AN1978 STMicroelectronics, AN1978 Datasheet
AN1978
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AN1978 Summary of contents
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... VOLTAGE SUPERVISOR ALARM En1 CLKUP En2 GENERATOR PV CC En5 RST BUFFER SEQUENCER En4 En4 CLOCK CIRCUITRY CLK THERMAL PROTECTIO OSCILLATOR En3 I/O TRANSCEIVER I/O TRANSCEIVER I/O TRANSCEIVER 22 GND AN1978 100nF GND 100nF VCC 100nF 14 CGND RST 16 CLK 15 CLOCK ...
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... AN1978 - APPLICATION NOTE 2. SEQUENCER Core of the ST8004 is the sequencer (shown in figure 1) that must coordinate the enable signals for the activation and deactivation sequence and check for possible fault conditions. This because the smart card is basically a microcontroller and needs to be activated/deactivated by a correct sequence as required by the ISO/IEC7816 standard ...
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... According to the EIA/ISO7816 specifications, the CLK duty cycle must be enclosed between 45% and 55% even if the clock division changes. In this case, at CLKDIV change, the ST8004 waits for the first falling edge to ensure the duty cycle accuracy, as shown in Figure 4. AN1978 - APPLICATION NOTE CLKDIV ...
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... AN1978 - APPLICATION NOTE Figure 4: Clock duty cycle on CLKDIV change The clock signal can be obtained by a crystal connected between the XTAL1 and XTAL2 pins external signal applied to the XTAL1 pin; in this case the XTAL2 pin must be left floating. The external signal voltage value must be enclosed between GND and VDD. ...
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... Figure 9 and are recommended with ESR lower than 50mΩ @ 100kHz such as MURATA GRM31M7U1H104JA01B. Anyway, also capacitor with ESR up to 100mΩ @ 100kHz are enough to work in specifications. V DDP 100nF STEP-UP CONVERTER ON/OFF OUTPUT ST8004 EN2 17 VCC P REGULATOR VCC AN1978 - APPLICATION NOTE P GND 100nF 5/14 ...
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... AN1978 - APPLICATION NOTE A better noise performance could be achieved connecting the V V instead of GND. Moreover, a 200nF capacitor should be connected to V DDP obtain a higher current from the charge pump when pulsed load is applied on Vcc. In the typical applications a 100nF filter capacitor is connected to the Vcc output, near the ST8004 pins and another 100nF is connected, between C1 and C5, near the card slot as shown in Figure 7 and Figure 9 ...
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... UP Vcc Vcc Vcc Vcc Vcc Vcc PRES and PRES PRES and PRES PRES and PRES AN1978 - APPLICATION NOTE CH1: Vcc voltage; offset=5V; BandWidth=250MHz. CH4: Vcc output current into GND. Conditions: VDD=3.3V; VDDP=4.75V; 5/3V=H. The Vcc voltage is between 4.6V and 5.3V even if a 65mA sink pulsed current is forced ...
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... AN1978 - APPLICATION NOTE 5. FAULT DETECTION ST8004 provides a fault detection circuitry as shown in Figure 1 monitoring the following conditions: - Over-temperature detection - Fault on card removing - VDD under-voltage - Vcc Short circuit protection 5.1. VDD under-voltage The ST8004 logic circuitry is supplied by VDD; in order to avoid voltage spikes causing bad behaviors of device and card, a voltage supervisor block is embedded as shown in Figure 1 ...
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... Figure 11: OFF behaviour on VDD drop. Figure 12: Deactivation sequence automatically when spikes on VDD are present. AN1978 - APPLICATION NOTE Conditions Floating; THSEL V = =5V; DDP 5/3V=L. CH1:CMDVCC CH2: VDD CH3: OFF CH4: Vcc When the V voltage falls below DD the Vth2 value (about 2.1V) a deactivation sequence starts and the OFF pin goes low until CMDVCC rising edge happens ...
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... AN1978 - APPLICATION NOTE Figure 13: Vth2 threshold. 5.2. Vcc short-circuit protection An important feature of the voltage regulator is the short-circuit protection that warns the sequencer block (see Figure 1) if the output current grows more than the short circuit current limit (about 90mA). In this case a deactivation sequence starts to protect the card and the OFF pin falls down warning the occurred fault as shown in Figure18 ...
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... Figure 14: Vup load curve Figure 15: Vcc load curve Vup voltage VS Iup Iup (mA) Vcc voltage VS Icc Iup (mA) AN1978 - APPLICATION NOTE 5/3V=H 5/3V=L 100 120 5/3V=H 5/3V=L 100 11/14 ...
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... AN1978 - APPLICATION NOTE Figure 16: Short-circuit on Vcc during the activation. Figure 17: Short-circuit on Vcc after the activation. 12/14 Conditions: Conditions: Conditions =4.75V; =4.75V; =4.75V; DDP DDP DDP 5/3V=H. 5/3V=H. 5/3V=H. CH1: Vcc CH1: Vcc CH1: Vcc CH2: CMDVCC. CH2: CMDVCC. CH2: CMDVCC. ...
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... CH4 : Vcc output current CH4 : Vcc output current When When occurs the OFF pin goes occurs the OFF pin goes low indicating a fault. low indicating a fault. Revision Description of Changes 1 First Release AN1978 - APPLICATION NOTE = =5V; =5V; the the short short circuit circuit 13/14 ...
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... AN1978 - APPLICATION NOTE Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice ...