Cirrus Logic CS5484 - Manual (Page 12)

CS5484
12 DS981F3
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) sine wave 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 CS5484 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 sensitive signal; the output of the VREF circuit has a
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. Therefore VREF intended for the CS5484 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 cannot 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. Cirrus 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    =