hc5549 Intersil Corporation, hc5549 Datasheet - Page 5

• Manufacturer Part Number: hc5549
• Description: Low Power Slic With Battery Switch
• Manufacturer: Intersil Corporation

Design Equations
Loop Supervision Thresholds
SWITCH HOOK DETECT
The switch hook detect threshold is set by a single external
resistor, R
The term I
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
current and the peak off hook current while still ringing.
The capacitor C
response time.
Electrical Specifications
R
R
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
V
V
V
V
V
SH
RT
CC
CC
BL
BL
BH
BH
to 2-Wire
to 4-Wire
to 2-Wire
to 4-Wire
to 2-Wire
to 4-Wire
=
=
1800 I
600 I
SH
RT
SH
⁄
. Equation 1 is used to calculate the value of R
⁄
. I
SH
is the desired DC loop current threshold. The
RT
RT
RT
should be set between the peak ringing
, in parallel with R
PARAMETER
5
Unless Otherwise Specified, T
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)
RT
, will set the ring trip
BSEL = 0
BSEL = 1
BSEL = 1
BSEL = 0
f = 300Hz
f = 1kHz
f = 3.4kHz
f = 300Hz
f = 1kHz
f = 3.4kHz
300Hz ≤ f ≤ 3.4kHz
300Hz ≤ f ≤ 3.4kHz
300Hz ≤ f ≤ 3.4kHz
300Hz ≤ f ≤ 1kHz
1kHz < f ≤ 3.4kHz
(EQ. 2)
(EQ. 1)
SH
A
= -40°C to 85°C, V
HC5549
.
TEST CONDITIONS
Loop Current Limit
The loop current limit of the device is programmed by the
external resistor R
using Equation 3.
The term I
current limit programming range is from 15mA to 45mA.
Impedance Matching
The impedance of the device is programmed with the
external component R
the feedback amplifier that provides impedance matching. If
complex impedance matching is required, then a complex
network can be substituted for R
RESISTIVE IMPEDANCE SYNTHESIS
The source impedance of the device, Z
in Equation 4.
The required impedance is defined by the terminating
impedance and protection resistors as shown in Equation 5.
R
R
Z
IL
S
O
=
=
=
BL
400 Z
Z
1760
------------ -
I
LIM
L
= -24V, V
–
(
LIM
2R
O
)
P
is the desired loop current limit. The loop
BH
IL
= -48V, V
. The value of R
S
. R
S
CC
is the gain setting resistor for
MIN
= +5V, AGND = BGND = 0V, loop
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
S
.
IL
TYP
290
44
90
37
40
35
28
45
43
33
30
35
33
40
45
can be calculated
O
, can be calculated
MAX
150
310
60
60
-
-
-
-
-
-
-
-
-
-
-
UNITS
(EQ. 3)
FN4539.3
mW
mW
mW
mW
(EQ. 4)
(EQ. 5)
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB