HI3086(1997) 데이터 시트보기 (PDF) - Intersil
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HI3086 Datasheet PDF : 19 Pages
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HI3086
Notes on Operation
• The HI3086 is a high-speed A/D converter which is
capable of TTL, ECL and PECL level clock input. Charac-
teristic impedance should be properly matched to ensure
optimum performance during high-speed operation.
• The power supply and grounding have a profound
influence on converter performance. The power supply
and grounding method are particularly important during
high-speed operation. General points for caution are as
follows:
- The ground pattern should be as large as possible. It is
recommended to make the power supply and ground
patterns wider at an inner layer using a multi-layer
board.
- To prevent interference between AGND and DGND and
between AVCC and DVCC, make sure the respective
patterns are separated. To prevent a DC offset in the
power supply pattern, connect the AVCC and DVCC
lines at one point each via a ferrite-bead filter. Shorting
the AGND and DGND patterns in one place immedi-
ately under the A/D converter improves A/D converter
performance.
- Ground the power supply pins (AVCC, DVCC1, DVCC2,
DVEE3) as close to each pin as possible with a 0.1µF or
larger ceramic chip capacitor. (Connect the AVCC pin to
the AGND pattern and the DVCC1, DVCC2, DVEE3 pins
to the DGND pattern.)
- The digital output wiring should be as short as possible.
If the digital output wiring is long, the wiring capacitance
will increase, deteriorating the output slew rate and
resulting in reflection to the output waveform since the
original output slew rate is quite fast.
• The analog input pin VIN has an input capacitance of
approximately 7pF. To drive the A/D converter with proper
frequency response, it is necessary to prevent perfor-
mance deterioration due to parasitic capacitance or
parasitic inductance by using a large capacity drive circuit;
keeping wiring as short as possible, and using chip parts
for resistors and capacitors, etc.
• The VRT and VRB pins must have adequate bypass to
protect them from high-frequency noise. Bypass them to
AGND with approximately 1µF tantal capacitor and, 0.1µF
chip capacitor as short as possible.
• The offset for residual is generated each for the reference
voltage pins VRT and VRB. When the offset voltage has
no influence on the IC operation, the voltage should be
applied to the VRT and VRB pins directly, keeping the
VRBS pin open. When the reference voltage is to be
supplied to these pins precisely, form the feedback loop
circuit with VRT and VRB as a force pin and adjust the
offset voltage to be 0V. See Figure 25 for details.
• If the CLKN/E pin is not used, bypass this pin to DGND
with an approximately 0.1µF capacitor. At this time,
approximately DGND3 -1.2V voltage is generated. How-
ever, this is not recommended for use as threshold voltage
VBB as it is too weak.
• When the digital input level is ECL or PECL level, ***/E
pins should be used and ***/T pins left open. When the
digital input level is TTL, ***/T pins should be used and
***/E pins left open.
Typical Performance Curves
70
65
60
55
50
-25
25
AMBIENT TEMPERATURE (oC)
FIGURE 12. CURRENT CONSUMPTION vs AMBIENT
TEMPERATURE CHARACTERISTICS
90
80
70
60
fIN =
fCLK -1kHz
4
50
DEMUX MODE
CL = 5pF
75
0
70
140
CONVERSION RATE (MSPS)
FIGURE 13. CURRENT CONSUMPTION vs CONVERSION RATE
CHARACTERISTICS
4-1418
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