LTC4440ES6#TR Linear Technology, LTC4440ES6#TR Datasheet - Page 8

• Manufacturer Part Number: LTC4440ES6#TR
• Description: IC DRIVER HIGHSIDE HS/HV SOT23-6
• Manufacturer: Linear Technology
• Type: High Sider

Specifications of LTC4440ES6#TR

• Input Type: Non-Inverting
• Number Of Outputs: 1
• On-state Resistance: 1.5 Ohm
• Current - Output / Channel: 2.4A
• Current - Peak Output: 4A
• Voltage - Supply: 8 V ~ 15 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-6
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
LTC4440
Power Dissipation
To ensure proper operation and long-term reliability, the
LTC4440 must not operate beyond its maximum tempera-
ture rating. Package junction temperature can be calcu-
lated by:
where:
Power dissipation consists of standby and switching
power losses:
where:
The LTC4440 consumes very little current during standby.
The DC power loss at V
only (250µA + 110µA)(12V) = 4.32mW.
AC switching losses are made up of the output capacitive
load losses and the transition state losses. The capacitive
load losses are primarily due to the large AC currents
needed to charge and discharge the load capacitance
during switching. Load losses for the output driver driving
a pure capacitive load C
The power MOSFET’s gate capacitance seen by the driver
output varies with its V
A power MOSFET’s capacitive load power dissipation can
be calculated using its gate charge, Q
corresponding to the MOSFET’s V
case) can be readily obtained from the manufacturer’s Q
vs V
Transition state power losses are due to both AC currents
required to charge and discharge the driver’s internal
nodal capacitances and cross-conduction currents in the
internal gates.
8
T
T
T
PD = Power Dissipation
θ
PD = P
P
P
Load Capacitive Power = (C
Load Capacitive Power (MOS) = (V
J
J
A
JA
STDBY
AC
GS
= T
= Junction Temperature
= Ambient Temperature
= Junction-to-Ambient Thermal Resistance
= AC Switching Losses
curves:
A
STDBY
+ PD (θ
= Standby Power Losses
+ P
JA
U
AC
)
GS
CC
OUT
U
voltage level during switching.
= 12V and V
would be:
OUT
)(f)(V
W
GS
BOOST–TS
value (V
BOOST–TS
BOOST–TS
G
. The Q
U
)(Q
CC
= 12V is
)
G
2
G
in this
)(f)
value
G
Undervoltage Lockout (UVLO)
The LTC4440 contains both low side and high side under-
voltage lockout detectors that monitor V
bootstrapped supply V
6.2V, the internal buffer is disabled and the output pin OUT
is pulled down to TS. When V
OUT is pulled down to TS. When both supplies are under-
voltage, OUT is pulled low to TS and the chip enters a low
current mode, drawing approximately 25µA from V
86µA from BOOST.
Bypassing and Grounding
The LTC4440 requires proper bypassing on the V
V
seconds) and large AC currents (Amperes). Careless
component placement and PCB trace routing may cause
excessive ringing and under/overshoot.
To obtain the optimum performance from the LTC4440:
A. Mount the bypass capacitors as close as possible
B. Use a low inductance, low impedance ground plane to
C. Plan the power/ground routing carefully. Know where
D. Keep the copper trace between the driver output pin and
E. When using the MS8E package, be sure to solder the
BOOST–TS
between the V
pins. The leads should be shortened as much as pos-
sible to reduce lead inductance.
reduce any ground drop and stray capacitance. Remem-
ber that the LTC4440 switches >2A peak currents and
any significant ground drop will degrade signal integrity.
the large load switching current is coming from and
going to. Maintain separate ground return paths for the
input pin and the output power stage.
the load short and wide.
exposed pad on the back side of the LTC4440 package
to the board. Correctly soldered to a 2500mm
sided 1oz copper board, the LTC4440 has a thermal
resistance of approximately 40°C/W. Failure to make
good thermal contact between the exposed back side
and the copper board will result in thermal resistances
far greater than 40°C/W.
supplies due to its high speed switching (nano-
CC
and GND pins and the BOOST and TS
BOOST–TS
BOOST – TS
. When V
falls below 6.9V,
CC
CC
falls below
2
and the
double-
CC
CC
and
and
4440f