SP213EHCA Datasheet, PDF (9/19 Pages) Exar Corporation – Low Power, High ESD +5V RS-232 Transceivers

RECEIVER ENABLE
SP211E and SP213E feature an enable
input, which allows the receiver outputs to
be either tri–stated or enabled. This can be
especially useful when the receiver is tied
directly to a shared microprocessor data
bus. For the SP211E, enable is active low;
that is, ZeroV applied to the ENABLE pin
will enable the receiver outputs. For the
SP213E, enable is active high; that is, +5V
applied to the ENABLE pin will enable the
receiver outputs.
SP211E
SD EN#
Drivers
0
1
Active
0
0
Active
1
1
Off
1
0
Off
Receivers
Tri-State
Active
Tri-State
Tri-State
SP213E
SD# EN Drivers RX 1-3 RX 4-5
0
1
Off Tri-State Active
0
0
Off Tri-State Tr-State
1
1
Active Active
Active
1
0 Active Tri-State Tri-State
Table 2. Shut-down and Wake–Up Truth Tables
POWER UP WITH SD ACTIVE (Charge pump in shutdown mode)
t_{0 (POWERUP)}
+5V
R_OUT
0V
ENABLE
SD
DISABLE
t_WAIT
DATA VALID
POWER UP WITH SD DISABLED (Charge pump in active mode)
t_{0 (POWERUP)}
+5V
R_OUT
0V
ENABLE
SD
DATA VALID
t_ENABLE
DISABLE
EXERCISING WAKE–UP FEATURE
t_{0 (POWERUP)}
+5V
R_OUT
0V
DATA VALID
t_ENABLE
DATA VALID
t_ENABLE
DATA VALID
t_ENABLE
SD
DISABLE
ENABLE
t_WAIT
V_CC = +5V –10%; T_A = 25 C
t_WAIT = 2ms typical, 3ms maximum
t_ENABLE = 1ms typical, 2ms maximum
DISABLE
Figure 6. Wake–Up Timing
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com

SP207E_100_072309