555L18

LTC1555L-1.8 LINER

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Technical content

LTC1555L-1.8 APPLICATIO S U

FEATURES

U TYPICAL APPLICATIO U 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. I SIM Interface in GSM Cellular Telephones I WCDMA SIM Interface I Smart Card Readers , LTC and LT are registered trademarks of Linear Technology Corporation. SIM Power Supply and Level Translator I Buck/Boost Charge Pump Generates 1.8V, 3V or 5V I Input Voltage Range: 2.6V to 6V I Controller VCC Range: 1.425V to 4.4V I >10kV ESD on All SIM Contact Pins I Short-Circuit and Overtemperature Protected I Meets all ETSI and IMT-2000 SIM Interface Requirements I 1.8V to 5V Signal Level Translators I Very Low Operating Current: 32µA I Very Low Shutdown Current: <1µA I Soft-Start Limits Inrush Current at Turn-On I 1MHz Switching Frequency I Available in 16-Pin Narrow SSOP Package GSM Cellular Telephone SIM Interface CIN RIN DATA DDRV DVCC CLK RST I/O VCC = 1.8V,3V,5V IVCC = 10mA GND CLK RST I/O VCC VIN C1+ C1– GND 0.1µF 1µF LTC1555L-1.8 GSM CONTROLLER SIM VIN 2.6V TO 6V 1.425V TO 4.4V 2.2µF 1555L TA01 VCC *U.S. Patent No.: 5,973,944

LTC1555L-1.8 Operating Temperature Range (Note 2) .. – 40°C to 85°C ORDER PART NUMBER TJMAX = 125°C, θJA = 150°C/W LTC1555LEGN-1.8 ABSOLUTE AXI U RATI GS W W W U PACKAGE/ORDER I FOR ATIO U U W (Note 1)

ELECTRICAL CHARACTERISTICS

The G denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (VIN = 2.6V to 6V, DVCC = 1.425V to 4.4V, controller digital pins tied to DVCC, SIM digital pins floating, C1 = 0.1µF, COUT = 2.2µF unless otherwise noted) PARAMETER CONDITIONS MIN TYP MAX UNITS VIN Operating Voltage G 2.6 V DVCC Operating Voltage G 1.425 4.4 V DVCC Undervoltage Lockout 1.2 V VIN Operating Current VCC = 3V, IVCC = 0V G µA VIN Shutdown Current M0, M1 = 0V G µA DVCC Operating Current M0, M1, DATA = DVCC, CIN = 1MHz G µA DVCC Shutdown Current M0, M1 = 0V, DATA, CIN = DVCC G µA VCC Output Voltage 0 < IVCC < 10mA M0, M1 = DVCC, 2.6V < VIN < 6V G 4.55 5.25 V M0, M1 = DVCC, 2.7V < VIN < 6V G 4.75 5.25 V M0 = DVCC, M1 = 0 G 2.8 3.2 V M0 = 0, M1 = DVCC G VIN – 0.2 VIN V M0 = DVCC, M1 = 0, M2 = DVCC, 0 ≤ IVCC ≤ 6mA G 1.71 1.8 1.89 V M0 = DVCC, M1 = 0, M2 = DVCC, VIN ≥ 3V, IVCC ≤ 10mA G 1.71 1.8 1.89 V VCC Short-Circuit Current VCC Shorted to GND G 150 mA Charge Pump fOSC MHz TOP VIEW GN PACKAGE 16-LEAD PLASTIC SSOP CIN RIN DATA DDRV DVCC CLK RST I/0 VCC VIN C1+ C1– GND GN PART MARKING 555L18 Consult factory for parts specified with wider operating temperature ranges.

LTC1555L-1.8 PARAMETER CONDITIONS MIN TYP MAX UNITS Controller Inputs/Outputs (DVCC = 1.8V) Input Current (IIH /IIL) M0, M1, M2, RIN, CIN G –100 100 nA Input Current (IIH /IIL) DDRV G µA High Level Input Current (IIH) DATA G –20 µA Low Level Input Current (IIL) DATA G mA High Input Voltage Threshold (VIH) M0, M1, M2, RIN, CIN, DDRV G 0.7 × DVCC V DATA G DVCC – 0.6 V Low Input Voltage Threshold (VIL) M0, M1, M2, RIN, CIN, DDRV G 0.2 × DVCC V DATA G 0.4 V High Level Output Voltage (VOH) DATA Source Current = 20µA I/O = VCC G 0.7 × DVCC V Low Level Output Voltage (VOL) DATA Sink Current = –200µA I/O = 0V (Note 3) G 0.4 V DATA Pull-Up Resistance Between DATA and DVCC G kΩ DATA Output Rise/Fall Time DATA Loaded with 30pF G 1.3 µs SIM Inputs/Outputs (VCC = 3V or 5V) I/O High Input Voltage Threshold (VIH) IIH(MAX) = ±20µA G 0.7 × VCC V I/O Low Input Voltage Threshold (VIL) IIL(MAX) = 1mA G 0.4 V High Level Output Voltage (VOH) I/O, Source Current = 20µA DATA or DDRV = DVCC G 0.8 × VCC V Low Level Output Voltage (VOL) I/O, Sink Current = –1mA DATA or DDRV = 0V (Note 3) G 0.4 V High Level Output Voltage (VOH) RST, CLK Source Current = 20µA G 0.9 × VCC V Low Level Output Voltage (VOL) RST, CLK Sink Current = –200µA G 0.4 V I/O Pull-Up Resistance Between I/O and VCC G 6.5 kΩ SIM Inputs/Outputs (VCC = 1.8V) I/O High Input Voltage Threshold (VIH) IIH(MAX) = ±20µA G 0.7 × VCC V I/O Low Input Voltage Threshold (VIL) IIL(MAX) = 1mA G 0.2 × VCC V High Level Output Voltage (VOH) I/O, Source Current = 20µA DATA or DDRV = DVCC G 0.8 × VCC V Low Level Output Voltage (VOL) I/O, Sink Current = –200µA DATA or DDRV = 0V (Note 3) G 0.4 V High Level Output Voltage (VOH) RST, CLK Source Current = 20µA G 0.9 × VCC V Low Level Output Voltage (VOL) RST, CLK Sink Current = –200µA G 0.2 × VCC V SIM Timing Parameters (DVCC = 1.8V, VCC = 5V) CLK Rise/Fall Time CLK Loaded with 30pF, VCC = 3V or 5V G ns VCC = 1.8V G ns RST, I/O Rise/Fall Time RST, I/O Loaded with 30pF G µs CLK Frequency CLK Loaded with 30pF G MHz VCC Turn-On Time COUT = 2.2µF, IVCC = 0 0.5 ms VCC Discharge Time to 1V IVCC = 0, VCC = 5V, COUT = 2.2µF 0.5 ms Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC1555LEGN-1.8 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 3: The DATA and I/O pull-down drivers must also sink current sourced by the internal pull-up resistor. The G denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (VIN = 2.6V to 6V, DVCC = 1.425V to 4.4V, controller digital pins tied to DVCC, SIM digital pins floating, C1 = 0.1µF, COUT = 2.2µF unless otherwise noted)

LTC1555L-1.8 TYPICAL PERFOR A CE CHARACTERISTICS U W VIN (V) IVIN (µA) 1555L • G01 VCC = 5V VCC = 3V VCC = 1.8V IVCC = 0mA TA = 25°C TEMPERATURE (°C) –40 IVIN (µA) 120 1555L • G02 VCC = 5V VCC = 3V VCC = 1.8V VIN = 3.6V IVCC = 0mA VDVCC (V) IDVCC (µA) 1555L • G03 FCLK = 1MHz TA = –40°C TA = 85°C TA = 25°C VIN (V) VCC (V) 5.0 5.5 1555L • G04 4.5 4.0 6.0 VCC = 5V IVCC = 10mA TA = –40°C TA = 85°C TA = 25°C VIN (V) VCC (V) 3.0 3.3 1555L • G05 2.7 2.4 3.6 TA = –40°C TA = 85°C VCC = 3V IVCC = 10mA TA = 25°C VIN (V) VCC (V) 1.8 2.0 1555L • G06 1.6 1.4 2.2 TA = –40°C VCC = 1.8V IVCC = 10mA TA = 85°C TA = 25°C IVIN vs VIN VCC vs VIN IVIN vs Temperature IDVCC vs VDVCC VCC vs VIN VCC vs VIN PIN FUNCTIONS U U U CIN (Pin 1): Clock Input Pin from Controller. RIN (Pin 2): Reset Input Pin from Controller. DATA (Pin 3): Controller Side Data Input/Output Pin. Can be used for single pin bidirectional data transfer between the controller and the SIM card as long as the controller data pin is open drain. The controller output must be able to sink 1mA max when driving the DATA pin low due to the internal pull-up resistors on the DATA and I/O pins. If the controller data output is not open drain, then the DDRV pin should be used for sending data to the SIM card and the DATA pin used for receiving data from the SIM card. DDRV (Pin 4): Optional Data Input Pin for Sending Data to the SIM Card. When not needed, the DDRV pin should either be left floating or tied to DVCC (an internal 1µA current source will pull the DDRV pin up to DVCC if left floating). DVCC (Pin 5): Supply Voltage for Controller Side Digital Input/Output Pins (typically 3V). May be between 1.425V and 4.4V. The DVCC supply may be powered-down in shutdown for further reduction in battery current. When DVCC drops below 1.2V, the charge pump is disabled and the LTC1555L-1.8 goes into shutdown mode regardless of the signals on the M0-M2 pins.

ouptut capacitor should connect close to the VCC pin. to the internal pull-up resistors on the I/O and DATA pins. The I/O pin is held active low during shutdown. connected to the SIM RST contact. recommended due to fast rise and fall edge speeds. Table 1. Truth Table 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. bypassing is required to meet 10kV ESD specifications. C1– (Pin 10): Charge Pump Flying Capacitor Negative␣Input. C1+ (Pin 11): Charge Pump Flying Capacitor Positive␣Input.

LTC1555L-1.8 APPLICATIO S I FOR ATIO W U U U The LTC1555L-1.8 performs the two primary functions necessary for low voltage controllers (e.g., GSM cellular telephone controllers, smart card readers, etc.) to com- municate with 5V SIMs or smart cards. The part produces a regulated 1.8V, 3V or 5V VCC supply for the SIM, and also provides level translators for communication between the SIM and the controller. VCC Voltage Regulator The regulator section of the LTC1555L-1.8 (refer to Block Diagram) consists of a buck/boost charge pump DC/DC converter. The charge pump can operate over a wide input voltage range (2.6V to 6V) while maintaining a regulated VCC output. The wide VIN range enables the part to be powered directly from a battery (if desired) rather than from a DC/DC converter output. When VIN is less than the selected VCC voltage, the part operates as a switched capacitor voltage doubler. When VIN is greater than VCC, the part operates as gated switch step-down converter. In either case, voltage conversion requires only one small flying capacitor and output capacitor. The VCC output can be programmed via the M0-M2 pins to either 1.8V, 3V, 5V or direct connection to VIN. This flexibility is useful in applications where multiple voltage SIMs may be used. When the charge pump is put into shutdown (M0, M1 = 0), VCC is pulled to GND via an internal switch to aid in proper system supply sequencing. An internal soft-start feature helps to limit inrush currents upon start-up or when coming out of shutdown mode. Inrush current limiting is especially useful when powering the LTC1555L-1.8 from a DC/DC output since the unlim- ited inrush current may approach 300mA and cause voltage transients on the 3V supply. The part is fully short- circuit and over temperature protected, and can survive an indefinite short from VCC to GND. Capacitor Selection For best performance, it is recommended that low ESR (<0.5Ω) capacitors be used for both CIN and COUT to reduce noise and ripple. The CIN and COUT capacitors should be either ceramic or tantalum and should be 1µF or greater (ceramic capacitors will produce the smallest output ripple). If the input source impedance is very low (<0.5Ω), CIN may not be needed. Increasing the size of COUT to 2.2µF or greater will reduce output voltage ripple—particularly with high VIN voltages (4V or greater). A ceramic capacitor is recom- mended for the flying capacitor C1 with a value of 0.1µF or 0.22µF. Output Ripple Normal LTC1555L-1.8 operation produces voltage ripple on the VCC pin. Output voltage ripple is required for the parts to regulate. Low frequency ripple exists due to the hysteresis in the sense comparator and propagation de- lays 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 (VIN < 4V) under maximum load is 75mV peak-to-peak with a low ESR, 2.2µF output capaci- tor (VCC = 5V). The magnitude of the ripple voltage depends on several factors. High input voltages increase the output ripple since more charge is delivered to COUT per charging cycle. A large C1 flying capacitor (> 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 all capaci- tors should be placed close to LTC1555L-1.8. Level Translators All SIMs and smart cards contain a clock input, a reset input, and a bidirectional data input/output. The LTC1555L-1.8 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.

LTC1555L-1.8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 G FAX: (408) 434-0507 G www.linear-tech.com  LINEAR TECHNOLOGY CORPORATION 2000 1555l18f LT/TP 0601 2K • PRINTED IN USA RELATED PARTS TYPICAL APPLICATIO U PART NUMBER

DESCRIPTION

SIM Power Supply and Level Translator VIN = 2.7V to 10V; Step-Up/-Down Charge Pump LTC1555L SIM Power Supply and Level Translator VIN = 2.6V to 6V; Step-Up/-Down Charge Pump; DVCC as low as 1.425V LTC1755 Smart Card Interface VIN = 2.7V to 6V; 24-Pin SSOP Package; IQ = 60µA LTC1756 Smart Card Interface VIN = 2.7V to 6V; 16-Pin SSOP Package; IQ = 75µA LTC1986 3V/5V SIM Power Supply in SOT-23 VIN = 2.6V to 4.4V; IQ = 14µA CIN RIN DATA DDRV DVCC CLK RST I/O VCC = 1.8V,3V IVCC = 6mA GND CLK RST I/O VCC VIN C1+ C1– GND 0.1µF 1µF LTC1555L-1.8 WCDMA CONTROLLER SIM VIN 2.6V TO 6V 1.425V TO 4.4V 2.2µF 1555L TA02 VCC WCDMA Cellular Telephone SIM Interface GN16 (SSOP) 1098 * 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 0.229 – 0.244 (5.817 – 6.198) 0.150 – 0.157 (3.810 – 3.988) 16 15 14 13 0.189 – 0.196* (4.801 – 4.978) 12 11 10 9 0.016 – 0.050 (0.406 – 1.270) 0.015 ± 0.004 0° – 8° TYP 0.007 – 0.0098 (0.178 – 0.249) 0.053 – 0.068 (1.351 – 1.727) 0.008 – 0.012 (0.203 – 0.305) 0.004 – 0.0098 (0.102 – 0.249) 0.0250 (0.635) BSC 0.009 (0.229) REF PACKAGE DESCRIPTIO U Dimensions in inches (millimeters) unless otherwise noted. 16-Lead Plastic SSOP (Narrow 0.150) (LTC DWG # 05-08-1641)