CDB5532U Cirrus Logic Inc, CDB5532U Datasheet - Page 13

• Manufacturer Part Number: CDB5532U
• Description: BOARD EVAL FOR CS5532U ADC
• Manufacturer: Cirrus Logic Inc

Specifications of CDB5532U

• Number Of Adc's: 2
• Number Of Bits: 24
• Sampling Rate (per Second): 3.84k
• Data Interface: Serial
• Inputs Per Adc: 1 Differential
• Input Range: ±2.5 V
• Power (typ) @ Conditions: 35mW @ 3.84kSPS
• Voltage Supply Source: Analog and Digital, Dual ±
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: CS5532
• Description/function: Audio DSPs
• Operating Supply Voltage: 5 V
• Product: Audio Modules
• For Use With/related Products: C8051F320
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 598-1159

DS755F3
instrumentation amplifier is typically 1200 pA
over
The common-mode plus signal range of the instru-
mentation amplifier is (VA-) + 0.7 V to (VA+) -
1.7 V.
Figure 4 illustrates the input models for the ampli-
fiers. The dynamic input current for each of the
pins can be determined from the models shown.
Note:
2.1.1. Analog Input Span
The full-scale input signal that the converter can
digitize is a function of the gain setting and the ref-
erence voltage connected between the VREF+ and
VREF- pins. The full-scale input span of the con-
verter is ((VREF+) - (VREF-))/(GxA), where G is
the gain of the amplifier and A is 2 for VRS = 0, or
A is 1 for VRS = 1. VRS is the Voltage Reference
Figure 4. Input models for AIN+ and AIN- pins
V
i = fV
n
os
V
i = fV
n
os
≤ 8 mV
-40°C to +85°C (MCLK=4.9152 MHz).
The C=3.9pF and C = 14pF capacitors are
for input current modeling only. For physical
input capacitance see ‘Input Capacitance’
specification under Analog Characteristics.
AIN
≤ 12 mV
os
AIN
os
C
Gain = 2, 4, 8, 16, 32, 64
C
f =
f = MCLK
Gain = 1
MCLK
128
16
φ Coarse
C = 3 .9 pF
1
φ Fine
C = 14 pF
1
Select bit, and must be set according to the differen-
tial voltage applied to the VREF+ and VREF- pins
on the part. See section 2.3.5 for more details.
After reset, the unity gain buffer is engaged. With a
2.5 V reference this would make the full-scale input
range default to 2.5 V. By activating the instrumen-
tation amplifier (i.e. a gain setting other than 1) and
using a gain setting of 32, the full-scale input range
can quickly be set to 2.5/32 or about 78 mV. Note
that these input ranges assume the calibration regis-
ters are set to their default values (i.e. Gain = 1.0 and
Offset = 0.0).
2.1.2. Multiplexed Settling Limitations
The settling performance of the CS5532/34 in mul-
tiplexed applications is affected by the single-pole,
low-pass filter which follows the instrumentation
amplifier (see Figure 3). To achieve data sheet set-
tling and linearity specifications, it is recommend-
ed that a 22 nF C0G capacitor be used. Capacitors
as low as 10 nF or X7R type capacitors can also be
used with some minor increase in distortion for AC
signals.
2.1.3. Voltage Noise Density Performance
Figure 5 illustrates the measured voltage noise
density versus frequency from 0.025 Hz to 10 Hz
of a CS5532-BS. The device was powered with
±2.5 V supplies, using 30 Sps OWR, the 64x gain
range, bipolar mode, and with the input short bit
enabled.
Figure 5. Measured Voltage Noise Density, 64x
1000
100
10
1
0.025
0.10
Frequency (Hz)
CS5532/34-BS
1.00
10.00
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