Cirrus Logic CS5372 - Manual (Page 7)

CS5371 CS5372
DS255F3 7
2. GENERAL DESCRIPTION .
The CS5371 and CS5372 are one- and two- chan-
nel fourth-order
∆Σ modulators, optimized for ex-
tremely high-resolution measurement of signals
between DC and 1600 Hz. They are designed to
be used with the CS5376A and CS5378 low-power
digital filters. Figure 3 on page 8 shows a four-
channel system connection diagram for two
CS5372 and one CS5376A.
High Performance
The CS5371/72 modulators have exceptional per-
formance characteristics. Modulator dynamic
range (SNR) is 127 dB over a 215 Hz bandwidth
(2 ms sampling), with total harmonic distortion
(THD) of -118 dB.
Low Power Consumption
The CS5371/72 modulators have very low power
consumption. Power consumption is only 25 mW
per channel in normal mode (LPWR=0,
MCLK=2.048 MHz), and 15 mW per channel in low
power mode (LPWR=1, MCLK=1.024 MHz).
An independently selectable power-down mode
(PWDN=1) can be used to disable a modulator and
reduces its power consumption to 1 mW. If MCLK
is then halted (MCLK=0), the modulator enters a
micropower state using only 10
µ W per channel.
Small Package Size
The CS5371/72 modulators are available in a very
small 24-pin SSOP package approximately
8 mm x 8 mm in size. The CS5372 has two mod-
ulator channels per package to increase board lay-
out density even further.
Multi-channel System Support
Combining the CS5371 and CS5372 modulators
with a digital filter permits multiple system configu-
rations:
1 Channel - CS5371, CS5378
2 Channel - CS5372, CS5376A
3 Channel - CS5371, CS5372, CS5376A
4 Channel - CS5372, CS5372, CS5376A
Differential Analog Signal Inputs
The CS5371/72 modulators have fully differential
analog inputs capable of measuring signals up to
5.0 V peak-to-peak when using a 2.5 V voltage ref-
erence. The inputs will tolerate a 5% over-range
voltage and continue operating at full specification.
Digital Filter Interface
The CS5371/72 modulators are designed to oper-
ate with the CS5376A and CS5378 digital filters.
The digital filter generates the modulator clock and
synchronization signal inputs (MCLK and
MSYNC), while receiving the modulator data and
over-range flag outputs (MDATA and MFLAG).
The modulators produce an oversampled
∆Σ serial
bit stream at 512 kbits per second when operated
from a 2.048 MHz modulator clock.
Multiple Power Supply Configurations
The CS5371/72 modulators support flexible power
supply configurations. They can run from single or
dual supplies in the following configurations:
ΠVA+ = +5V; VA- = 0V; VD = +3.3V to +5V
ΠVA+ = +2.5V; VA- = -2.5V; VD = +3.3V