CPC5610 Datasheet, PDF (12/18 Pages) Clare, Inc. – LITELINK™ II Silicon Data Access Arrangement (DAA) IC

CPC5610/CPC5611
rent. The photocurrent, a linear representation of the
receive signal, is amplified and converted to a differen-
tial voltage output on RX+ and RX-.
Variations in gain are controlled to within ±1 dB by an
on-chip automatic gain control (AGC) circuit, which
sets the output of the photoamplifier to unity gain.
To accommodate single-supply operation, LITELINK
includes a small DC bias on the RX outputs of 1.0
Vdc. Most applications should AC couple the RX out-
puts as shown in Figure 6.
LITELINK may be used for differential or single-ended
output as shown in Figure 6. Single-ended use will
produce 6 dB less signal output amplitude. Do not
exceed 0 dBm into 600 Ω (2.2 V_P-P) signal input.
Figure 7. Differential and Single-ended Transmit
Path Connections to LITELINK
Host CODEC or
Transmit Circuit
LITELINK
TXA1
TXA2
0.1uf TX-
-
0.1uf TX+
+
Host CODEC or
Transmit Circuit
TXA1
LITELINK
0.1uf _TX-
-
0.1uf _TX+
+
Figure 6. Differential and Single-ended Receive
Path Connections to LITELINK
Host-side CODEC
or Voice Circuit
LITELINK
RX+
RX-
0.1uF
RX+
0.1uF
RX-
RX
0.1uF
RX+
3.3.2 Transmit Signal Path
Connect transmit signals from the host equipment to
the TX+ and TX- pins of LITELINK. Do not exceed a
signal level of 0 dBm in 600 Ω (or 2.2 V_P-P). Differen-
tial transmit signals are converted to single-ended sig-
nals in LITELINK. The signal is coupled to the transmit
photodiode amplifier in a similar manner to the receive
path.
The output of the photodiode amplifier is coupled to a
voltage-to-current converter via a transconductance
stage where the transmit signal modulates the tele-
phone line loop current. As in the receive path, gain is
set to unity automatically, limiting insertion loss to 0,
±1 dB.
3.4 DC Characteristics
The CPC5610 and CPC5611 are designed for world-
wide application regarding DC characteristics, includ-
ing use under the requirements of TBR-21. The ZDC,
DCS1, and DCS2 pins control the VI slope character-
istics of LITELINK. Selecting appropriate resistor val-
ues for R_ZDC (R16) and R_DCS (R15) in the provided
application circuits assure compliance with DC
requirements.
3.4.1 Resistive Termination Applications
LITELINK includes a telephone line current limit fea-
ture that is selectable by selecting the desired value
for R_ZDC (R16) using the following formula:
I_CLAmps = -_R---¹_Z---^V_D----_C-- + 0.011A
Clare recommends using 8.2 Ω for R_ZDC in North
America and Japan, limiting telephone line current to
133 mA.
3.4.2 Reactive Termination Applications
TBR-21 sets the telephone line current limit at 60 mA.
To meet this requirement, set R_ZDC (R16) to 22.1 Ω.
See Clare application note AN-146 Guidelines for Effec-
tive LITELINK Designs for information on FET heat sink-
ing in this application.
12
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Rev. 9.0