SP335E_17 Datasheet, PDF (13/23 Pages) Exar Corporation – TRANSCEIVER WITH INTERNAL TERMINATION

REV. 1.0.2
TEST CIRCUITS
SP335E
RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION
FIGURE 4. RS-485/422 RECEIVER TERMINATION RESISTANCE
R_TERM = 2 (V_A – V_B)
B
I_B
I_A – I_B
±2V
R_TERM
Rx
-7V ≤ V_A, V_B ≤ +12V
I_A
A
Termination is enabled when both TERM and RS-485/RS-232 are logic high.
FIGURE 5. RS-485/422 DIFFERENTIAL DRIVER OUTPUT VOLTAGE
DI = 0V or V_L
D
V_OD
DE = V_L
Z
R_L
2
V_CM
R_L
2
Y
FIGURE 6. RS-485/422 DIFFERENTIAL DRIVER OUTPUT VOLTAGE OVER COMMON MODE
DI = 0V or V_L
D
DE = V_L
Z
375Ω
V_OD 60Ω
V_CM
375Ω
Y
FIGURE 7. RS-485/422 DRIVER OUTPUT SHORT CIRCUIT CURRENT
Z
DI = 0V or V_L
D
DE = 0V or V_L
I_OSD
-7V to +12V _V
Y
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