PCA9306D.112 NXP Semiconductors, PCA9306D.112 Datasheet - Page 11

• Manufacturer Part Number: PCA9306D.112
• Manufacturer: NXP Semiconductors

Specifications of PCA9306D.112

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Package Type: SO
• Pin Count: 8
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

NXP Semiconductors
PCA9306
Product data sheet
11.2.1 Maximum frequency calculation
Table 10.
Calculated for V
[1]
The maximum frequency is totally dependent upon the specifics of the application and the
device can operate > 33 MHz. Basically, the PCA9306 behaves like a wire with the
additional characteristics of transistor device physics and should be capable of performing
at higher frequencies if used correctly.
Here are some guidelines to follow that will help maximize the performance of the device:
In a 3.3 V to 1.8 V direction level shift, if the 3.3 V side is being driven by a totem pole type
driver no pull-up resistor is needed on the 3.3 V side. The capacitance and line length of
concern is on the 1.8 V side since it is driven through the ON resistance of the PCA9306.
If the line length on the 1.8 V side is long enough there can be a reflection at the
chip/terminating end of the wire when the transition time is shorter than the time of flight of
the wire because the PCA9306 looks like a high-impedance compared to the wire. If the
wire is not too long and the lumped capacitance is not excessive the signal will only be
slightly degraded by the series resistance added by passing through the PCA9306. If the
lumped capacitance is large the rise time will deteriorate, the fall time is much less
affected and if the rise time is slowed down too much the duty cycle of the clock will be
degraded and at some point the clock will no longer be useful. So the principle design
consideration is to minimize the wire length and the capacitance on the 1.8 V side for the
clock path. A pull-up resistor on the 1.8 V side can also be used to trade a slower fall time
for a faster rise time and can also reduce the overshoot in some cases.
V
5 V
3.3 V
2.5 V
1.8 V
1.5 V
1.2 V
•
•
•
•
pu(D)
+10 % to compensate for V
Keep trace length to a minimum by placing the PCA9306 close to the processor.
The trace length should be less than half the time of flight to reduce ringing and
reflections.
The faster the edge of the signal, the higher the chance for ringing.
The higher the drive strength (up to 15 mA), the higher the frequency the device can
use.
Pull-up resistor values
Nominal
OL
310
197
143
97
77
57
All information provided in this document is subject to legal disclaimers.
= 0.35 V; assumes output driver V
15 mA
Rev. 6 — 25 November 2010
Dual bidirectional I
+10 %
CC
341
217
158
106
range and resistor tolerance.
85
63
[1]
Pull-up resistor value (Ω)
Nominal
465
295
215
145
115
85
2
C-bus and SMBus voltage-level translator
10 mA
OL
= 0.175 V at stated current.
+10 %
512
325
237
160
127
94
[1]
Nominal
1550
983
717
483
383
283
PCA9306
© NXP B.V. 2010. All rights reserved.
3 mA
+10 %
1705
1082
788
532
422
312
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