Use these steps for testing the EVM with a static
DC external load:
- Verify all supplies are off prior to connecting
the EVM.
- Verify proper polarity of power supply and load
connections.
- Remove jumper on J6 to set device to enable.
- Place a jumper on J5 (pins 1 and 2), connecting
VDDQSNS to VLDOIN.
- Alternatively a separate
voltage source can be used for VLDOIN and a separate voltage source of
VDDQSNS, thus isolating the two. This method isolates the transients
introduced on VLDOIN from impacting VDDQSNS. Additionally, this method
allows for reduced internal power dissipation. VLDOIN can be reduced to
VTT + VDO.
- Set the load to sink desired current up to 3
A.
- Connect a power supply VDD using J2/J1, or test
points TP1 and TP2. Vin current is less than 100 mA.
- Connect power supply to J7/J9 - VLDOIN. VLDOIN
current can be up to 3 A and possibly higher during startup.
- Connect VTT voltmeter (+) terminal to TP6 and (–)
terminal to TP13, or J10.
- Connect the load (+) to J11 and (–) to J12. If
desired, connect a current meter in series to test VTT sourcing current.
Alternatively, connect isolated load (+) from J7 VLDOIN and (-) to J11 to test
VTT sinking.
- Set the power supply for VLDOIN to 1.5 V.
- Set the power supply for VIN to 3
V.
- Enable both VIN and VLDOIN
supplies.
- Connect a scope or voltmeter monitoring VTTREF to
TP9 and GND TP, or using SMA J8.
- The voltmeter monitoring VTTREF
reads approximately 0.75 V
- The voltmeter monitoring VTT
reads approximately 0.75 V
- Enable the VTT load to observed Sink or Source effect on VTT.
- Place jumper on J6 to disable the device.
- The voltmeter monitoring VTT
reads near zero volts, as VTT is discharged when disabled.
- The voltmeter monitoring VTTREF
still reads approximately 0.75 V as VTTREF is still active when disabled.
- Disable supplies to complete the DC static
loading test.
Table 3-2 displays the input voltage and output voltage measurement test points. Using the
following connection points, monitor VTT and VTTREF regulation overline and
overload.
Table 3-2 I/O Voltage Measurement Test PointsEVM | Input / Output Voltage | | Test point |
---|
TPS7H3302EVM-SEP | VIN | 2.375 V ≤ VIN ≤ 3.5 V | TP15 (+) TP16(–) |
| VLDOIN | 0.9 V ≤ VLDOIN ≤ 3.5 V | TP7(+) TP11(–) |
| VDDQSNS | 1.2 V ≤ VDDQSNS ≤ 3.5 V | J4 or (Pin2 J5)(+) TP12(–) |
| VTT | ½ VDDQSNS | TP6(+) TP13(–) |
| VTTREF | ½ VDDQSNS | TP9(+) TP11(–) |