Rainbow Electronics ADC1173 - Manual (Page 7)

Converter Electrical Characteristics
(Continued)
The following specifications apply for AV
DD
= DV
DD
= +3.0V
DC
, OE = 0V, V
RT
= +2.0V, V
RB
= 0V, C
L
= 20 pF, f
CLK
= 15MHz
at 50% duty cycle. Boldface limits apply for T
A
= T
MIN
to T
MAX
; all other limits T
A
= 25˚C (Notes 7, 8)
Symbol Parameter Conditions
Typical
(Note 9)
Limits Units
SFDR Spurious Free Dynamic Range
f
IN
= 1.31 MHz
f
IN
= 3.58 MHz
f
IN
= 7.5 MHz
65
55
51
dB
THD Total Harmonic Distortion
f
IN
= 1.31 MHz
f
IN
= 3.58 MHz
f
IN
= 7.5 MHz
−62
−54
−51
dB
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 = AV SS = DV SS = 0V, unless otherwise specified.
Note 3: When the input voltage at any pin exceeds the power supplies (that is, less than AV SS or DV SS , or greater than AV DD or DV DD ), 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 temperatures (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 24-pin
TSSOP, θ
JA is 92˚C/W, so P D MAX = 1,358 mW at 25˚C and 815 mW at the maximum operating ambient temperature of 75˚C. (Typical thermal resistance, θ
JA , of
this part is 98˚C/W for the EIAJ SOIC). Note that the power dissipation of this device under normal operation will typically be about 49 mW (33 mW quiescent power
+ 13 mW reference ladder power + 3 mW due to 1 TTL loan on each digital output. The values for maximum power dissipation listed above will be reached only when
the ADC1173 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 1.5k Ω resistor. Machine model is 220 pf discharged through ZERO Ω.
Note 6: See AN450, "Surface Mounting Methods and Their Effect on Product Reliability", or the section entitled "Surface Mount" found in any post 1986 National
Semiconductor Linear Data Book, for other methods of soldering surface mount devices.
Note 7: The analog inputs are protected as shown below. Input voltage magnitudes up to 6.5V or to 500 mV below GND will not damage this device. However, errors
in the A/D conversion can occur if the input goes above V
DD
or below GND by more than 50 mV. As an example, if AV
DD
is 2.7V
DC
, the full-scale input voltage must
be ≤2.75V
DC
to ensure accurate conversions.
10089010
Note 8: To guarantee accuracy, it is required that AV DD and DV DD be well bypassed. Each supply pin must be decoupled with separate bypass capacitors.
Note 9: Typical figures are at T
J
= 25˚C, and represent most likely parametric norms. Test limits are guaranteed to National’s AOQL (Average Outgoing Quality
Level).
Note 10: At least two clock cycles must be presented to the ADC1173 after power up. See Section 4.0 for details.
ADC1
173
www.national.com 7