Cirrus Logic CRD48L10 - Manual (Page 38)

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Chapter 11
Measuring Power
Current measurement points are available for the CS48L10, CS42L73, and for the entire CRD48L10 using the provided
current measurement headers.
Figure 11-1. Current Measurement Points for CS42L73 and CS48L10
Figure 11-2. Current Measurement Point for CRD48L10 Main Power
When shipped, each header has a bypass resistor (either 0.5O or 0.1O) to eliminate the need for shunts. This also allows
the user to make voltage measurements across the pins of each header and use the following formulae to convert those
readings to current.
Measurement Method:
• TP20—Measure voltage across header and multiply by 2 to get current
• TP21—Measure voltage across header and multiply by 2 to get current
• TP23—Measure voltage across header and multiply by 2 to get current
• TP22—Measure voltage across header and multiply by 10 to get current
• P16—Remove shunt; insert current meter in series and measure current
Table 11-1. Power Measurement Headers
Header Voltage Signal Bypass Resistor
TP20 +1.0 V – +1.2 V CS48L10 Core Power Rail R170
TP21 +1.8 V CS48L10/O Power Rail R171
TP22 +4.0 V Battery Voltage for CS42L73 R180
TP23 +1.8 V CS48L73 + 1.8 V Power Rail R192
P16 +4.0 V Main Power Rail for CRD48L10-4in4out N/A