LTC3026
1.5A Low Input Voltage
VLDO Linear Regulator
FeaTures
n
DescripTion
The LTC
®
3026 is a very low dropout (VLDO™) linear regula-
tor 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. To allow opera-
tion at low input voltages the LTC3026 includes a boost
converter that provides the necessary headroom for the
internal LDO circuitry.
Output current comes directly from the input supply to
maximize efficiency. The boost converter requires only a
small chip inductor and ceramic capacitor for operation.
Additionally, the boosted output voltage of one LTC3026
can supply the boost voltage for other LTC3026s, thus
requiring a single inductor for multiple LDOs. A user sup-
plied boost voltage can be used eliminating the need for
an inductor altogether.
The LTC3026 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 is avail-
able in a small 10-lead MSOP or low profile (0.75mm)
10-lead 3mm
×
3mm DFN package.
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Input Voltage Range:
1.14V to 3.5V (with Boost Enabled)
1.14V to 5.5V (with External 5V Boost)
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
= 950µA at V
IN
= 1.5V
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
n
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High Efficiency Linear Regulator
Post Regulator for Switching Supplies
Microprocessor Supply
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.
Typical applicaTion
1.2V Output Voltage from 1.5V Input Supply
150
L1
10µH
5V BOOST BST
CONVERTER
IN
4.7µF
0.4V
SW
Dropout Voltage vs Output Current
4.7µF
DROPOUT (mV)
100
V
IN
= 1.5V
+
–
1.2V
1.5V
2.0V
2.6V
OUT
8.06k
V
OUT
= 1.2V,
1.5A
C
OUT
10µF
50
OFF ON
SHDN
LTC3026
GND
ADJ
100k
PG
4.02k
3026 TA01a
0
0
0.5
I
OUT
(A)
1.0
1.5
3026 TA01b
L1: MURATA LQH2MCN100K02
3026ff
1
LTC3026
absoluTe MaxiMuM raTings
(Note 1)
V
BST
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)
Output Short-Circuit Duration .......................... Indefinite
Operating Junction Temperature Range
(Note 8) ............................................. –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
SW
BST
1
2
3
4
5
11
GND
10 OUT
9 OUT
8 ADJ
7 PG
6
SHDN
TOP VIEW
IN
IN
GND
SW
BST
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
T
JMAX
= 125°C,
θ
JA
= 40°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
MSE PACKAGE
10-LEAD PLASTIC MSOP
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#PBF
LTC3026IDD#PBF
LTC3026EMSE#PBF
LTC3026IMSE#PBF
LEAD BASED FINISH
LTC3026EDD
LTC3026IDD
LTC3026EMSE
LTC3026IMSE
TAPE AND REEL
LTC3026EDD#TRPBF
LTC3026IDD#TRPBF
LTC3026EMSE#TRPBF
LTC3026IMSE#TRPBF
TAPE AND REEL
LTC3026EDD#TR
LTC3026IDD#TR
LTC3026EMSE#TR
LTC3026IMSE#TR
PART MARKING
LBHW
LBHW
LTBJB
LTBJB
PART MARKING
LBHW
LBHW
LTBJB
LTBJB
PACKAGE DESCRIPTION
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead Plastic MSOP
10-Lead Plastic MSOP
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
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.
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/
3026ff
2
LTC3026
elecTrical characTerisTics
SYMBOL
V
IN
I
IN
PARAMETER
Operating Voltage
Operating Current
(BOOST ENABLED, L
SW
= 10µH)
The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at
T
J
= 25°C. V
IN
= 1.5V, V
OUT
= 1.2V, C
IN
= C
BST
= 4.7µF C
OUT
= 10µF (all capacitors ceramic) unless otherwise noted.
,
CONDITIONS
(Note 2)
I
OUT
= 0mA, V
OUT
= 0.8V, V
SHDN
= V
IN
, V
IN
= 1.2V
I
OUT
= 0mA, V
OUT
= 1.2V, V
SHDN
= V
IN
, V
IN
= 1.5V
I
OUT
= 0mA, V
OUT
= 1.2V, V
SHDN
= V
IN
, V
IN
= 2.5V
I
OUT
= 0mA, V
OUT
= 1.2V, V
SHDN
= V
IN
, V
IN
= 3.5V
V
SHDN
= 0V, V
IN
= 3.5V
l
l
MIN
1.14
TYP
1160
950
640
400
0.6
MAX
3.5
UNITS
V
µA
µA
µA
µA
I
INSHDN
Shutdown Current
Inductor Size Requirement
Inductor Peak Current Requirement
20
40
5.2
4.4
µA
µH
mA
V
V
mA
mA
4.7
150
V
SHDN
= V
IN
l
10
5
4.2
7
10
V
BST
V
BSTUVLO
Boost Output Voltage Range
Boost Undervoltage Lockout
Boost Output Drive (Note 3)
4.8
4.0
V
IN
< 1.4V
V
IN
≥ 1.4V
(BOOST DISABLED, V
SW
= 0V or Floating)
The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at
T
J
= 25°C. V
IN
= 1.5V, V
OUT
= 1.2V, V
BST
= 5V, C
IN
= C
BST
= 1µF C
OUT
= 10µF (all capacitors ceramic) unless otherwise noted.
,
SYMBOL
V
IN
I
IN
I
INSHDN
V
BST
V
BSTUVLO
I
BST
I
BSTSHDN
PARAMETER
Operating Voltage
Operating Current
Shutdown Current
Boost Operating Voltage (Note 7)
Undervoltage Lockout
Boost Operating Current
Boost Shutdown Current
I
OUT
= 100µA, V
SHDN
= V
IN
V
SHDN
= 0V
CONDITIONS
(Note 2)
I
OUT
= 100µA, V
SHDN
= V
IN
, 1.2V ≤ V
IN
≤ 5V
V
SHDN
= 0V, V
IN
= 3.5V
V
SHDN
= V
IN
l
l
l
l
l
l
MIN
1.14
TYP
95
0.6
MAX
5.5
200
20
5.5
4.4
275
5
UNITS
V
µA
µA
V
V
µA
µA
4.5
4.0
5
4.25
175
1
(BOOST ENABLED or DISABLED)
The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at
T
J
= 25°C. V
IN
= 1.5V, V
OUT
= 1.2V, C
IN
= C
BST
= 1µF C
OUT
= 10µF (all capacitors ceramic) unless otherwise noted.
,
SYMBOL PARAMETER
V
ADJ
OUT
I
ADJ
I
OUT
I
LIM
e
n
Regulation Voltage (Note 5)
Programming Range
Dropout Voltage (Note 6)
ADJ Input Current
Continuous Output Current
Output Current Current Limit
Output Voltage Noise
f = 10Hz to 100kHz, I
L
= 800mA
Boost Disabled
Boost Enabled
V
IN
= 1.5V, V
ADJ
= 0.38, I
OUT
= 1.5A
V
ADJ
= 0.4V
V
SHDN
= V
IN
CONDITIONS
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
l
l
l
MIN
0.397
0.395
0.4
TYP
0.4
0.4
100
MAX
0.403
0.405
2.6
250
100
UNITS
V
V
V
mV
nA
A
A
µV
RMS
µV
RMS
–100
1.5
3
110
210
3026ff
3
LTC3026
elecTrical characTerisTics
SYMBOL PARAMETER
V
IHSHDN
V
ILSHDN
I
IHSHDN
I
ILSHDN
V
OLPG
I
OHPG
PG
SHDN
Input High Voltage
SHDN
Input Low Voltage
SHDN
Input High Current
SHDN
Input Low Current
PG Output Low Voltage
Output Threshold (Note 4)
CONDITIONS
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
PG High to Low
PG Low to High
l
l
l
l
(BOOST ENABLED or DISABLED)
The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at
T
J
= 25°C. V
IN
= 1.5V, V
OUT
= 1.2V, C
IN
= C
BST
= 1µF C
OUT
= 10µF (all capacitors ceramic) unless otherwise noted.
,
MIN
1.0
1.2
0.4
–1
–1
0.1
0.01
–12
–10
–9
–7
1
1
0.4
1
–6
–4
TYP
MAX
UNITS
V
V
V
µA
µA
V
µA
%
%
PG Output High Leakage Current V
PG
= 5.5V
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:
When using BST to drive loads other than LTC3026s, the load
must be high impedance during start-up (i.e. prior to PG going high).
Note 4:
PG threshold expressed as a percentage difference from the
“V
ADJ
Regulation Voltage” as given in the table.
Note 5:
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 6:
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 7:
To maintain correct regulation
V
OUT
≤ V
BST
– 2.4V
Note 8:
The LTC3026 is tested under pulsed load conditions such
that T
J
≈ T
A
. The LTC3026E 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 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 (P
D
, in watts) according to the formula:
T
J
= T
A
+ (P
D
•
θ
JA
), where
θ
JA
(in °C/W) is the package thermal
impedance.
Typical perForMance characTerisTics
IN Supply Current with Boost
Converter Enabled
1.50
1.25
INPUT CURRENT (mA)
150
1.00
I
BST
(µA)
0.75
0.50
0.25
0
–40°C
25°C
85°C
1.0
1.5
2.0
2.5
V
IN
(V)
3.0
3.5
3026 G01
BST Supply Current with Boost
Converter Disabled
200
200
IN Supply Current with Boost
Converter Disabled
150
I
IN
(µA)
100
V
BST
= 5V
–40°C
25°C
85°C
125°C
100
V
BST
= 5V
–40°C
25°C
85°C
125°C
50
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)
3026 G02
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
V
IN
(V)
3026 G03
3026ff
4
LTC3026
Typical perForMance characTerisTics
ADJ Voltage vs Temperature
404
403
ADJUST VOLTAGE (mV)
INPUT CURRENT (µA)
402
401
400
399
398
397
396
–50
–25
0
25
50
V
BST
= 5V
V
IN
= 1.5V
V
OUT
=1.2V
75
TEMPERATURE (°C)
100
125
3026 G04
IN Shutdown Current
5.0
4.5
4.0
BST VOLTAGE (V)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
–50
2.5V
–25
0
25
50
75
TEMPERATURE (°C)
1.2V
100
125
3026 G05
BST Voltage vs Temperature
5.050
V
IN
= 1.5V
5.025
1mA
1.5A
5.000
3.5V
4.975
4.950
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
3026 G06
Dropout Voltage vs Input Voltage
200
V
FB
= 0.38V
180 I
OUT
=1.5A
160
RIPPLE REJECTION (dB)
DROPOUT (mV)
140
120
100
80
60
40
20
0
1.2
1.4
1.6
1.8
2.0
2.2
–40°C
25°C
85°C
125°C
2.4
2.6
3026 G07
Ripple Rejection
60
10kHz
50
40
30
20
10
0
1.2
V
BST
= 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
3026 G08
Ripple Rejection
70
60
RIPPLE REJECTION (dB)
50
40
30
20
10
0
100
1000
10000
V
BST
= 5V
V
IN
= 1.5V
V
OUT
=1.2V
I
OUT
= 800mA
C
OUT
= 10µF
100000 1000000 1E+07
FREQUENCY (Hz)
3026 G09
1MHz
100kHz
V
IN
(V)
Shutdown Threshold
1200
RISE
RISE
FALL
FALL
RISE
FALL
600
–40°C
25°C
125°C
1
2
3
V
IN
(V)
4
5
6
3026 G10
Output Current Limit
5.0
4.5
4.0
3.5
I
OUT
(A)
3.0
2.5
2.0
1.5
1.0
1.0
1.5
2.0
CURRENT LIMIT
THERMAL LIMIT
V
BST
– V
OUT
(V)
V
OUT
= 0V
T
A
= 25°C
2.22
2.20
2.18
2.16
2.14
2.12
2.10
2.08
2.06
2.04
2.5
V
IN
(V)
3.0
3.5
3026 G11
BST to OUT Headroom Voltage
V
SHDN
THRESHOLD (mV)
900
300
2.02
–50
–25
50
25
0
75
TEMPERATURE (°C)
100
125
3026 G12
3026ff
5
