Datasheet
I
2
C INTERFACE TIMING REQUIREMENTS
RESET TIMING REQUIREMENTS
SWITCHING CHARACTERISTICS
PCA9557
www.ti.com
.................................................................................................................................................... SCPS133I – DECEMBER 2005 – REVISED JUNE 2008
over recommended operating free-air temperature range (unless otherwise noted) (see Figure 10 )
STANDARD MODE FAST MODE
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2
C BUS I
2
C BUS
UNIT
MIN MAX MIN MAX
f
scl
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2
C clock frequency 0 100 0 400 kHz
t
sch
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2
C clock high time 4 0.6 µ s
t
scl
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2
C clock low time 4.7 1.3 µ s
t
sp
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2
C spike time 50 50 ns
t
sds
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2
C serial data setup time 250 100 ns
t
sdh
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2
C serial data hold time 0 0 ns
t
icr
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2
C input rise time 1000 20 + 0.1C
b
(1)
300 ns
t
icf
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2
C input fall time 300 20 + 0.1C
b
(1)
300 ns
t
ocf
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2
C output fall time, 10-pF to 400-pF bus 300 20 + 0.1C
b
(1)
300 ns
t
buf
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2
C bus free time between Stop and Start 4.7 1.3 µ s
t
sts
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2
C Start or repeated Start condition setup time 4.7 0.6 µ s
t
sth
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2
C Start or repeated Start condition hold time 4 0.6 µ s
t
sps
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2
C Stop condition setup time 4 0.6 µ s
t
vd(data)
Valid data time, SCL low to SDA output valid 1 0.9 µ s
Valid data time of ACK condition, ACK signal from SCL low to
t
vd(ack)
1 0.9 µ s
SDA (out) low
C
b
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2
C bus capacitive load 400 400 pF
(1) C
b
= total capacitance of one bus line in pF
over recommended operating free-air temperature range (unless otherwise noted) (see Figure 13 )
STANDARD MODE FAST MODE
I
2
C BUS I
2
C BUS
UNIT
MIN MAX MIN MAX
t
W
Reset pulse duration
(1)
16 16 ns
t
REC
Reset recovery time 0 0 ns
t
RESET
Time to reset
(2)
400 400 ns
(1) A pulse duration of 16 ns minimum must be applied to RESET to return the PCA9557 to its default state.
(2) The PCA9557 requires a minimum of 400 ns to be reset.
over recommended operating free-air temperature range (unless otherwise noted) (see Figure 10 )
STANDARD MODE FAST MODE
I
2
C BUS I
2
C BUS
PARAMETER FROM TO UNIT
MIN MAX MIN MAX
SCL P0 250 250
t
pv
Output data valid ns
SCL P1 – P7 200 200
t
ps
Input data setup time P port SCL 0 0 ns
t
ph
Input data hold time P port SCL 200 200 ns
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