
38
Am79213/Am79C203/031 Data Sheet
Table 10. User-Programmable Components
ZT is connected between the VTX and RSN pins. The fuse re-
sistors are RF. Z2WIN is the desired 2-wire AC input imped-
ance. When computing ZT, the internal current amplifier pole
and any external stray capacitance between VTX and RSN
must be taken into account.
ZRX is connected from VRX to RSN. ZT is defined above, and
G42L is the desired receive gain.
Thermal Management Equations (Normal Active and Tip Open States)
RTMG is connected from TMG to VBAT and is used to reduce
power dissipation within the ASLIC device in normal Active
and Tip Open states.
Power dissipated in the thermal management resistor, RTMG,
during normal Active and Tip Open states
Power dissipated in the ASLIC device while in normal Active
and Tip Open states
Thermal Management equations (Polarity Reverse State)
Note: ASLIC device die temperature should not exceed 140°C.
Power dissipated in the ASLIC device while in the Polarity
Reverse state
Total die temperature
Thermal impedance of the 32-pin plastic leaded chip carrier
package
Z
T
63.5
Z
2WIN
2R
F
–
()
•
=
Z
RX
Z
L
G
42L
------------
254
Z
T
•
Z
T
63.5
Z
L
2R
F
+
()
•
+
---------------------------------------------------------
•
=
R
TMG
V
BAT
VOFF
–
I
LOOP
-------------------------------------
=
P
RTMG
V
BAT
VOFF
–
I
LOOP
R
L
•
()
–
()
2
R
TMG
-----------------------------------------------------------------------------------
=
P
SL IC
V
BAT
I
LOOP
•
P
RTMG
–
R
L
I
LOOP
()
•
2
–
0.12 W
+
=
P
SL IC
V
BAT
I
LOOP
R
L
I
LOOP
()
2
•
()
–
•
0.12 W
+
=
T
SLIC
P
SLIC
θ
jA
T
AMBIE NT
+
•
=
ThetajA
θ
jA
() 43°⁄ watt
=