Datasheet
V
INMAX
= OVP
TH
+
R8 x OVP
TH
R9
V
INMIN
= UVLO
TH
+
UVLO
TH
R11
R10 x
UVLO
BIAS
+
R8 = R9 x
V
INMAX
- OVP
TH
OVP
TH
R10 =
V
INMIN
- UVLO
TH
UVLO
TH
R11
UVLO
BIAS
+
OVP
VIN
LM5060
R10
R8
R9
OVP
TH
2.00V
UVLO
UVLO
TH
1.60V
UVLO
BIAS
5.5 PA
V
IN
R11
LM5060
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SNVS628F –OCTOBER 2009–REVISED APRIL 2013
Figure 30. Programming the Thresholds with Resistors R8-R11
Choose the upper UVLO thresholds to ensure operation down to the lowest required operating input voltage
(V
INMIN
). Select R11 based on resistive divider current consumption and noise sensitivity. A value less than 100
kΩ is recommended, with lower values providing improved immunity to variations in ULVO
BIAS
.
(12)
To calculate the UVLO low threshold including its hysteresis, use (UVLO
TH
-UVLO
HYS
) instead of UVLO
TH
in the
formula above. Choose the lower OVP threshold to ensure operation up to the highest VIN voltage required
(V
INMAX
). Select R9 based on resistive divider current consumption A value less than 100 kΩ is recommended.
(13)
To calculate the OVP low threshold including hysteresis, use (OVP
TH
-OVP
HYS
) instead of OVP
TH
. Where the R9-
R11 resistor values are known, the threshold voltages are calculated from the following:
(14)
Also in these two formulas, the respective low value including the threshold hysteresis is calculated by using
(UVLO
TH
-UVLO
HYS
) instead of UVLO
TH
and (OVP
TH
-OVP
HYS
) instead of OVP
TH
. The worst case thresholds, over
the operating temperature range, can be calculated using the respective minimum and maximum values in bold
font in the Electrical Characteristics.
Option C: The OVP function can be disabled by grounding the OVP pin. The UVLO thresholds are set as
described in Figure 30.
POWER GOOD INDICATOR
A resistor between a supply voltage and the nPGD pin limits the current into the nPGD pin in a logic low
condition. A nPGD pin sink current in the range of 1 mA to 5 mA is recommended. The example in Figure 31
connects the nPGD pull-up resistor R4 to the VIN pin. Any positive supply voltage less than 65V may be used
instead of V
IN
.
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