S8821 datasheet(13/24 Pages) SII

13 / 24 page

VOLTAGE REGULATION BOOST CHARGE PUMP DC-DC CONVERTER

Rev.5.1_02

S-8821 Series



Precautions

• Regarding the wiring to the VIN pin, VOUT pin, C+ pin, C− pin and GND pin, be careful to perform

pattern wiring so as to obtain low impedance.

• Always connect a capacitor to the VOUT pin, C+ pin, and C− pin.

• Connect CIN and COUT in the vicinity of the IC and sufficiently strengthen the wiring for GND pin and VIN

pin in order to lower the impedance of the wiring resistance, etc. High impedance may cause unstable

operation.

Moreover, in selecting CIN and COUT, perform a full evaluation of the actual usage conditions.

• Connect CPUMP in the vicinity of the IC and sufficiently strengthen the wiring for the C+ pin and C− pin in

order to lower the impedance of the wiring resistance, etc. High impedance may cause instable

operation.

Moreover, in selecting CPUMP, perform a full evaluation of the actual usage conditions.

• The ON/OFF pin is configured as shown in Figure 9 and is neither pulled up or down internally, so do not

use this pin in a floating state. When not using the ON/OFF pin, connect it to the VIN pin.

Moreover, please do not apply voltage higher than VIN

+ 0.3 V to an ON/OFF pin. Current flows for a

VIN pin through the protection diode inside IC.

• Since this IC consists of double boost circuits, it cannot set more than twice voltage of VIN to VOUT(S).

• Be careful about the usage conditions for the input/output voltages and output current to make sure that

dissipation within the IC does not exceed the allowable power dissipation of the package.

For reference, the calculation of the power consumption in this IC is shown below.

PD=(VIN

× 2.0 − VOUT) × (IOUT)

Reference: VIN=4.2 V, VOUT=5.5 V, IOUT=10 mA

PD=(4.2

× 2.0 − 5.5) × 0.010=29 mW

• Since the information described herein is subject to change without notice, confirm that this is the latest

one before using.

• Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in

electrostatic protection circuit.

• SII Semiconductor Corporation claims no responsibility for any and all disputes arising out of or in

connection with any infringement of the products including this IC upon patents owned by a third party.

S8821 Datasheet(PDF) 13 Page - Seiko Instruments Inc