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ADVANCED COMMUNICATIONS & SENSING

DATASHEET

SX8120/21

1V Motor/LED control timer

ACS - Revision 2.2

August 2010

© Semtech Corp.

TECHNICAL DESCRIPTION

4

System architecture

4.1

SX8120/21 architecture

The system is based on an integrated 5% precise counter. It starts and stops pulses based on the command of

a button and times-out after a selectable period of time.

The MOTOR output polarity is controlled by the POLARITY input. If POLARITY is connected the VDD that the

MOTOR will be active high, if POLARITY is connected the VSS, the MOTOR will be active low. MOTOR output is

usually followed by an NPN transistor to drive the motor, in this case it is active high.

In parallel with the motor there is a LED output that sends 3 us pulses at 43 kHz that can be used to drive a

white or green LED with an NPN transistor and a 40-200 uH coil.

Figure 2. SX8120/21 Architecture

SX8120/21

VDD

MOTOR

VSS

LED

TO

BUTTON

POLARITY

NIMH

1.4V

Pulse

(counter )

Start/Stop

+

debounce

Motor

polarity

Burst

43kHz

VDD