LTC1693-3CMS8 Linear Technology, LTC1693-3CMS8 Datasheet - Page 10

• Manufacturer Part Number: LTC1693-3CMS8
• Description: IC MOSFET DVR N-CH SINGLE 8-MSOP
• Manufacturer: Linear Technology

Specifications of LTC1693-3CMS8

• Configuration: High-Side
• Input Type: Inverting and Non-Inverting
• Delay Time: 38ns
• Current - Peak: 1.5A
• Number Of Configurations: 1
• Number Of Outputs: 1
• Voltage - Supply: 4.5 V ~ 13.2 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• High Side Voltage - Max (bootstrap): -

APPLICATIONS
LTC1693
corresponding to MOSFET’s V
can be readily obtained from the manafacturer’s Q
V
Transition state power losses are due to both AC currents
required to charge and discharge the drivers’ internal
nodal capacitances and cross-conduction currents in the
internal gates.
UVLO and Thermal Shutdown
The LTC1693’s UVLO detector disables the input buffer
and pulls the output pin to ground if V
remains off from V
during start-up or improper supply voltage values, the
LTC1693 will keep the output power MOSFET off.
The LTC1693 also has a thermal detector that similarly
disables the input buffer and grounds the output pin if
junction temperature exceeds 145 C. The thermal shut-
down circuit has 20 C of hysteresis. This thermal limit
helps to shut down the system should a fault condition
occur.
Input Voltage Range
LTC1693’s input pin is a high impedance node and essen-
tially draws neligible input current. This simplifies the
input drive circuitry required for the input.
The LTC1693 typically has 1.2V of hysteresis between its
low and high input thresholds. This increases the driver’s
robustness against any ground bounce noises. However,
care should still be taken to keep this pin from any noise
pickup, especially in high frequency switching
applications.
In applications where the input signal swings below the
GND pin potential, the input pin voltage must be clamped
to prevent the LTC1693’s parastic substrate diode from
turning on. This can be accomplished by connecting a
series current limiting resistor R1 and a shunting Schottky
diode D1 to the input pin (Figure 4). R1 ranges from 100
to 470 while D1 can be a BAT54 or 1N5818/9.
10
GS
Load Capacitive Power (MOS) = (V
curves:
CC
U
= 1V to V
INFORMATION
U
GS
CC
value (V
= 4V. This ensures that
W
CC
CC
)(Q
< 4V. The output
CC
G
in this case)
)(f)
U
GS
vs
Bypassing and Grounding
LTC1693 requires proper V
to its high speed switching (ns) and large AC currents (A).
Careless component placement and PCB trace routing may
cause excessive ringing and under/overshoot.
To obtain the optimum performance from the LTC1693:
A. Mount the bypass capacitors as close as possible to the
B. Use a low inductance, low impedance ground plane to
C. Plan the ground routing carefully. Know where the large
D. Keep the copper trace between the driver output pin and
INPUT SIGNAL
GOING BEL0W
V
much as possible to reduce lead inductance. It is
recommended to have a 0.1 F ceramic in parallel with
a low ESR 4.7 F bypass capacitor.
For high voltage switching in an inductive environment,
ensure that the bypass capacitors’ V
high enough to prevent breakdown. This is especially
important for floating driver applications.
reduce any ground drop and stray capacitance. Re-
member that the LTC1693 switches 1.5A peak currents
and any significant ground drop will degrade signal
integrity.
load switching current is coming from and going to.
Maintain separate ground return paths for the input pin
and output pin. Terminate these two ground traces only
at the GND pin of the driver (STAR network).
the load short and wide.
POTENTIAL
CC
GND PIN
and GND pins. The leads should be shortened as
R1
D1
SUBSTRATE
PARASITIC
IN
Figure 4
DIODE
CC
bypassing and grounding due
LTC1693
MAX
GND
V
CC
ratings are
1693 F04