MOTOROLA LT1585ACT, LT1585ACM-1.5, LT1585ACM, LT1585ACT-1.5 Datasheet

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The L T1585A is a low dropout 3–terminal voltage regulator with 5A output

current capability .

Design has been optimized for low voltage applications where transient
response and minimum input voltage are critical. This voltage regulator
features a low dropout voltage and fast transient response. These
improvements make them ideal for low voltage microprocessor applications
requiring a regulated 2.5V to 3.6V output with an input supply below 7V.

Current limits is trimmed to ensure specified output current and controlled
short–circuit current. On–chip thermal limiting provides protection against
any combination of overload that would create excessive junction
temperatures. The LT1585A is available in the industry standard 3–pin
TO–220 and D2P AK power package.

Features

• Fast Transient Response

• Guaranteed Dropout Voltage at Multiple Currents

• Load Regulation: 0.05% Typ

• Trimmed Current Limit

• On–Chip Thermal Limiting

• Standard 3–Pin Power Package

Applications

• Pentium

• Power PC Supplies

• Other 2.5V to 3.6V Microprocessor Supplies

• Low Voltage Logic Supplies

• Battery–Powered Circuitry

• Post Regulator for Switching Supply



Processor Supplies

5A LOW DROPOUT FAST

RESPONSE POSITIVE

ADJUSTABLE AND FIXED

VOLTAGE REGULATOR

SILICON MONOLITHIC
INTEGRATED CIRCUIT

1

2

3

T SUFFIX

PLASTIC PACKAGE

CASE 221A

Adjustable output:
Pin 1. Adjust

Pin 2. V

out

Pin 3. V

in

Fixed 1.5V output:
Pin 1. Gnd

Pin 2. V

out

Pin 3. V

in

V

in

MOTOROLA ANALOG IC DEVICE DATA

Simplified Block Diagram

Thermal

Limit

Adjust

1

2

3

CM SUFFIX

+
–

Device

LT1585ACT 0 to 125°C TO–220

V

out

LT1585ACM 0 to 125°C D2PAK

LT1585ACT–1.5 0 to 125°C TO–220

LT1585ACM–1.5 0 to 125°C D2PAK

 Motorola, Inc. 1999 Rev 0

PLASTIC PACKAGE

CASE 936

(D2PAK)

ORDERING INFORMATION

Tested

Operating

Temp.

Range

Output

Voltage

Type

ADJ.
ADJ.

FIXED

1.5V

FIXED

1.5V

Package

1

LT1585A

Á

Á

Á

ABSOLUTE MAXIMUM RATINGS

Maximum Supply Voltage
Power Dissipation

Case 221A (TO–220) (TJ = +25°C) P

Thermal Resistance, Junction–to–Ambient R
Thermal Resistance, Junction–to–Case R

Case 936 (D2PAK) (TJ = +25°C) P

Thermal Resistance, Junction–to–Ambient R

Thermal Resistance, Junction–to–Case R
Storage Temperature Range
Minimum ESD Rating (Human Body Model: C = 100pF, R = 1.5 kW)

Lead Temperature (Soldering, 10 sec.)
Maximum Junction Temperature

OPERATING RATINGS (Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee

specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics)

Operating Junction Temperature Range
Supply Voltage

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ELECTRICAL CHARACTERISTICS (0 < T

Characteristic

Reference Voltage (LT1585A)

(Vin–V

1.5V ≤ (Vin–V

Output Voltage (LT1585A–1.5)

Vin = 5V, TJ = 25°C, I
3V ≤ Vin ≤ 7V, 0mA ≤ I

Line Regulation [Notes 1, 2]

LT1585A: 2.75V ≤ Vin ≤ 7V, I
LT1585A–1.5: 3V ≤ Vin ≤ 7V, I

Load Regulation [Notes 1, 2]

LT1585A: (Vin–V
LT1585A–1.5: Vin = 5V, TJ = 25°C, 0mA ≤ I
LT1585A: (Vin–V
LT1585A–1.5: Vin = 5V, 0mA ≤ I

Dropout Voltage

LT1585A: DV
LT1585A–1.5: DV
LT1585A: DV
LT1585A–1.5: DV

Current Limit [Note 3]

Adjust Pin Current (LT1585A)
Adjust Pin Current Change (LT1585A) [Note 3]

1.5V ≤ (Vin–V
Minimum Load Current (LT1585A) 1.5V ≤ (Vin–V
Quiescent Current (LT1585A–1.5) Vin = 5V

Ripple Rejection

LT1585A: f = 120Hz, C

LT1585A–1.5: f = 120Hz, C
Thermal Regulation TJ = 25°C, 30ms Pulse
T emperature Stability
Long Term Stability TJ = 125°C, 1000 Hrs
RMS Output Noise (% of V

NOTES 1. See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are measured at a constant
junction temperature by low duty cycle pulse testing.

determined by input/output differential and the output current. Guaranteed maximum output power will not be available over the full input/output voltage range.

out

(Vin–V

) = 3V, I

) = 5.5V 5.0 6.0 –

out

= 10mA, TJ = 25°C 1.238 1.250 1.262

out

) ≤ 5.75V , 10mA ≤ I

out

= 0mA 1.485 1.5 1.515

out

≤ 5A 1.470 1.5 1.530

out

) = 3V, TJ = 25°C, 10mA ≤ I

out

) = 3V, 10mA ≤ I

out

= 1%, I

REF

REF

) ≤ 5.75V , 10mA ≤ I

out

= 1%, I

OUT
= 1%, I

= 1%, I

OUT

out

OUT

OUT

= 25µF T

out

out

2.Line and load regulations are guaranteed up to the maximum power dissipation 28.8W for the LT1585A in T–package. Power dissipation is

3.The LT1585A has constant current limit with changes in input–to–output voltage.

(Absolute Maximum Ratings indicate limits beyond which damage to the device may occur)

Rating Symbol Pin # Value Unit

V

T

in

D

θJA
θJC

D

θJA
θJC

stg

3

12

Internally Limited W

65 °C/W

5.0 °C/W

Internally Limited W

70 °C/W

5.0 °C/W

–65 to 150

3.0

260

T

J

150

Rating Symbol Pin # Value Unit

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< +125°C, unless otherwise noted)

J

T

J

0 to +125

7.0

Symbol Pin # Min Typ Max Unit

V

ref

≤ 5A 1.225 1.250 1.275

out

1

2

Reg

Reg

Vin–V

line

load

out

= 10mA – 0.005 0.2

out

= 0mA – 0.005 0.2

out

≤ 5A – 0.05 0.3

out

≤ 5A – 0.05 0.3

out

≤ 5A – 0.05 0.5

out

≤ 5A – 0.05 0.5

out

= 3A

= 3A

OUT
= 5A

= 5A

OUT

I

Limit

I

Adj

2

2

– 1.150 1.300
– 1.150 1.300
– 1.200 1.400
– 1.200 1.400

2

1

–

55

120

1

≤ 5A – 0.2 5.0

out

, (Vin–V

ant.

= 25µF T

ant.

) TJ = 25°C, 10Hz ≤ f ≤ 10kHz

) ≤ 5.75V

out

) = 3V, I

out

, Vin = 4.5V, I

I

Load min

RR

= 5A 60 72 –

out

= 5A 60 72 –

out

T°

T°

Reg

Stab

2
1

–
–

2.0

7.0

2

–

0.004
–
–
–

0.5

0.03

0.003

10
13

–
–

1.0
–

V

°C
kV

°C
°C

°C

V

Á

V

V

%

%

V

A

µA
µA

mA
mA

dB

%/W

%
%
%

2

MOTOROLA ANALOG IC DEVICE DATA

LT1585A

Figure 1. Dropout Voltage vs Output Current

1.4

1.3

1.2

1.1

1.0

0.9

0.8

DROPOUT VOLTAGE (V)

0.7

0.6

0.5
0 2.0 6.0

1.0 3.0 5.0
OUTPUT CURRENT (A)

–5°C
25°C

125°C

4.0

Figure 3. Load Regulation vs T emperature

0.1

0.05

0

–0.05

–0.1

LOAD REGULATION (%)

–0.15

–0.2

–40–60 20

0–20 60 80 140120

40 100

TEMPERATURE (

°

C)

Figure 2. Short–Circuit Current vs Temperature

7.0

6.8

6.6

6.4

6.2

(A)

6.0

sc

I

5.8

5.6

5.4

5.2

5.0
–40–60 20 140

0–20 60 80 120

40 100

TEMPERATURE (

°

C)

Figure 4. L T1585A Reference Voltage vs

T emperature

1.275

1.27

1.265

1.26

1.255

(V)

1.25

ref

V

1.245

1.24

1.235

1.23

1.225
–40–60 20 160

0–20 60 80 140120

40 100

TEMPERATURE (

°

C)

Figure 5. L T1585A–1.5 Output Voltage vs

T emperature

1.515

1.51

1.505

(V)

1.5

out

V

1.495

1.49

1.485
–40–60 20

0–20 60 80 140120

40 100

TEMPERATURE (

°

C)

MOTOROLA ANALOG IC DEVICE DATA

Figure 6. L T1585A–1.5 Quiescent Current vs

T emperature

10

9.5

9.0

8.5

8.0

(mA)

7.5

q

I

7.0

6.5

6.0

5.5

5.0
–40–60 20

0–20 60 80 140120

40 100

TEMPERATURE (

°

C)

3