MCP18480_13 Datasheet, PDF (34/64 Pages) Microchip Technology – -48V Hot Swap Controller

MCP18480
TABLE 3-1: MCP18480 PIN DESCRIPTIONS (CONTINUED)
Pin Name
Pin
Number
SSOP
Pin
Direction
Buffer
Type
Description
V_REFOUT
6
O
V_REFIN
7
I
CL
8
I
I_SET
9
I
Legend: TTL = TTL compatible input
I = Input
P = Power
A = Analog
A Reference output.
Internal reference output voltage (typically 2.5V). Usually tied back to
the V_REFIN pin unless an external high-precision reference voltage is
desired.
A Reference input.
This pin allows a high-precision reference voltage for the following
functions:
• Undervoltage Comparator
• Overvoltage Comparator
• DRAIN Comparator
• Current Limit Timer
If the precision of the V_REFOUT output voltage is acceptable, tie the
V_REFOUT pin to the V_REFIN pin.
A Current Limit.
Input used to set the maximum current limit threshold allowed by the
system via a resistor divider network (with the resistor R_CL1 between
the V_REFIN pin and the CL pin and resistor R_CL between the V_NEG pin
and the CL pin). If the voltage across the sense resistor exceeds the
voltage on the CL pin, it implies that there is excessive current over the
allowed limit and forces the GATE pin to the V_NEG pin voltage level
without delay.
A Current source set.
Establishes the internal I_SOURCE for the following:
• Undervoltage Delay
• Current Limit Timer
• GATE Pin Source Current
An external resistor R_ISET from the I_SET pin must be connected to
either the V_NEG pin or the V_REFIN pin to set I_BIAS, which will then estab-
lish the current sources throughout the device. The I_BIAS current is the
same for either connection.
Connecting the R_ISET resistor to the V_NEG pin will establish the
PWRGOOD pin output polarity to be active-high. Connecting the R_ISET
resistor to the V_REFIN pin will establish the PWRGOOD pin output
polarity to be active-low.
ST = Schmitt Trigger input with CMOS levels
O = Output
CMOS = CMOS-compatible input
D = Digital
DS20091C-page 34
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