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PDF LTC1555L-1.8 Data sheet ( Hoja de datos )
| Número de pieza | LTC1555L-1.8 | |
| Descripción | SIM Power Supply and Level Translator | |
| Fabricantes | Linear | |
| Logotipo |  |
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LTC1555L-1.8
SIM Power Supply and
Level Translator
FEATURES
s Buck/Boost Charge Pump Generates 1.8V, 3V or 5V
s Input Voltage Range: 2.6V to 6V
s Controller VCC Range: 1.425V to 4.4V
s >10kV ESD on All SIM Contact Pins
s Short-Circuit and Overtemperature Protected
s Meets all ETSI and IMT-2000 SIM Interface
Requirements
s 1.8V to 5V Signal Level Translators
s Very Low Operating Current: 32µA
s Very Low Shutdown Current: <1µA
s Soft-Start Limits Inrush Current at Turn-On
s 1MHz Switching Frequency
s Available in 16-Pin Narrow SSOP Package
U
APPLICATIO S
s SIM Interface in GSM Cellular Telephones
s WCDMA SIM Interface
s Smart Card Readers
DESCRIPTIO
The LTC®1555L-1.8 provides power conversion and level
shifting needed for low voltage GSM and WCDMA cellular
telephones to interface with either 1.8V, 3V or 5V sub-
scriber identity modules (SIMs). The part contains a
patented buck/boost charge pump DC/DC converter* that
delivers a regulated VCC supply voltage to the SIM card.
Input voltage may range from 2.6V to 6V allowing direct
connection to the battery. The output voltage may be
programmed to 1.8V, 3V, 5V or direct connection to the
VIN pin.
Internal level translators allow controllers operating with
supplies as low as 1.425V to interface with 1.8V, 3V and
5V SIMs. A soft-start feature limits inrush current at turn-
on, mitigating start-up problems that may result when the
input is supplied by another low-power DC/DC converter.
Battery life is maximized by 32µA operating current, and
1µA shutdown current. Board area is minimized by the
miniature 16-pin narrow SSOP packages and the need for
only three small external capacitors.
, LTC and LT are registered trademarks of Linear Technology Corporation.
*U.S. Patent No.: 5,973,944
TYPICAL APPLICATIO
GSM Cellular Telephone SIM Interface
GSM
CONTROLLER
VCC
1.425V TO 4.4V LTC1555L-1.8
1
CIN
2
RIN
3
DATA
4
DDRV
5
DVCC
6
M2
7
M1
8
M0
16
CLK
15
RST
14
I/O
13
VCC
12
VIN
C1+ 11
C1– 10
9
GND
VIN
2.6V TO 6V
0.1µF
1µF
SIM
CLK
RST
I/O
VCC = 1.8V,3V,5V
IVCC = 10mA
2.2µF
GND
1555L TA01
1
1 page  
LTC1555L-1.8
PIN FUNCTIONS
M2 (Pin 6): Mode Control Bit 2 (see Table 1). (Pin 6 was
previously used for soft-start control on the LTC1555.)
M1 (Pin 7): Mode Control Bit 1 (see Table 1).
M0 (Pin 8): Mode Control Bit 0 (see Table 1).
GND (Pin 9): Ground for Both the SIM and the Controller.
Should be connected to the SIM GND contact as well as to
the VIN/controller GND. Proper grounding and supply
bypassing is required to meet 10kV ESD specifications.
C1–(Pin10): ChargePumpFlyingCapacitorNegative␣ Input.
C1+ (Pin 11): Charge Pump Flying Capacitor Positive␣ Input.
Table 1. Truth Table
M0
0V
0V
DVCC
DVCC
DVCC
M1
0V
DVCC
0V
0V
DVCC
M2
0V or DVCC
0V or DVCC
0V
DVCC
0V or DVCC
OPERATING MODE
Shutdown (VCC = 0V)
VCC = VIN
VCC = 3V
VCC = 1.8V
VCC = 5V
VIN (Pin 12): Charge Pump Input Pin. May be between 2.6V
and 6V. There is no power-up sequencing requirement for
VIN with respect to DVCC.
VCC (Pin 13): SIM Card VCC Output. Should be connected
to the SIM VCC contact. The VCC output voltage is deter-
mined by the M0-M2 pins (see Table 1). VCC is discharged
to GND during shutdown (M0, M1 = 0V). A 2.2µF low ESR
ouptut capacitor should connect close to the VCC pin.
I/O (Pin 14): SIM Side I/O Pin. The pin is an open drain
output with a nominal pull-up resistance of 10kΩ and
should be connected to the SIM I/O contact. The SIM card
must sink up to 1mA max when driving the I/O pin low due
to the internal pull-up resistors on the I/O and DATA pins.
The I/O pin is held active low during shutdown.
RST (Pin 15): Level Shifted Reset Output Pin. Should be
connected to the SIM RST contact.
CLK (Pin 16): Level Shifted Clock Output Pin. Should be
connected to the SIM CLK contact. Careful trace routing is
recommended due to fast rise and fall edge speeds.
BLOCK DIAGRA
VBATT
CIN
1µF
1.8V
VCC
CONTROLLER
VIN
M0
M1
M2
DVCC
RIN
CIN
0.1µF
C1+ C1–
LTC1555L-1.8
VCC
STEP-UP/
STEP-DOWN
CHARGE PUMP
DC/DC
CONVERTER
UVLO
RST
CLK
DATA
20k
OPTIONAL
1µA
DDRV
10k
I/O
GND
COUT
2.2µF
VCC
RST
SIM
CLK
I/O
GND
1555L BD
5
5 Page | ||
| Páginas | Total 8 Páginas | |
| PDF Descargar | [ Datasheet LTC1555L-1.8.PDF ] | |
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