MAX34565EVKIT# Maxim Integrated, MAX34565EVKIT# Datasheet - Page 7

• Manufacturer Part Number: MAX34565EVKIT#
• Description: Power Management IC Development Tools MAX34565 Eval Kit
• Manufacturer: Maxim Integrated
• Type: Power Driversr
• Series: MAX34565r

Specifications of MAX34565EVKIT#

• Rohs: yes
• Product: Evaluation Kits
• Tool Is For Evaluation Of: MAX34565
• Input Voltage: 12 V
• Output Voltage: 1.95 V
• Output Current: 3.6 A
• Part # Aliases: 90-34565#K00

The voltage ramp circuit uses an operational amplifier to
control the gate bias of the n-channel power MOSFET.
When the voltage on EN/FAULT is below V
is used to keep C
output voltage to GND. Once the voltage on EN/FAULT
is above V
charge the external capacitor, C
VRAMP pin. The amplifier controls the gate of the power
MOSFET so that the LOAD output voltage divided by
two tracks the rising voltage level of C
voltage continues to ramp until it reaches either the input
V
The overvoltage-limiting clamp monitors the VRAMP
voltage level compared to an internal voltage reference.
When the voltage on VRAMP exceeds V
voltage of the n-channel power MOSFET is reduced,
limiting the voltage on LOAD to V
increases. If the device is in overvoltage for an extended
period of time, the device may overheat and enter ther-
mal shutdown. This is caused by the power created by
the voltage drop across the power MOSFET and the load
current.
The load current is continuously monitored during the
initial voltage ramping (I
tion (I
set by the external resistance at ILIM, the gate voltage
of the power MOSFET is decreased, reducing the output
current to the set current limit. Current is limited by the
device comparing the voltage difference between the
LOAD and ILIM pins to an internal reference voltage.
When the output power is initially ramping up, the current
limit is I
current limit is I
the source if there is a dead short on initial power-up. If
the high current is maintained, the device will heat up
and the internal temperature will eventually reach T
The device act as a fuse and automatically disable the
current flowing to the load when the temperature of the
power MOSFET has exceeded the shutdown junction
temperature, T
CC
level or the overvoltage clamp limits.
OVL
SCL
). If the current exceeds the current limit that is
. Once the voltage ramping is complete, the
OHT
SHDN
OVL
, an internal current source begins to
Output-Voltage Ramp (VRAMP)
VRAMP
. The lower I
.
SCL
discharged, which forces the
) and during normal opera-
12V Hot-Plug Switch in TDFN Package
SCL
VRAMP
Overvoltage Limit
current limit protects
OVC
VRAMP
, connected to the
Current Limit
OVC
even as V
. The output
/2, the gate
OLT
, a FET
SHDN
CC
.
The current limit circuit can be biased in one of two ways:
direct sensing or Kelvin sensing. Using direct sensing,
the sense resistor is connected between the ILIM pin and
the LOAD pins
five LOAD pins are in parallel, the on-resistance is slightly
lower. Using Kelvin sensing, only one of the LOAD pins
is connected to the ILIM pin through the sense resistor
(Figure
sensed, negating any impact of the bond wire resistance.
Because four LOAD pins are connected in parallel, the
on-resistance is slightly higher.
The device enters a thermal shutdown state when the
temperature of the power MOSFET reaches or exceeds
T
ed, the thermal-limiting circuitry disables the device
using the enable circuitry. The EN/FAULT pin is driven to
V
an autoretry version and a latchoff version.
Figure 3. Direct Sensing Circuit
Figure 4. Kelvin Sensing Circuit
SHDN
FAULT
, approximately +155NC. When T
. The device is offered in two different versions:
4). Using this circuit, the voltage on the die is
MAX34565
MAX34565
Direct and Kelvin Current Sensing
(Figure
3). Because the bond wires of all
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
ILIM
ILIM
MAX34565
Thermal Shutdown
R
R
LIM
LIM
I
I
LOAD
LOAD
TO APPLICATION
TO APPLICATION
SHDN
is exceed-
7