MAX6746KA46+T Maxim Integrated, MAX6746KA46+T Datasheet - Page 18

• Manufacturer Part Number: MAX6746KA46+T
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX6746, MAX6747, MAX6748, MAX6749, MAX6750, MAX6751, MAX6752, MAX6753r

Specifications of MAX6746KA46+T

• Number Of Voltages Monitored: 1
• Monitored Voltage: 1.575 V to 5 V
• Undervoltage Threshold: 4.533 V
• Overvoltage Threshold: 4.718 V
• Output Type: Active Low, Push-Pull
• Manual Reset: Resettable
• Watchdog: Watchdog
• Battery Backup Switching: No Backup
• Power-up Reset Delay (typ): 9.487 ms
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-23
• Chip Enable Signals: No
• Maximum Power Dissipation: 714 mW
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Supply Current (typ): 5 uA
• Supply Voltage - Min: 1 V

The MAX5984 internally generates digital supplies (ref-
erenced to V
logic inputs and outputs are referenced to V
Electrical Characteristics table for digital input thresh-
olds. If digital logic inputs are driven externally, the
nominal digital logic level is 3.3V.
The MAX5984 contains undervoltage and overvoltage
protection features. An internal V
(V
reset until V
2.5ms. An internal V
down the port when (V
Force OSC to V
vate DC load-disconnect monitoring. If I
rent across R
threshold, I
off port power.
The MAX5984 features AC load-disconnect monitoring.
Bypass OSC with a 100nF (Q10% tolerance) external
capacitor to V
enable AC disconnect. When AC disconnect is enabled,
Figure 4. LED Code Timing for Overcurrent Fault During Port Power-On
Single-Port, 40W, IEEE 802.3af/802.3at PSE
Controller with Integrated MOSFET
Figure 5. LED Code Timing for Detection Fault Due to High- or Low-Discovery Signature Resistance
18
EE_UVLO
Undervoltage and Overvoltage Protection
_____________________________________________________________________________________
PORT POWERED ON
74ms
) circuit keeps the port off and the MAX5984 in
LED ON
LED
ON
AGND
DCTH
EE
SENSE
EE
) to power the internal logic circuitry. All
EE
, for more than t
- V
223ms
LED
OFF
and power or reset the device to acti-
and power or reset the device to
) falls below the DC load-disconnect
EE
EE
AGND
INVALID HIGH OR LOW
DC Disconnect Monitoring
AC Disconnect Monitoring
overvoltage (V
exceeds 28.5V (typ) for more than
74ms
LED
ON
- V
LED OFF
223ms
EE
EE
) exceeds 62.5V (typ).
223ms
DISC
PORT POWERED DOWN, DUE TO OVERCURRENT FAULT
LED
OFF
DISCOVERY SIGNATURE
undervoltage lockout
EE_OV
, the device turns
LED ON
74ms
RSENSE
Digital Logic
74ms
LED
ON
) circuit shuts
EE
. See the
(the cur-
LED OFF
223ms
223ms
LED
OFF
RESISTANCE DETECTED
SEQUENCE REPEATS
74ms
LED
ON
LED ON
74ms
a blocking diode in series to OUT and an RC circuit in
parallel to the DET diode must be used, as shown in
Figure 7.
The AC disconnect uses an internal triangle wave gen-
erator to supply the probing signal. Then the resulting
4V
mode of the output signal probed on DET is 5V below
AGND. If the AC current peak into DET falls below I
for more than t
The MAX5984 includes a multifunction LED driver to
inform the user of the port status. LED is an open-drain,
multifunction output referenced to V
to 10mA (typ) while driving an external LED. The LED is
turned on when the port is connected to a valid PD and
powered. If the port is not powered or is disconnected,
the LED will be off.
For two other conditions, the MAX5984 blinks a code to
communicate the port status. A series of two flashes indi-
cates an overcurrent fault occurred during port power-on,
and has a timing characteristic detailed by Figure 4. A
series of five flashes indicates that during detection an
invalid low or high discovery signature resistance was
detected and has a timing characteristic detailed by
Figure 5.
P-P
223ms
LED
OFF
LED OFF
amplitude wave is forced on DET. The common
74ms
LED
ON
DISC
LED
OFF
, the device powers down the port.
PWM and LED Signals
PORT POWERED ON AGAIN
1.4s
EE
LED ON
and can sink up
ACTH