pca9306gm NXP Semiconductors, pca9306gm Datasheet - Page 10

• Manufacturer Part Number: pca9306gm
• Description: Pca9306 Dual Bidirectional I2c-bus And Smbus Voltage-level Translator
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9306_2
Product data sheet
11.1 Bidirectional translation
11.2 Sizing pull-up resistor
R
For the bidirectional clamping configuration (higher voltage to lower voltage or lower
voltage to higher voltage), the EN input must be connected to VREF2 and both pins pulled
to HIGH side V
regulate the EN input. A filter capacitor on VREF2 is recommended. The I
output can be totem-pole or open-drain (pull-up resistors may be required) and the
I
pull the SCL2 and SDA2 outputs to V
must be unidirectional or the outputs must be 3-stateable and be controlled by some
direction-control mechanism to prevent HIGH-to-LOW contentions in either direction. If
both outputs are open-drain, no direction control is needed.
The reference supply voltage (V
voltage. When VREF2 is connected through a 200 k resistor to a 3.3 V to 5.5 V V
power supply, and V
and SDA1 has a maximum output voltage equal to VREF1, and the output of each SCL2
and SDA2 has a maximum output voltage equal to V
Table 9.
Refer to
[1]
The pull-up resistor value needs to limit the current through the pass transistor when it is
in the ON state to about 15 mA. This ensures a pass voltage of 260 mV to 350 mV. If the
current through the pass transistor is higher than 15 mA, the pass voltage also is higher in
the ON state. To set the current through each pass transistor at 15 mA, the pull-up resistor
value is calculated as:
Table 10
3 mA. The resistor values shown in the +10 % column or a larger value should be used to
ensure that the pass voltage of the transistor would be 350 mV or less. The external driver
must be able to sink the total current from the resistors on both sides of the PCA9306
device at 0.175 V, although the 15 mA only applies to current flowing through the
PCA9306 device.
Symbol
V
V
V
I
I
T
2
sw(pass)
ref
PU
C-bus device output can be totem-pole or open-drain (pull-up resistors are required to
amb
bias(ref)(2)
I(EN)
ref(1)
All typical values are at T
=
V
-------------------------------------- -
Figure
summarizes resistor reference voltages and currents at 15 mA, 10 mA, and
pu D
Application operating conditions
0.015 A
Parameter
reference bias voltage (2)
input voltage on pin EN
reference voltage (1)
pass switch current
reference current
ambient temperature
9.
–
pu(D)
0.35 V
through a pull-up resistor (typically 200 k ). This allows VREF2 to
ref(1)
Rev. 02 — 21 February 2007
Dual bidirectional I
amb
is set between 1.0 V and (V
= 25 C.
ref(1)
) is connected to the processor core power supply
Conditions
transistor
operating in
free-air
pu(D)
). However, if either output is totem-pole, data
2
C-bus and SMBus voltage-level translator
pu(D)
pu(D)
Min
V
V
0
-
-
40
ref(1)
ref(1)
.
1 V), the output of each SCL1
+ 0.6
+ 0.6
Typ
2.1
2.1
1.5
14
5
-
[1]
PCA9306
© NXP B.V. 2007. All rights reserved.
2
C-bus master
Max
5
5
4.4
-
-
+85
pu(D)
10 of 21
Unit
V
V
V
mA
C
A