SP503 Datasheet, PDF (10/29 Pages) Sipex Corporation – Multiprotocol Transceiver

V_CC = +5V
+
C_{1 –}
–5V
+5V
+
C_{2 –}
–5V
C₄
+ – _{VDD Storage Capacitor}
– + _{VSS Storage Capacitor}
C₃
Figure 4. Charge Pump Phase 3.
V_CC = +5V
+
C_{1 –}
+10V
+
C_{2 –}
C₄
+ – _{VDD Storage Capacitor}
– + _{VSS Storage Capacitor}
C₃
Figure 5. Charge Pump Phase 4.
There are three basic types of driver circuits —
RS-232, RS-423, and RS-485. The RS-232 driv-
ers output a minimum of ±5V level single–
ended signals (with 3kΩ and 2500pF loading),
and can operate up to 120kbps. The RS-232
drivers are used in RS-232 mode for all signals,
and also in V.35 mode where they are used as the
control line signals.
The RS-423 drivers output a minimum of ±3.6V
level single–ended signals (with 450Ω loading)
and can operate up to 120kbps. Open circuit V_OL
and V_OH measurements may exceed the ±6V
limitation of RS-423. The RS-423 drivers are
used in RS-449 and EIA-530 modes as RL and
LL outputs.
The third type of driver supports RS-485, which
is a differential signal that can maintain ±1.5V
differential output levels with a worst case load
of 54Ω. The signal levels and drive capability of
the RS-485 drivers allow the drivers to also
support RS-422 requirements of ±2V differen-
tial output levels with 100Ω loads. The RS-422
drivers are used in RS-449 and EIA-530 modes
as clock, data, and some control line signals.
The RS-485–type drivers are also used in the
V.35 mode. V.35 levels require ±0.55V signals
with a load of 100Ω. In order to meet the voltage
requirements of V.35, external series resistors
with source impedance termination resistors
must be implemented to voltage divide the driver
outputs from 0 to +5V to 0 to +0.55V. Figure 6
shows the values of the resistor network and
how to connect them. The termination network
also achieves the 50Ω to 150Ω source imped-
ance for V.35. For applications that require
V.11 signals for clock and data instead of V.35
levels, omit the external termination networks.
All of the differential drivers, RS-485, RS-422,
and V.35 can operate up to 5Mbps.
Pin Label
TDEC₃–TDEC₀
SD(a)
SD(b)
TR(a)
TR(b)
RS(a)
RS(b)
RL(a)
RL(b)
LL(a)
LL(b)
ST(a)
ST(b)
TT(a)
TT(b)
Mode:
0000
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
tri–state
Table 1. SP503 Drivers
RS-232
0010
RS-232
tri–state
RS-232
tri–state
RS-232
tri–state
RS-232
tri–state
RS-232
tri–state
RS-232
tri–state
RS-232
tri–state
V.35
1110
V.35–
V.35+
RS-232
tri–state
RS-232
tri–state
RS-232
tri–state
RS-232
tri–state
V.35–
V.35+
V.35–
V.35+
RS-422
0100
RS-422–
RS-422+
RS-422–
RS-422+
RS-422–
RS-422+
RS-422–
RS-422+
RS-422–
RS-422+
RS-422–
RS-422+
RS-422–
RS-422+
RS-485
0101
RS-485–
RS-485+
RS-485–
RS-485+
RS-485–
RS-485+
RS-485–
RS-485+
RS-485–
RS-485+
RS-485–
RS-485+
RS-485–
RS-485+
RS-449
1100
RS-422–
RS-422+
RS-422–
RS-422+
RS-422–
RS-422+
RS-423
tri–state
RS-423
tri–state
RS-422–
RS-422+
RS-422–
RS-422+
EIA-530
1101
RS-422–
RS-422+
RS-422–
RS-422+
RS-422–
RS-422+
RS-423
tri–state
RS-423
tri–state
RS-422–
RS-422+
RS-422–
RS-422+
Date: 7/29/04
SP503 Multiprotocol Transceiver
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© Copyright 2004 Sipex Corporation