Cirrus Logic CS5490 - Manual (Page 11)

CS5490
DS982F3 11
Notes: 5. All outputs unloaded. All inputs CMOS level.
6. Temperature accuracy measured after calibration is performed.
7. Measurement method for PSRR: VDDA = +3.3V, a 150mV (zero-to-peak) (60Hz) sinewave is imposed onto the +3.3V DC supply
voltage at the VDDA pin. The “+” and “-” input pins of both input channels are shorted to GNDA. The CS5490 is then commanded
to continuous conversion acquisition mode, and digital output data is collected for the channel under test. The (zero-to-peak) value
of the digital sinusoidal output signal is determined, and this value is converted into the (zero-to-peak) value of the sinusoidal
voltage (measured in mV) that would need to be applied at the channel’s inputs, in order to cause the same digital sinusoidal
output. This voltage is then defined as V
eq
PSRR is (in dB) :
VOLTAGE REFERENCE
Notes: 8. It is strongly recommended that no connection other than the required filter capacitor be made to VREF±.
9. The voltage at VREF± is measured across the temperature range. From these measurements the following formula is used to
calculate the VREF temperature coefficient:
10. Specified at maximum recommended output of 1µA sourcing. VREF is a very sensitive signal, the output of the VREF circuit has
a very high output impedance so that the 0.1µF reference capacitor provides attenuation even to low frequency noise, such as
50Hz noise on the VREF output. As such VREF intended for the CS5490 only and should not be connected to any external
circuitry. The output impedance is sufficiently high that standard digital multi-meters can significantly load this voltage. The
accuracy of the metrology IC can not be guaranteed when a multimeter or any component other than the 0.1µF capacitor is
attached to VREF. If it is desired to measure VREF for any reason other than a very course indicator of VREF functionality, Cirrus
recommends a very high input impedance multimeter such as the Keithley Model 2000 Digital Multimeter be used, but still cannot
guarantee the accuracy of the metrology with this meter connected to VREF.
Power Supplies
Power Supply Currents (Active State)
I
A+
(VDDA = +3.3V) PSCA - 3.9 - mA
Power Consumption
(Note 5) Active State (VDDA = +3.3V)
Stand-by State
PC -
- 12.9
4.5
-
- mW
mW
Parameter Symbol Min Typ Max Unit
Reference (Note 8)
Output Voltage VREF +2.3 +2.4 +2.5 V
Temperature Coefficient (Note 9) TC
VREF
- 25 - ppm/°C
Load Regulation (Note 10)
V
R
- 30 - mV
Parameter Symbol Min Typ Max Unit
PSRR 20
150
Veq
----------- log  =
TC
VREF
VREF
MAX
VREF
MIN
–
VREF
AVG
------------------------------------------------------------
 
  1
T
A
MAX T
A
MIN –
----------------------------------------------
 
  1.0 10
6    =