R

PU

+

V

DPU

* 0.35 V

0.015 A

–9

–8

–7

–6

–5

–4

–3

–2

–1

0

0.1

1

10

100

1000

Frequency (MHz)

PCA9306

www.ti.com

SCPS113J – OCTOBER 2004 – REVISED OCTOBER 2010

Sizing Pullup Resistor

The pullup 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 pullup resistor value is calculated as:

The following table summarizes resistor values, reference voltages, and currents at 15 mA, 10 mA, and 3 mA.

The resistor value shown in the +10% column (or a larger value) should be used to ensure that the pass voltage

of the transistor is 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 applies only to current flowing through the

PCA9306 device.

PULLUP RESISTOR VALUE (

Ω)

15 mA

10 mA

3 mA

NOMINAL

NOMINAL

NOMINAL

5 V

310

341

465

512

1550

1705

3.3 V

197

217

295

325

983

1082

2.5 V

143

158

215

237

717

788

1.8 V

97

106

145

160

483

532

1.5 V

77

85

115

127

383

422

1.2 V

57

63

85

94

283

312

(1)

(2)

(3)

PCA9306 Bandwidth

The maximum frequency of the PCA9306 is dependent on the application. The device can operate at speeds of

> 100MHz given the correct conditions. The maximum frequency is dependent upon the loading of the

application. The PCA9306 behaves like a standard switch where the bandwidth of the device is dictated by the

on resistance and on capacitance of the device.

Figure 4 shows a bandwidth measurement of the PCA9306 using a two-port network analyzer.

Figure 4. Bandwidth

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