1555L

LTC1555L SIM Power Supply and Level Translator FEATURES s s s s s s s s s s s DESCRIPTIO Buck/Boost Charge Pump Generates 3V or 5V Input Voltage Range: 2.6V to 6V Controller VCC Range: 1.425V to 4.4V >10kV ESD on All SIM Contact Pins Short-Circuit and Overtemperature Protected 3V to 5V Signal Level Translators Very Low Operating Current: 40µA Very Low Shutdown Current: 0.22µF) also increases ripple in step-up mode for the same reason. Large output current load and/or a small output capacitor (< 1µF) results in higher ripple due to higher output voltage dV/dt. High ESR capacitors (ESR > 0.5Ω) on the output pin cause high frequency voltage spikes on VOUT with every clock cycle. A 2.2µF ceramic capacitor on the VCC pin should produce acceptable levels of output voltage ripple in nearly all applications. Also, in order to keep noise down to a minimum all capacitors should be placed close to LTC1555L. Level Translators All SIMs and smart cards contain a clock input, a reset input, and a bidirectional data input/output. The LTC1555L provides level translators to allow controllers to communicate with the SIM. (See Figure 1a and 1b). The CLK and RST inputs to the SIM are level shifted from the controller supply rails (DVCC and GND) to the SIM supply rails (VCC and GND). The data input to the SIM may be provided two different ways. The first method is to use the DATA pin as a bidirectional level translator. This configuration is only allowed if the controller data output pin is The LTC1555L performs the two primary functions necessary for low voltage controllers (e.g., GSM cellular telephone controllers, smart card readers, etc.) to communicate with 5V SIMs or smart cards. The part produces a regulated 3V or 5V VCC supply for the SIM, and also provides level translators for communication between the SIM and the controller. 6 W U U LTC1555L APPLICATIO S I FOR ATIO open drain (all SIM I/O pins are open drain). Internal pull-up resistors are provided for both the DATA pin and the I/O pin on the SIM side. The second method is to use the DDRV pin to send data to the SIM and use the DATA pin to receive data from the SIM. When the DDRV pin is not used, it should either be left floating or tied to DVCC. Shutting Down the DVCC Supply To conserve power, the DVCC supply may be shut down while the VIN supply is still active. When the DVCC supply is forced below 1.2V, an undervoltage lockout circuit LTC1555L CLK TO SIM RST TO SIM DATA TO/FROM SIM CIN RIN DATA DDRV CONTROLLER SIDE DVCC CLK RST I/O VCC SIM SIDE 1555L F01a Figure 1a. Level Translator Connections for Bidirectional Controller DATA Pin 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. U forces the LTC1555L into shutdown mode regardless of the status of the M0-M1 pins. 10kV ESD Protection All pins that connect to the SIM (CLK, RST, I/O, VCC, GND) withstand over 10kV of human body model ESD. In order to ensure proper ESD protection, careful board layout is required. The GND pin should be tied directly to a GND plane. The VCC capacitor should be located very close to the VCC pin and tied immediately to the GND plane. LTC1555L CLK TO SIM RST TO SIM DATA FROM SIM DATA TO SIM CONTROLLER SIDE CIN RIN DATA DDRV DVCC CLK RST I/O VCC SIM SIDE 1555L F01b W U U Figure 1b. Level Translator Connections for One-Directional Controller Side DATA Flow 7 LTC1555L TYPICAL APPLICATIO GSM CONTROLLER VCC PACKAGE DESCRIPTIO 0.007 – 0.0098 (0.178 – 0.249) 0.016 – 0.050 (0.406 – 1.270) * 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 RELATED PARTS PART NUMBER LTC1555L-1.8 LTC1555/LTC1556 LTC1755 LTC1756 LTC1986 DESCRIPTION SIM Power Supply and Level Translator SIM Power Supply and Level Translator Smart Card Interface Smart Card Interface 3V/5V SIM Power Supply in SOT-23 COMMENTS VIN = 2.6V to 6V; Interface with 1.8V, 3V and 5V SIMs VIN = 2.7V to 10V; Step-Up/Step-Down Charge Pump; 3V and 5V VOUT VIN = 2.7V to 6V; 24-Pin SSOP Package; IQ = 60µA VIN = 2.7V to 6V; 16-Pin SSOP Package; IQ = 75µA VIN = 2.6V to 4.4V; IQ = 14µA 1555lf LT/TP 0601 2K • PRINTED IN USA 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com U U GSM Cellular Telephone SIM Interface 1.425V TO 4.4V 1 2 3 4 5 6 7 8 LTC1555L CIN RIN DATA DDRV DVCC N/C M1 M0 CLK RST I/O VCC VIN C1 + C1 – GND 16 15 14 13 12 11 10 9 0.1µF 1µF 2.2µF VIN 2.6V TO 6V CLK RST I/O VCC = 3V, 5V or VIN IVCC = 10mA SIM GND 1555L TA01a Dimensions in inches (millimeters) unless otherwise noted. GN Package 16-Lead Plastic SSOP (Narrow 0.150) (LTC DWG # 05-08-1641) 0.189 – 0.196* (4.801 – 4.978) 16 15 14 13 12 11 10 9 0.009 (0.229) REF 0.229 – 0.244 (5.817 – 6.198) 0.150 – 0.157** (3.810 – 3.988) 1 0.015 ± 0.004 × 45° (0.38 ± 0.10) 0° – 8° TYP 0.053 – 0.068 (1.351 – 1.727) 23 4 56 7 8 0.004 – 0.0098 (0.102 – 0.249) 0.008 – 0.012 (0.203 – 0.305) 0.0250 (0.635) BSC GN16 (SSOP) 1098 © LINEAR TECHNOLOGY CORPORATION 2000