HT19_14 Datasheet, PDF (1/4 Pages) Supertex, Inc – Electronic Telephone Line Switch

Supertex inc.
HT19
Electronic Telephone
Line Switch
Features
►►350V breakdown voltage
►►18Ω maximum switch resistance
►►Current limiting protection
►►Operates at 2.3V input
Applications
►►Telephone handsets
►►Modems
►►Fax machines
►►Answering machines
►►Remote meter reading
►►Telephone interface products
General Description
The Supertex HT19LG is an electronic line switch circuit that
replaces the mechanical hook switch contact or a discrete
hook switch in a telephone handset or modem. It switches
the positive side of the telephone line using control inputs
that are referenced to the negative side of the line. In its off
state, it can withstand 350V on the positive input. In its on
state, it has a maximum series resistance of 18Ω.
The device provides current limiting determined by an
external resistor. There are three control inputs. The HKS
pin turns on the hook switch when connected to the TPG
pin. This can be accomplished by using a mechanical switch
which closes when the handset is physically off-hook. The
LS pin allows a logic signal to turn on the hook switch. The
dial pulse, Pin 6, is used to turn the hook switch off for pulse
dialing. The dial pulse (DP) is active low.
Typical Application Circuit
Tip
Transient
Protection
Ring
TPG
TP
HKS
HT19
R_SEN
CS
15V
LS
Telecom
Circuit
DP
GND
Doc.# DSFP-HT19
B031414
Supertex inc.
www.supertex.com