PCA9306_4

© NXP B.V. 2009. All rights reserved.

Product data sheet

Rev. 04 — 26 October 2009

10 of 23

NXP Semiconductors

PCA9306

11.1 Bidirectional translation

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

output can be totem-pole or open-drain (pull-up resistors may be required) and the

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.

voltage. When VREF2 is connected through a 200 k

Ω resistor to a 3.3 V to 5.5 V V

pu(D)

and SDA1 has a maximum output voltage equal to VREF1, and the output of each SCL2

[1]

11.2 Sizing pull-up resistor

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 summarizes resistor reference voltages and currents at 15 mA, 10 mA, and

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.

Table 9.

Application operating conditions

Refer to Figure 9.

Symbol

Parameter

Conditions

Min

Typ[1]

Max

Unit

reference bias voltage (2)

2.1

5

V

input voltage on pin EN

2.1

5

V

reference voltage (1)

0

1.5

4.4

V

pass switch current

-

14

-

mA

reference current

transistor

-

5

-

µA

ambient temperature

operating in

free-air

−40

-

+85

°C

R

PU

V

pu D

()

0.35 V

–

0.015 A

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