LM5060Q1 National Semiconductor Corporation, LM5060Q1 Datasheet - Page 18

• Manufacturer Part Number: LM5060Q1
• Description: High-side Protection Controller With Low Quiescent Current
• Manufacturer: National Semiconductor Corporation

www.national.com
3. Calculate R2 with the following formula:
V
age of the design specification. All other variables can be
found in the Electrical Characteristics table of this document.
To calculate the UVLO lower threshold including its hysteresis
for falling V
the formulas above. To calculate the OVP lower threshold in-
cluding hysteresis for falling V
stead of OVP
the thresholds can be calculated with the formulas below:
Also in these two formulas, the respective lower threshold
value including the hysteresis is calculated by using (UV-
LO
instead of OVP
ating temperature range, can be calculated using the respec-
tive min and max values in bold font in the
Characteristics
Option B: UVLO and OVP can be independently adjusted
using two resistor dividers as shown in
FIGURE 10. Programming the Thresholds with Resistors
Choose the upper UVLO thresholds to ensure operation down
to the lowest required operating input voltage (V
R11 based on resistive divider current consumption and noise
sensitivity. Values between 10 kΩ and 200 kΩ are suggested.
INMIN
TH
-UVLO
is the minimum and V
IN
HYS
, use (UVLO
TH
TH
) instead of UVLO
.
. With three given resistors R1, R2, and R3,
. The worst case thresholds, over the oper-
TH
R8-R11
-UVLO
INMAX
IN
, use (OVP
is the maximum input volt-
HYS
TH
, and (OVP
) instead of UVLO
Figure
TH
10.
-OVP
INMIN
TH
-OVP
Electrical
30104235
). Select
HYS
TH
) in-
HYS
in
)
18
To calculate the UVLO low threshold including its hysteresis,
use (UVLO
above. Choose the lower OVP threshold to ensure operation
up to the highest VIN voltage required (V
based on resistive divider current consumption and noise
sensitivity. Values between 10 kΩ and 200 kΩ are suggested.
To calculate the OVP low threshold including hysteresis, use
(OVP
sistor values are known, the threshold voltages are calculated
from the following:
Also in these two formulas, the respective low value including
the threshold hysteresis is calculated by using (UVLO
LO
OVP
perature range, can be calculated using the respective mini-
mum and maximum values in bold font in the
Characteristics
Option C: The OVP function can be disabled by grounding
the OVP pin. The UVLO thresholds are set as described in
Option B.
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
R4 to the VIN pin. Any positive supply voltage less than 65V
may be used instead of V
INPUT BYPASS CAPACITOR
Some input capacitance from the VIN pin to the GND pin may
be necessary to filter noise and voltage spikes from the V
rail. If the current through Q1 in
shutdown of Q1 will cause an inductive kick across the line
input and pc board trace inductance which could damage the
LM5060. In order to protect the VIN pin as well as SENSE,
HYS
TH
TH
) instead of UVLO
. The worst case thresholds, over the operating tem-
-OVP
FIGURE 11. Circuitry at the nPGD Pin
TH
HYS
-UVLO
.
Figure 11
) instead of OVP
HYS
) instead of UVLO
TH
IN
connects the nPGD pull-up resistor
.
and (OVP
Figure 1
TH
. Where the R9-R11 re-
TH
is very large a sudden
-OVP
TH
INMAX
HYS
in the formula
30104239
). Select R9
) instead of
Electrical
TH
-UV-
IN