SYMBOL
DESCRIPTION
Convert Pulse Width
BUSY Delay
MIN TYP MAX UNITS
t1
CS, R/C
BUSY
t1
t2
t3
t4
40
4500
65
ns
ns
µs
ns
t3
BUSY LOW
8
t2
t4
t5
BUSY Delay after
End of Conversion
220
Convert
t6
Acquire
t7
MODE Acquire
t5
t6
Aperture Delay
Conversion Time
40
ns
µs
µs
µs
ns
ns
ns
5.7
8
2
t7
Acquisition Time
FIGURE 1. Basic Conversion Timing.
t6 + t7
t8
Throughput Time
9
10
R/C LOW to DATACLK Delay
DATACLK Period
450
440
75
t9
t10
Data Valid to DATACLK
HIGH Delay
20
t11
Data Valid after
100 125
ns
DATACLK LOW Delay
t12
t13
t14
t15
External DATACLK Period
External DATACLK HIGH
External DATACLK LOW
100
20
ns
ns
ns
30
DATACLK HIGH
Setup Time
20
t12 + 5 ns
t16
R/C to CS
Setup Time
10
15
ns
t17
SYNC Delay After
DATACLK HIGH
35
55
ns
t18
t19
t20
Data Valid Delay
25
25
ns
ns
µs
CS to Rising Edge Delay
Data Available after CS LOW
4.5
TABLE II. Conversion and Data Timing TA = –40°C to +85°C.
t8
R/C
t9
DATACLK
1
2
3
11
12
t11
t10
SDATA
BUSY
MSB Valid
Bit 10 Valid
Bit 9 Valid
Bit 1 Valid
LSB Valid
t2
t3
FIGURE 2. Serial Data Timing Using Internal Clock. (CS, EXT/INT and TAG Tied LOW.)
ADS7808
SBAS018A
5
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