The Supertex HT18LG and HT19LG are electronic line switch
circuits that replace the mechanical hook switch contact or a
discrete hook switch in a telephone handset or modem. They
switch the positive side of the telephone line using control inputs
that are referenced to the negative side of the line. In the off state,
they can withstand 350V on the positive input. In the on state
their series resistances are 18鈩?maximum. The devices provide
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. For the HT18, the dial pulse is active high (DP)
whereas for the HT19, it is active low (DP).
Applications
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Telephone handsets
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Modems
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Fax machines
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Answering machines
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Remote meter reading
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Phone interface products
Pin Configuration
Absolute Maximum Ratings
V
TPG
, Input line voltage
V
TP
, Output line voltage
DP/DP continuous input voltage
Storage temperature
Junction temperature
Soldering temperature*
Power dissipation
Notes: All voltages are referenced to ground.
*Distance of 1.6mm from case for 10 seconds.
+350V
+18V
+10V
鈥?5擄C to +150擄C
+150擄C
+300擄C
0.8 Watt
TPG
HKS
GND
N/C
1
2
3
4
8
7
6
5
TP
CS
DP/DP *
LS
top view
SO-8
*
For HT18, Pin 6 is DP.
For HT19, Pin 6 is DP.
Note:
See Package Outline section for dimensions.
12/13/01
Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate "products liability
indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be defective due to
workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications, refer to the
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Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, refer to the most current databook or to the Legal/Disclaimer page on the Supertex website.
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