LTC1555L View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC1555L Datasheet PDF : 8 Pages
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LTC1555L
PIN FUNCTIONS
N/C (Pin 6): No Internal Connection.
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 15kV ESD specifications.
C1–(Pin10): ChargePumpFlyingCapacitorNegative␣ Input.
C1+ (Pin 11):Charge Pump Flying Capacitor Positive␣ Input.
Table 1. Truth Table
M0
M1
OPERATING MODE
0V
0V
DVCC
DVCC
0V
DVCC
0V
DVCC
Shutdown (VCC = 0V)
VCC* = VIN
VCC = 3V
VCC = 5V
*Actual VCC will depend on the output current in this mode.
VIN (Pin 12): Charge Pump Input Pin. May be between
2.6V and 6V. There is no power-up sequencing require-
ment 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-M1 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
DVCC
RIN
CIN
0.1µF
C1+
C1–
LTC1555L
VCC
STEP-UP/
STEP-DOWN
CHARGE PUMP
DC/DC
CONVERTER
UVLO
RST
CLK
20k
DATA
OPTIONAL
1µA
DDRV
10k
I/O
GND
VCC
COUT
2.2µF
RST
SIM
CLK
I/O
GND
1555L BD
5
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