CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
1.
θ
JA
is measured with the component mounted on an evaluation PC board in free air.
Electrical Specifications
Unless Otherwise Specified, T
A
= -40
o
C to 85
o
C, V
BL
= -24V, V
BH
= -48V, V
CC
= +5V, AGND = BGND = 0V, loop
current limit = 25mA. All AC Parameters are specified at 600Ω 2-wire terminating impedance over the frequency
band of 300Hz to 3.4kHz. Protection resistors = 0Ω.
TEST CONDITIONS
MIN
TYP
MAX
UNITS
PARAMETER
RINGING PARAMETERS
VRB Input Impedance
480
-
-
kΩ
AC TRANSMISSION PARAMETERS
(Forward Active and Reverse Active, BSEL = 0, unless otherwise specified.)
Receive Input Impedance
Transmit Output Impedance
4-Wire Port Overload Level
2-Wire Port Overload Level
2-Wire Return Loss
THD = 1%
THD = 1%
300Hz
≤
f
<
1kHz
1kHz
≤
f
≤
3.4kHz
Longitudinal Current Capability (Per Wire)
Test for False Detect
Test for False Detect, Low Power Standby, BSEL = 0
2-Wire Longitudinal Balance
4-Wire Longitudinal Balance
4-Wire to 4-Wire Insertion Loss
2-Wire to 4-Wire Level Linearity
4-Wire to 2-Wire Level Linearity
Referenced to -10dBm
Idle Channel Noise 2-Wire
+3 to -40dBm, 1kHz
-40 to -50dBm, 1kHz
-50 to -55dBm, 1kHz
C-Message
Psophometric
DC PARAMETERS
Loop Current Limit Programming Range
Loop Current Accuracy
Loop Current During Low Power Standby
Open Circuit Voltage
(|Tip - Ring|)
Low Power Standby Open Circuit Voltage (Tip - Ring)
Ring Trip Programming Current Accuracy
Max Low Battery = -52V, BSEL = 0
I
L
= 25mA, BSEL = 0
Forward polarity only.
BSEL = 0
BSEL = 1
BSEL = 1
15
-
17
14
37.5
43
-
-
-
-
15.5
40
45
-
45
10
26
17
42.5
47
10
mA
%
mA
V
V
V
%
Tested per IEEE455-1985, with 368Ω per wire.
Tested per IEEE455-1985, with 368Ω per wire.
160
-
3.1
3.1
30
35
-
-
53
59
-6.22
-
-
-
-
-
-
-
3.5
3.5
45
45
20
10
-
-
-6.02
0.025
0.050
0.100
16
-74
-
1
-
-
-
-
-
-
-
-
-5.82
-
-
-
19
-71
kΩ
Ω
V
PK
V
PK
dB
dB
mA
RMS
mA
RMS
dB
dB
dB
dB
dB
dB
dBrnC
dBmp
4-82
HC5549
Electrical Specifications
Unless Otherwise Specified, T
A
= -40
o
C to 85
o
C, V
BL
= -24V, V
BH
= -48V, V
CC
= +5V, AGND = BGND = 0V, loop
current limit = 25mA. All AC Parameters are specified at 600Ω 2-wire terminating impedance over the frequency
band of 300Hz to 3.4kHz. Protection resistors = 0Ω.
(Continued)
TEST CONDITIONS
MIN
10
IC junction temperature
-
TYP
12
175
MAX
13.5
-
UNITS
mA
o
C
PARAMETER
Ground Key Threshold
Thermal Alarm Output
RELAY DRIVER
On Voltage
LOGIC INPUTS (F0, F1, F2, E0, SWC)
Input Low Voltage
Input High Voltage
Input Low Current
Input High Current
LOGIC OUTPUTS (DET, ALM)
Output Low Voltage
Output High Voltage
I
OL
= 5mA
I
OH
= 100
µA
V
IL
= 0.4V
V
IH
= 2.4V
I
L
= 45 mA
-
-
0.60
V
-
2.0
-20
-
-
-
-
-
0.8
-
-
5
V
V
µA
µA
-
2.4
-
-
0.4
-
V
V
SUPPLY CURRENTS
(Supply currents not listed are considered negligible and do not contribute significantly to total power dissipation. All
measurements made under open circuit load conditions.)
Low Power Standby
I
CC
I
BH
, BSEL = 1
Forward or Reverse (Note 5)
I
CC
I
BL
, BSEL = 0
Forward
I
CC
I
BL
, BSEL = 1
I
BH
, BSEL = 1
Power Denial
I
CC
I
BL
, BSEL = 1 or 0
ON HOOK POWER DISSIPATION
Forward or Reverse
Forward or Reverse
Low Power Standby
OFF HOOK POWER DISSIPATION
Forward or Reverse
POWER SUPPLY REJECTION RATIO
V
CC
to 2-Wire
f = 300Hz
f = 1kHz
f = 3.4kHz
V
CC
to 4-Wire
f = 300Hz
f = 1kHz
f = 3.4kHz
V
BL
to 2-Wire
V
BL
to 4-Wire
V
BH
to 2-Wire
V
BH
to 4-Wire
300Hz
≤
f
≤
3.4kHz
300Hz
≤
f
≤
3.4kHz
300Hz
≤
f
≤
3.4kHz
300Hz
≤
f
≤
1kHz
1kHz
<
f
≤
3.4kHz
-
-
-
-
-
-
-
-
-
-
-
40
35
28
45
43
33
30
35
33
40
45
-
-
-
-
-
-
-
-
-
-
-
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
BSEL = 0
-
290
310
mW
BSEL = 0
BSEL = 1
BSEL = 1
-
-
-
44
90
37
60
150
60
mW
mW
mW
2.0
-
2.5
-
3.5
-
-
0.5
-
3.7
0.375
4.0
1.0
4.5
0.7
1.0
3.0
0.2
5.0
0.600
5.0
2.0
6.5
1.5
2.0
5.0
0.5
mA
mA
mA
mA
mA
mA
mA
mA
mA
4-83
HC5549
Design Equations
Loop Supervision Thresholds
SWITCH HOOK DETECT
The switch hook detect threshold is set by a single external
resistor, R
SH
. Equation 1 is used to calculate the value of R
SH
.
R
SH
=
600
⁄
I
SH
(EQ. 1)
4-WIRE TO 2-WIRE GAIN
The 4-wire to 2-wire gain is defined as the receive gain. It is
a function of the terminating impedance, synthesized
impedance and protection resistors. Equation 6 calculates
the receive gain, G
42
.
Z
L
-
G
42
= –
2
-----------------------------------------
Z
O
+ 2R
P
+ Z
L
(EQ. 6)
The term I
SH
is the desired DC loop current threshold. The
loop current threshold programming range is from 5mA to
15mA.
GROUND KEY DETECT
The ground key detector senses a DC current imbalance
between the Tip and Ring terminals when the ring terminal is
connected to ground. The ground key detect threshold is not
externally programmable and is internally fixed to 12mA
regardless of the switch hook threshold.
RING TRIP DETECT
The ring trip detect threshold is set by a single external
resistor, R
RT
. I
RT
should be set between the peak ringing
current and the peak off hook current while still ringing.
R
RT
=
1800
⁄
I
RT
(EQ. 2)
When the device source impedance and protection resistors
equals the terminating impedance, the receive gain equals
unity.
2-WIRE TO 4-WIRE GAIN
The 2-wire to 4-wire gain (G
24
) is the gain from tip and ring to
the VTX output. The transmit gain is calculated in Equation 7.
Z
O
-
G
24
= –
-----------------------------------------
Z
O
+ 2R
P
+ Z
L
(EQ. 7)
When the protection resistors are set to zero, the transmit
gain is -6dB.
TRANSHYBRID GAIN
The transhybrid gain is defined as the 4-wire to 4-wire gain
(G
44
).
Z
O
-
G
44
= –
--------------------------------------
Z
O
+
2R
P
+
Z
L
(EQ. 8)
The capacitor C
RT
, in parallel with R
RT
, will set the ring trip
response time.
Loop Current Limit
The loop current limit of the device is programmed by the
external resistor R
IL
. The value of R
IL
can be calculated
using Equation 3.
1760
R
IL
= ------------
-
I
LIM
(EQ. 3)
When the protection resistors are set to zero, the transhybrid
gain is -6dB.
COMPLEX IMPEDANCE SYNTHESIS
Substituting the impedance programming resistor, R
S
, with a
complex programming network provides complex
impedance synthesis.
2-WIRE
NETWORK
C
2
R
1
R
2
PROGRAMMING
NETWORK
C
P
R
S
R
P
The term I
LIM
is the desired loop current limit. The loop
current limit programming range is from 15mA to 45mA.
Impedance Matching
The impedance of the device is programmed with the
external component R
S
. R
S
is the gain setting resistor for
the feedback amplifier that provides impedance matching. If
complex impedance matching is required, then a complex
network can be substituted for R
S
.
RESISTIVE IMPEDANCE SYNTHESIS
The source impedance of the device, Z
O
, can be calculated
in Equation 4.
R
S
=
400
(
Z
O
)
(EQ. 4)
FIGURE 1. COMPLEX PROGRAMMING NETWORK
The reference designators in the programming network
match the evaluation board. The component R
S
has a
different design equation than the R
S
used for resistive
impedance synthesis. The design equations for each
component are provided below.
R
S
=
400
× (
R
1
–
2
(
R
P
) )
R
P
=
400
×
R
2
C
P
=
C
2
⁄
400
(EQ. 9)
(EQ. 10)
(EQ. 11)
The required impedance is defined by the terminating
impedance and protection resistors as shown in Equation 5.
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