s-8521b51mc-aukt2g Seiko Instruments Inc., s-8521b51mc-aukt2g Datasheet - Page 24

• Manufacturer Part Number: s-8521b51mc-aukt2g
• Description: Step-down, Pwm Control Or Pwm / Pfm Switchable Switching Regulator Controller
• Manufacturer: Seiko Instruments Inc.

On the other hand, a reactive current flows through R
negligible value with respect to the load current in the actual use of the IC so that the efficiency characteristics
will not be degraded. This requires that the value of R
However, too large a value (more than 1 MΩ) for the R
Check the influence of this value on actual equipment.
There is a tradeoff between the voltage accuracy of the OUT and the reactive current. This should be taken
into consideration based on the requirements of the intended application.
Deviations in the absolute value of the internal resistances (R
the S-8520 / 8521 Series, and are broadly classified as follows:
24
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR
S-8520 / 8521 Series
When a value of R
the output OUT, a median voltage deviation will be obtained for the OUT.
Moreover, add a capacitor (C
oscillations and other types of instability. (Refer to Figure 14 .)
Make sure that C
If a large C
• SII is equipped with a tool that allows you to automatically calculate the necessary resistance values of
• Moreover, SII also has ample information on which peripheral components are suitable for use with this
*1. // shows the combined resistance in parallel.
Caution
R
of R
C
R
determining the R
IC and data concerning the deviations in the IC's characteristics. We are ready to help our customers
with the design of application circuits. Please contact the SII Components Sales Dept.
Output voltage
1.5 V to 2.0 V
2.1 V to 2.5 V
2.6 V to 3.3 V
3.4 V to 4.9 V
5.0 V to 6.0 V
1
C
A
+R
(F)≥1÷(2×π×R
and R
1
2
and R
=2÷(1÷maximum deviation in absolute value of R
The above connection diagram and constant will not guarantees successful operation.
Perform through evaluation using the actual application to set the constant.
C
B
value is selected, a longer soft start time than the one set up in the IC will be set.
from the required voltage accuracy of the OUT. SII will be pleased to assist its customers in
2
)
C
is larger than the value given by the following equation:
A
1
A
+R
Deviations in the absolute value of R
(Ω)×7.5 kHz)
and R
2
given by the equation indicated below is taken in calculating the voltage value of
B
values. Should such assistance be desired, please inquire.
C
) in parallel to the external resistance (R
Table 10
5.16 MΩ to 28.9 MΩ
4.44 MΩ to 27.0 MΩ
3.60 MΩ to 23.3 MΩ
2.44 MΩ to 19.5 MΩ
2.45 MΩ to 15.6 MΩ
Seiko Instruments Inc.
A
A
A
and R
and R
and R
1
1
1
B
B
and R
and R
B
and R
would make the IC vulnerable to external noise.
be made sufficiently large.
. This reactive current must be reduced to a
2
2
2
) in the IC vary with the output voltage of
in the IC
+1÷minimum deviation in absolute value
A
) in order to avoid output
Rev.8.3
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