ADS-325A Ver la hoja de datos (PDF) - DATEL Data Acquisition products
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ADS-325A Datasheet PDF : 8 Pages
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ADS-325A
®
®
ABSOLUTE MAXIMUM RATINGS (TA = +25°C)
PARAMETERS
Supply Voltages (+AVS and +DVS )
Reference Voltage (VRT and VRB)
Input Voltage, Analog (VIN)
Input Voltage, Digital (VIH and VIL)
Output Voltage, Digital (VOH and VOL)
LIMITS
0 to +7
–0.5 to +AVS +0.5
–0.5 to +AVS +0.5
–0.5 to +AVS +0.5
–0.5 to +DVS +0.5
UNITS
Volts
Volts
Volts
Volts
Volts
FUNCTIONAL SPECIFICATIONS
(Typical at fS = 20MHz, +AVS = +5V, +DVS = +3.3V, VRB = +2.0V, VRT = +4.0V,
and TA = +25°C unless otherwise specified.)
ANALOG INPUTS
Input Voltage Range, VIN
Input Current
VIN = +4V
VIN = +2V
Capacitance, CIN
Bandwidth (–1dB)
MIN.
—
–50
—
—
TYP.
+2 to +4
40
–40
9
70
MAX.
50
—
—
—
UNITS
Volts
µA
µA
pF
MHz
REFERENCE
Reference Input Voltage
VRT
VRB
Input Current
IRT
IRB
Offset Voltage
VRT
VRB
Resistance (VRT – VRB)
—
+4
+4.6
Volts
+1.8
+2
—
Volts
5
7
11
mA
–11
–7
–5
mA
+40
+90
+140
mV
–120
–70
–20
mV
180
280
380
Ω
DIGITAL INPUTS
Input Voltage
VIH, Logic "1"
VIL, Logic "0"
Input Current
IIH, Logic Loading "1"
IIL, Logic Loading "0"
A/D Clock Pulse Width
TPW1
TPW0
+2.3
—
—
Volts
—
—
+0.8
Volts
—
—
5
µA
—
—
5
µA
25
—
—
ns
25
—
—
ns
DIGITAL OUTPUTS
Output Logic Current
IOH, Logic "1"
IOL, Logic "0"
Leak Current at OE = "1"
3-State Enable Time, TPZE
3-State Disable Time, TPEZ
Data Delay, TDL (CL = 20pF)
–3.5
—
—
mA
3.5
—
—
mA
—
—
1
µA
10
15
20
ns
20
25
30
ns
8
13
18
ns
PERFORMANCE
Resolution
Max. Throughput Rate
Min. Throughput Rate
Integral Linearity Error
Differential Linearity Error
Differential Gain Error
Differential Phase Error
Aperture Delay, Tsd
SNR & Distortion
fIN = 100kHz
fIN = 500kHz
fIN = 1MHz
fIN = 3MHz
fIN = 7MHz
fIN = 10MHz
10
—
—
Bits
20
—
—
MHz
—
—
0.5
MHz
—
±1.3
±2
LSB
—
±0.5
±1
LSB
—
1.0
—
%
—
0.3
—
Degrees
2
4
6
ns
—
53
—
dB
—
52
—
dB
—
53
—
dB
—
54
—
dB
—
47
—
dB
—
45
—
dB
PERFORMANCE (CONT.)
Spurious Free Dynamic Range
fIN = 100kHz
fIN = 500kHz
fIN = 1MHz
fIN = 3MHz
fIN = 7MHz
fIN = 10MHz
MIN.
—
—
—
—
—
—
POWER REQUIREMENTS
Power Supply Voltage
+AVS
+DVS
|DGND – AGND |
Supply Current
Analog, +AIS
Digital, +DIS
Standby Current (CE = "1")
Analog, +AIS
Digital, +DIS
Power Dissipation
+4.75
+3.0
—
20
—
—
—
—
PHYSICAL/ENVIRONMENTAL
Operating Temperature Range
–20
Storage Temperature Range
–55
Weight
Package
TYP. MAX.
60
—
59
—
60
—
65
—
50
—
49
—
+5.0 +5.25
—
+5.25
—
100
27
34
3
5
—
1
—
1
150
—
—
+75
—
+150
0.2 grams
48-pin plastic LQFP
UNITS
dB
dB
dB
dB
dB
dB
Volts
Volts
mV
mA
mA
mA
µA
mW
°C
°C
Footnotes:
+DVS = Max., VIH = +DVS
+DVS = Max., VIL = 0V
OE = AGND, +DVS = Min.,
VOH = +DVS-0.5V
OE = AGND, +DVS = Min.,
VOL = 0.4V
OE = +AVS, +DVS = Max.,
VOH = +DVS, and VOL = 0V
Hi-Z to Active, asynchronous with clock.
Active to Hi-Z, asynchronous with clock.
Fin = 1kHz
NTSC 401RE mod. ramp, fc = 14.3MHz
TECHNICAL NOTES
1. Caution to ESD: Since the ADS-325A is a CMOS device,
precautions against static electricity should be taken.
2. +AVS and +DVS: While the unit has separate pins for both
the analog supply (+AVS) and the digital supply (+DVS), a
time skew between supplying (or removing) both +AVS and
+DVS may cause a latch-up problem. DATEL recommends
using a common power supply for both +AVS and +DVS to
avoid latch-up conditions. It is possible to use +3.3V for
+DVS along with +5V for +AVS. Compared to the singe +5V
supply application, there will be no significant difference in
performance. However, special care should be taken to
minimize the time skew between +AVS and +DVS when
turning on/off.
3. PC board layout: To obtain fully specified performance
careful attention to PC board layout is required. Place large
ground planes on the board and connect both analog and
digital grounds at one point right beneath the converter. In
the case where the grounds are tied at a location distant
from the converter, the voltage difference between the
grounds must be within 100mV. Tie all ground pins directly
to the appropriate ground plane beneath the converter.
Bypass +AVS and +DVS pins to ground using 10µF
tantalum capacitors in parallel with 0.1µF ceramic
capacitors at locations as close to the unit as possible.
4. Reference Input: Two external voltage references are
required for the two reference inputs VRT (pin 29, 30) and
VRB (pin 34, 35). Typically, these are +4V for VRT and +2V
2
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