AT84AD001BCTD ATMEL [ATMEL Corporation], AT84AD001BCTD Datasheet - Page 42

• Manufacturer Part Number: AT84AD001BCTD
• Description: Dual 8-bit 1 Gsps ADC
• Manufacturer: ATMEL [ATMEL Corporation]

Table 14. Timing Description
Calibration Description
42
Name
Tsclk
Twsclk
Tssldn
Thsldn
Tssdata
Thsdata
Twlmode
Tdmode
AT84AD001B
Parameter
Sclk period
High or low time of sclk
Setup time of sldn before rising edge of sclk
Hold time of sldn after rising edge of sclk
Setup time of sdata before rising edge of sclk
Hold time of sdata after rising edge of sclk
Minimum low pulse width of mode
Minimum delay between an edge of mode and the
rising edge of sclk
The AT84AD001B offers the possibility of reducing offset and gain matching between
the two ADC cores. An internal digital calibration may start right after the 3-wire serial
interface has been loaded (using data D12 of the 3-wire serial interface with address
000).
The beginning of calibration disables the two ADCs and a standard data acquisition is
performed. The output bit CAL goes to a high level during the entire calibration phase.
When this bit returns to a low level, the two ADCs are calibrated with offset and gain and
can be used again for a standard data acquisition.
If only one channel is selected (I or Q) the offset calibration duration is divided by two
and no gain calibration between the two channels is necessary.
Figure 46. Internal Timing Calibration
The Tcal duration is a multiple of the clock frequency ClockI (master clock). Even if a
dual clock scheme is used during calibration, ClockQ will not be used.
The control wait bits (D13 and D14) give the possibility of changing the calibration’s set-
ting depending on the clock’s frequency:
•
•
•
•
For high clock rates (> 500 Msps) use a = b = 1, Tcal = 10112 clock I periods.
For clock rates > 250 Msps and < 500 Msps use a = 1, b = 0, Tcal = 6016 clock I
periods.
For clock rates > 125 Msps and < 250 Msps use a = 0, b = 1 ,Tcal = 3968 clock I
periods.
For low clock rates (< 125 Msps) use a = 0, b = 0 , Tcal = 2944 clock I periods.
3-wire Serial Interface
CAL
LDN
Min
20
10
5
4
2
4
2
5
Value
Typ
Tcal
Max
2153C–BDC–04/04
Unit
ns
ns
ns
ns
ns
ns
ns
ns