S1721 datasheet(19/42 Pages) SII

19 / 42 page

SUPER-SMALL PACKAGE 2-CIRCUIT HIGH RIPPLE-REJECTION LOW CURRENT CONSUMPTION LOW DROPOUT CMOS VOLTAGE REGULATOR

Rev.2.0_00

S-1721 Series

Seiko Instruments Inc.

Explanation of Terms

1. Low dropout voltage regulator

This IC’s voltage regulator has the low dropout voltage due to its built-in low on-resistance transistor.

2. Output voltage (VOUT)

The accuracy of the output voltage is ensured at

±1.0% under the specified conditions of fixed input voltage*1, fixed

output current, and fixed temperature.

*1.

Differs depending on the product.

Caution

If the above conditions change, the output voltage value may vary and exceed the accuracy

range of the output voltage. See “

Electrical Characteristics” and “

Characteristics (Typical

Data) (Per Circuit)” for details.

3. Line regulation

Indicates the dependency of the output voltage on the input voltage. That is, the values show how much the output

voltage changes due to a change in the input voltage with the output current remaining unchanged.

4. Load regulation (

ΔV

OUT2)

Indicates the dependency of the output voltage on the output current. That is, the values show how much the output

voltage changes due to a change in the output current with the input voltage remaining unchanged.

5. Dropout voltage (Vdrop)

Indicates the difference between input voltage VIN and the output voltage when; decreasing input voltage VIN

gradually until the output voltage has dropped out to the value of 98% of output voltage VOUT3, which is at VIN =

VOUT(S) + 1.0 V.

Vdrop = VIN1 − (VOUT3 × 0.98)

ΔV

OUT1

ΔV

IN •VOUT

S1721 Datasheet(PDF) 19 Page - Seiko Instruments Inc