LTC1986ES6 [Linear]
3V/5V SIM Power Supply in SOT-23; 3V / 5V SIM电源采用SOT -23
| 型号： | LTC1986ES6 |
| 厂家： | 
Linear |
| 描述： | 3V/5V SIM Power Supply in SOT-23 |
| 文件： | 总8页 (文件大小：145K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC1986
3V/5V SIM Power Supply
in SOT-23
U
DESCRIPTIO
FEATURES
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
3Vmode, VOUT isconnecteddirectlytoVIN througha2.5Ω
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
■
Step-Up Charge Pump Generates 5V
■
Output Current: 10mA
■
VIN to VOUT Direct Connection for 3V SIMs
■
Ultralow Power
Operating Current: 14µA
Shutdown Current: <1
µA
■
■
■
■
■
■
■
No Inductors
Short-Circuit/Thermal Protected
Switching Frequency: 900kHz
Soft-Start Limits Inrush Current at Turn-On
Output Driven to Ground During Shutdown
Ultrasmall Application Circuit (<0.045in2)
6-Lead SOT-23 Package
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 6-lead SOT-23 package.
U
APPLICATIO S
■
GSM Cellular Telephones
■
PCS/DCS Cellular Telephones
■
Portable POS Terminals
, LTC and LT are registered trademarks of Linear Technology Corporation.
U
TYPICAL APPLICATIO
3V/5V SIM Power Supply
Output Voltage vs Input Voltage
V
= 5V
IN
6
OUT
V
= 2.6V TO 4.4V
OR V
IN
T
OUT
= 25°C
A
I
= 10mA
5V MODE
GSM
5
4
3
2
LTC1986
CONTROLLER
0.1µF
1
2
3
6
5
4
V
V
IN
OUT
2.2µF
3/5
+
C1
C1
GND
3V MODE
(V = V
1M
0.047µF
)
IN
OUT
–
MODE
750k
SHDN
SHDN 3/5
MODE
0
0
1
1
0
1
0
1
SHUTDOWN
SHUTDOWN
V
= 5V
IN
3.5
INPUT VOLTAGE (V)
2.5
4.0
4.5
3.0
OUT
OUT
V
= V
1986 TA01
1986 TA02
1
LTC1986
W W U W
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W U
ABSOLUTE MAXIMUM RATINGS
PACKAGE/ORDER INFORMATION
(Note 1)
ORDER PART
NUMBER
TOP VIEW
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
V
1
6 V
IN
OUT
+
GND 2
5 C1
4 C1
LTC1986ES6
–
MODE 3
S6 PACKAGE
6-LEAD PLASTIC SOT-23
S6 PART MARKING
LTKX
TJMAX = 125°C, θJA = 230°C/ W
Consult factory for Military grade parts.
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
CONDITIONS
MIN
TYP
MAX
UNITS
V
Operating Voltage
●
2.6
4.4
V
IN
V
Output Voltage
Shutdown Mode
0
V
V
V
V
V
OUT
3V Mode. V = 2.85V to 4.4V, I
≤ 10mA
≤ 10mA
V – 0.025
IN
OUT
< 10mA
≤ 10mA
IN
3V Mode, V < 2.85V, I
●
●
●
2.75
4.55
4.75
2.9
5
5
3.05
5.25
5.25
IN
OUT
5V Mode, V < 2.7V, I
IN
OUT
5V Mode, V = 2.7V to 4.4V, I
IN
OUT
V
Operating Current
Shutdown Mode, V
= 0V
●
●
●
0.001
10
14
1
25
30
µA
µA
µA
IN
MODE
3V Mode, I
5V Mode, I
= 0mA
= 0mA
OUT
OUT
V -to-V
ON Resistance
3V Mode, V = 3V
●
●
●
2.5
100
70
5
Ω
mA
Ω
IN
OUT
IN
V
V
Short-Circuit Current
Discharge Resistance
3V or 5V Mode, V
= 0V
20
0
200
200
OUT
OUT
OUT
Switching Frequency
MODE Input Ranges
Oscillator Free-Running
900
kHz
Shutdown Mode
5V Mode
3V Mode
●
●
●
V /2 – 0.1
V – 1.0
V
V
V
IN
V /2 + 0.1
IN
IN
V
– 0.25
V
IN
IN
MODE Input Current
●
–1
1
µA
Undervoltage Lockout Threshold
1.4
V
Note 2: The LTC1986 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.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
2
LTC1986
W
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TYPICAL PERFORMANCE CHARACTERISTICS
Output Voltage vs Output Current
(3V Mode)
Efficiency vs Input Voltage
100
80
60
40
20
3.10
I
= 10mA
= 5V
V
T
= V
= 3V
OUT
OUT
IN
A
MODE
V
= 25°C
T
= 25°C
A
3.05
3.00
2.95
2.90
3.5
INPUT VOLTAGE (V)
4.0
2.5
4.5
0.1
1
3.0
0.001
10
0.01
OUTPUT CURRENT (mA)
1986 G02
1986 G01
Positive Supply Current vs
Input Voltage
Efficiency vs Output Current
40
30
20
10
0
100
80
60
40
20
0
I
= 0mA
OUT
A
T
= 25°C
5V MODE (V
= 0.6V )
IN
MODE
MODE
V
= 3V
3V MODE (V
3.0
= V )
IN
IN
5V MODE (V
= 0.6V )
IN
MODE
T
A
= 25°C
3.5
4.0
2.5
4.5
0.01
0.1
1
0.001
10
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
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
2ms/DIV
VIN = 4V
TA = 25°C
IOUT = 10mA
1986 G06
T
A = 25°C
1986 G05
3
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.Thisfeatureallowstheinputvoltagetobebelowthe
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.
C1+ (Pin 5): Charge Pump Flying Capacitor Positive
Terminal.
GND (Pin 2): Ground. Connect to a ground plane for best
performance.
MODE (Pin 3): MODE Input Pin. The voltage on this pin
determines the operating mode of the LTC1986. It oper-
ates 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.
W
W
SI PLIFIED BLOCK DIAGRA
–
+
C1
C1
4
5
LTC1986
50Ω
2.5Ω
V
6
3V MODE
IN
CHARGE
PUMP
V
OUT
1
5V MODE
SOFT START
–
+
2.9V BOOST
1.25V
+
–
900kHz
OSC
+
–
V
IN
– 0.6V
3V
UVLO/
THERMAL
SHDN
1.25V
REF
MODE
LOGIC
3
5V
+
–
SHDN
SHDN
V
/2
IN
GND
2
1986 BD
4
LTC1986
U
W U U
APPLICATIONS INFORMATION
Operation
The three modes can be selected using two totem pole
digital outputs and two external resistors as shown in
Figure 1.
TheLTC1986isachargepumpDC/DCconverterdesigned
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 volt-
age through a resistor divider and enabling the charge
pump as needed to maintain regulation.
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 shut-
downmode, thevoltageontheMODEpinshouldbepulled
below0.4V.3VmodeconnectsVOUT toVIN througha2.5Ω
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.
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 discharg-
ing 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. Thismethodofburstingthechargepumponand
off enables the LTC1986 to achieve high efficiency at
extremely low output loads.
V
IN
6
V
IN
3/5
LTC1986
1M
3
MODE
750k
SHDN
SHDN 3/5
MODE
SHUTDOWN (I < 1µA)
0
0
1
1
0
1
0
1
CC
SHUTDOWN (I = 10µA)
CC
V
= 5V
OUT
OUT
V
= V
IN
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 thresh-
olds—all of which are referenced to 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).
Shutdown Mode VMODE < VIN/2 – 0.1V
5V Mode
3V Mode
VIN/2 + 0.1V < VMODE < VIN – 1V
VIN – 0.25V < VMODE
For example, if VIN = 3V, then the following table applies:
V
OPERATING MODE
Shutdown Mode
5V Mode
MODE
0V to 1.4V
1.6V to 2V
2.75V to 3V
3V Mode (V
= V )
IN
OUT
5
LTC1986
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W U U
APPLICATIONS INFORMATION
Output Ripple
Protection Features
Normal 5V mode operation produces voltage ripple on the
The LTC1986 provides several protection features.
Undervoltage lockout prevents any current from flowing
between VIN and VOUT until the VIN 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 volt-
age,operatingmodeandoutputloadbydisablingthemain
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.
V
OUT 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 resis-
tance) 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 applica-
tions requiring <75mV of peak-to-peak ripple, a 3.3µF to
10µF COUT capacitor is recommended. Slight further de-
creases in output ripple can be achieved by using COUT
capacitors larger than 10µF.
6
LTC1986
U
PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted.
S6 Package
6-Lead Plastic SOT-23
(LTC DWG # 05-08-1634)
2.80 – 3.00
(0.110 – 0.118)
(NOTE 3)
0.95
(0.037)
REF
1.90
(0.074)
REF
2.6 – 3.0
(0.110 – 0.118)
1.50 – 1.75
(0.059 – 0.069)
0.00 – 0.15
(0.00 – 0.006)
0.90 – 1.45
(0.035 – 0.057)
0.35 – 0.55
(0.014 – 0.022)
0.35 – 0.50
(0.014 – 0.020)
SIX PLACES (NOTE 2)
0.90 – 1.30
(0.035 – 0.051)
S6 SOT-23 0898
0.09 – 0.20
(0.004 – 0.008)
(NOTE 2)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DIMENSIONS ARE INCLUSIVE OF PLATING
3. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
4. MOLD FLASH SHALL NOT EXCEED 0.254mm
5. PACKAGE EIAJ REFERENCE IS SC-74A (EIAJ)
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-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
7
LTC1986
TYPICAL APPLICATION
U
3V/5V SIM Power Supply
V
= 5V
IN
OUT
V
= 2.6V TO 4.4V
OR V
IN
GSM
LTC1986
CONTROLLER
0.1µF
1
2
3
6
5
4
V
V
IN
OUT
2.2µF
3/5
+
C1
C1
GND
1M
0.047µF
–
MODE
750k
SHDN
SHDN 3/5
MODE
0
0
1
1
0
1
0
1
SHUTDOWN
SHUTDOWN
V
= 5V
OUT
OUT
V
= V
IN
1986 TA01
RELATED PARTS
PART NUMBER
LTC1503
LTC1517
LTC1555
LT1615
DESCRIPTION
COMMENTS
High Efficiency Step-Down Charge Pump
Micropower Charge Pump in 5-Pin SOT-23
SIM Power Supply and Level Translator
V
= 2.4V to 6V, 100mA Output Current
= 6µA, Short-Circuit/Thermal Protected
= 2.7V to 10V, 10kV ESD on SIM Contact Pins
= 1.2V to 15V; 350mA, 36V Switch
IN
I
CC
V
V
IN
IN
Micropower Step-Up DC/DC Converter in SOT-23
LT1682
Charge Pump Plus Low Noise LDO Regulator in MSOP
5V Charge Pump with Shutdown in SOT-23
3.3V Charge Pump with Shutdown in SOT-23
Low Noise, 100mA Micropower LDO Regulator
Smart Card Power Supply and Level Translator
50mA Output Current; 60µV
Output Noise
RMS
LTC1754-5
LTC1754-3.3
LT1761
50mA Output Current, I = 13µA
CC
V
= 2V to 4.4V; I = 40mA; Ripple = 23mV
OUT P-P
IN
I = 20µA, 20µV
Q
Noise, SOT-23 Package
RMS
LTC1755
ISO 7816-3 and EMV Compliant
1986f LT/TP 0100 4K • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
8
●
●
(408)432-1900 FAX:(408)434-0507 www.linear-tech.com
LINEAR TECHNOLOGY CORPORATION 1999
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