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ADS7852_14 Datasheet, PDF (11/19 Pages) Texas Instruments – 12-Bit, 8-Channel, Parallel Output ANALOG-TO-DIGITAL CONVERTER
◁
CLK
WR
CS
BUSY
RD
Address
Bus
Data
Bus
HOLD
tCKH
tCKP
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8
tCKL
t1
t2
t4
t3
t5
Conversion n
tCONV
Address n + 1
Hi-Z
t4
tACQ
t6
t7
t8
t9
Data
Valid
Conversion n + 1
Address n + 2
t10
Hi-Z
Data
Valid
Hi-Z
SYMBOL
tCONV
tACQ
tCKP
tCKL
tCKH
t1
t2
t3
t4
t5
t6
t7
t8
t9
t10
t11
t12
t13
t14
t15
DESCRIPTION
Conversion Time
Acquisition Time
Clock Period
Clock LOW
Clock HIGH
WR LOW Prior to Rising Edge of CLK
WR LOW After Rising Edge of CLK
CS LOW After Rising Edge of CLK
CS and RD HIGH
BUSY Delay After CS LOW
RD LOW
Address Hold Time
Address Setup Time
Bus Access Time
Bus Relinquish Time
CS to RD Setup Time
RD to CS Hold Time
CLK LOW to BUSY HIGH
BUSY to RD Delay
RD HIGH to CLK LOW
MIN TYP MAX UNITS
1.75 µs
0.25 µs
125
5000 ns
40
ns
40
ns
35
ns
20
ns
20
ns
25
ns
20
ns
25
ns
5
ns
5
ns
30
ns
5
ns
0
ns
0
ns
10
ns
0
ns
50
ns
FIGURE 2. ADS7852 Write/Read Timing.
READING DATA
Data from the ADS7852 will appear at pins 15 through 26.
The MSB will output on pin 15 while the LSB will output
on pin 26. The outputs are coded in Straight Binary (with
0V = 000H and 5V = FFFH). Following a conversion, the
BUSY pin will go HIGH. After BUSY has been HIGH for
at least t14 seconds, the CS and RD pins may be brought
LOW to enable the 12-bit output bus. CS and RD must be
held LOW for at least 25ns following BUSY HIGH. Data
will be valid 30ns after the falling edge of both CS and RD.
The output data will remain valid for 20ns following the
rising edge of both CS and RD (see Figure 2 for the read
cycle timing diagram).
ADS7852
SBAS111C
DESCRIPTION
Least Significant
Bit (LSB)
Full Scale
Midscale
Midscale –1LSB
Zero Full Scale
ANALOG INPUT
1.2207mV
4.99878V
2.5V
2.49878V
0V
DIGITAL OUTPUT
STRAIGHT BINARY
BINARY CODE
HEX CODE
1111 1111 1111
FFF
1000 0000 0000
800
0111 1111 1111
7FF
0000 0000 0000
000
Table I. Ideal Input Voltages and Output Codes.
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