LTC4259ACGW#TRPBF Linear Technology, LTC4259ACGW#TRPBF Datasheet - Page 9

• Manufacturer Part Number: LTC4259ACGW#TRPBF
• Description: IC CTRLR POE QUAD AC DISC 36SSOP
• Manufacturer: Linear Technology

Specifications of LTC4259ACGW#TRPBF

• Controller Type: Power over Ethernet Controller (POE)
• Interface: I²C
• Voltage - Supply: 3 V ~ 4 V
• Current - Supply: 2.5mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 36-SSOP
• Linear Misc Type: Negative Voltage
• Family Name: LTC4259A
• Operating Supply Voltage (min): -48V
• Operating Supply Voltage (max): -57V
• Operating Temperature (min): 0C
• Operating Temperature (max): 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 36
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PI FU CTIO S
AGND (Pin 21): Analog Ground. AGND should be con-
nected to the return from the – 48V supply. AGND and
DGND should be tied together.
SENSE4 (Pin 22): Port 4 Current Sense Input. SENSE4
monitors the external MOSFET current via a 0.5Ω sense
resistor between SENSE4 and V
across the sense resistor exceeds the overcurrent detec-
tion threshold V
If the voltage across the sense resistor reaches the current
limit threshold V
GATE4 pin voltage is lowered to maintain constant current
in the external MOSFET. See Applications Information for
further details. If the port is unused, the SENSE4 pin must
be tied to V
GATE4 (Pin 23): Port 4 Gate Drive. GATE4 should be
connected to the gate of the external MOSFET for port 4.
When the MOSFET is turned on, a 50µA pull-up current
source is connected to the pin. The gate voltage is clamped
to 13V (typ) above V
the voltage at GATE4 will be reduced to maintain constant
current through the external MOSFET. If the fault timer
expires, GATE4 is pulled down with 50µA, turning the
MOSFET off and recording a t
port is unused, float the GATE4 pin or tie it to V
OUT4 (Pin 24): Port 4 Output Voltage Monitor. OUT4
should be connected to the output port through a 10k
series resistor. A current limit foldback circuit limits the
power dissipation in the external MOSFET by reducing the
current limit threshold when the port voltage is within 18V
of AGND. The port 4 Power Good bit is set when the voltage
from OUT4 to V
is connected internally from OUT4 to AGND. If the port is
unused, the OUT4 pin can be tied to AGND or allowed to
float.
U
U
EE
.
EE
CUT
LIM
drops below 2V (typ). A 2.5MΩ resistor
, the current limit fault timer counts up.
U
EE
(typically 25mV/50mA higher), the
. During a current limit condition,
ICUT
EE
. Whenever the voltage
or t
START
event. If the
EE
.
SENSE3 (Pin 25): Port 3 Current Sense Input. See SENSE4.
GATE3 (Pin 26): Port 3 Gate Drive. See GATE4.
OUT3 (Pin 27): Port 3 Output Voltage Monitor. See OUT4.
V
– 57V supply, relative to AGND.
SENSE2 (Pin 29): Port 2 Current Sense Input. See SENSE4.
GATE2 (Pin 30): Port 2 Gate Drive. See GATE4.
OUT2 (Pin 31): Port 2 Output Voltage Monitor. See OUT4.
SENSE1 (Pin 32): Port 1 Current Sense Input. See SENSE4.
GATE1 (Pin 33): Port 1 Gate Drive. See GATE 4.
OUT1 (Pin 34): Port 1 Output Voltage Monitor. See OUT4.
AUTO (Pin 35): Auto Mode Input. Auto mode allows the
LTC4259A to detect and power up a PD even if there is no
host controller present on the I
AUTO pin determines the state of the internal registers
when the LTC4259A is reset or comes out of V
(see the Register map in Table 1). The states of these
register bits can subsequently be changed via the I
interface. The real-time state of the AUTO pin is read at bit
0 in the Pin Status register (11h). Pull AUTO high or low
with ≤10k or tie to V
OSCIN (Pin 36): Oscillator Input. Connect to an oscillating
signal source, preferably a sine wave, of approximately
100Hz with 2V peak-to-peak amplitude, negative peaks
above – 0.3V and positive peaks below 2.5V. When a port
is powered and AC disconnect is enabled, this signal is
amplified and driven onto the appropriate DETECT pin to
determine the AC impedance of the PD.
EE
(Pin 28): – 48V Supply Input. Connect to a – 48V to
DD
or DGND.
2
C bus. The voltage of the
LTC4259A
DD
UVLO
4259afb
9
2
C