LINER LTC1986 3v/5v sim power supply in thinsot Datasheet

LTC1986
3V/5V SIM Power Supply
in ThinSOT
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DESCRIPTIO
FEATURES
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The LTC®1986 is a micropower charge pump DC/DC
converter that provides power for either 3V or 5V GSM
SIM cards. It operates in one of three modes: VOUT = 5V
(5V mode), VOUT = VIN (3V mode) or shutdown. The input
voltage range is 2.6V to 4.4V and the part can provide
10mA of output current. The LTC1986 allows VIN to drop
as low as 2.6V by providing a boost feature in 3V mode. In
3V mode, VOUT is connected directly to VIN through a 2.5Ω
switch until VIN drops below 2.85V. When VIN is below
2.85V, the part automatically boosts VOUT to maintain a
regulated 2.9V output, thereby ensuring VOUT stays within
the 3V SIM VCC specification.
VIN Range: 2.6V to 4.4V
Ultralow Power
Operating Current: 14µA
Shutdown Current: <1µA
No Inductors
Short-Circuit/Thermal Protected
Ultrasmall Application Circuit (< 0.045in2)
Low Profile (1mm) ThinSOTTM
Step-Up Charge Pump Generates 5V
Output Current: 10mA
VIN to VOUT Direct Connection for 3V SIMs
Switching Frequency: 900kHz
Soft-Start Limits Inrush Current at Turn-On
Output Driven to Ground During Shutdown
Extremely low operating current (14µA typical with no
load) and low external parts count make the part ideally
suited for small, light load battery-powered applications.
The total PCB area of the application circuit shown below
is less than 0.045in2. Protection features include inrush
current limiting, undervoltage lockout, short circuit and
thermal overload protection. The LTC1986 is available in
a low profile (1mm) SOT-23 package.
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APPLICATIO S
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GSM Cellular Telephones
PCS/DCS Cellular Telephones
Portable POS Terminals
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
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TYPICAL APPLICATIO
Output Voltage vs Input Voltage
3V/5V SIM Power Supply
VOUT = 5V
OR VIN
1
2.2µF
3/5
2
1M
3
LTC1986
VOUT
VIN
GND
C1+
MODE C1–
6
0.1µF
5
4
0.047µF
750k
SHDN
SHDN 3/5
MODE
0
0 SHUTDOWN
0
1 SHUTDOWN
1
0
VOUT = 5V
VOUT = VIN
1
1
TA = 25°C
IOUT = 10mA
OUTPUT VOLTAGE (V)
GSM
CONTROLLER
6
VIN = 2.6V TO 4.4V
3V MODE
(VOUT = VIN)
4
3
2
2.5
1986 TA01
5V MODE
5
3.0
3.5
4.0
4.5
INPUT VOLTAGE (V)
1986 TA02
1986fa
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LTC1986
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ABSOLUTE MAXIMUM RATINGS
PACKAGE/ORDER INFORMATION
(Note 1)
VIN, VOUT to GND .........................................– 0.3V to 6V
All Other Pins to GND ..................................– 0.3V to 6V
VOUT Short-Circuit Duration ............................. Indefinite
Operating Temperature Range
(Note 2) .................................................. – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
TOP VIEW
VOUT 1
6 VIN
GND 2
5 C1+
MODE 3
4 C1–
LTC1986ES6
S6 PACKAGE
6-LEAD PLASTIC SOT-23
S6 PART MARKING
TJMAX = 125°C, θJA = 230°C/ W
LTKX
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C.
VIN = VMIN to VMAX, MODE = VIN, C1 = 0.047µF, COUT = 2.2µF, unless otherwise specified.
PARAMETER
VIN Operating Voltage
CONDITIONS
MAX
4.4
UNITS
V
VOUT Output Voltage
Shutdown Mode
3V Mode. VIN = 2.85V to 4.4V, IOUT ≤ 10mA
3V Mode, VIN < 2.85V, IOUT < 10mA
5V Mode, VIN < 2.7V, IOUT ≤ 10mA
5V Mode, VIN = 2.7V to 4.4V, IOUT ≤ 10mA
0
VIN – 0.025
2.9
5
5
3.05
5.25
5.25
V
V
V
V
V
●
●
●
VIN Operating Current
Shutdown Mode, VMODE = 0V
3V Mode, IOUT = 0mA
5V Mode, IOUT = 0mA
●
●
●
0.001
10
14
1
25
30
µA
µA
µA
VIN-to-VOUT ON Resistance
3V Mode, VIN = 3V
●
2.5
5
Ω
VOUT Short-Circuit Current
3V or 5V Mode, VOUT = 0V
●
100
200
mA
VOUT Discharge Resistance
VIN = 3V
●
70
200
Switching Frequency
Oscillator Free-Running
MODE Input Ranges
Shutdown Mode
5V Mode
3V Mode
●
MODE Input Current
Undervoltage Lockout Threshold
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
MIN
2.6
2.75
4.55
4.75
TYP
900
●
●
●
0
VIN/2 + 0.1
VIN – 0.25
●
–1
1.4
Ω
kHz
VIN/2 – 0.1
VIN – 1.0
VIN
V
V
V
1
µA
V
Note 2: The LTC1986E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the – 40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
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LTC1986
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TYPICAL PERFORMANCE CHARACTERISTICS
Output Voltage vs Output Current
(3V Mode)
Efficiency vs Input Voltage
100
3.10
IOUT = 10mA
VOUT = 5V
TA = 25°C
80
3.05
EFFICIENCY (%)
OUTPUT VOLTAGE (V)
VIN = VMODE = 3V
TA = 25°C
3.00
60
40
2.95
2.90
0.001
0.1
1
0.01
OUTPUT CURRENT (mA)
20
2.5
10
3.0
3.5
4.0
1986 G02
1986 G01
Positive Supply Current vs
Input Voltage
Efficiency vs Output Current
40
POSITIVE SUPPLY CURRENT (mA )
100
80
EFFICIENCY (%)
4.5
INPUT VOLTAGE (V)
60
40
20
VIN = 3V
5V MODE (VMODE = 0.6VIN)
TA = 25°C
0
0.001
0.1
0.01
1
OUTPUT CURRENT (mA)
IOUT = 0mA
TA = 25°C
30
20
5V MODE (VMODE = 0.6VIN)
10
3V MODE (VMODE = VIN)
0
2.5
10
3.0
3.5
4.0
4.5
INPUT VOLTAGE (V)
1986 G04
1986 G03
Output Voltage vs
VMODE Waveforms
Output Voltage Ripple
(5V Mode)
5V
VOUT
2V/DIV
VOUT
50mV/DIV
AC COUPLED
0V
4V
VMODE
2V/DIV
0V
5ms/DIV
VIN = 3V
IOUT = 10mA
TA = 25°C
2ms/DIV
VIN = 4V
TA = 25°C
1986 G06
1986 G05
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LTC1986
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PIN FUNCTIONS
VOUT (Pin 1): Charge Pump Output. The VOUT voltage will
depend on the MODE pin input voltage. VOUT = 0V in
shutdown mode, VOUT = VIN in 3V mode and VOUT = 5V in
5V mode. The LTC1986 provides a 2.9V regulated output
when the part is in 3V mode and the VIN voltage is below
2.85V. This feature allows the input voltage to be below the
minimum voltage specification for 3V SIM cards without
violating the SIM VCC specification. Bypass the VOUT pin
with a ≥ 2.2µF low ESR capacitor to ground.
The three different modes can be realized by using two
external resistors as shown in the typical application
circuit. If VMODE < VIN/2 – 0.1V, the part is in shutdown
mode.If VIN/2 + 0.1V < VMODE < VIN – 1V, the part is in 5V
mode. If VIN – 0.25V < VMODE, the part is in 3V mode. To
achieve the lowest possible shutdown current, the MODE
pin should be pulled to 0V, i.e., both the SHDN and 3/5
signals from the controller should be pulled low.
C1– (Pin 4): Charge Pump Flying Capacitor Negative
Terminal.
GND (Pin 2): Ground. Connect to a ground plane for best
performance.
C1+ (Pin 5): Charge Pump Flying Capacitor Positive
Terminal.
MODE (Pin 3): MODE Input Pin. The voltage on this pin
determines the operating mode of the LTC1986. It operates in either shutdown mode, 3V mode or 5V mode
depending on the MODE pin voltage with respect to VIN.
VIN (Pin 6): Input Supply Voltage. Bypass VIN with a
≥ 0.1µF low ESR capacitor to ground.
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SI PLIFIED BLOCK DIAGRA
C1 –
C1 +
4
5
LTC1986
50Ω
2.5Ω
VIN 6
SOFT START
–
2.9V BOOST
+
900kHz
OSC
+
3V
–
MODE 3
+
VIN/2
–
VIN – 0.6V
1 VOUT
+
1.25V
3V MODE
CHARGE
PUMP
5V MODE
–
LOGIC
5V
UVLO/
THERMAL
SHDN
1.25V
REF
SHDN
SHDN
2
GND
1986 BD
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LTC1986
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APPLICATIONS INFORMATION
Operation
The LTC1986 is a charge pump DC/DC converter designed
specifically to supply VCC power for either 3V or 5V SIM
cards. The part can operate in one of three modes: a low
power shutdown mode which disconnects VIN from VOUT
and actively pulls down the VOUT supply, 3V mode which
provides a direct connection between VIN and VOUT for
powering 3V SIM cards, and 5V mode which provides a
regulated 5V output for powering 5V SIM cards. In 5V
mode, regulation is achieved by sensing the output voltage through a resistor divider and enabling the charge
pump as needed to maintain regulation.
When the charge pump is enabled, a 2-phase
nonoverlapping clock controls the internal charge pump
switches. Flying capacitor C1 is charged to VIN on phase
one of the clock. On phase two of the clock, C1 is stacked
in series with VIN and connected to VOUT through an
internal switch. This sequence of charging and discharging the flying capacitor occurs at a free-running frequency
of 900kHz (typ) and continues until the divided output
voltage reaches the upper trip point of the comparator.
Once the output is in regulation, the charge pump is
disabled. This method of bursting the charge pump on and
off enables the LTC1986 to achieve high efficiency at
extremely low output loads.
The three modes can be selected using two totem pole
digital outputs and two external resistors as shown in
Figure 1.
Shutdown mode disconnects VIN from VOUT and enables
an internal pull-down device which forces VOUT to GND.
To achieve the lowest possible quiescent current in shutdown mode, the voltage on the MODE pin should be pulled
below 0.4V. 3V mode connects VOUT to VIN through a 2.5Ω
internal switch. The LTC1986 has the additional capability
of boosting VOUT to a regulated 2.9V in 3V mode when the
input voltage drops below 2.85V. This ensures that the 3V
SIM VCC specification is not violated if VIN drops below
2.7V during transients or low battery conditions.
VIN
VIN
3/5
LTC1986
1M
3
MODE
750k
SHDN
SHDN 3/5
MODE
0
0 SHUTDOWN (ICC < 1µA)
0
1 SHUTDOWN (ICC = 10µA)
VOUT = 5V
1
0
VOUT = VIN
1
1
1986 F01
Figure 1
Mode Selection
The operating mode is determined by the voltage applied
to the MODE pin. The MODE pin has three voltage thresholds—all of which are referenced to VIN:
Shutdown Mode ⇒ VMODE < VIN/2 – 0.1V
5V Mode
⇒ VIN/2 + 0.1V < VMODE < VIN – 1V
3V Mode
⇒ VIN – 0.25V < VMODE
For example, if VIN = 3V, then the following table applies:
VMODE
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OPERATING MODE
0V to 1.4V
Shutdown Mode
1.6V to 2V
5V Mode
2.75V to 3V
3V Mode (VOUT = VIN)
Capacitor Selection
For best performance, it is recommended that low ESR
capacitors be used for both CIN and COUT to reduce noise
and ripple. The CIN and COUT capacitors should be either
ceramic or tantalum. Ceramic capacitors will provide the
smallest size for a given capacitance. If the input source
impedance is very low (< 0.5Ω), CIN may not be needed.
For best performance, COUT should be 2.2µF or greater.
Ceramic capacitors are also recommended for the flying
capacitor C1 with values between 0.047µF and 0.22µF. If
a small value output capacitor (3.3µF or less) is used, a
small flying capacitor should also be used to prevent high
output ripple in 5V mode. The recommended capacitor
values to minimize board space and cost are: CIN = 0.1µF,
C1 = 0.047µF and COUT = 2.2µF (ceramic).
1986fa
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LTC1986
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APPLICATIONS INFORMATION
Output Ripple
Protection Features
Normal 5V mode operation produces voltage ripple on the
VOUT pin. Output voltage ripple is required for regulation.
Low frequency ripple exists due to the hysteresis in the
sense comparator and propagation delays in the charge
pump enable/disable circuits. High frequency ripple is
also present mainly from the ESR (equivalent series resistance) in the output capacitor. Typical output ripple with
VIN = 3V under maximum load is 75mVP-P with a low ESR
2.2µF output capacitor and a 0.047µF C1 capacitor. For
applications requiring VIN to exceed 3.3V or for applications requiring < 75mV of peak-to-peak ripple, a 3.3µF to
10µF COUT capacitor is recommended. Slight further decreases in output ripple can be achieved by using COUT
capacitors larger than 10µF.
The LTC1986 provides several protection features.
Undervoltage lockout prevents any current from flowing
between V IN and V OUT until the V IN voltage
exceeds 1.4V (typ). This prevents undesirable glitches
during power-up. The parts also limit inrush current
during power-up to under 200mA regardless of VIN voltage, operating mode and output load by disabling the main
direct connect switch (3V mode) or the charge pump
(5V mode) and enabling a 50Ω series switch between VIN
and VOUT until VOUT reaches VIN/2. The parts are also
short-circuit protected and can survive an indefinite short
from VOUT to GND regardless of operating mode or input
voltage. In the event of thermal overload, the parts will
enter thermal shutdown if the junction temperature
exceeds 165°C and return to normal operation once the
junction temperature drops to 150°C.
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LTC1986
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PACKAGE DESCRIPTION
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
2.90 BSC
(NOTE 4)
0.95
REF
1.22 REF
3.85 MAX 2.62 REF
1.4 MIN
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45
6 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
1.90 BSC
S6 TSOT-23 0302
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
1986fa
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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LTC1986
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TYPICAL APPLICATION
3V/5V SIM Power Supply
VOUT = 5V
OR VIN
GSM
CONTROLLER
VIN = 2.6V TO 4.4V
1
2.2µF
3/5
2
1M
3
LTC1986
6
VOUT
VIN
GND
C1+
5
MODE C1–
4
0.1µF
0.047µF
750k
SHDN
SHDN 3/5
MODE
0
0 SHUTDOWN
0
1 SHUTDOWN
1
0
VOUT = 5V
VOUT = VIN
1
1
1986 TA01
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PART NUMBER
DESCRIPTION
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VIN = 2.4V to 6V, 100mA Output Current
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ICC = 6µA, Short-Circuit/Thermal Protected
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50mA Output Current, ICC = 13µA
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3.3V Charge Pump with Shutdown in ThinSOT
VIN = 2V to 4.4V; IOUT = 40mA; Ripple = 23mVP-P
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IQ = 20µA, 20µVRMS Noise, ThinSOT
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ISO 7816-3 and EMV Compliant
LTC1911-1.5/LTC1911-1.8
High Efficiency, Inductorless, Low Noise Step-Down
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Up to 85% Efficiency, 1.5MHz, VIN: 2.7V to 5.5V,
IQ = 180µA, MS8
LTC3250-1.5
High Efficiency, Inductorless, Low Noise Step-Down
DC/DC Converter
Up to 90% Efficiency, 1.5MHz, VIN: 3.1V to 5.5V,
IQ = 35µA, ThinSOT
1986fa
8
Linear Technology Corporation
LT/TP 0902 1K REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
 LINEAR TECHNOLOGY CORPORATION 1999
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