CDB5378
DS639DB4
33
The VA+ and VA- power supplies to the analog components on CDB5378 can be jumpered to use regu-
lated bipolar power supplies (+2.5 V, -2.5 V) or unregulated direct connections (, EXT_VA-).
When using direct connections to and EXT_VA-, extreme care must be taken not to exceed the
maximum specified power supply voltages of the analog components on CDB5378. It is recommended to
always use the regulated bipolar analog power supplies for optimal performance.
The VA+ and VA- power supply nets to the analog components on CDB5378 include reverse-biased
Schottkey diodes to ground to protect against reverse voltages that could latch-up the CMOS analog com-
ponents. Also included on VA+ and VA- are 100 uF bulk capacitors for bypassing and to help settle tran-
sients plus individual 0.1 uF bypass capacitors local to the analog power supply pins of each device.
2.4.2
Digital Voltage Regulators
Linear voltage regulators create the positive digital power supply voltages on CDB5378. Jumper options
select which external power supply input voltage, EXT_VD or , is supplied to the digital voltage
regulators to create the VD and VCORE power supplies.
The VD and VCORE power supplies on CDB5378 can be jumpered to use reg3.3 V or +2.5 V
power supplies or an unregulated direct connection to EXT_VD. Extreme care must be taken when using
a direct connection to EXT_VD not to exceed the maximum specified power supply voltages of the digital
components on CDB5378.
Even though the Cirrus Logic components on CDB5378 will tolerate up to 5 V from the VD power supply,
other components are specified for +3.3 V operation only and so it is recommended to use only the reg-
3.3 V jumper setting for VD.
Specification Value
Negative Analog Supply, -2.5VA
-2.5 V
Low Noise Micropower Regulator - Linear Tech
LT1964ES5-BYP
Surface Mount Package Type
SOT-23
Load Regulation, -40 C to +85 C
+/- 30 mV
Quiescent Current, Current @ 100 mA Load
30
µ
A, 1.3 mA
Output Voltage Noise, 10 Hz - 100 kHz
20
µ
V
RMS
Ripple Rejection, DC - 200 Hz
> 45 dB
Specification Value
Positive Digital Power Supply
+2.5 V, +3.3 V
Low Noise Micropower Regulator - Linear Tech
LT1763CS8
Surface Mount Package Type
SO-8
Load Regulation, -40 C to +85 C
+/- 25 mV
Quiescent Current, Current @ 100 mA Load
40
µ
A, 2 mA
Output Voltage Noise, 10 Hz - 100 kHz
20
µ
V
RMS
Ripple Rejection, DC - 200 Hz
> 50 dB
Summary of Contents for CDB5378
Page 58: ...CDB5378 58 DS639DB4 5 LAYER PLOTS ...
Page 59: ...CDB5378 DS639DB4 59 ...
Page 60: ...CDB5378 60 DS639DB4 ...
Page 61: ...CDB5378 DS639DB4 61 ...
Page 62: ...CDB5378 62 DS639DB4 ...
Page 63: ...CDB5378 DS639DB4 63 ...
Page 64: ...CDB5378 64 DS639DB4 6 SCHEMATICS ...
Page 65: ...CDB5378 DS639DB4 65 ...
Page 66: ...CDB5378 66 DS639DB4 ...
Page 67: ...CDB5378 DS639DB4 67 ...
Page 68: ...CDB5378 68 DS639DB4 ...
Page 69: ...CDB5378 DS639DB4 69 ...
Page 70: ...CDB5378 70 DS639DB4 ...
Page 71: ...CDB5378 DS639DB4 71 ...
Page 72: ...CDB5378 72 DS639DB4 ...
Page 73: ...CDB5378 DS639DB4 73 ...