1
LTC1515 Series
Step-Up/Step-Down
Switched Capacitor DC/DC
Converters with Reset
Daisy-Chained Control Outputs
FEATURES
The LTC
1515, LTC1515-3/5 and LTC1515-3.3/5 are
micropower switched capacitor DC/DC converters that
produce a regulated output voltage by either stepping up
or stepping down the input voltage. Output voltage is
adjustable using an external resistor divider (LTC1515) or
programmable to either 3V/5V (LTC1515-3/5) or 3.3V/5V
(LTC1515-3.3/5) using a logic pin.
A unique architecture allows the parts to accommodate a
wide input voltage range (2V to 10V) while maintaining
4% regulation. Additional circuitry prevents excessive
inrush current and output voltage ripple when large V
IN
to
V
OUT
differentials are present.
An internal power-on reset circuit forces the POR pin low
on initial power-up. The POR output remains low until
200ms (typ) after V
OUT
is in regulation.
The parts are short-circuit and overtemperature protected.
Battery life is maximized by very low operating currents
(I
CC
= 60
A typ, I
CC
< 1
A in shutdown). All three parts are
available in an SO-8 package.
DESCRIPTIO
N
U
s
Adjustable/Selectable 3V, 3.3V or 5V
Output Voltages
s
2V to 10V Input Voltage Range
s
Up to 50mA Output Current
s
Only Three External Capacitors Required
s
Soft Start Limits Inrush Current at Turn-On
s
Low Operating Current: 60
A
s
Very Low Shutdown Current: < 1
A
s
Shutdown Disconnects Load from V
IN
s
V
OUT
Programmable to 3V/5V or 3.3V/5V
s
Short-Circuit and Overtemperature Protected
s
650kHz Switching Frequency
s
Open-Drain Power-On Reset Output
s
Available in SO-8 Package
TYPICAL APPLICATIO
N
U
APPLICATIO
N
S
U
s
SIM Interface in GSM Cellular Telephones
s
Smart Card Readers
s
Local Power Supplies
s
Portable Equipment
, LTC and LT are registered trademarks of Linear Technology Corporation.
Programmable 3.3V/5V Power Supply with Power-On Reset
SHDN
POR
GND
5/3
V
OUT
V
IN
C1
C1
+
LTC1515-3.3/5
1
2
3
4
8
7
6
5
0.22
F
10
F
10
F
V
IN
4-CELL
NiCd
100k
V
OUT
= 3.3V OR 5V
I
OUT
= 50mA
ON OFF
RESET
5V 3.3V
LTC1515 TA01
+
+
LTC1515-X 5V Output vs Input Voltage
INPUT VOLTAGE (V)
2
OUTPUT VOLTAGE (V)
10
LT1515 TA02
4
6
8
3
5
7
9
5.2
5.1
5.0
4.9
4.8
I
OUT
= 10mA
5/3 = 3V
2
LTC1515 Series
ABSOLUTE
M
AXI
M
U
M
RATINGS
W
W
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(Note 1)
V
IN
to GND ................................................ 0.3V to 12V
V
OUT
to GND ............................................. 0.3V to 12V
SHDN, 5/3, FB to GND .............................. 0.3V to 12V
V
OUT
Short-Circuit Duration ............................. Indefinite
Operating Temperature Range
Commercial ............................................. 0
C to 70
C
Industrial ............................................ 40
C to 85
C
Storage Temperature Range ................ 65
C to 150
C
Lead Temperature (Soldering, 10 sec)................. 300
C
W
U
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PACKAGE/ORDER I FOR ATIO
ORDER PART NUMBER
ORDER PART
NUMBER
S8 PART MARKING
LTC1515CS8-3/5
LTC1515CS8-3.3/5
LTC1515IS8-3/5
LTC1515IS8-3.3/5
151535
515335
515I35
15I335
T
JMAX
= 125
C,
JA
= 110
C/W
1
2
3
4
8
7
6
5
TOP VIEW
V
OUT
V
IN
C1
+
C1
SHDN
POR
5/3
GND
S8 PACKAGE
8-LEAD PLASTIC SO
LTC1515CS8
LTC1515IS8
S8 PART MARKING
1515
1515I
T
JMAX
= 125
C,
JA
= 110
C/W
1
2
3
4
8
7
6
5
TOP VIEW
V
OUT
V
IN
C1
+
C1
SHDN
POR
FB
GND
S8 PACKAGE
8-LEAD PLASTIC SO
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
V
IN
= 2V to 10V, SHDN = 3V, C1 = 0.22
F, C
IN
= C
OUT
= 10
F unless otherwise noted (Note 2).
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IN
Operating Voltage
V
OUT
= 5V
q
2.7
10
V
V
OUT
= 3V/3.3V
q
2.0
8
V
V
OUT
= ADJ
q
2.0
10
V
V
OUT
= 3V (LTC1515-3/5)
2V
V
IN
8V, I
OUT
15mA
q
2.88
3.0
3.12
V
3V
V
IN
8V, I
OUT
50mA
q
2.88
3.0
3.12
V
V
OUT
= 3.3V (LTC1515-3.3/5)
2V
V
IN
8V, I
OUT
15mA
q
3.17
3.3
3.43
V
3V
V
IN
8V, I
OUT
50mA
q
3.17
3.3
3.43
V
V
OUT
= 5V (LTC1515-3/5, LTC1515-3.3/5)
2.7V
V
IN
10V, I
OUT
15mA
q
4.8
5.0
5.2
V
3.3V
V
IN
10V, I
OUT
50mA
q
4.8
5.0
5.2
V
V
FB
Feedback Voltage
LTC1515, V
FB
Ramping Negative
q
1.190
1.232
1.275
V
V
FB
Feedback Hysteresis
LTC1515
1
%
Effective Output Resistance
LTC1515, V
IN
= 3V, Step-Up Mode
q
30
V
IN
Operating Current
V
IN
5V, I
OUT
= 0, SHDN = 3V
q
60
100
A
V
IN
> 5V, I
OUT
= 0, SHDN = 3V
q
75
135
A
V
IN
Shutdown Current
SHDN = 0V, V
IN
5V
q
1
A
SHDN = 0V, V
IN
> 5V
25
A
Output Ripple
Full Load (Note 2)
100
mV
P-P
Switching Frequency
Full Load
q
500
650
800
kHz
5/3, SHDN Input Threshold
V
IL
q
0.4
1.0
V
V
IH
q
1.0
1.6
V
5/3, SHDN Input Current
5/3, SHDN = V
IN
q
1
1
A
5/3, SHDN = 0V
q
1
1
A
FB Input Current
FB = 1.232V
q
50
50
nA
POR Output Low Voltage
I
SINK
= 100
A, V
IN
= 3V
q
0.05
0.4
V
3
LTC1515 Series
LTC1515-X 3.3V Output Voltage
vs Input Voltage
INPUT VOLTAGE (V)
0
OPERATING CURRENT (
A)
120
100
80
60
40
20
8
1515 G06
2
4
6
10
85
C
40
C
25
C
V
OUT
= 5V
I
OUT
= 0mA
LTC1515-X Operating Current
vs Input Voltage
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
LTC1515-X
5V Efficiency vs Output Current
OUTPUT CURRENT (mA)
EFFICIENCY (%)
0.01
1
10
1515 G02
0.1
100
100
80
60
40
20
0
V
OUT
= 5V
T
A
= 25
C
V
IN
= 8V
V
IN
= 3.3V
V
IN
= 6V
V
IN
= 2.7V
LTC1515-X 3.3V Output Voltage
Ripple vs Input Voltage
ELECTRICAL CHARACTERISTICS
V
IN
= 2V to 10V, SHDN = 3V, C1 = 0.22
F, C
IN
= C
OUT
= 10
F unless otherwise noted (Note 2).
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
POR Leakage Current
V
POR
= 5V
q
1
1
A
POR Trip Point (With Respect to V
OUT
)
V
OUT
Ramping Negative
q
10
7.5
5
%
POR Trip Point Hysteresis
1
%
I
OUT
Short-Circuit Current
V
OUT
= 0V
q
12
40
mA
t
ON
Soft Start Turn-On Time
4
ms
POR Delay
After V
OUT
Above POR Threshold
q
140
200
280
ms
The
q
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: For V
IN
8V, C
OUT
= 22
F.
INPUT VOLTAGE (V)
0
OUTPUT VOLTAGE RIPPLE (mV
P-P
)
250
200
150
100
50
0
8
1515 G03
2
4
6
10
V
OUT
= 3.3V
I
OUT
= 10mA
T
A
= 25
C
C
OUT
= 10
F
C
OUT
= 22
F
C
OUT
= 47
F
INPUT VOLTAGE (V)
0
OUTPUT VOLTAGE RIPPLE (mV
P-P
)
250
200
150
100
50
0
8
1515 G04
2
4
6
10
V
OUT
= 5V
I
OUT
= 10mA
T
A
= 25
C
C
OUT
= 10
F
C
OUT
= 47
F
C
OUT
= 22
F
LTC1515-X 5V Output Voltage
Ripple vs Input Voltage
LTC1515-X
3.3V Efficiency vs Output Current
OUTPUT CURRENT (mA)
EFFICIENCY (%)
0.01
1
10
1515 G01
0.1
100
100
80
60
40
20
0
V
OUT
= 3.3V
T
A
= 25
C
V
IN
= 2V
V
IN
= 4.4V
V
IN
= 2.7V
V
IN
= 6V
INPUT VOLTAGE (V)
0
OUTPUT VOLTAGE (V)
3.45
3.40
3.35
3.30
3.25
3.20
8
1515 G05
2
4
6
10
V
OUT
= 3.3V
I
OUT
= 10mA
C
OUT
= 10
F
T
A
= 25
C
4
LTC1515 Series
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
LTC1515-X Shutdown Supply
Current vs Input Voltage
LTC1515-X Step-Down Mode
5V Load Transient Response
INPUT VOLTAGE (V)
0
POSITIVE SUPPLY CURRENT (
A)
25
20
15
10
5
0
8
1515 G12
2
4
6
10
85
C
SHDN = 0V
40
C
25
C
V
OUT
AC COUPLED
100mV/DIV
I
OUT
50mA/DIV
V
IN
= 8V, V
OUT
= 5V, C
OUT
= 10
F, T
A
= 25
C
1515 G10
50mA
0mA
V
OUT
AC COUPLED
100mV/DIV
I
OUT
50mA/DIV
LTC1515-X Step-Up Mode
5V Load Transient Response
V
IN
= 3.3V, V
OUT
= 5V, C
OUT
= 10
F, T
A
= 25
C
1515 G11
low will force V
OUT
to 3V (LTC1515-3/5) or 3.3V (LTC1515-
3.3/5). As with the SHDN pin, the 5/3 pin may be driven with
3V logic over the entire V
IN
range. The 5/3 pin may not float.
FB (LTC1515) (Pin 3): Feedback Input. The voltage on this
pin is compared to the internal reference voltage (1.232V)
to keep the output in regulation. An external resistor divider
is required between V
OUT
and FB to adjust the output
voltage. Total divider resistance should not exceed 2M.
GND (Pin 4): Ground. Should be tied to a ground plane for
best performance.
C1
(Pin 5): Charge Pump Flying Capacitor, Negative
Terminal.
SHDN (Pin 1): Shutdown Input. A logic low on the SHDN
pin puts the part into shutdown mode. A logic high (V
SHDN
1.6V) enables the part. At high V
IN
voltages, the SHDN
pin may still be controlled with 3V logic without causing a
large rise in V
IN
quiescent current. The SHDN pin may not
float; connect to V
IN
if unused.
POR (Pin 2): Open-Drain Power-On Reset Output. This pin
will pull low upon initial power-up, during shutdown or
until V
OUT
has been within 6.5% of its regulated value for
more than 200ms typ.
5/3 (LTC1515-X) (Pin 3): Output Voltage Select. A logic
high on the 5/3 pin will force V
OUT
to regulate to 5V. A logic
PI
N
FU
N
CTIO
N
S
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U
U
INPUT VOLTAGE (V)
0
EFFICIENCY (%)
100
80
60
40
20
8
1515 G09
2
4
6
10
V
OUT
= 3V
I
OUT
= 10mA
T
A
= 25
C
LTC1515-X
3V Efficiency vs Input Voltage
LTC1515-X
5V Efficiency vs Input Voltage
INPUT VOLTAGE (V)
2
EFFICIENCY (%)
100
80
60
40
20
10
1515 G08
4
6
8
12
V
OUT
= 5V
I
OUT
= 10mA
TA = 25
C
INPUT VOLTAGE (V)
0
EFFICIENCY (%)
100
80
60
40
20
8
1515 G07
2
4
6
10
V
OUT
= 3.3V
I
OUT
= 10mA
TA = 25
C
LTC1515-X
3.3V Efficiency vs Input Voltage
5
LTC1515 Series
PI
N
FU
N
CTIO
N
S
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C1
+
(Pin 6): Charge Pump Flying Capacitor, Positive
Terminal.
V
IN
(Pin 7): Charge Pump Input Voltage. May be between
2V and 10V. V
IN
should be bypassed with a
10
F low
ESR capacitor as close as possible to the pin for best
performance.
V
OUT
(Pin 8): Regulated Output Voltage. Pin selectable to
either 3V/5V, 3.3V/5V or adjustable using an external
resistor divider (LTC1515). V
OUT
should be bypassed with
a
10
F low ESR capacitor as close as possible to the pin
for best performance.
BLOCK DIGRA
M
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SI PLIFIED
APPLICATIO
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Regulator Operation
The regulator section of the LTC1515, LTC1515-3/5 and
LTC1515-3.3/5 consists of a charge pump, reference,
comparator and some logic. The divided down output
voltage is compared to the internal reference voltage.
When the divided output drops below the reference volt-
age, the charge pump is enabled, which boosts the output
back into regulation. Hysteresis in the comparator forces
the regulator to burst on and off and causes approximately
100mV of peak-to-peak ripple to appear at the output. By
enabling the charge pump only when needed, the parts
achieve high efficiencies with low output load currents.
Each part's charge pump has a unique architecture that
allows the input voltage to be either stepped up or stepped
down to produce a regulated output. Internal circuitry
senses the V
IN
to V
OUT
differential voltage and controls the
charge pump operating mode. In addition, the effective
output impedance of the charge pump is internally
adjusted to prevent large inrush currents and allow for a
wide input voltage range. When the input voltage is lower
than the output voltage, the charge pump operates as a
step-up voltage doubler. When the input voltage is greater
than the output, the charge pump operates as a step-down
gated switch.
+
+
V
OS
1.232V
V
REF
650kHz
OSCILLATOR
RESET
COUNTER
STEP-UP/STEP-DOWN
CHARGE PUMP
V
IN
SHDN
POR
GND
C1
C1
+
V
OUT
(LTC1515-X)
(LTC1515-X)
LTC1515 BD
FB
(LTC1515)
5/3
(LTC1515-X)
EN
EN
6
LTC1515 Series
Output Voltage Selection
The LTC1515-X versions have internal resistor networks
which set the output voltage. The 5/3 pin controls an
internal switch that shorts out a portion of the resistor
network to change the output voltage. A logic high on this
pin produces a 5V output and a low produces either a 3V
output or a 3.3V output.
The output voltage of the LTC1515 is selected using an
external resistor divider (see Figure 1). The output voltage
is determined using the following formula:
V
OUT
= (1.232V)[1 + (R1/R2)]
The total resistance of R1 and R2 should not exceed 2M,
otherwise excess ripple may appear at V
OUT
.
APPLICATIO
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FOR
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ATIO
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Figure 1. LTC1515 Output Voltage Selection
SHDN
POR
GND
FB
V
OUT
V
IN
C1
C1
+
LTC1515
1
2
3
4
8
7
6
5
LTC1515 F01
R1
R2
Maximum V
OUT
and I
OUT
Calculations for the LTC1515
The maximum output voltage and current available with
the LTC1515 can be calculated based on the effective
output resistance of the charge pump and the open circuit
output voltage. In step-up mode, the open circuit output
voltage is approximately 2V
IN
(see Figure 2). In step-down
mode, the open circuit output voltage equals V
IN
. The
relationship between R
OUT
and V
IN
in step-up mode is shown
in Figure 3.
The following formulas can be used to find the maximum
output voltage that may be programmed using the LTC1515
for a given minimum input voltage and output current
load.
Step-Up Mode: Max V
OUT
= (2)(Min V
IN
) (I
OUT
)(R
OUT
)
Step-Down Mode: Max V
OUT
= (Min V
IN
) (I
OUT
)(R
OUT
)
When V
IN
(I
OUT
)(R
OUT
) is less than the programmed
V
OUT
, the part will automatically switch from step-down
mode to step-up mode. In both step-up mode and step-
+
+
I
OUT
C
OUT
2V
IN
R
OUT
V
OUT
LT1515 F02
Figure 2. Step-Up Mode Equivalent Circuit
INPUT VOLTAGE (V)
1
OUTPUT RESISTANCE (
)
20
30
5
LT1515 F03
10
0
2
3
4
40
I
OUT
= 50mA
I
OUT
= 20mA
Figure 3. Step-Up Mode R
OUT
vs Input Voltage
down mode, R
OUT
is internally adjusted to ensure that the
maximum output current rating can be met.
Capacitor Selection
For best performance, low ESR capacitors are recom-
mended for both C
IN
and C
OUT
to reduce noise and ripple.
The C
IN
and C
OUT
capacitors should be either ceramic or
tantalum and should be 10
F or greater. If the input source
impedance is very low (< 0.5
) C
IN
may not be needed.
Increasing the size of C
OUT
to 22
F or greater will reduce
output voltage ripple -- particularly with high V
IN
voltages
(8V or greater). A ceramic capacitor is recommended for
the flying capacitor C1 with a value of 0.1
F or 0.22
F.
Smaller values may be used in low output current
applications.
Output Ripple
Normal LTC1515 series operation produces voltage ripple
on the V
OUT
pin. Output voltage ripple is required for the
parts to regulate. Low frequency ripple exists due to the
hysteresis in the sense comparator and propagation de-
lays in the charge pump enable/disable circuits. High
frequency ripple is also present mainly from the ESR
7
LTC1515 Series
APPLICATIO
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FOR
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ing out of shutdown mode. Whenever large V
IN
(or boosted
V
IN
) to V
OUT
voltage differentials are present, most charge
pumps will pull large current spikes from the input supply.
Only the effective charge pump output impedance limits
the current while the charge pump is enabled. This may
disrupt input supply regulation, especially if the input
supply is a low power DC/DC converter or linear regulator.
The LTC1515 family minimizes inrush currents both at
start-up and under high V
IN
to V
OUT
operation.
Internal soft start circuitry controls the rate at which V
OUT
may be charged from 0V to its final regulated value. The
typical start-up time from V
OUT
= 0V to 5V is 4ms. This
corresponds to an effective V
OUT
charging current of only
12.5mA for a 10
F output capacitor (27.5mA for 22
F,
etc.). Note that any output current load present during
start-up will add directly to the charging currents men-
tioned above. The soft start circuitry limits start-up cur-
rent both at initial power-up and when coming out of
shutdown.
As the V
IN
(or boosted V
IN
) to V
OUT
voltage differential
grows, the effective output impedance of the charge pump
is automatically increased by internal voltage sensing
circuitry. This feature minimizes the current spikes pulled
from V
IN
whenever the charge pump is enabled and helps
to reduce both input and output ripple.
Power-On Reset
The POR pin is an open-drain output that pulls low when
the output voltage is out of regulation. When the V
OUT
rises to within 6.5% of regulation, an internal timer is
started which releases POR after 200ms (typ). In shut-
down, the POR output is pulled low. In normal operation,
an external pull-up resistor is generally used between the
POR pin and V
OUT
.
Protection Features
All of the parts contain thermal shutdown and short-
circuit protection features. The parts will shut down when
the junction temperature reaches approximately 150
C
and will resume operation once the junction temperature
has dropped back to approximately 140
C. The parts will
limit output current to 12mA (typ) when a short circuit
condition (V
OUT
< 100mV) exists. The parts can survive an
indefinite short to GND.
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
(equivalent series resistance) in the output capacitor.
Typical output ripple (V
IN
< 8V) under maximum load is
100mV peak-to-peak with a low ESR, 10
F output capaci-
tor. For applications requiring V
IN
to exceed 8V, a 22
F or
larger C
OUT
capacitor is recommended to maintain maxi-
mum ripple in the 100mV range.
The magnitude of the ripple voltage depends on several
factors. High input voltages increase the output ripple
since more charge is delivered to C
OUT
per charging cycle.
A large C1 flying capacitor (> 0.22
F) also increases ripple
in step-up mode for the same reason. Large output
current load and/or a small output capacitor (<10
F)
results in higher ripple due to higher output voltage dV/dt.
High ESR capacitors (ESR > 0.5
) on the output pin cause
high frequency voltage spikes on V
OUT
with every clock
cycle.
There are several ways to reduce the output voltage ripple.
A large C
OUT
capacitor (22
F or greater) will reduce both
the low and high frequency ripple due to the lower C
OUT
charging and discharging dV/dt and the lower ESR typi-
cally found with higher value (larger case size) capacitors.
A low ESR (<0.5
) ceramic output capacitor will mini-
mize the high frequency ripple, but will not reduce the low
frequency ripple unless a high capacitance value is cho-
sen. A reasonable compromise is to use a 10
F to 22
F
tantalum capacitor in parallel with a 1
F to 3.3
F ceramic
capacitor on V
OUT
to reduce both the low and high
frequency ripple. An RC or LC filter may also be used to
reduce high frequency voltage spikes (see Figure 4).
Inrush Currents
A common problem with switched capacitor regulators is
inrush current--particularly during power-up and com-
15
F
TANTALUM
LT1515 F04
V
OUT
V
OUT
8
1
F
CERAMIC
10
F
TANTALUM
V
OUT
V
OUT
8
10
F
TANTALUM
2
LTC1515/
LTC1515-X
LTC1515/
LTC1515-X
+
+
+
Figure 4. Output Ripple Reduction Techniques
8
LTC1515 Series
LINEAR TECHNOLOGY CORPORATION 1997
1515f LT/TP 0298 4K PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
q
(408) 432-1900
FAX: (408) 434-0507
q
TELEX: 499-3977
q
www.linear-tech.com
PART NUMBER
DESCRIPTION
COMMENTS
LTC1514 Series
Step-Up/Step-Down Switched Capacitor DC/DC Converters
V
IN
2V to 10V, 3.3V and 5V Versions, I
OUT
to 50mA
LTC1516
Micropower, Regulated 5V Charge Pump DC/DC Converter
I
OUT
= 20mA (V
IN
2V), I
OUT
= 50mA (V
IN
3V)
LTC1517-5
Micropower, Regulated 5V Charge Pump DC/DC Converter
LTC1522 Without Shutdown and Packaged in SOT-23
LTC1522
Micropower, Regulated 5V Charge Pump DC/DC Converter
Available in 8-Pin MSOP, 6
A Quiescent Current, I
OUT
= 20mA
LTC1555/LTC1556
SIM Power Supply and Level Translators
Step-Up/Step-Down SIM Power Supply and Level Translators
LTC660
100mA CMOS Voltage Converter
5V to 5V Conversion with Low Voltage Loss
TYPICAL APPLICATIO
N
S
U
RELATED PARTS
1
2
3
4
0.150 0.157**
(3.810 3.988)
8
7
6
5
0.189 0.197*
(4.801 5.004)
0.228 0.244
(5.791 6.197)
0.016 0.050
0.406 1.270
0.010 0.020
(0.254 0.508)
45
0
8
TYP
0.008 0.010
(0.203 0.254)
SO8 0996
0.053 0.069
(1.346 1.752)
0.014 0.019
(0.355 0.483)
0.004 0.010
(0.101 0.254)
0.050
(1.270)
TYP
DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
*
**
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
PACKAGE DESCRIPTIO
N
U
Dimensions in inches (millimeters) unless otherwise noted.
Low Power, Low Noise Step-Up/Step-Down 5V Supply with Reset
SHDN
POR
GND
FB
V
OUT
V
IN
C1
C1
+
LTC1515
1
2
3
4
8
7
6
5
0.22
F
10
F
22
F
1.4M
V
IN
= 3V TO 10V
ON OFF
RESET
LTC1515 TA03
402k
470k
LT1121-5
IN
GND
OUT
10
F
8
3
1
V
OUT
= 5V
I
OUT
= 20mA
V
RIPPLE
< 1mV
P-P
5.5V
+
+
2
10
F
+
+
Programmable 3V/5V GSM SIM Card Power Supply
SHDN
POR
GND
5/3
V
OUT
V
IN
C1
C1
+
LTC1515-3/5
1
2
3
4
8
7
6
5
0.1
F
NC
10
F
10
F
Li-Ion
V
OUT
= 3V OR 5V
I
OUT
= 15mA
ON OFF
5V 3V
LTC1515 TA04
+
+
Positive and Negative Supply
SHDN
POR
GND
5/3
V
OUT
V
IN
V
IN
C1
C1
+
LTC1515-3/5
1
2
3
4
8
7
6
5
0.22
F
0.22
F
**
* CENTRAL SEMICONDUCTOR
CMPSH-35 DUAL SCHOTTKY
** OPTIONAL CIRCUITRY FOR MAINTAINING
V
OUT
WITH LOW V
OUT
LOADS
Q1, Q2: 2N3904
*
10
F
V
OUT
= 5V
I
OUT
= 15mA, 2.7V
V
IN
4.4V
I
OUT
= 50mA, 3.3V
V
IN
4.4V
V
IN
= 2.7V TO 4.4V
V
OUT
= 1V TO 3.5V
I
OUT
= 5mA
ON OFF
NC
LTC1515 TA05
+
+
10
F
10
F
470
8.2k
2.4k
+
Q1
Q2
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