Texas Instruments TPS7A78EVM-011, Руководство пользователя

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EVM Setup
7 SBVU048 – March 2019
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TPS7A78EVM-011 Evaluation module
5.1.5 J6 and J7: Power-Good (PG) and Power-Fail (PF) Signals
The TPS7A78 device has two open-drain signals (power-good and power-fail) that are both pulled up to
V
LDO_IN
by default.
Becuase of the high-impedance open-drain logic, the AC supply frequency noise may be present on those
signals when they are high. A low-impedance digital buffer isolation circuit is recommended, such as the
U2 device in
Section 4 , to obtain noise-free PG ans PF signals. Jumpers J6 and J7 connect the device PG
and PF signals directly to the TP7 and TP5 test points because the digital buffer circuit is not populated
with the default EVM setting.
NOTE: When high-voltage differential scope probes are used when testing the TPS7A78EVM-011,
the digital buffer circuit U2 in Section 4 is recommended to be populated and jumpers J6 and
J7 must be open to obtain noise-free PG and PF signals.
5.1.6 J2: V
LDO_OUT
Regulated DC output voltage connector.
NOTE: This EVM is optimized for a 3.3-V output and a 27-mA to 55-mA (max) load current. If your
application requires higher output current, see the TPS7A78 Application and Implementation
section for the proper setting of your application requirement.
5.2 Test Points
Table 3 lists the test points for the TPS7A78EVM-011.
Table 3. Test Point Functions
TEST POINTS NAME DESCRIPTION
TP1 AC_P AC supply line input to the device after the cap-drop capacitor and surge
resistor.
TP2 SC_IN Rectified DC voltage pin; see the TPS7A78 Application and Implementation
section for the proper setting of your application requirement.
TP3 LDO_IN Charge-pump output pin.
TP4 AC_N AC supply neutral input to the device after the cap-drop capacitor and surge
resistor.
TP5 PF Power-fail pin.
TP6 PFD Power-fail detect pin.
TP7 PG Power-good pin.
TP8 LDO_OUT Regulated DC output pin.
TP9 GND
Device GND connected to the thermal pad.
TP10 GND
5.3 Performance Data for the TPS7A78EVM-011
As specified in Section 5.1.2 , this EVM is configured for an HB 3.3-V output voltage and 27 mA of output
current, and the EVM can also be configured for FB use.