Rainbow Electronics ADC12020 - Manual (Page 7)

DC and Logic Electrical Characteristics
(Continued)
Unless otherwise specified, the following specifications apply for AGND = DGND = DR GND = 0V, V
A
= V
D
= +5V, V
DR
=
+3.0V, PD = 0V, V
REF
= +2.0V, f
CLK
= 20 MHz, t
r
= t
f
= 3 ns, C
L
= 25 pF/pin. Boldface limits apply for T
A
= T
J
= T
MIN
to
T
MAX
: all other limits T
A
= T
J
= 25˚C (Notes 7, 8, 9)
Symbol Parameter Conditions
Typical
(Note 10)
Limits
(Note 10)
Units
(Limits)
PSRR1− Power Supply Rejection Ratio
Rejection of Positive Full-Scale Error
with V
A
= 4.75V to 5.25V
51 dBFS
PSRR2 Power Supply Rejection Ratio
Rejection of Power Supply Noise with
10 MHz, 250 mV
P-P
riding on V
A
48 dBFS
AC Electrical Characteristics
Unless otherwise specified, the following specifications apply for AGND = DGND = DR GND = 0V, V
A
= V
D
= +5V, V
DR
=
+3.0V, PD = 0V, V
REF
= +2.0V, f
CLK
= 20 MHz, t
r
= t
f
= 3 ns, C
L
= 25 pF/pin. Boldface limits apply for T
A
= T
J
= T
MIN
to
T
MAX
: all other limits T
A
= T
J
= 25˚C (Notes 7, 8, 9, 12)
Symbol Parameter Conditions
Typical
(Note 10)
Limits
(Note 10)
Units
(Limits)
f
CLK1
Maximum Clock Frequency 20 30 MHz (min)
f
CLK2
Minimum Clock Frequency 100 kHz
t
CH
Clock High Time 20 ns(min)
t
CL
Clock Low Time 20 ns(min)
t
CONV
Conversion Latency 6
Clock
Cycles
t
OD
Data Output Delay after Rising
CLK Edge
V
DR
= 2.5V 11 16.8 ns(max)
V
DR
= 3.0V 11 16.8 ns(max)
t
AD
Aperture Delay 1.2 ns
t
AJ
Aperture Jitter 2 ps rms
t
DIS
Data outputs into TRI-STATE
Mode
4 ns
t
EN
Data Outputs Active after
TRI-STATE
4 ns
t
PD
Power Down Mode Exit Cycle 0.1µF capacitor on pins 30, 31, 32 500 ns
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
Note 2: All voltages are measured with respect to GND = AGND = DGND = 0V, unless otherwise specified.
Note 3: When the input voltage at any pin exceeds the power supplies (that is, V IN
< AGND, or V IN
> V A ), the current at that pin should be limited to 25 mA. The
50 mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 25 mA to two.
Note 4: The absolute maximum junction temperature (T J max) for this device is 150˚C. The maximum allowable power dissipation is dictated by T J max, the
junction-to-ambient thermal resistance ( θ
JA ), and the ambient temperature, (T A ), and can be calculated using the formula P D MAX = (T J max - T A )/ θ
JA . In the 32-pin
LQFP, θ
JA is 79˚C/W, so P D MAX = 1,582 mW at 25˚C and 823 mW at the maximum operating ambient temperature of 85˚C. Note that the power consumption of
this device under normal operation will typically be about 205 mW (185 typical power consumption + 20 mW TTL output loading). The values for maximum power
dissipation listed above will be reached only when the device is operated in a severe fault condition (e.g. when input or output pins are driven beyond the power
supply voltages, or the power supply polarity is reversed). Obviously, such conditions should always be avoided.
Note 5: Human body model is 100 pF capacitor discharged through a 1.5 k Ω resistor. Machine model is 220 pF discharged through 0Ω.
Note 6: The 235˚C reflow temperature refers to infrared reflow. For Vapor Phase Reflow (VPR), the following Conditions apply: Maintain the temperature at the top
of the package body above 183˚C for a minimum 60 seconds. The temperature measured on the package body must not exceed 220˚C. Only one excursion above
183˚C is allowed per reflow cycle.
Note 7: The inputs are protected as shown below. Input voltage magnitudes above V A or below GND will not damage this device, provided current is limited per
(Note 3). However, errors in the A/D conversion can occur if the input goes above V A or below GND by more than 100 mV. As an example, if V A is 4.75V, the full-scale
input voltage must be ≤4.85V to ensure accurate conversions.
ADC12020
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