HIGH RIPPLE-REJECTION AND LOW DROPOUT CMOS VOLTAGE REGULATOR
Rev.5.1_00
S-L2980 Series
Seiko Instruments Inc.
9
Explanation of Terms
1. Low Dropout Voltage Regulator
This voltage regulator has the low dropout voltage due to its built-in low on-resistance transistor.
2. Low ESR
Low ESR means the Equivalent Series Resistance of a capacitor is small. The low ESR ceramics
output capacitor (C
L
) can be used in the S-L2980 Series. A capacitor whose ESR is 10Ω or less
can be used.
3. Output Voltage (V
OUT
)
The accuracy of the output voltage is ensured at ± 2.0 % under the specified conditions of fixed input
voltage
*1
, fixed output current, and fixed temperature.
*1. Differs depending upon the product.
Caution If the above conditions change, the output voltage value may vary and exceed the
accuracy range of the output voltage. Refer to the “ Electrical Characteristics” and
“ Typical Characteristics” for details.
⎟
⎠
⎞
⎜
⎝
⎛
•
OUTIN
OUT1
V ΔV
ΔV
Regulation Line 4.
Indicates the dependency of the output voltage on the input voltage. That is, the value shows how
much the output voltage changes due to a change in the input voltage with the output current remaining
unchanged.
5. Load Regulation (ΔV
OUT2
)
Indicates the dependency of the output voltage on the output current. That is, the value shows how
much the output voltage changes due to a change in the output current with the input voltage remaining
unchanged.
6. Dropout Voltage (V
drop
)
Indicates the difference between the input voltage (V
IN1
) and output voltage when the output voltage
falls to 98 % of the output voltage (V
OUT(E)
) by gradually decreasing the input voltage.
V
drop
=V
IN1
–(V
OUT(E)
×0.98)