LTC1644CGN#TR Linear Technology, LTC1644CGN#TR Datasheet - Page 22

• Manufacturer Part Number: LTC1644CGN#TR
• Description: IC CONTROLLER HOT SWAP 20-SSOP
• Manufacturer: Linear Technology
• Type: Hot-Swap Controllerr

Specifications of LTC1644CGN#TR

• Applications: CompactPCI™
• Internal Switch(s): No
• Voltage - Supply: 3.3V, 5V, ±12V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP (0.154", 3.91mm Width)
• Family Name: LTC1644
• Package Type: SSOP N
• Operating Supply Voltage (min): 2.75/10.8/-10.8V
• Operating Supply Voltage (max): 13.2/-14V
• Operating Temperature (min): 0C
• Operating Temperature (max): 70C
• Operating Temperature Classification: Commercial
• Product Depth (mm): 3.99mm
• Product Height (mm): 1.5mm
• Mounting: Surface Mount
• Pin Count: 20
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: LTC1644CGNTR

APPLICATIO S I FOR ATIO
LTC1644
PCB Layout Considerations
For proper operation of the LTC1644’s circuit breaker
operation, 4-wire Kelvin-sense connections between the
sense resistor and the LTC1644’s 5V
and 3V
The PCB layout should be balanced and symmetrical to
minimize wiring errors. In addition, the PCB layout for the
sense resistors and the power MOSFETs should include
good thermal management techniques for optimal device
power dissipation.
A recommended PCB layout for the sense resistor, the
power MOSFET and the GATE drive components around
the LTC1644 is illustrated in Figure 18. In Hot Swap
applications where load currents can be 10A, narrow PCB
tracks exhibit more resistance than wider tracks and
operate at more elevated temperatures. Since the sheet
resistance of 1 ounce copper foil is approximately
0.45m / , track resistances add up quickly in high
current applications. Thus, to keep PCB track resistance
and temperature rise to a minimum, the suggested trace
width in these applications for 1 ounce copper foil is 0.03"
for each ampere of DC current.
In the majority of applications, it will be necessary to use
plated-through vias to make circuit connections from
component layers to power and ground layers internal to
the PC board. For 1 ounce copper foil plating, a general rule
is 1 ampere of DC current per via, making sure the via is
properly dimensioned so that solder completely fills any
void. For other plating thicknesses, check with your PCB
fabrication facility.
Power MOSFET and Sense Resistor Selection
Table 8 lists some current sense resistors that can be used
the LTC1644’s circuit breakers and Table 9 list some
power MOSFET transistors that are available. Table 7 lists
supplier web site addresses for discrete component men-
tioned throughout the LTC1644 data sheet.
22
IN
and 3V
SENSE
U
pins are strongly recommended.
U
W
IN
and 5V
SENSE
U
pins
Table 7. Manufacturers’ Web Site
Obtaining Information on Specific Parts
For more information regarding or to request a copy of the
CompactPCI specification, contact the PCI Industrial Com-
puter Manufacturers Group at:
TransZorb SMAJ12CA and diodes BAV99 are supplied by:
Transistors MMBT2222A and TVS 1PMT5.0AT3 are
supplied by:
PCI Industrial Computer Manufacturers Group
Wakefield, MA 01880 USA
Phone: [phone]
Web Site: http://www.picmg.com
Diodes, Incorporated
Westlake Village, CA 91362 USA
Phone: [phone]
Web Site: http://www.vishay-liteon.com or
http://www.diodes.com
Semiconductor Components Industries, LLC
Phoenix, AZ 85008 USA
Phone: [phone]
Web Site: http://www.onsemi.com
International Rectifier
ON Semiconductor
MANUFACTURER
Vishay-Siliconix
Diodes, Inc.
Vishay-Dale
IRC-TT
www.irf.com
www.onsemi.com
www.irctt.com
www.vishay.com
www.vishay.com
www.diodes.com
WEB SITE
1644f