isl90727 Intersil Corporation, isl90727 Datasheet - Page 5

• Manufacturer Part Number: isl90727
• Description: Single Volatile 128-tap Digitally Controlled Potentiometer Xdcp?
• Manufacturer: Intersil Corporation

Operating Specifications
SDA vs SCL Timing
NOTES:
Principles of Operation
The ISL90727 and ISL90728 are integrated circuits
incorporating one DCP with its associated registers and an
I
a host and the potentiometer.
DCP Description
The DCP is implemented with a combination of resistor
elements and CMOS switches. The physical ends of the DCP
are equivalent to the fixed terminals of a mechanical
potentiometer (R
connected to intermediate nodes, and is equivalent to the wiper
terminal of a mechanical potentiometer. The position of the
wiper terminal within the DCP is controlled by a 7-bit volatile
Wiper Register (WR). The DCP has its own WR. When the WR
of the DCP contains all zeroes (WR<6:0> = 00h), its wiper
10. RINL = [R
12. This parameter is not 100% tested.
13. V
14. These are I
11.
2
Rpu (Note 14) SDA and SCL Bus Pull-up Resistor
3. Typical values are for T
4. LSB: [V(R
5. ZS error = V(R
6. FS error = [V(R
7. MI =
8. Roffset = R
9. RDNL = (R
Cb (Note 14)
C serial interface providing direct communication between
t
F
(OUTPUT TIMING)
SYMBOL
(INPUT TIMING)
incremental voltage when changing from one tap to an adjacent tap.
Roffset = R
TC
(Note 14)
IL
R
= 0V, V
|
R
=
127
--------------------------------------------------------------- -
[
Max Ri
W
i
[
SDA
SCL
– (MI • i) – R
Max Ri
IH
i
0
127
2
– R
SDA
)
– R
/
C-specific parameters and are not directly tested. However, they are used in the device testing to validate specifications.
127
SDA and SCL Fall Time
Capacitive Loading of SDA or SCL
Off-chip
MI, when measuring between R
= V
H
(
t
W
/
0
MI, when measuring between R
SU:STA
W
i-1
(
|
and R
– V(R
)
/
)
CC.
0
127. R
)
)
127
/
/
LSB.
+
) Min Ri
MI - 1, for i = 32 to 127.
–
Min Ri
– V
W
L
A
0
127
)
pins). The R
PARAMETER
]
(
0
= 25°C and 3.3V supply voltage.
CC
/
MI, for i = 32 to 127.
]
(
/
127. V(R
and R
]
)
t
/
HD:STA
] 2 ⁄
5
LSB.
)
]
(Continued)
×
0
---------------- -
125°C
are the measured resistances for the DCP register set to FF hex and 00 hex respectively.
W
10
W
)
t
127
F
6
pin of the DCP is
t
SU:DAT
and V(R
for i = 32 to 127, T = -40°C to 85°C. Max( ) is the maximum value of the resistance and Min ( ) is the
minimum value of the resistance over the temperature range.
W
W
and R
and R
W
From 70% to 30% of V
Total on-chip and off-chip
Maximum is determined by t
For Cb = 400pF, max is about 2~2.5kΩ.
For Cb = 40pF, max is about 15~20kΩ
ISL90727, ISL90728
)
L
0
t
.
HIGH
are V(R
H
.
W
) for the DCP register set to FF hex and 00 hex respectively. LSB is the
t
TEST CONDITIONS
LOW
t
HD:DAT
terminal (R
WR of the DCP contains all ones (WR<6:0> = 7Fh), its wiper
terminal (R
of the WR increases from all zeroes (00h) to all ones (127
decimal), the wiper moves monotonically from the position
closest to R
the resistance between R
while the resistance between R
monotonically. R
the wiper movement will always be relative to R
While the ISL90727 and ISL90728 are being powered up,
the WR is reset to 40h (64 decimal), which locates R
roughly at the center between R
CC
R
and t
t
R
W
W
L
F
) is closest to its “Low” terminal (R
) is closest to its “High” terminal (R
to the position closest to R
.
t
AA
L
is connected to the GND pin of the device, so
t
DH
W
0.1 * Cb
and R
20 +
MIN
10
1
H
and R
L
L
and R
(Note 3)
increases monotonically,
t
BUF
TYP
W
H
. At the same time,
H
decreases
t
SU:STO
.
MAX
L
H
250
400
L
). When the
). As the value
.
August 2, 2006
W
FN8247.4
UNIT
kΩ
pF
ns