s-8521b51mc-aukt2g Seiko Instruments Inc., s-8521b51mc-aukt2g Datasheet - Page 17

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

Rev.8.3
1. 3 Overload protection circuit
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLOR
Products can be chosen either with an overload protection circuit (A, C, E types) or without one (B, D,
F types).
Products with an overload protection circuit (A, C, E types) enter intermittent operation mode when the
overload protection circuit operates to accommodate overloads or load short-circuiting.
protects the switching elements and inductors. Nonetheless, in an application where the load needs to
be fed continually with a current by taking advantage of the 100 % duty cycle state, even if the input
voltage falls below the output voltage value, a B, D, F types product will have to be used. Choose
whichever product best handles the conditions of your application.
In making the selection, please keep in mind that the upper limit of the operating voltage range is
either 10 V (A, C, E types) or 16 V (B, D, F types), depending on whether the product comes with an
overload protection circuit built in.
Table 9 provides a rough guide for selecting a product type depending on the requirements of the
application. Choose the product that gives you the largest number of circles ( ).
_00
An overload protection circuit is required
The input voltage range exceeds 10 V
The efficiency under light loads (load
current ≤ 1 mA) is an important factor
To be operated with a medium load
current (200 mA class)
To be operated with a high load current
(1 A class)
It is important to have a low-ripple voltage
Importance is attached to the downsizing
of external components
Remark
: Indispensable condition
: Superiority of requirement
: Particularly superiority of requirement
Seiko Instruments Inc.
A
Table 9
B
S-8520 Series
C
D
E
F
A
S-8520 / 8521 Series
B
S-8521 Series
C
D
E
This
17
F