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LT1575CN8#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
1
LT1575/LT1577
Ultrafast Transient Response,
Low Dropout Regulators
Adjustable and Fixed
TYPICAL APPLICATION
U
1
2
3
4
8
7
6
5
SHDN
V
IN
GND
OUT
IPOS
INEG
GATE
COMP
C2
1µF
C5
220µF
5V
GND
1575/77 TA01
V
OUT
3.3V
5A
R2
5Ω
R1
7.5k
12V
LT1575-3.3
C4
1000pF
FOR T > 45°C:
C6 = 24 × 1µF X7R 
CERAMIC SURFACE 
MOUNT CAPACITORS.
PLACE C6 IN THE 
MICROPROCESSOR 
SOCKET CAVITY
FOR T < 45°C:
C6 = 24 × 1µF Y5V 
CERAMIC SURFACE 
MOUNT CAPACITORS.
*
Q1
IRFZ24
+
C3
10pF
C6*
24µF
Ultrafast Transient Response 5V to 3.3V Low Dropout Regulator
(For Schematic Including Current Limit, See Typical Applications)
50mV/DIV
2A/DIV
100µs/DIV
1575/77 TA02
Transient Response for
0.2A to 5A Output Load Step
■
Pentium
®
Processor Supplies
■
PowerPC
TM
Supplies
■
5V to 3.XXV or 3.3V to 2.XXV Microprocessor Supplies
■
GTL Termination
■
Low Voltage Logic Supplies
LT1575CN8/LT1575CS8 Adjustable
LT1575CN8-1.5/LT1575CS8-1.5 1.5V Fixed
LT1575CN8-2.8/LT1575CS8-2.8 2.8V Fixed
LT1575CN8-3.3/LT1575CS8-3.3 3.3V Fixed
LT1575CN8-3.5/LT1575CS8-3.5 3.5V Fixed
LT1575CN8-5/LT1575CS8-5 5V Fixed
LT1577CS-ADJ/ADJ Adjustable, Adjustable
LT1577CS-3.3/ADJ 3.3V Fixed, Adjustable
LT1577CS-3.3/2.8 3.3V Fixed, 2.8V Fixed
Consult factory for additional output voltage combinations available
in the LT1577.
APPLICATIONS
U
DESCRIPTION
U
■
UltraFast
TM
Transient Response
Eliminates
Tantalum and Electrolytic Output Capacitors
■
FET R
DS(ON)
Defines Dropout Voltage
■
1% Reference/Output Voltage Tolerance Over
Temperature
■
Typical Load Regulation: 1mV
■
High Side Sense Current Limit
■
Multifunction Shutdown Pin with Latchoff
FEATURES
The LT
®
1575/LT1577 are single/dual controller ICs that
drive low cost external N-channel MOSFETs as source
followers to produce ultrafast transient response, low
dropout voltage regulators.
The LT1575/LT1577 achieve unprecedented transient-
load performance by eliminating expensive tantalum or
bulk electrolytic output capacitors in the most demanding
modern microprocessor applications. Precision-trimmed
adjustable and fixed output voltage versions accommo-
date any required microprocessor power supply voltage.
Selection of the N-channel MOSFET R
DS(ON)
allows very
low dropout voltages to be achieved.
Unique protection features include a high side current
limit amplifier that activates a fault protection timer
circuit. A multifunction Shutdown pin provides either
current limit time-out with latchoff, overvoltage protec-
tion, thermal shutdown or a combination of these func-
tions. The LT1575 is available in 8-pin SO or PDIP and the
LT1577 is available in 16-pin narrow body SO.
UltraFast is a trademark of Linear Technology Corporation.
Pentium is a registered trademark of Intel Corporation.
PowerPC is a trademark of IBM Corporation.
, LTC and LT are registered trademarks of Linear Technology Corporation.
2
LT1575/LT1577
A
U
G
W
A
W
U
W
ARB
S
O
LU
T
EXI T
I
S
(Note 1)
V
IN
, IPOS, INEG ...................................................... 22V
SHDN....................................................................... V
IN
Operating Ambient Temperature Range ..... 0°C to 70°C
Junction Temperature (Note 2)................ 0°C to 100°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
WU
U
PACKAGE
/
O
RDER I FOR ATIO
1
2
3
4
8
7
6
5
TOP VIEW
SHDN
V
IN
GND
OUT
IPOS
INEG
GATE
COMP
S8 PACKAGE
8-LEAD PLASTIC SO
N8 PACKAGE
8-LEAD PDIP
T
JMAX
= 100°C, θ
JA
= 100°C/ W (N8)
T
JMAX
= 100°C, θ
JA
= 130°C/ W (S8)
LT1575CN8-1.5
LT1575CS8-1.5
LT1575CN8-2.8
LT1575CS8-2.8
LT1575CN8-3.3
ORDER PART NUMBER
ORDER PART NUMBER
LT1575CS8-3.3
LT1575CN8-3.5
LT1575CS8-3.5
LT1575CN8-5
LT1575CS8-5
157535
15755
157515
157528
157533
ORDER PART NUMBER
LT1577CS-ADJ/ADJ
T
JMAX
= 100°C, θ
JA
= 100°C/W
TOP VIEW
S PACKAGE
16-LEAD PLASTIC NARROW SO
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
SHDN1
V
IN1
GND1
FB1
SHDN2
V
IN2
GND2
FB2
IPOS1
INEG1
GATE1
COMP1
IPOS2
INEG2
GATE2
COMP2
1
2
3
4
8
7
6
5
TOP VIEW
SHDN
V
IN
GND
FB
IPOS
INEG
GATE
COMP
S8 PACKAGE
8-LEAD PLASTIC SO
N8 PACKAGE
8-LEAD PDIP
T
JMAX
= 100°C, θ
JA
= 100°C/ W (N8)
T
JMAX
= 100°C, θ
JA
= 130°C/ W (S8)
LT1575CN8
LT1575CS8
1575
S8 PART MARKING S8 PART MARKING
Consult factory for Industrial and Military grade parts.
ORDER PART NUMBER
LT1577CS-3.3/ADJ
T
JMAX
= 100°C, θ
JA
= 100°C/W
TOP VIEW
S PACKAGE
16-LEAD PLASTIC NARROW SO
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
SHDN1
V
IN1
GND1
OUT-3.3
SHDN2
V
IN2
GND2
FB
IPOS1
INEG1
GATE1
COMP1
IPOS2
INEG2
GATE2
COMP2
ORDER PART NUMBER
LT1577CS-3.3/2.8
T
JMAX
= 100°C, θ
JA
= 100°C/W
TOP VIEW
S PACKAGE
16-LEAD PLASTIC NARROW SO
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
SHDN1
V
IN1
GND1
OUT-3.3
SHDN2
V
IN2
GND2
OUT-2.8
IPOS1
INEG1
GATE1
COMP1
IPOS2
INEG2
GATE2
COMP2
3
LT1575/LT1577
ELECTRICAL CHARACTERISTICS
T
A
= 25°C, V
IN
= 12V, GATE = 6V, IPOS = INEG = 5V, SHDN = 0.75V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
Q
Supply Current ● 51219 mA
V
FB
LT1575 Reference Voltage –0.6 1.210 0.6 %
● –1.0 1.210 1.0 %
V
OUT
LT1575-1.5 Output Voltage –0.6 1.500 0.6 %
● –1.0 1.500 1.0 %
LT1575-2.8 Output Voltage –0.6 2.800 0.6 %
● –1.0 2.800 1.0 %
LT1575-3.3 Output Voltage –0.6 3.300 0.6 %
● –1.0 3.300 1.0 %
LT1575-3.5 Output Voltage –0.6 3.500 0.6 %
● –1.0 3.500 1.0 %
LT1575-5 Output Voltage –0.6 5.000 0.6 %
● –1.0 5.000 1.0 %
Line Regulation 10V ≤ V
IN
≤ 20V ● 0.01 0.03 %/V
I
FB
FB Input Bias Current FB = V
FB
● –0.6 –4.0 µA
I
OUT
OUT Divider Current OUT = V
OUT
● 0.5 1.0 1.5 mA
A
VOL
LT1575 Large-Signal Voltage Gain V
GATE
= 3V to 10V ● 69 84 dB
LT1575-1.5 Large-Signal Voltage Gain V
GATE
= 3V to 10V ● 67 82 dB
LT1575-2.8 Large-Signal Voltage Gain V
GATE
= 3V to 10V ● 60 76 dB
LT1575-3.3 Large-Signal Voltage Gain V
GATE
= 3V to 10V ● 60 75 dB
LT1575-3.5 Large-Signal Voltage Gain V
GATE
= 3V to 10V ● 60 74 dB
LT1575-5 Large-Signal Voltage Gain V
GATE
= 3V to 10V ● 56 71 dB
V
OL
GATE Output Swing Low (Note 3) I
GATE
= 0mA ● 2.5 3.0 V
V
OH
GATE Output Swing High I
GATE
= 0mA ● V
IN
– 1.6 V
IN
– 1 V
IPOS + INEG Supply Current 3V ≤ IPOS ≤ 20V ● 0.3 0.625 1.0 mA
Current Limit Threshold Voltage 42 50 58 mV
● 37 50 63 mV
Current Limit Threshold Voltage 3V ≤ IPOS ≤ 20V ● –0.20 –0.50 %/V
Line Regulation
SHDN Sink Current Current Flows Into Pin ● 2.5 5.0 8.0 µA
SHDN Source Current Current Flows Out of Pin ● –8 –15 –23 µA
SHDN Low Clamp Voltage ● 0.1 0.25 V
SHDN High Clamp Voltage ● 1.50 1.85 2.20 V
SHDN Threshold Voltage ● 1.18 1.21 1.240 V
SHDN Threshold Hysteresis ● 50 100 150 mV
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LT1575CN8: T
J
= T
A
+ (P
D
• 100°CW)
LT1575CS8: T
J
= T
A
+ (P
D
• 130°CW)
LT1577CS: T
J
= T
A
+ (P
D
• 100°CW)
Because the LT1577 consists of two regulators in the package, the total
LT1577 power dissipation must be used for its junction temperature
calculation. The total LT1577 P
D
= P
D
(Regulator 1) + P
D
(Regulator 2).
Note 3: The V
GS(th)
of the external MOSFET must be greater than
3V – V
OUT
.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20

LT1575CN8#PBF

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Buy LT1575CN8#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Linear Voltage Regulators Prec Linear Reg Controller
Lifecycle:
New from this manufacturer.
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