detect voltage value (V
following equation.
V
* An assumed value of tolerance among the DC
RON: ON resistance of the built-in driver transistor to the DC/DC (= 0.5Ω<TYP.>)
RON=Rpon x PchOnDuty / 100
DF
(The VD detect voltage and hysteresis range).
≦
(Setting voltage on both the D
+ Rnon x (1 - PchOnDuty / 100)
VDD
VDD
and P
& A
IN
's voltage level, we recommend that a by-pass capacitor (C
GND
VDD
pins. Should it not be possible to place the input capacitors nearby, the regulated
pins with the same electric potential.
IN
– VR
COUT
OUT
voltage and the V
) x IR
OUT
OUT
voltage, the VR
ROUT
voltage) × 85%*
GND
DOUT
OUT
pin through C
2
voltage, and the VD release voltage
x RON
DD
pin voltage, the DC/DC output pin
IN
IN
. Characteristic degradation
) be connected as close as
DF
XC9511
) by the
13/35
Series