FEATURES
■
Low Dropout, 540mV at 7A Output Current
■
Fast Transient Response
■
Remote Sense
■
1mV Load Regulation
■
Fixed 2.5V Output and Adjustable Output
■
No Supply Sequencing Problems in
Dual Supply Mode
LT1580/LT1580-2.5
7A, Very Low
Dropout Regulator
U
DESCRIPTION
The LT®1580 is a 7A low dropout regulator designed to
power the new generation of microprocessors. The dropout voltage of this device is 100mV at light loads rising to
just 540mV at 7A. To achieve this dropout, a second low
current input voltage 1V greater than the output voltage, is
required. The device can also be used as a single supply
device where dropout is comparable to an LT1584.
U
APPLICATIONS
■
Microprocessor Supplies
■
Post Regulators for Switching Supplies
■
High Current Regulators
■
5V to 3.XXV for Pentium® Processors Operating
at 90MHz to 166MHz and Beyond
■
3.3V to 2.9V for Portable Pentium Processor
■
PowerPCTM Series Power Supplies
U
TYPICAL APPLICATION
2.5V Microprocessor Supply
3.3V
0.2A
V
7A
+
330µF
OS-CON
5V
+
10µF
TANT
POWER
V
CONTROL
LT1580-2.5
V
OUT
SENSE
ADJGND
0.1µF
2.5V/7A
+
100µF TANT
AVX TPS
× 7
1580 TA01
Several other new features have been added to the LT1580.
A remote SENSE pin is brought out. This feature virtually
eliminates output voltage variations due to load changes.
Typical load regulation, measured at the SENSE pin, for a
load current step of 100mA to 7A is less than 1mV.
The LT1580 has fast transient response, equal to the
LT1584. On fixed voltage devices, the ADJ pin is brought
out. A small capacitor on the ADJ pin further improves
transient response.
This device is ideal for generating processor supplies of
2V to 3V on motherboards where both 5V and 3.3V
supplies are available.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Pentium is a registered trademark of Intel Corporation.
PowerPC is a trademark of IBM Corporation.
Dropout Voltage—
Minimum Power Voltage
1.0
INDICATES GUARANTEED TEST POINTS
≤ 125°C
0°C ≤ T
J
DATA SHEET LIMIT
0.5
TJ = 125°C
TJ = 25°C
MINIMUM POWER VOLTAGE (V)
0
0
1
3
2
OUTPUT CURRENT (A)
4
5
6
7
1580 G03
1
LT1580/LT1580-2.5
WW
W
U
ABSOLUTE MAXIMUM RATINGS
V
V
Storage Temperature ............................ – 65°C to 150°C
Operating Junction Temperature Range
Input Voltage ................................................ 6V
POWER
CONTROL
Input Voltage ........................................... 13V
Control Section
LT1580C ........................................... 0°C to 125°C
LT1580I........................................ – 40°C to 125°C
U
W
PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
LT1580CQ
LT1580IQ
TAB
OUTPUT
IS
5-LEAD PLASTIC DD
FRONT VIEW
5
4
3
2
1
Q PACKAGE
θJA = 30°C/ W
V
POWER
V
CONTROL
V
OUT
ADJ
SENSE
Power Transistor
LT1580C ........................................... 0°C to 150°C
LT1580I........................................ – 40°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
UUU
PRECONDITIONING
100% Thermal Limit Functional Test
U
ORDER PART
NUMBER
LT1580CT
LT1580IT
TAB
OUTPUT
FRONT VIEW
5
IS
5-LEAD PLASTIC TO-220
4
3
2
1
T PACKAGE
θJA = 50°C/ W
V
POWER
V
CONTROL
V
OUT
ADJ
SENSE
TAB
OUTPUT
IS
FRONT VIEW
7
6
5
4
3
2
1
R PACKAGE
7-LEAD PLASTIC DD
θJA = 30°C/W
NC
V
POWER
ADJ
V
OUT
V
CONTROL
GND
SENSE
ORDER PART
NUMBER
LT1580CR-2.5
LT1580IR-2.5
TAB
OUTPUT
FRONT VIEW
7
6
IS
7-LEAD PLASTIC TO-220
5
4
3
2
1
T7 PACKAGE
θJA = 50°C/W
NC
V
POWER
ADJ
V
OUT
V
CONTROL
GND
SENSE
ORDER PART
NUMBER
LT1580CT7-2.5
LT1580IT7-2.5
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
(Note 1)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Voltage: LT1580-2.5 V
Reference Voltage: LT1580 V
(V
= 0V) V
ADJ
Line Regulation: LT1580-2.5 V
LT1580 V
V
V
I
V
I
V
I
V
I
= 5V, V
CONTROL
= 4V to 12V, V
CONTROL
= 4V to 12V, V
CONTROL
= 0mA to 7A, 0°C ≤ TJ ≤ 125°C
LOAD
= 4V to 12V, V
CONTROL
= 0mA to 6.5A, –40°C ≤ TJ < 0°C
LOAD
= 2.75V, V
CONTROL
= 2.7V to 12V, V
CONTROL
= 2.7V to 12V, V
CONTROL
= 10mA to 7A, 0°C ≤ TJ ≤ 125°C
LOAD
= 2.7V to 12V, V
CONTROL
= 10mA to 6.5A, –40°C ≤ TJ < 0°C
LOAD
= 3.65V to 12V, V
CONTROL
= 2.5V to 12V, V
CONTROL
POWER
POWER
= 3.3V, I
POWER
POWER
POWER
= 2V, I
POWER
POWER
POWER
POWER
POWER
= 0mA 2.485 2.500 2.515 V
LOAD
= 3V to 5.5V, I
= 0mA to 4A ● 2.475 2.500 2.525 V
LOAD
= 3V to 5.5V, 2.475 2.500 2.525 V
= 3V to 5.5V, 2.460 2.500 2.525 V
= 10mA 1.243 1.250 1.257 V
LOAD
= 1.75V to 5.5V, I
= 10mA to 4A ● 1.237 1.250 1.263 V
LOAD
= 2.05V to 5.5V, 1.237 1.250 1.263 V
= 2.05V to 5.5V, 1.232 1.250 1.263 V
= 3V to 5.5V, I
= 1.75V to 5.5V, I
= 10mA ● 13 mV
LOAD
= 10mA ● 13 mV
LOAD
2
LT1580/LT1580-2.5
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
Load Regulation: LT1580-2.5 V
LT1580 (V
= 0V) V
ADJ
Minimum Load Current: LT1580 V
Control Pin Current: LT1580-2.5 V
(Note 4) V
V
V
V
V
V
V
Control Pin Current: LT1580 V
(Note 4) V
V
V
V
V
V
V
Ground Pin Current: LT1580-2.5 V
ADJ Pin Current: LT1580 (V
= 0V) V
ADJ
Current Limit: LT1580-2.5 V
V
LT1580 (V
= 0V) V
ADJ
V
Ripple Rejection: LT1580-2.5 V
LT1580 VC = VP = 3.75V Avg, V
Thermal Regulation 30ms Pulse 0.002 0.020 %/W
Thermal Resistance, Junction-to-Case T, T7 Packages, Control Circuitry/Power Transistor 0.65/2.70 °C/W
Dropout Voltage (Note 2)
Minimum V
(V
CONTROL
– V
: LT1580-2.5 V
CONTROL
)V
OUT
V
V
V
V
V
V
Minimum V
(V
(V
– V
CONTROL
= 0V) V
ADJ
: LT1580 V
CONTROL
)V
OUT
V
V
V
V
V
V
V
= 5V, V
CONTROL
= 2.75V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 2.75V, V
CONTROL
= 2.75V, V
CONTROL
= 2.75V, V
CONTROL
= 2.75V, V
CONTROL
= 2.75V, V
CONTROL
= 2.75V, V
CONTROL
= 2.75V, V
CONTROL
= 2.75V, V
CONTROL
= 5V, V
CONTROL
= 2.75V, V
CONTROL
= 5V, V
CONTROL
= 5V, V
CONTROL
= 2.75V, V
CONTROL
= 2.75V, V
CONTROL
= VP = 5V Avg, V
C
= 3.3V, I
POWER
= 3.3V, I
POWER
= 3.3V, I
POWER
= 3.3V, I
POWER
= 3.3V, I
POWER
= 3.3V, I
POWER
= 3.3V, I
POWER
= 3.3V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 3.3V, I
POWER
POWER
POWER
POWER
POWER
POWER
POWER
POWER
POWER
POWER
POWER
POWER
POWER
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
= 2.1V, I
POWER
= 3.3V, V
= 3.3V, I
= 3.3V, I
= 3.3V, I
= 3.3V, I
= 3V, I
= 3V, I
= 3.3V, I
= 3.3V, I
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 1.75V, I
POWER
= 1.75V, I
POWER
= 2.05V, I
POWER
= 2.05V, I
POWER
= 3.3V, I
= 2.05V, I
POWER
= 3.3V, ∆V
= 3.3V, ∆V
= 2.05V, ∆V
POWER
= 2.05V, ∆V
POWER
= 1V
RIPPLE
RIPPLE
= 100mA, 0°C ≤ TJ ≤ 125°C 1.00 1.15 V
= 100mA, –40°C ≤ TJ < 0°C 1.20 V
= 1A, 0°C ≤ TJ ≤ 125°C 1.00 1.15 V
= 1A, –40°C ≤ TJ < 0°C 1.20 V
= 4A, 0°C ≤ TJ ≤ 125°C 1.06 1.20 V
= 4A, –40°C ≤ TJ < 0°C 1.25 V
= 7A, 0°C ≤ TJ ≤ 125°C 1.15 1.30 V
= 6.5A, –40°C ≤ TJ < 0°C 1.35 V
= 100mA, 0°C ≤ TJ ≤ 125°C 1.00 1.15 V
LOAD
= 100mA, –40°C ≤ TJ < 0°C 1.20 V
LOAD
= 1A, 0°C ≤ TJ ≤ 125°C 1.00 1.15 V
LOAD
= 1A, –40°C ≤ TJ < 0°C 1.20 V
LOAD
= 2.75A, 0°C ≤ TJ ≤ 125°C 1.05 1.18 V
LOAD
= 2.75A, –40°C ≤ TJ < 0°C 1.23 V
LOAD
= 4A, 0°C ≤ TJ ≤ 125°C 1.06 1.20 V
LOAD
= 4A, –40°C ≤ TJ < 0°C 1.25 V
LOAD
= 7A, 0°C ≤ TJ ≤ 125°C 1.15 1.30 V
LOAD
= 6.5A, –40°C ≤ TJ < 0°C 1.35 V
LOAD
= 0mA to 7A ● 15mV
LOAD
= 10mA to 7A ● 15mV
LOAD
= 0V (Note 3) ● 510mA
ADJ
= 100mA, 0°C ≤ TJ ≤ 125°C610mA
LOAD
= 100mA, –40°C ≤ TJ < 0°C12mA
LOAD
= 4A, 0°C ≤ TJ ≤ 125°C3060mA
LOAD
= 4A, –40°C ≤ TJ < 0°C70mA
LOAD
= 4A, 0°C ≤ TJ ≤ 125°C3370mA
LOAD
= 4A, –40°C ≤ TJ < 0°C80mA
LOAD
= 7A, 0°C ≤ TJ ≤ 125°C 60 120 mA
LOAD
= 6.5A, –40°C ≤ TJ < 0°C 130 mA
LOAD
= 100mA, 0°C ≤ TJ ≤ 125°C610mA
LOAD
= 100mA, –40°C ≤ TJ < 0°C12mA
LOAD
= 4A, 0°C ≤ TJ ≤ 125°C3060mA
LOAD
= 4A, –40°C ≤ TJ < 0°C70mA
LOAD
= 4A, 0°C ≤ TJ ≤ 125°C3370mA
LOAD
= 4A, –40°C ≤ TJ < 0°C80mA
LOAD
= 7A, 0°C ≤ TJ ≤ 125°C 60 120 mA
LOAD
= 6.5A, –40°C ≤ TJ < 0°C 130 mA
LOAD
= 0mA ● 610mA
LOAD
= 10mA ● 50 120 µA
LOAD
= 100mV, 0°C ≤ TJ ≤ 125°C 7.1 8 A
OUT
= 100mV, –40°C ≤ TJ < 0°C 6.6 A
OUT
= 100mV, 0°C ≤ TJ ≤ 125°C 7.1 8 A
OUT
= 100mV, –40°C ≤ TJ < 0°C 6.6 A
OUT
, I
= 4A, TJ = 25°C6080dB
P-P
OUT
= 1V
, V
P-P
ADJ
= 0V, I
= 4A, TJ = 25°C6080 dB
OUT
3
LT1580/LT1580-2.5
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum V
– V
(V
POWER
Minimum V
– V
(V
POWER
(V
= 0V) V
ADJ
: LT1580-2.5 V
POWER
)V
OUT
V
V
V
V
V
: LT1580 V
POWER
)V
OUT
V
V
V
V
V
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
CONTROL
= 5V, I
= 5V, I
= 5V, I
= 5V, I
= 5V, I
= 5V, I
= 5V, I
= 2.75V, I
= 2.75V, I
= 2.75V, I
= 2.75V, I
= 2.75V, I
= 2.75V, I
= 2.75V, I
= 2.75V, I
= 100mA ● 0.10 0.17 V
LOAD
= 1A ● 0.15 0.22 V
LOAD
= 4A, TJ = 25°C 0.34 0.40 V
LOAD
= 4A ● 0.50 V
LOAD
= 7A, TJ = 25°C 0.54 0.62 V
LOAD
= 7A, 0°C ≤ TJ ≤ 125°C 0.70 0.80 V
LOAD
= 6.5A, –40°C ≤ TJ ≤ 0°C 0.70 0.80 V
LOAD
= 100mA ● 0.10 0.17 V
LOAD
= 1A ● 0.15 0.22 V
LOAD
2.75A ● 0.26 0.38 V
LOAD
= 4A, TJ = 25°C 0.34 0.40 V
LOAD
= 4A ● 0.50 V
LOAD
= 7A, TJ = 25°C 0.54 0.62 V
LOAD
= 7A, 0°C ≤ TJ ≤ 125°C 0.70 0.80 V
LOAD
= 6.5A, –40°C ≤ TJ ≤ 0°C 0.70 0.80 V
LOAD
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Unless otherwise specified V
adjustable device V
ADJ
= 0V.
OUT
= V
. For the LT1580
SENSE
Note 2: For the LT1580, dropout is caused by either minimum control
voltage (V
) or minimum power voltage (V
CONTROL
). Both parameters
POWER
are specified with respect to the output voltage. The specifications represent
Note 3: For the LT1580 adjustable device the minimum load current is the
minimum current required to maintain regulation. Normally the current in
the resistor divider used to set the output voltage is selected to meet the
minimum load current requirement.
Note 4: The control pin current is the drive current required for the output
transistor. This current will track output current with roughly a 1:100 ratio.
The minimum value is equal to the quiescent current of the device.
the minimum input/output voltage required to maintain 1% regulation.
UW
TYPICAL PERFORMANCE CHARACTERISTICS
Control Pin Current
vs Output Current
140
INDICATES GUARANTEED TEST POINTS
≤ 125°C
0°C ≤ T
120
100
80
60
40
CONTROL PIN CURRENT (mA)
20
J
DATA SHEET LIMIT
TYPICAL
DEVICE
Minimum Control Voltage
2
INDICATES GUARANTEED TEST POINTS
≤ 125°C
0°C ≤ T
J
) (V)
OUT
1
– V
CONTROL
(V
MINIMUM CONTROL VOLTAGE
DATA SHEET LIMIT
TJ = 125°C
TJ = 25°C
Dropout Voltage—
Minimum Power Voltage
1.0
INDICATES GUARANTEED TEST POINTS
≤ 125°C
0°C ≤ T
J
DATA SHEET LIMIT
0.5
MINIMUM POWER VOLTAGE (V)
TJ = 125°C
TJ = 25°C
4
0
0
12
OUTPUT CURRENT (A)
467
35
1580 G01
0
0
1
3
2
OUTPUT CURRENT (A)
4
5
6
7
1580 G02
0
0
1
3
2
OUTPUT CURRENT (A)
4
5
6
7
1580 G03
UW
TYPICAL PERFORMANCE CHARACTERISTICS
LT1580/LT1580-2.5
LT1580 Reference Voltage
vs Temperature
1.258
1.256
1.254
1.252
1.250
1.248
REFERENCE VOLTAGE (V)
1.246
1.244
1.242
–50 –25
0 25 75 125
TEMPERATURE (°C)
50
100
150
1580 G04
LT1580-2.5 Output Voltage
vs Temperature
2.508
2.506
2.504
2.502
2.500
2.498
OUTPUT VOLTAGE (V)
2.496
2.494
2.492
–50 –25
0 25 75 125
TEMPERATURE (°C)
UUU
PIN FUNCTIONS
SENSE (Pin 1): This pin is the positive side of the reference
voltage for the device. With this pin it is possible to Kelvin
sense the output voltage at the load.
ADJ (Pin 2/5):
reference voltage for the device. Transient response can
be improved by adding a small bypass capacitor from the
ADJ pin to ground. For fixed voltage devices the ADJ pin
is also brought out to allow the user to add a bypass
capacitor
.
GND (Pin 2, 7-Lead Only): For fixed voltage devices this
is the bottom of the resistor divider that sets the output
voltage.
This pin is the negative side of the
(5-Lead/7-Lead)
Load Current Step Response
V
OUT
50mV/DIV
7A
LOAD
50
V
POWER
400mA
100
150
1580 G05
(Pin 5/6): This is the collector to the power device
50µs/DIV 1580 TA02
of the LT1580. The output load current is supplied through
this pin. For the device to regulate, the voltage at this pin
must be between 0.1V and 0.8V greater than the output
voltage (see Dropout specifications).
V
CONTROL
(Pin 4/3): This pin is the supply pin for the
control circuitry of the device. The current flow into this
pin will be about 1% of the output current. For the device
to regulate, the voltage at this pin must be between 1.0V
and 1.3V greater than the output voltage (see Dropout
specifications).
V
(Pin 3/4): This is the power output of the device.
OUT
5
Loading...