SPT7938 查看數據表（PDF） - Cadeka Microcircuits LLC.
零件编号
产品描述 (功能)
比赛名单
SPT7938 Datasheet PDF : 10 Pages
| |||
Figure 6 – On-Chip Protection Circuit
VDD
120 Ω
Analog
120 Ω
Pad
INPUT PROTECTION
All I/O pads are protected with an on-chip protection circuit
shown in figure 6. This circuit provides ESD robustness to
3.5 kV and prevents latch-up under severe discharge condi-
tions without degrading analog transition times.
CLOCK INPUT
The SPT7938 is driven from a single-ended TTL-input
clock. The duty cycle of the clock should be kept as close to
50% (±5%) as possible.
DIGITAL OUTPUTS
The digital outputs (D0–D12) are driven by a separate sup-
ply (OVDD) ranging from +3 V to +5 V. This feature makes it
possible to drive the SPT7938’s TTL/CMOS-compatible
outputs with the user’s logic system supply. The format of
the output data (D0–D11) is straight binary. (See table III.)
The outputs are latched on the rising edge of CLK. These
outputs can be switched into a tri-state mode by bringing EN
high.
Table III – Output Data Information
ANALOG INPUT
+F.S. + 1/2 LSB
OVERRANGE
D12
1
OUTPUT CODE
D11–D0
11 1111 1111
+F.S. –1/2 LSB
0
11 1111 111Ø
+1/2 F.S.
0
ØØ ØØØØ ØØØØ
+1/2 LSB
0
00 0000 000Ø
0.0 V
0
00 0000 0000
(Ø indicates the flickering bit between logic 0 and 1).
OVERRANGE OUTPUT
The Overrange Output (D12) is an indication that the analog
input signal has exceeded the positive full-scale input volt-
age by 1 LSB. When this condition occurs, D12 will switch to
logic 1. All other data outputs (D0 to D11) will remain at
logic 1 as long as D12 remains at logic 1. This feature
makes it possible to include the SPT7938 in higher resolu-
tion systems.
EVALUATION BOARD
The EB7938 evaluation board is available to aid designers
in demonstrating the full performance of the SPT7938. This
board includes a reference circuit, clock driver circuit, output
data latches and an on-board reconstruction of the digital
data. An application note (AN7938) describing the operation
of this board, as well as information on the testing of the
SPT7938, is also available. Contact the factory for price and
availability.
SPT7938
8
5/24/00
Share Link: 