LT1580IQ#TR Linear Technology, LT1580IQ#TR Datasheet - Page 6

• Manufacturer Part Number: LT1580IQ#TR
• Description: IC REGULATOR LDO ADJ 7A DDPAK-5
• Manufacturer: Linear Technology

Specifications of LT1580IQ#TR

• Applications: Converter, Intel Pentium®
• Voltage - Input: 1.79 ~ 6 V
• Number Of Outputs: 1
• Voltage - Output: 1.25 ~ 4.65 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: D²Pak, TO-263 (5 leads + tab)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

BLOCK DIAGRA
APPLICATIONS
LT1580/LT1580-2.5
The LT1580 is a low dropout regulator designed to power
the new generation of microprocessors. Low dropout
regulators have become more common in desktop com-
puter systems as microprocessor manufacturers have
moved away from 5V only CPUs. A wide range of supply
requirements exists today with new voltages just over the
horizon. In many cases the input-output differential is very
small, effectively disqualifying many of the low dropout
regulators on the market today. The LT1580 is designed to
make use of multiple power supplies, present in most
systems, to reduce the dropout voltage. This two supply
approach maximizes efficiency.
The second supply, at least 1V greater than the output
voltage, is used to provide power for the control circuitry
and supply the drive current to the NPN output transistor.
This allows the NPN to be driven into saturation, thereby
6
U
INFORMATION
U
W
ADJ
W
SENSE
GND
V
CONTROL
U
FOR FIXED
VOLTAGE
DEVICE
reducing the dropout voltage by a V
conventional designs. The current requirement for the
control voltage is relatively small, equal to approximately
1% of the output current or about 70mA for a 7A load. The
bulk of this current is drive current for the NPN output
transistor. This drive current becomes part of the output
current.
The control voltage must be at least 1V greater than the
output voltage to obtain optimum performance. The maxi-
mum voltage on the V
voltage at the V
for fixed voltage devices is 6mA (typ) and is constant as a
function of load. ADJ pin current for adjustable devices is
60 A at 25 C and varies proportional to absolute tempera-
ture.
POWER
+
–
pin is limited to 7V. GDN pin current
CONTROL
pin is 13V. The maximum
V
POWER
V
1580 BD
OUT
BE
compared to