Datasheet

I
IN
V
OUT
1 V/div
2 V/div
V
IN
C
1
C
2
C
4
www.ti.com LDO Ground Current Measurement
4 LDO Ground Current Measurement
The LDO ground, or quiescent current (isolated from the load current), can be measured after taking these
steps:
Step 1. Turn off the input power supply.
Step 2. Remove the 0-Ω resistor R1 on the TPS70433PKEVM-712 EVM (or R2 on the
TPS70433DBVEVM-712 EVM).
Step 3. Connect a current meter across pin 1 of J3 and pin 2 of J3.
Step 4. Turn on the power supply, as disussed in Section 3.
5 Test Results
This section provides typical performance waveforms for the TLV70433DBEVM-712 and the
TLV70433PKEVM-712.
5.1 Turn-On Sequence
Figure 1 shows the turn-on characteristic of the LDO. V
IN
(C
1
, yellow) quickly transitions to 5.0 V to turn on
the LDO. The output voltage, V
OUT
(C
2
, red), then ramps up to its nominal 3.3-V output in accord with the
control loop design after the input current surge I
IN
(C
4
, green) has sufficiently charged the input and
output capacitors.
Note:
• C
1
, V
IN
: turn-on to 5 V;
• C
2
, V
OUT
: 3.3-V turn-on ramp;
• C
3
, Input rush current at turn-on
Figure 1. Turn-On Sequence
3
SBVU017–January 2011 TLV70433DBVEVM-712, TLV70433PKEVM-712 Evaluation Modules
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