LTC3025-4 Linear Technology, LTC3025-4 Datasheet

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LTC3025-4

Manufacturer Part Number
LTC3025-4
Description
500mA Micropower VLDO Linear Regulators
Manufacturer
Linear Technology
Datasheet
FEATURES
APPLICATIONS
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TYPICAL APPLICATION
3-CELL
Li-Ion
NiMH
OR
Wide Input Voltage Range: 0.9V to 5.5V
Stable with Ceramic Capacitors
Very Low Dropout: 85mV at 500mA
Adjustable Output Range: 0.4V to 3.6V (LTC3025-1)
Fixed Output: 1.2V(LTC3025-2), 1.5V(LTC3025-3),
1.8V(LTC3025-4)
±2% Voltage Accuracy over Temperature,
Supply and Load
Low Noise: 80μV
BIAS Voltage Range: 2.5V to 5.5V
Fast Transient Recovery
Shutdown Disconnects Load from V
Low Operating Current: I
Low Shutdown Current: I
Output Current Limit
Thermal Overload Protection
Available in 6-Lead (2mm × 2mm) DFN Package
Low Power Handheld Devices
Low Voltage Logic Supplies
DSP Power Supplies
Cellular Phones
Portable Electronic Equipment
Handheld Medical Instruments
Post Regulator for Switching Supply Noise Rejection
EFFICIENCY
1.5V HIGH
DC/DC
BUCK
1.2V Output Voltage from 1.5V Input Supply
1.5V
RMS
OFF ON
0.1μF
0.1μF
(10Hz to 100kHz)
IN
IN
BIAS
IN
SHDN
= 4μA, I
= 1μA, I
LTC3025-2
SENSE
GND
OUT
BIAS
BIAS
IN
and V
= 50μA Typ
= 0.01μA Typ
30251234 TA01
BIAS
1μF
V
I
OUT
OUT
≤ 500mA
= 1.2V
DESCRIPTION
The LTC
out) linear regulator which operates from input voltages as
low as 0.9V. The device is capable of supplying 500mA of
output current with a typical dropout voltage of only 85mV.
A BIAS supply is required to run the internal reference and
LDO circuitry while output current comes directly from the
IN supply for high effi ciency regulation. The LTC3025-1
features an adjustable output with a low 0.4V reference
while the LTC3025-2, LTC3025-3, and LTC3025-4 have
fi xed 1.2V, 1.5V and 1.8V output voltages respectively.
The LTC3025-X’s low quiescent current makes it an ideal
choice for use in battery-powered systems. For 3-cell NiMH
and single cell Li-Ion applications, the BIAS voltage can
be supplied directly from the battery while the input can
come from a high effi ciency buck regulator, providing a
high effi ciency, low noise output.
Other features include high output voltage accuracy,
excellent transient response, stability with ultralow ESR
ceramic capacitors as small as 1μF , short-circuit and
thermal overload protection and output current limiting.
The LTC3025-X is available in a tiny, low profi le (0.75mm)
6-lead DFN (2mm × 2mm) package.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
VLDO is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 7224204, 7218082.
VLDO Linear Regulators
®
3025-X is a micropower, VLDO™ (very low drop-
LTC3025-1/LTC3025-2/
LTC3025-3/LTC3025-4
50
45
40
35
30
25
20
15
10
500mA Micropower
5
0
1.2
1MHz V
BIAS = 3.6V
V
OUT
1.4
= 1.2V
IN
1.6
Supply Rejection
C
C
OUT
1.8
OUT
V
IN
= 10μF
= 1μF
(V)
2.0
www.DataSheet4U.com
I
I
2.2
OUT
OUT
= 100mA
= 300mA
30251234 TA01b
2.4
2.6
30251234fc
1

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LTC3025-4 Summary of contents

Page 1

... LDO circuitry while output current comes directly from the IN supply for high effi ciency regulation. The LTC3025-1 features an adjustable output with a low 0.4V reference while the LTC3025-2, LTC3025-3, and LTC3025-4 have fi xed 1.2V, 1.5V and 1.8V output voltages respectively. The LTC3025-X’s low quiescent current makes it an ideal ...

Page 2

... LTC3025-4 2 PIN CONFIGURATION + 0. EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB *ADJ FOR LTC3025-1, SENSE FOR LTC3025-2, LTC3025-3, LTC3025-4 PART MARKING* PACKAGE DESCRIPTION 6-Lead (2mm × 2mm) Plastic DFN LDDW 6-Lead (2mm × 2mm) Plastic DFN LDDW 6-Lead (2mm × 2mm) Plastic DFN LDMK 6-Lead (2mm × ...

Page 3

... LTC3025-4 OUT IN ≤ 500mA, 2.0V ≤ V ≤ 5V, LTC3025-4 OUT IN = 0.45V, LTC3025-1 ADJ = 1mA to 500mA, LTC3025-1 OUT = 1mA to 500mA, LTC3025-2 OUT = 1mA to 500mA, LTC3025-3 OUT = 1mA to 500mA, LTC3025-4 OUT = 1. 3.6V 1.2V, IN BIAS OUT = 1mA, LTC3025-1 OUT = 1. 3.6V 1mA, LTC3025-2 IN BIAS OUT = 1 ...

Page 4

... Note 4: For the LTC3025-1, a regulated output voltage will only be available when the minimum IN and BIAS operating voltages as well as the IN to OUT and BIAS to OUT dropout voltages are all satisfi ed. For the LTC3025-2/LTC3025-3/LTC3025-4 the minimum IN operating voltage assumes I OUT ...

Page 5

... OUT 3.6V BIAS 1.2V OUT I = 100mA OUT 0 10M 100 1k 10k 100k 1M FREQUENCY (Hz) LTC3025-1/LTC3025-2/ LTC3025-3/LTC3025-4 www.DataSheet4U.com (T = 25°C unless otherwise noted) A Adjust Voltage vs Temperature 405 V = 3.6V BIAS 404 10μA OUT 403 402 401 400 399 398 397 396 395 5 ...

Page 6

... The output voltage range is 0.4V to 3.6V and is typically set by connecting ADJ to a resistor divider from OUT to GND. See Figure 2. SENSE (Pin 5) LTC3025-2, LTC3025-3, LTC3025-4: Out- put Sense. The sense is the input to the resistor divider driving the error amplifi er. Optimum regulation will be obtained at the point where SENSE is connected to OUT. The SENSE pin bias current is 10μ ...

Page 7

... A low reference voltage allows the LTC3025-1 output to be programmed to much lower voltages than available in common LDOs (range of 0. 6V). The LTC3025-2/LTC3025-3/LTC3025-4 have fi xed outputs of 1.2V, 1.5V and 1.8V respectively, eliminating the need for an external resistor divider. As shown in the Block Diagram, the BIAS input supplies the internal reference and LDO circuitry while all output current comes directly from the IN input for high effi ...

Page 8

... LTC3025-1/LTC3025-2/ LTC3025-3/LTC3025-4 APPLICATIONS INFORMATION in R1 should be at least 8μA, thus the value of R1 should be no greater than 50k. The current the current in R1 plus the ADJ pin bias current. Since the ADJ pin bias current is typically <10nA, it can be ignored in the output voltage calculation ...

Page 9

... When soldered to 2500mm double-sided 1 oz. copper plane, the actual junction-to- ambient thermal resistance can be less than 60°C/W. LTC3025-1/LTC3025-2/ LTC3025-3/LTC3025-4 Calculating Junction Temperature Example: Given an output voltage of 1.2V, an input voltage of 1.8V to 3V, an output current range of 0mA to 100mA and a maximum ambient temperature of 50° ...

Page 10

... LTC3025-1/LTC3025-2/ LTC3025-3/LTC3025-4 APPLICATIONS INFORMATION shutdown without latch-up or damage until the overstress condition is removed. Long term overstress (T should be avoided as it can degrade the performance or shorten the life of the part. Soft-Start Operation The LTC3025-X includes a soft-start feature to prevent excessive current fl ow during start-up. When the LDO is enabled, the soft-start circuitry gradually increases the LDO reference voltage from ...

Page 11

... LTC3025-1/LTC3025-2/ DC Package 6-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1703) 0.675 ±0.05 PIN 1 BAR PACKAGE TOP MARK OUTLINE (SEE NOTE 6) 0.25 ± 0.05 0.75 ±0.05 0.200 REF LTC3025-3/LTC3025-4 www.DataSheet4U.com R = 0.115 0.38 ± 0.05 TYP 0.56 ± 0. SIDES) 2.00 ±0.10 (4 SIDES) PIN 1 CHAMFER OF EXPOSED PAD ...

Page 12

... LTC3025-1/LTC3025-2/ LTC3025-3/LTC3025-4 RELATED PARTS PART NUMBER DESCRIPTION ® LT 1129 700mA, Micropower, LDO LT1175 500mA, Micropower, Negative LDO LT1185 3A, Negative LDO LT1761 100mA, Low Noise Micropower, LDO LT1762 150mA, Low Noise Micropower LDO LT1763 500mA, Low Noise Micropower LDO LT1764/LT1764A ...

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