DIGITAL OUTPUTS
OVERRANGE OUTPUT
The digital outputs (D0–D10) are driven by a separate The OVERRANGE OUTPUT (D10) is an indication that
supply (OVDD) ranging from +3 V to +5 V. This feature the analog input signal has exceeded the positive full-
makes it possible to drive the SPT7860’s TTL/CMOS- scale input voltage by 1 LSB. When this condition occurs,
compatible outputs with the user’s logic system supply. D10 will switch to logic 1. All other data outputs (D0 to D9)
The format of the output data (D0–D9) is straight binary. will remain at logic 1 as long as D10 remains at logic 1.
(See table III.) The outputs are latched on the rising edge This feature makes it possible to include the SPT7860 in
of CLK. These outputs can be switched into a tri-state higher resolution systems.
mode by bringing EN high.
EVALUATION BOARD
Table III – Output Data Information
The EB7860 evaluation board is available to aid designers
ANALOG INPUT
OVERRANGE
D10
OUTPUT CODE
in demonstrating the full performance of the SPT7860.
This board includes a reference circuit, clock driver circuit,
output data latches, and an on-board reconstruction of the
digital data. An application note describing the operation
of this board, as well as information on the testing of the
SPT7860, is also available. Contact the factory for price
and availability.
D9–D0
+F.S. + 1/2 LSB
+F.S. –1/2 LSB
+1/2 F.S.
+1/2 LSB
0.0 V
1
0
0
0
0
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1Ø
ØØ ØØØØ ØØØØ
0 0 0 0 0 0 0 0 0 Ø
0 0 0 0 0 0 0 0 0 0
(Ø indicates the flickering bit between logic 0 and 1.)
SPT7860
10
5/25/01
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
