CS5532-BS Cirrus Logic Inc, CS5532-BS Datasheet - Page 41

• Manufacturer Part Number: CS5532-BS
• Description: IC, ADC, 24BIT, 3.84KSPS, SSOP-20
• Manufacturer: Cirrus Logic Inc

Specifications of CS5532-BS

• Resolution (bits): 24bit
• Sampling Rate: 3.84kSPS
• Input Channel Type: Differential
• Data Interface: 3-Wire, Serial
• Supply Current: 13mA
• Digital Ic Case Style: SSOP
• No. Of Pins: 20
• Rohs Compliant: No

2.10. Clock Generator
The CS5531/32/33/34 include an on-chip inverting
amplifier which can be connected with an external
crystal to provide the master clock for the chip. Fig-
ure 20 illustrates the on-chip oscillator. It includes
loading capacitors and a feedback resistor to form
a Pierce oscillator configuration. The chips are de-
signed to operate using a 4.9152 MHz crystal; how-
ever, other crystals with frequencies between 1
MHz to 5 MHz can be used. One lead of the crystal
should be connected to OSC1 and the other to
OSC2. Lead lengths should be minimized to reduce
stray capacitance. Note that while using the on-chip
oscillator, neither OSC1 or OSC2 is capable of di-
rectly driving any off chip logic. When the on-chip
oscillator is used, the voltage on OSC2 is typically
1/2 V peak-to-peak. This signal is not compatible
with external logic unless additional external cir-
cuitry is added. The OSC2 output should be used if
the on-chip oscillator output is used to drive other
circuitry.
The designer can use an external CMOS compati-
ble oscillator to drive OSC2 with a 1 MHz to 5
MHz clock for the ADC. The external clock into
OSC2 must overdrive the 60 microampere output
of the on-chip amplifier. This will not harm the on-
chip circuitry. In this scheme, OSC1 should be left
unconnected.
DS289PP5
OSC1
20 pF
Figure 20. On-chip Oscillator Model
1 M
~ ~ 60 A
2.11. Power Supply Arrangements
The CS5531/32/33/34 are designed to operate from
single or dual analog supplies and a single digital
supply. The following power supply connections
are possible:
VA+ = +5 V; VA- = 0 V; VD+ = +3 V to +5 V
VA+ = +2.5 V; VA- = -2.5 V; VD+ = +3 V to +5 V
VA+ = +3 V; VA- = -3 V; VD+ = +3 V
A VA+ supply of +2.5 V, +3.0 V, or +5.0 V should
be maintained at ±5% tolerance. A VA- supply of
-2.5 V or -3.0 V should be maintained at ±5% tol-
erance. VD+ can extend from +2.7 V to +5.5 V
with the additional restriction that [(VD+) - (VA-)
< 7.5 V].
Figure 21 illustrates the CS5532 connected with a
single +5.0 V supply to measure differential inputs
relative to a common mode of 2.5 V. Figure 22 il-
lustrates the CS5532 connected with ±2.5 V bipolar
analog supplies and a +3 V to +5 V digital supply
to measure ground referenced bipolar signals. Fig-
ures 23 and 24 illustrate the CS5532 connected
with ±3 V analog supplies and a +3 V digital supply
to measure ground referenced bipolar signals.
Figure 25 illustrates alternate bridge configurations
which can be measured with the converter. Voltage
V1 can be measured with the PGIA gain set to 1x
as the input amplifier on this gain setting can go
rail-to-rail. Voltage V2 should be measured with
the PGIA gain set at 2x or higher as the instrumen-
tation amplifier used on these gain ranges achieves
lower noise.
20 pF
V
TH
OSC2
+
-
CS5531/32/33/34
MCLK
41