XC9303B093KR-G Torex Semiconductor, XC9303B093KR-G Datasheet - Page 8

• Manufacturer Part Number: XC9303B093KR-G
• Description: Specifications: PWM Type: Controller ; Number of Outputs: 1 ; Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) ; Packaging: Tape & Reel (TR) ; Duty Cycle: 88% ; Voltage - Supply: 2 V ~ 10 V ; Frequency - Max: 345kHz ; Buck: Yes ; Boost: Yes
• Manufacturer: Torex Semiconductor

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■NOTES ON USE
■TYPICAL APPLICATION CIRCUIT
1. PWM/PFM Automatic Switching
2. Ratings
3. Notes on How to Select Transistor
<The check method of whether selected MOSFET is oscillating simultaneously>
4. Instruction on Layout
If PWM/PFM automatic switching control is selected and the step-down ratio is high (e.g., from 10 V to 1.0 V), the control
mode remains in PFM setting over the whole load range, since the duty ratio under continuous-duty condition is smaller
than the PFM duty ratio of the XC9303 series. The output voltage's ripple voltage becomes substantially high under heavy
load conditions, with the XC9303 series appearing to be producing an abnormal oscillation. If this operation becomes a
concern, set pins PWM1 and PWM2 to High to set the control mode to PWM setting.
Synchronous rectification operation prepares fixed time when switching changes so that the high side P-ch MOSFET and
the low side N-ch MOSFET do not oscillate simultaneously. Also it is designed to prevent the penetration current when the
both MOSFET oscillate at the same time. However, some MOSFET may oscillate simultaneously and worsen efficiency.
Please select MOSFET with high Vth with small input capacity on high side P-ch MOSFET and the low side N-ch MOSFET.
(When using with large current, please note that there is a tendency for ON resistance to become large when the input
capacity of MOSFET is small and Vth is high.)
XC9303
Use the XC9303 series and peripheral components within the limits of their ratings.
In order to check that MOSFET is not oscillating simultaneously, please observe Lx terminal waveform of coil current at the
time of the continuation mode. If the MOSFET parasitism diode waveform on Lx terminal waveform can be formed in the
period EXT 1 is 'H' and EXT2 is 'L', it can be thought that MOSFETs are not oscillating simultaneously.
(1) The performance of the XC9303 DC/DC converter is greatly influenced by not only its own characteristics, but also by
(2) Please mount each external component as close to the IC as possible. Wire external components as close to the IC as
(3) Make sure that the GND wiring is as strong as possible as variations in ground potential caused by ground current at the
(4) For stable operation, please connect by-pass capacitor between the V
(5) Wiring between the GND pin of C
those of the external components it is used with.
component to be used and take sufficient care when selecting components.
possible and use thick, short connecting wires to reduce wiring impedance. In particular, minimize the distance
between the EXT2 pin and the Gate pin of the low side N-ch MOSFET. It may decrease efficiency.
time of switching may result in unstable operation of the IC. Specifically, strengthen the ground wiring in the proximity
of the V
It may result in unstable operation of the IC.
SS
pin.
Series
IN
and the Sauce pin of the low side N-ch MOSFET connect to the GND pin of the IC.
We recommend that you refer to the specifications of each
DD
and the GND.