SC28L91 Philips Semiconductors, SC28L91 Datasheet - Page 36

• Manufacturer Part Number: SC28L91
• Description: 3.3V-5.0V Universal Asynchronous Receiver/Transmitter (UART)
• Manufacturer: Philips Semiconductors

Philips Semiconductors
2000 Sep 22
3.3V–5.0V Universal Asynchronous
Receiver/Transmitter (UART)
NOTES:
1.
2.
INTRN or OP3-OP7 when used as interrupt outputs.
The test for open-drain outputs is intended to guarantee switching of the output transistor. Measurement of this response is referenced from the midpoint of the switching
signal, V
test environment are pronounced and can greatly affect the resultant measurement.
C1 = C2
C1 and C2 should be chosen according to the crystal manufacturer’s specification.
C1 and C2 values will include any parasitic capacitance of the wiring and X1 X2 pins.
Gain at 3.6864MHz: 9 to 13 dB
Package capacitance approximately 4pF.
X1/CLK
CTCLK
M
RxC
TxC
, to a point 0.5V above V
24pF FOR C
L
= 20pF
PARASITIC CAPACITANCE
PARASITIC CAPACITANCE
OL
INTERRUPT
INTERRUPT
. This point represents noise margin that assures true switching has occurred. Beyond this level, the effects of external circuitry and
t
t
t
t
CLK
CTC
Rx
Tx
OUTPUT
OUTPUT
3pF
3pF
C2
C1
WRN
RDN
1
1
Figure 10. Interrupt Timing (80xxx mode)
3.6864MHz
Figure 11. Clock Timing
t
t
t
t
CLK
CTC
Rx
Tx
X1
X2
V
M
36
4pF
2pF
t
IR
V
*NOTE: X2 MUST BE LEFT OPEN.
CLK
M
NOTE:
RESISTOR REQUIRED
FOR TTL INPUT.
SC28L91
50k
to
100k
t
IR
V
OL
V
OL
+0.5V
+0.5V
V
OL
V
V
CC
OL
470
Product specification
X2*
TO UART
CIRCUIT
X1
SD00704
SC28L91
SD00136