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DS22245A-page 9

RE46C162/163

2.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in Table 2-1.

TABLE 2-1:

PIN FUNCTION TABLE

RE46C162/163

Name

Description

PDIP, SOIC

1

TSTART

This input is used to invoke the push-to-test alarm, alarm memory indication,

and the timer mode. This input has an internal pull-down.

2

I/O

This bidirectional pin provides the capability to interconnect many detectors in a

single system. This pin has an internal pull-down.

3

TONE

This pin selects the NFPA72 horn tone (high) or the 2/3 duty cycle continuous

tone (low).

4

TSTROBE

This pin is strobed on with the internal clock in timer mode. A resistor

connected to this pin is used to modify the detector sensitivity for the timer

period.

5

LED

Open drain NMOS output used to drive a visible LED.

Connect to the positive supply voltage.

7

RBIAS

8

FEED

Usually connected to the feedback electrode through a current limiting resistor.

Connect to the negative supply voltage.

10

HB

This pin is connected to the metal electrode of a piezoelectric transducer.

11

HS

HS is a complementary output to HB and connects to the ceramic electrode of

the piezoelectric transducer.

12

OSCAP

13

VSEN

This pin can be used to modify the set point for the smoke comparator by use of

14

GUARD1

Output of the guard amplifier.

15

DETECT

Connect to the collector electrode (CEV) of the ion smoke chamber.

16

GUARD2

Output of the guard amplifier.