Power Supply Section - Cirrus Logic CDB5490U Manual

1.5

Power Supply Section

Table 4 illustrates the power supply connections on the evaluation board. The positive analog (VDDA) for
the CS5490 can be supplied using the +3.3V binding post (J36 and J37) or the onboard +3.3V regulator.
Jumper J38 allows the VDDA supply to be sourced from the +3.3V binding post (J37) or the regulated
+3.3V supply. The DC-DC converter (U8) powers the onboard +3.3V regulator. Jumper J26 allows the
+5V supply to be sourced from either the +5V EXT screw connector (J27) or the +5V USB supply. The
+5V supplies the power for the microcontroller (8051_REGIN) and the DC-DC converter (U8). Jumper J21
is used to measure the CS5490 analog supply current and must be installed.
When connecting the CDB5490U board to the AC line through non-isolated sensors, it is strongly recom-
mended that the CS5490 GND reference is connected to the neutral, the non-isolated current sensor is
connected on neutral, and the CS5490 is supplied by +3.3V isolated from AC line. The DC-DC converter
(U8) provides 1kVDC isolation, while no isolation is provided for the 3.3V binding post connections. If
+3.3V is used from the binding post, then the external 3.3VDC power supply must be isolated from the
AC line. To prevent electric shock and damages, always use an isolated power source.
DS923DB5
Table 4. Power Supply Selection
J36&J37
On-board
3 V
3. NC
Regulator
Binding
+3.3 V
Post
On-board
3.3V
NC
regulator
J24 J27 J21
VDDA
VDDA
+5V NC
(default)
VDDA
+5V NC
VDDA
VDDA
NC +5V
VDDA
CDB5490U
J38 J26
+3.3V +5V EXT
VDDA +5V
+3.3V_2 +5V USB
(default) (default)
+5V EXT
+3.3V
+5V
VDDA
+5V USB
+3.3V_2
+3.3V +5V EXT
VDDA +5V
+3.3V_2 +5V USB
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