LTC3026-1
1.5A Low Input Voltage
VLDO Linear Regulator
FEATURES
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DESCRIPTION
The LTC
®
3026-1 is a very low dropout (VLDO™) linear
regulator that can operate at input voltages down to
1.14V. The device is capable of supplying 1.5A of output
current with a typical dropout voltage of only 100mV.
Output current comes directly from the input supply to
maximize efficiency.
The LTC3026-1 is the same as the LTC3026 but has the
boost converter internally disabled. With the boost con-
verter disabled, the SW pin of the LTC3026 is replaced with
a ground pin and the BST pin is replaced with a BIAS pin
that requires an external 5V supply for operation.
The LTC3026-1 regulator is stable with 10μF or greater
ceramic output capacitors. The device has a low 0.4V
reference voltage which is used to program the output
voltage via two external resistors. The device also has
internal current limit, overtemperature shutdown, and
reverse output current protection. The LTC3026-1 is avail-
able in a small 10-lead MSOP or low profile (0.75mm)
10-lead 3mm
×
3mm DFN package.
L,
LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and ThinSOT, VLDO are trademarks of Linear Technology Corporation. All other trademarks are
the property of their respective owners.
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Input Voltage Range: 1.14V to 5.5V
Low Dropout Voltage: 100mV at I
OUT
= 1.5A
Adjustable Output Range: 0.4V to 2.6V
Output Current: Up to 1.5A
Excellent Supply Rejection Even Near Dropout
Shutdown Disconnects Load from V
IN
and V
BST
Low Operating Current:
I
IN
= 95μA at V
IN
= 1.5V
I
BIAS
= 175μA at V
BIAS
= 5V
Low Shutdown Current:
I
IN
< 1μA (Typ), I
BST
= 0.1μA (Typ)
Stable with 10μF or Greater Ceramic Capacitors
Short-Circuit, Reverse Current Protected
Overtemperature Protected
Available in 10-Lead MSOP and 10-Lead
(3mm
×
3mm) DFN Packages
APPLICATIONS
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High Efficiency Linear Regulator
Post Regulator for Switching Supplies
Microprocessor Supply
TYPICAL APPLICATION
1.2V Output Voltage from 1.5V Input Supply
150
LTC3026-1
BIAS
V
IN
= 1.5V
1μF
IN
0.4V
1μF
DROPOUT (mV)
V
BIAS
= 5V
100
1.2V
1.5V
2.0V
2.6V
50
Dropout Voltage vs Output Current
+
–
OUT
8.06k
V
OUT
= 1.2V,
1.5A
C
OUT
10μF
100k
4.02k
OFF ON
SHDN
GNDS
GND
ADJ
PG
30261 TA01a
0
0
0.5
I
OUT
(A)
1.0
1.5
30261 TA01b
30261f
1
LTC3026-1
ABSOLUTE MAXIMUM RATINGS
(Note 1)
V
BIAS
to GND................................................ –0.3V to 6V
V
IN
to GND ................................................... –0.3V to 6V
PG to GND ................................................... –0.3V to 6V
SHDN
to GND............................................ –0.3V to 6.3V
ADJ to GND.................................. –0.3V to (V
IN
+ 0.3V)
GND to GNDS............................................ –0.3V to 0.3V
Output Short-Circuit Duration .......................... Indefinite
Operating Junction Temperature Range
(Note 7) ............................................. –40°C to 125°C
Storage Temperature Range .................. –65°C to 125°C
Lead Temperature (MSE, Soldering, 10 sec) ......... 300°C
PIN CONFIGURATION
TOP VIEW
IN
IN
GND
GNDS
BIAS
1
2
3
4
5
11
GND
10 OUT
9 OUT
8 ADJ
7 PG
6
SHDN
TOP VIEW
IN
IN
GND
GNDS
BIAS
1
2
3
4
5
11
GND
10
9
8
7
6
OUT
OUT
ADJ
PG
SHDN
DD PACKAGE
10-LEAD (3mm 3mm) PLASTIC DFN
MSE PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
T
JMAX
= 125°C,
θ
JA
= 40°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3026EDD-1#PBF
LTC3026IDD-1#PBF
LTC3026EMSE-1#PBF
LTC3026IMSE-1#PBF
TAPE AND REEL
LTC3026EDD-1#TRPBF
LTC3026IDD-1#TRPBF
LTC3026EMSE-1#TRPBF
LTC3026IMSE-1#TRPBF
PART MARKING*
LGHG
LGHG
LTGHH
LTGHH
PACKAGE DESCRIPTION
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead Plastic MSOP
10-Lead Plastic MSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
30261f
2
LTC3026-1
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IN
I
IN
V
BIAS
I
BIAS
V
ADJ
OUT
I
ADJ
I
OUT
I
LIM
e
n
V
IHSHDN
V
ILSHDN
I
IHSHDN
I
ILSHDN
V
OLPG
I
OHPG
PG
PARAMETER
Operating Voltage
Operating Current
Shutdown Current
V
BIASUVLO
BIAS Undervoltage Lockout
BIAS Operating Current
BIAS Shutdown Current
Regulation Voltage (Note 4)
Programming Range
Dropout Voltage (Note 5)
ADJ Input Current
Continuous Output Current
Output Current Current Limit
Output Voltage Noise
SHDN
Input High Voltage
SHDN
Input Low Voltage
SHDN
Input High Current
SHDN
Input Low Current
PG Output Low Voltage
PG Output High Leakage
Current
Output Threshold (Note 3)
f = 10Hz to 100kHz, I
L
= 800mA
1.14V ≤ V
IN
≤ 3.5V
3.5V ≤ V
IN
≤ 5.5V
1.14V ≤ V
IN
≤ 5.5V
SHDN
= V
IN
SHDN
= 0V
I
PG
= 2mA
V
PG
= 5.5V
PG High to Low
PG Low to High
–12
–10
l
l
l
l
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
J
= 25°C. (Note 7) V
IN
= 1.5V, V
OUT
= 1.2V, V
BIAS
= 5V, C
IN
= C
BIAS
= 1μF
,
C
OUT
= 10μF (all capacitors ceramic) unless otherwise noted.
CONDITIONS
(Note 2)
I
OUT
= 100μA, V
SHDN
= V
IN
, 1.2V ≤ V
IN
≤ 5V
V
SHDN
= 0V, V
IN
= 3.5V
l
l
l
l
l
MIN
1.14
TYP
95
0.6
MAX
5.5
200
20
5.5
4.4
275
5
0.403
0.405
2.6
250
100
UNITS
V
μA
μA
V
V
μA
μA
V
V
V
mV
nA
A
A
μV
RMS
V
V
BIAS Operating Voltage (Note 6) V
SHDN
= V
IN
I
OUT
= 100μA, V
SHDN
= V
IN
V
SHDN
= 0V
4.5
4.0
5
4.25
175
1
l
1mA ≤ I
OUT
≤ 1.5A, 1.14V ≤ V
IN
≤ 3.5V, V
BST
= 5V, V
OUT
= 0.8V
1mA ≤ I
OUT
≤ 1.5A, 1.14V ≤ V
IN
≤ 3.5V, V
BST
= 5V, V
OUT
= 0.8V
l
l
0.397
0.395
0.4
0.4
0.4
100
V
IN
= 1.5V, V
ADJ
= 0.38, I
OUT
= 1.5A
V
ADJ
= 0.4V
V
SHDN
= V
IN
l
l
l
–100
1.5
3
110
1.0
1.2
0.4
–1
–1
0.1
0.01
–9
–7
1
1
0.4
1
–6
–4
V
μA
μA
V
μA
%
%
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime. This IC has overtemperature protection that is
intended to protect the device during momentary overload conditions.
Junction temperatures will exceed 125°C when overtemperature is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 2:
Minimum Operating Voltage required for regulation is:
V
IN
≥ V
OUT(MIN)
+ V
DROPOUT
Note 3:
PG threshold expressed as a percentage difference from the
“V
ADJ
Regulation Voltage” as given in the table.
Note 4:
Operating conditions are limited by maximum junction
temperature. The regulated output voltage specification will not apply
for all possible combinations of input voltage and output current. When
operating at maximum input voltage, the output current range must be
limited. When operating at maximum output current, the input voltage
range must be limited.
Note 5:
Dropout voltage is minimum input to output voltage differential
needed to maintain regulation at a specified output current. In dropout, the
output voltage will be equal to V
IN
– V
DROPOUT
.
Note 6:
To maintain correct regulation
V
OUT
≤ V
BIAS
– 2.4V
Note 7:
The LTC3026-1 is tested under pulsed load conditions such
that T
J
≈ T
A
. The LTC3026E-1 is guaranteed to meet specifications from
0°C to 125°C junction temperature. Specifications over the –40°C to
125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3026I-1 is guaranteed over the –40°C to 125°C operating junction
temperature range. Note that the maximum ambient temperature
consistent with these specifications is determined by specific operating
conditions in conjunction with board layout, the rated package thermal
impedance and other environmental factors. The junction temperature
(T
J
, in °C) is calculated from the ambient temperature (T
A
, in °C) and
power dissipation (PD, in Watts) according to the formula:
T
J
= T
A
+ (PD •
θ
JA
), where
θ
JA
(in °C/W) is the package thermal
impedance.
30261f
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LTC3026-1
TYPICAL PERFORMANCE CHARACTERISTICS
BIAS Supply Current
200
200
IN Supply Current
404
403
ADJUST VOLTAGE (mV)
ADJ Voltage vs Temperature
150
I
BIAS
(μA)
I
IN
(μA)
150
402
401
400
399
398
397
396
–50
–25
0
25
50
V
BIAS
= 5V
V
IN
= 1.5V
V
OUT
=1.2V
75
TEMPERATURE (°C)
100
125
30261 G03
1mA
1.5A
100
100
V
BST
==5V
BIAS
5V
125°C
85°C
25°C
–40°C
50
V
BIAS
= 5V
125°C
85°C
25°C
–40°C
50
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
V
IN
(V)
30261 G01
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
V
IN
(V)
30261 G02
IN Shutdown Current
5.0
4.5
4.0
INPUT CURRENT (μA)
DROPOUT (mV)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
–50
2.5V
1.2V
–25
0
25
50
75
TEMPERATURE (°C)
100
125
3.5V
200
Dropout Voltage vs Input Voltage
60
V
FB
= 0.38V
180 I
OUT
=1.5A
160
140
120
100
80
60
40
20
0
1.2
1.4
1.6
1.8
2.0
2.2
125°C
85°C
25°C
–40°C
2.4
2.6
30261 G05
V
IN
Ripple Rejection
10kHz
50
RIPPLE REJECTION (dB)
1MHz
40
100kHz
30
20
10
0
1.2
V
BIAS
= 5V
V
OUT
=1.2V
I
OUT
= 800mA
C
OUT
= 10μF
1.4
1.6
1.8 2.0
V
IN
(V)
2.2
2.4
2.6
30261 G06
30261 G04
V
IN
(V)
V
IN
Ripple Rejection
70
60
V
SHDN
THRESHOLD (mV)
RIPPLE REJECTION (dB)
50
40
30
20
10
0
100
V
BIAS
= 5V
V
IN
= 1.5V
V
OUT
=1.2V
I
OUT
= 800mA
C
OUT
= 10μF
1000
100000 1000000 1E+07
FREQUENCY (Hz)
30261 G07
Shutdown Threshold
1200
RISE
RISE
FALL
FALL
RISE
FALL
5.0
4.5
4.0
3.5
I
OUT
(A)
3.0
2.5
Output Current Limit
V
OUT
= 0V
T
A
= 25°C
900
600
125°C
25°C
–40°C
300
1
2
3
V
IN
(V)
4
5
6
30261 G08
CURRENT LIMIT
2.0
1.5
1.0
1.0
1.5
2.0
THERMAL LIMIT
10000
2.5
V
IN
(V)
3.0
3.5
30261 G09
30261f
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LTC3026-1
TYPICAL PERFORMANCE CHARACTERISTICS
BIAS to OUT Headroom Voltage
2.22
2.20
2.18
V
BIAS
– V
OUT
(V)
2.16
DELAY (μs)
2.14
2.12
2.10
2.08
2.06
2.04
2.02
–50
–25
50
25
0
75
TEMPERATURE (°C)
100
125
250
375
350
325
300
275
400
Delay from Enable to PG
V
OUT
= 0.8V
R
OUT
= 8Ω
85°C
25°C
–40°C
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
V
IN
(V)
30261 G11
30261 G10
Output Load Transient Response
1.5A
I
OUT
2mA
V
IN
OUT
AC 20mV/DIV
2V
1.5V
IN Supply Transient Response
V
OUT
AC
10mV/DIV
V
OUT
= 1.5V
C
OUT
= 10μF
V
IN
= 1.7V
V
BIAS
= 5V
50μs/DIV
30261 G12
V
OUT
= 1.2V
I
OUT
= 800mA
C
OUT
= 10μF
V
BIAS
= 5V
T
A
= 25°C
10μs/DIV
30261 G13
30261f
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