STLC3055
EXTERNAL COMPONENTS
Name
RREF
Function
Bias setting current
CSVR Negative Battery Filter
RD
CAC
Ring Trip threshold setting
resistor
AC/DC split capacitance
Formula
RREF = 1.3/Ibias
Ibias = 50µA
CSVR = 1/(2π ⋅ fp ⋅ 1.8MΩ)
fp = 50Hz
RD = 100/IRTH
2KΩ < RD < 5KΩ
RP
RS
ZAC
Line protection resistor
Protection and series switches
resistance image
Two wire AC impedance
Rp > 30Ω
RS = 100 ⋅ (Rp + 9Ω)
ZAC = 50 ⋅ (Zs - 2Rp - 18Ω)
ZA (1)
ZB (1)
CCOMP
CH
RLIM
RTH
CREV
RTTX (3)
CTTX (3)
RLV
CS
CFL
SLIC impedance balancing
network
Line impedance balancing
network
AC feedback loop compensation
Trans-Hybrid Loss frequency
compensation
Current limiting programming
Off-hook threshold programming
(ACTIVE mode)
Reverse polarity transition time
programming
Pulse metering cancellation
resistor
Pulse metering cancellation
capacitor
Pulse metering level resistor
Pulse metering shaping
capacitor
Pulse metering filter capacitor
ZA = 50 ⋅ Zs
ZB = 50 ⋅ Zl
CCOMP = 1/(2π⋅fo⋅100⋅(RP+9Ω))
fo = 250kHz
CH = CCOMP
RLIM = 1300/Ilim
32.5kΩ < RLIM < 65kΩ
RTH = 260/ITH
27kΩ < RTH < 52kΩ
CREV = (1/3750) ⋅ ∆T/∆VTR)
RTTX = 50Re[(Zlttx+2Rp+18Ω)]
CTTX = 1/{50⋅2π⋅fttx[-lm(Zlttx)]}
RLV = 63.3⋅103⋅α⋅VLOTTX
α = (|Zlttx + 2Rp + 18Ω|/|Zlttx|)
CS = τ/(2⋅RLV)
CFL = 2/(2π⋅fttx⋅RLV)
RDD
CVCC
CVpos
CV
CVB
Pull up resistors
Internally supply filter capacitor
Positive supply filter capacitor
with low impedance for switch
mode power supply
Battery supply filter capacitor
with low impedance for switch
mode power supply
High frequency noise filter
Typ. Value
26kΩ 1%
1.5nF 10%
100VL
4.12kΩ 1%
@ IRTH = 24mA
22µF 20% 15VL
@ RD = 4.12kΩ
41Ω 1%
5kΩ @ Rp = 41Ω
25kΩ 1%
@ Zs = 600Ω
30kΩ 1%
@ Zs = 600Ω
30kΩ 1%
@ Zl = 600Ω
120pF 10% 10VL
@ Rp = 41Ω
120pF 10% 10VL
52.3kΩ 1%
@ Ilim = 25mA
28.7kΩ 1%
@ITH = 9mA
22nF 10% 10V
@ 12V/ms
15kΩ
@Zlttx = 200Ω real
100nF 10% 10V (2)
@ Zlttx = 200Ω real
27kΩ 1%
@ VLOTTX = 275mVrms
100nF 10% 10V
@ τ = 6ms, RLV = 27.1kΩ
1nF 10% 10V
@fttx = 12kHz
RLV = 27kΩ
100kΩ
100nF 20% 10V
100µF(4)
100µF 20% 100V (5)
470nF 20% 100VL
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