CDB5378 Datasheet, PDF (30/72 Pages) Cirrus Logic – Single-channel Seismic Evaluation System

CDB5378
2.3.7 External Connector
Power supplies and telemetry signals route to a 20-pin double row connector with 0.1" spacing (J26). This
header provides a compact standardized connection to the CDB5378 external signals.
Pins
1, 2
3, 4
5, 6
7, 8
9, 10
11, 12
13, 14
15, 16
17, 18
19, 20
Name
CLK+, CLK-
SYNC+, SYNC-
SCL+, SCL-
SDA+, SDA-
BYP_SDA+, BYP_SDA-
BYP_SCL+, BYP_SCL-
TX, GND
RX, GND
EXT_VA-, GND
EXT_VA+, GND
Signal
Clock Input
Synchronization Input
I2C Clock
I2C Data
I2C Data Bypass
I2C Clock Bypass
UART transmit
UART receive
Negative Power Supply
Positive Power Supply
2.4 Power Supplies
Power is supplied to CDB5378 through banana jacks (J6, J7, J8, J9) or through the external connector
(J26). The banana jacks make separate connections to the EXT_VA-, EXT_VA+, GND, and EXT_VD
power supply nets, which connect to the analog and digital linear voltage regulator inputs. The external
connector makes separate connections only to the EXT_VA-, GND, and EXT_VA+ power supply inputs
and it is required to jumper EXT_VA+ to EXT_VD when powering CDB5378 from the external connector.
The EXT_VA-, EXT_VA+ and EXT_VD power supply inputs have zener protection diodes that limit the
maximum input voltages to +13 V or -13 V with respect to ground. Each input also has 100 uF bulk ca-
pacitance for bypassing and to help settle transients and another 0.01 uF capacitor to bypass high-fre-
quency noise.
2.4.1 Analog Voltage Regulators
Linear voltage regulators create the positive and negative analog power supply voltages to the analog
components on CDB5378. These regulate the EXT_VA+ and EXT_VA- power supply inputs to create the
VA+ and VA- analog power supplies.
Specification
Positive Analog Power Supply
Low Noise Micropower Regulator - Linear Tech
Surface Mount Package Type
Load Regulation, -40 C to +85 C
Quiescent Current, Current @ 100 mA Load
Output Voltage Noise, 10 Hz - 100 kHz
Ripple Rejection, DC - 200 Hz
Value
+2.5 V, +5 V
LT1763CS8
SO-8
+/- 25 mV
40 µA, 2 mA
20 µV_RMS
> 50 dB
30
DS639DB3