EVAL-AD7877EBZ Analog Devices Inc, EVAL-AD7877EBZ Datasheet - Page 5

BOARD EVALUATION FOR AD7877

EVAL-AD7877EBZ

Manufacturer Part Number
EVAL-AD7877EBZ
Description
BOARD EVALUATION FOR AD7877
Manufacturer
Analog Devices Inc

Specifications of EVAL-AD7877EBZ

Main Purpose
Interface, Touch Screen Controller
Embedded
No
Utilized Ic / Part
AD7877
Primary Attributes
4-Wire Resistive Touch Screen Controller, SPI Interface, On-Chip: Temp Sensor, Voltage Reference, 8-Bit DAC
Secondary Attributes
USB GUI, LCD Noise Reduction Feature, 2.7 ~ 5.25 V, Wake Up on Touch Feature
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
TIMING SPECIFICATIONS
T
signals are specified with t
Table 2.
Parameter
f
t
t
t
t
t
t
t
t
t
1
2
3
TIMING DIAGRAMS
DCLK
1
2
3
4
5
6
7
8
9
Mark/space ratio for the DCLK input is 40/60 to 60/40.
Measured with the load circuit of Figure 3 and defined as the time required for the output to cross 0.4 V or 2.0 V.
t
extrapolated back to remove the effects of charging or discharging the 50 pF capacitor. This means that the time, t
relinquish time of the part and is independent of the bus loading.
A
2
2
3
8
is derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit shown in Figure 3. The measured number is then
= T
1
MIN
to T
MAX
, unless otherwise noted, V
10
20
16
20
20
12
12
16
16
16
0
Limit at T
R
= t
F
MIN
= 5 ns (10% to 90% of V
, T
MAX
DCLK
DOUT
DIN
CS
Figure 3. Load Circuit for Digital Output Timing Specifications
CC
t
6
= 2.7 V to 5.25 V, V
t
MSB
1
1
MSB
TO OUTPUT
ns max
ns max
Unit
kHz min
MHz max
ns min
ns min
ns min
ns min
ns min
ns max
ns min
t
2
Figure 2. Detailed Timing Diagram
4
CC
t
2
PIN
) and timed from a voltage level of 1.6 V.
3
Rev. C | Page 5 of 44
50pF
C
t
t
7
L
5
200μA
200μA
t
REF
3
= 2.5 V. Sample tested at 25°C to ensure compliance. All input
Description
CS falling edge to first DCLK rising edge
DCLK high pulse width
DCLK low pulse width
DIN setup time
DIN hold time
CS falling edge to DOUT, three-state disabled
DCLK falling edge to DOUT valid
CS rising edge to DOUT high impedance
CS rising edge to DCLK ignored
I
I
OL
OH
15
1.6V
16
LSB
LSB
t
t
9
8
8
, quoted in the timing characteristics is the true bus
AD7877

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