Datasheet

PCA9527_1 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 01 — 29 June 2009 6 of 22
NXP Semiconductors
PCA9527
3-channel bidirectional bus extender for HDMI, I
2
C-bus and SMBus
6.3.2 Port A (CECA)
CECA does not have a rise time accelerator, but has a standard open-drain I/O. In
addition to incurring no offset voltage, it has edge rate control and a lower capacitance
than those of standard discrete MOSFET, and isolates the input/output capacitance. It is
designed for a lower speed channel for consumer electronic control (less than 10 kHz) or
general purpose interrupt or reset over long cable.
CECA does not have internal pull-up. The pull-up resistor is calculated using standard
I
2
C-bus pull-up resistor formula, as shown in Section 6.3.3 “Port B (SDAB, SCLB, CECB)”.
Table 3. HDMI DDC pull-up resistors specification
Pin Where Minimum Maximum
SDAA at the source (DVD/STB) 1.5 kΩ 2.0 kΩ
at the sink (LCD TV) - -
SCLA at the source (DVD/STB) 1.5 kΩ 2.0 kΩ
at the sink (LCD TV) 47 kΩ±10 %
rise time = 1 µs; V
CC(A)
=5V
Fig 4. SDAA/SCLA line pull-up resistor versus load capacitance
C
L
(nF)
0 4.03.02.01.0
002aad620
4.5
6.5
2.5
8.5
10.5
R
PU
(kΩ)
0.5
does not comply with
1 µs rise time
complies with
1 µs rise time