PCA9600_4

© NXP B.V. 2009. All rights reserved.

Product data sheet

Rev. 04 — 11 November 2009

13 of 30

NXP Semiconductors

PCA9600

Dual bidirectional bus buffer

For more examples of faster alternatives for driving over longer cables such as Cat5

communication cable, see

AN10658. Communication at 1 MHz is possible over short

cables and > 400 kHz is possible over 50 m of cable.

Fig 14. Driving ribbon or flat telephone cables

PCA9600

SCL

RX

TX

002aac851

SX

TY

RY

SY

R2

R2

C2

C2

MASTER

SDA

GND

R1

R1

BAT54A

cable

propagation

delay

≈ 5 ns/m

BAT54A

R1

R1

PCA9600

RX

TX

TY

RY

SX

SY

R2

R2

SCL

SDA

GND

SLAVE(S)

C2

C2

+V cable drive

Table 7.

Examples of bus capability

Refer to Figure 14.

(V)

+V

cable

(V)

(V)

R1

(

Ω)

R2

(k

Ω)

C2

(pF)

Cable

length

(m)

Cable

capacitance

Cable

delay

Set master

nominal SCL

Effective

bus clock

speed

(kHz)

Max. slave

response

delay

HIGH

period

(ns)

LOW

period

(ns)

5

12

5

750

2.2

400

250

n/a

(delay based)

1.25

µs 600

3850

125

normal

specification

400 kHz parts

5

12

5

750

2.2

220

100

n/a

(delay based)

500 ns

600

2450

195

normal

specification

400 kHz parts

3.3

5

3.3

330

1

220

25

1 nF

125 ns

260

770

620

meets Fm+

specification

3.3

5

3.3

330

1

100

3

120 pF

15 ns

260

720

690

meets Fm+

specification