LTC1755 LINER [Linear Technology], LTC1755 Datasheet
LTC1755
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LTC1755 Summary of contents
Page 1
... Automatic DC/DC converter soft start mitigates start-up problems that may result when the input power is provided by another regulator. Multiple LTC1755 devices may be paralleled and connected to a single controller for multicard applications. Battery life is maximized operating current and 1 A shutdown current. The 24-pin SSOP package mini- mizes PCB area for compact portable systems ...
Page 2
... OUT I = 0mA 5V VCC CC OUT = 3V CC Source Current = 20 A Sink Current = – 500 A (Note 3) Loaded with 30pF ORDER PART TOP VIEW NUMBER 24 5V/3V 23 CARD LTC1755EGN 22 ALARM READY – AUX1IN 17 AUX2IN 16 DATA 15 RIN 14 CIN 13 GN PACKAGE ...
Page 3
... PRES Debounce Time Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC1755 is guaranteed to meet performance specifications from Specifications over the – operating temperature range are assured by design, characterization and correlation with statistical process controls ...
Page 4
... below its correct level (for as little the LTC1755 switches to the Alarm state (see the State Diagram). The V capacitor to ground. For optimum performance a low ESR ceramic capacitor should be used. During the Idle and Alarm states the V discharged to ground to comply with the deactivation requirements of the EMV and ISO-7816 specifications ...
Page 5
... CLK with these signals differ for several mi croseconds then the LTC1755 switches to the Alarm state. CC This fault checking is only performed after the V reached its final value (as indicated by the READY pin). The clock channel is optimized for signal integrity in order to meet the stringent duty cycle requirements of the EMV specification ...
Page 6
... OR connections of multiple LTC1755s to a single micro- controller. ALARM (Pin 22): (Output) A low on this pin indicates that a fault has occurred and that the LTC1755 is in the Alarm state (see the State Diagram). Possible faults include V underrange for at least 5 s, overtemperature shutdown, CLK or RST invalid output levels, and card removal during the Active state ...
Page 7
... W BLOCK DIAGRA DV PRES 1 PWR NC/NO 4 GND AUX1 8 * AUX2 9 * I/O 10 RST 11 CLK 12 * DYNAMIC PULL-UP CURRENT SOURCE CC DC/DC CONVERTER AND CONTROL LOGIC LTC1755 24 5V/3V 23 CARD 22 ALARM 21 READY – AUX1IN * 16 AUX2IN * 15 DATA 1755 BD 7 ...
Page 8
... The bypass capacitor at V output the input supply due to ESR may cause problems with the internal circuitry of the LTC1755. A good choice for the input bypass capacitor Y5V style ceramic Dynamic Pull-Up Current Sources The current sources on the bidirectional pins (DATA, ...
Page 9
... Smart Card is present and that V charge pump voltage its final value. The Smart Card remains powered as long detected by the PRES pin. When the Smart Card is removed the LTC1755 will auto- matically be deactivated by the fault detection circuitry. Deactivation Sequence For maximum flexibility the Smart Card can be deactivated either manually or automatically ...
Page 10
... CC Same as Idle/Deactivation except: ALARM = L NO FAULT FAULT The only possible next state is Idle/Deactivation which is achieved by disabling the LTC1755 via the PWR pin FAULT (i.e., PWR = DV TIMEOUT or The alarm indication can be cleared by rapidly cycling the 1755 F04 PWR pin. However, a new activation cycle will not begin ...
Page 11
... Plastic SSOP (Narrow 0.150) (LTC DWG # 05-08-1641) 0.229 – 0.244 (5.817 – 6.198) 0.015 0.004 0.053 – 0.068 45 (0.38 0.10) (1.351 – 1.727) 0 – 8 TYP 0.008 – 0.012 (0.203 – 0.305) LTC1755 0.337 – 0.344* (8.560 – 8.738) 0.033 (0.838 ...
Page 12
... CLK PRES 5V/ PWR CARD ALARM 4 21 NC/NO READY GND – LTC1755 0. AUX1 AUX1IN 9 16 AUX2 AUX2IN 10 15 I/O DATA 11 14 RST CLK C IN COMMENTS Regulated Output Up to 50mA, V 5V/50mA Output from Input, S0-8 Package Step-Up/Step-Down Charge Pump + SIM Level Translators, > ...