Supertex inc.

HT19Electronic Telephone
Line SwitchFeatures►► 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 offstate, it can withstand 350V on the positive input. In its onstate, 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. TheLS 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
TPTPG

TipTransient
Protection

HT19HKSRSENCS

15V

Telecom
Circuit

LSDPRing
GND

Doc.# DSFP-HT19
B031414Supertex inc.
www.supertex.com

HT19
Pin Configuration

Ordering Information
Part Number

Package

Packing

TPG 1

8

TPHT19LG-G

8-Lead SOIC (Narrow Body)

2500/Reel

HKS 2

7CS

GND 3

6DP

NC 4

5LS-G denotes a lead (Pb)-free / RoHS compliant package

Absolute Maximum Ratings

8-Lead SOIC (Narrow Body)

Parameter

Value

VTPG, Input line voltage+350V

VTP, Output line voltage+18V

DP continuous input voltage+10V

Operating temperature range

0°C to +50°C

Storage temperature range(top view)

Product Marking
YYWW

HT19LLLL-65°C to +150°C

Power dissipation

0.8W

YY = Year Sealed
WW = Week Sealed
L = Lot Number= “Green” Packaging

Package may or may not include the following marks: Si or

Absolute Maximum Ratings are those values beyond which damage to the device mayoccur. Functional operation under these conditions is not implied. Continuous operationof the device at the absolute rating level may affect device reliability. All voltages arereferenced to device ground.

8-Lead SOIC (Narrow Body)

Typical Thermal Resistance
Packageθja

8-Lead SOIC (Narrow Body)

101OC/W

Electrical Characteristics (T = 25°C unless otherwise specified)A

Sym

Parameter

Min

TypMax

Units

VTPG

High voltage positive supply

--350

V

ITPG

Input leakage current--2.0-

-200-

-

18-

-

18-

-30-

-75-

-

100

RSW

ITPG - ITP

TPG to TP switch resistance

Bias currentµAConditions
ITPG = 500µA, HKS, LS, DP = open circuitVTPG = 100V, HKS, LS, DP = open circuit
VTPG = 290V, HKS, LS, DP = open circuit
VTPG = 17V, ITPG = 180mA, SW = onΩVTPG = 3.0V, ITPG = 20mA, SW = on
VTPG = 2.3V, ITPG = 5.0mA, SW = onµA

VTPG = 5.0V, SW = on
VTPG = 10V, SW = on

ILIM

ITPG current limiting

188

250330mA

REXT = 200Ω ± 1%

IHKS

HKS input current--200µA

VHKS = 40 to 70V

ILS

LS logic input current--30µA

VLS = 3.0V

IDP

DP logic input current---30µA

VDP = 0V

VIL(HKS)HKS input low0-

0.2V

VTPG = 3.0 to 70V

VIH(HKS)HKS input high

2.0-

VTPGV

VTPG = 3.0 to 70V

VIL(LS),VIL(DP)Input logic low for DP and LS0-0.2

V

VTPG = 3.0 to 70V

VIH(LS),VIH(DP)

Input logic high for DP and LS

1.5-10V

VTPG = 3.0 to 70V

TON

Turn-on time

--

1.0ms

VTPG = 4.5V

TOFF

Turn-off time--

1.0ms

VTPG = 4.5V

Doc.# DSFP-HT19
B031414

2

Supertex inc.
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HT19Logic Truth Table
HKS

LSDP

Switch StateH

L or Z

H or Z

ONH

H

H or ZON

L or Z

L or Z

H or ZOFFL or Z

H

H or ZONXXLOFFZ = high impedance, open circuit
X = irrelevant
L = logic level low
H = logic level highBlock Diagram
TPG
HKS

(1)

(8)

(2)
H = ON
L = OFF

LSDPTP(5)

Charge Pump
andLogic Control

(7)

(3)

(6)

CS

GND

Pin Description
Pin Name Description
1

TPG

Positive input side of a telephone line, typically tip side.

2HKS

Hookswitch input. Connect HKS to TPG to turn on the hook switch. Internally pulled low with a high value
resistor.

3

GND

Device ground. Negative side of a telephone line, typically ring side.

4

NCNo connect. Open circuit. No internal connections to the device.

5LSLine switch input. Input logic high turns on the hook switch. Internally pulled low with a high value resistor.

6

DP

Dial pulse input. Input logic low turns off the hook switch. Used for pulse dialing. Internally pulled high witha high value resistor.

7

CS

Current sense input. An external resistor connected between CS and TP sets the current limit.

8TPPositive output side of a telephone line. Zener protection to prevent this output from rising above 18V isrequired.

Doc.# DSFP-HT19
B0314143Supertex inc.
www.supertex.com

HT198-Lead SOIC (Narrow Body) Package Outline (LG)
4.90x3.90mm body, 1.75mm height (max), 1.27mm pitchθ1D8
Note 1(Index Area
D/2 x E1/2)

E1

EL

1

L1

Top View

L2

GaugePlaneθSeating
Plane

View B
Note 1

View BhAh
A A2

SeatingPlane

A1eb

Side View

View A-AA

Note:
1. This chamfer feature is optional. A Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier can be: a molded mark/identifier;an embedded metal marker; or a printed indicator.

SymbolDimension(mm)A

A1A2bMIN

1.35*

0.10

1.25

0.31

NOM----

MAX

1.75

0.25

1.65*

0.51

DE

E1

4.80* 5.80* 3.80*
4.90

6.00

3.90

5.00* 6.20* 4.00*e

1.27
BSCh

L

0.25

0.40

--0.50

1.27

L11.04REF

L20.25
BSC

θθ10O

5O

--8O

15O

JEDEC Registration MS-012, Variation AA, Issue E, Sept. 2005.
* This dimension is not specified in the JEDEC drawing.
Drawings are not to scale.
Supertex Doc. #: DSPD-8SOLGTG, Version I041309.

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline
information go to http://www.supertex.com/packaging.html.)
Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives
an adequate “product liability indemnification insurance agreement.” Supertex inc. does not assume responsibility for use of devices described, and limits its liability
to the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry andspecifications are subject to change without notice. For the latest product specifications refer to the Supertex inc. (website: http//www.supertex.com)

Supertex inc.

©2014 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited.

Doc.# DSFP-HT19
B03141441235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com