Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - voltage regulator - special purpose DDPAK 5

LT1580/LT1580-2.5

■

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

The LT®1580 is a 7A low dropout regulator designed to

power the new generation of microprocessors. The drop-

out 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.

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.

7A, Very Low

Dropout Regulator

FEATURES

DESCRIPTION

, 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.

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

■

PowerPC

Series Power Supplies

OUTPUT CURRENT (A)

MINIMUM POWER VOLTAGE (V)

1.0

1580 G03

0.5

DATA SHEET LIMIT

= 25°C

= 125°C

INDICATES GUARANTEED TEST POINTS

0°C ≤ T

≤ 125°C

Dropout Voltage—

Minimum Power Voltage

TYPICAL APPLICATION

2.5V Microprocessor Supply

OUT

SENSE

ADJGND

0.1µF

1580 TA01

10µF

TANT

330µF

OS-CON

2.5V/7A

LT1580-2.5

100µF TANT

AVX TPS

× 7

POWER

3.3V

0.2A

CONTROL

Summary of content (16 pages)

PAGE 1
LT1580/LT1580-2.5 7A, Very Low Dropout Regulator U DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ 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.
PAGE 2
LT1580/LT1580-2.5 U W W W ABSOLUTE MAXIMUM RATINGS Power Transistor LT1580C ........................................... 0°C to 150°C LT1580I ........................................ – 40°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C UU U VPOWER Input Voltage ................................................ 6V VCONTROL Input Voltage ........................................... 13V Storage Temperature ............................
PAGE 3
LT1580/LT1580-2.5 ELECTRICAL CHARACTERISTICS PARAMETER Load Regulation: LT1580-2.5 LT1580 (VADJ = 0V) CONDITIONS VCONTROL = 5V, VPOWER = 3.3V, ILOAD = 0mA to 7A VCONTROL = 2.75V, VPOWER = 2.1V, ILOAD = 10mA to 7A ● ● TYP 1 1 MAX 5 5 Minimum Load Current: LT1580 VCONTROL = 5V, VPOWER = 3.3V, VADJ = 0V (Note 3) ● 5 10 mA Control Pin Current: LT1580-2.5 (Note 4) VCONTROL = 5V, VPOWER = 3.3V, ILOAD = 100mA, 0°C ≤ TJ ≤ 125°C VCONTROL = 5V, VPOWER = 3.
PAGE 4
LT1580/LT1580-2.5 ELECTRICAL CHARACTERISTICS PARAMETER Minimum VPOWER: LT1580-2.5 (VPOWER – VOUT) CONDITIONS VCONTROL = 5V, ILOAD = 100mA VCONTROL = 5V, ILOAD = 1A VCONTROL = 5V, ILOAD = 4A, TJ = 25°C VCONTROL = 5V, ILOAD = 4A VCONTROL = 5V, ILOAD = 7A, TJ = 25°C VCONTROL = 5V, ILOAD = 7A, 0°C ≤ TJ ≤ 125°C VCONTROL = 5V, ILOAD = 6.5A, – 40°C ≤ TJ ≤ 0°C Minimum VPOWER: LT1580 (VPOWER – VOUT) (VADJ = 0V) MIN ● ● ● 0.54 0.70 0.70 VCONTROL = 2.75V, ILOAD = 100mA VCONTROL = 2.75V, ILOAD = 1A VCONTROL = 2.
PAGE 5
LT1580/LT1580-2.5 U W TYPICAL PERFORMANCE CHARACTERISTICS LT1580-2.5 Output Voltage vs Temperature 1.258 2.508 1.256 2.506 1.254 2.504 OUTPUT VOLTAGE (V) REFERENCE VOLTAGE (V) LT1580 Reference Voltage vs Temperature 1.252 1.250 1.248 LOAD 2.498 1.244 2.494 25 50 75 100 125 150 TEMPERATURE (°C) 7A 2.500 2.496 0 VOUT 50mV/DIV 2.502 1.246 1.242 –50 –25 2.
PAGE 6
LT1580/LT1580-2.5 W BLOCK DIAGRA VCONTROL VPOWER + – SENSE VOUT FOR FIXED VOLTAGE DEVICE 1580 BD ADJ GND U W U U APPLICATIONS INFORMATION The LT1580 is a low dropout regulator designed to power the new generation of microprocessors. Low dropout regulators have become more common in desktop computer 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.
PAGE 7
LT1580/LT1580-2.5 U W U U APPLICATIONS INFORMATION The LT1580 has improved frequency compensation which permits the use of capacitors with very low ESR. This is critical in addressing the needs of modern, low voltage, high speed microprocessors. Current generation microprocessors cycle load current from several hundred milliamperes to several amperes in tens of nanoseconds. Output voltage tolerances are tighter and include transient response as part of the specification.
PAGE 8
LT1580/LT1580-2.5 U U W U APPLICATIONS INFORMATION pin and the top of the resistor divider are connected to the top of the load. The bottom of the resistor divider is connected to the bottom of the load. RP is now effectively connected inside the regulating loop of the LT1580 and the load regulation at the load will be negligible for reasonable 5V VCONTROL 3.3V SENSE VPOWER LT1580 values of RP. Trace B of Figure 3 illustrates the effect on output regulation.
PAGE 9
LT1580/LT1580-2.5 U W U U APPLICATIONS INFORMATION load current changes. Output capacitance can increase without limit and larger values of output capacitance further improve the stability and transient response of the LT1580. Modern microprocessors generate large high frequency current transients. The load current step contains higher order frequency components that the output coupling network must handle until the regulator throttles to the load current level.
PAGE 10
LT1580/LT1580-2.5 U W U U APPLICATIONS INFORMATION A protection diode between the VOUT pin and the VPOWER pin is usually not needed. An internal diode between the VOUT pin and the VPOWER pin on the LT1580 can handle microsecond surge currents of 50A to 100A. Even with large value output capacitors it is difficult to obtain those values of surge currents in normal operation.
PAGE 11
LT1580/LT1580-2.5 U W U U APPLICATIONS INFORMATION low dropout applications the power dissipation will be less than 12W. The power in the device is made up of two main components: the power in the output transistor and the power in the drive circuit. The additional power in the control circuit is negligible. The power in the drive circuit will be equal to: PDRIVE = (VCONTROL – VOUT)(ICONTROL) where ICONTROL is equal to between IOUT/100 (typ) and IOUT/58 (max).
PAGE 12
LT1580/LT1580-2.5 U TYPICAL APPLICATION 2.5V/6A Regulator 5V 5 3.3V VPOWER VCONT SENSE LT1580 ADJ C3 22µF 25V + + C2 220µF 10V C4 0.33µF RTN 2 VOUT 4 1 VOUT = 2.
PAGE 13
LT1580/LT1580-2.5 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. Q Package 5-Lead Plastic DD Pak (LTC DWG # 05-08-1461) 0.256 (6.502) 0.060 (1.524) 0.060 (1.524) TYP 0.390 – 0.415 (9.906 – 10.541) 0.165 – 0.180 (4.191 – 4.572) 0.045 – 0.055 (1.143 – 1.397) 15° TYP 0.060 (1.524) 0.183 (4.648) 0.059 (1.499) TYP 0.330 – 0.370 (8.382 – 9.398) ( +0.008 0.004 –0.004 +0.203 0.102 –0.102 ) 0.095 – 0.115 (2.413 – 2.921) 0.075 (1.905) 0.300 (7.620) ( +0.012 0.
PAGE 14
LT1580/LT1580-2.5 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. T Package 5-Lead Plastic TO-220 (Standard) (LTC DWG # 05-08-1421) 0.390 – 0.415 (9.906 – 10.541) 0.165 – 0.180 (4.191 – 4.572) 0.147 – 0.155 (3.734 – 3.937) DIA 0.045 – 0.055 (1.143 – 1.397) 0.230 – 0.270 (5.842 – 6.858) 0.460 – 0.500 (11.684 – 12.700) 0.570 – 0.620 (14.478 – 15.748) 0.330 – 0.370 (8.382 – 9.398) 0.620 (15.75) TYP 0.700 – 0.728 (17.78 – 18.491) 0.152 – 0.202 0.260 – 0.320 (3.
PAGE 15
LT1580/LT1580-2.5 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. T7 Package 7-Lead Plastic TO-220 (Standard) (LTC DWG # 05-08-1422) 0.390 – 0.415 (9.906 – 10.541) 0.165 – 0.180 (4.191 – 4.572) 0.147 – 0.155 (3.734 – 3.937) DIA 0.045 – 0.055 (1.143 – 1.397) 0.230 – 0.270 (5.842 – 6.858) 0.460 – 0.500 (11.684 – 12.700) 0.570 – 0.620 (14.478 – 15.748) 0.330 – 0.370 (8.382 – 9.398) 0.620 (15.75) TYP 0.700 – 0.728 (17.780 – 18.491) 0.152 – 0.202 0.260 – 0.320 (3.
PAGE 16
LT1580/LT1580-2.5 U TYPICAL APPLICATION Dual Regulators Power Pentium Processor or Upgrade CPU R12 0.0075Ω* 5V + 12V R1 10k C8 0.1µF VIN C1 220µF 10V VOUT D1 1N4148 R2 470Ω LT1006 R10 10k + C9 220µF 10V + C4 0.33µF D2 1N4148 12V R13 0.005Ω* R4 178Ω 1% C6 0.01µF C11 22µF 35V C2 220µF 10V 4 + VCONTROL SENSE R11 10k C10 1µF VPOWER VOUT ADJ + 3 C7 330µF 6.3V R7 107Ω 0.25% R6 89.8Ω 0.5% R8 107Ω 0.