ISO 7816 Interface Monitor
--------------------------

Markus Kuhn <mgk25@cl.cam.ac.uk> -- 2000-07-28


This circuit has been designed for power analysis measurements and
passive asynchronous protocol monitoring on ISO 7816 smartcard
interfaces. A small resistor can be inserted into the smartcard GND
line to observe the card's supply current. Its signal can either be
observed directly, or it can be decoupled and amplified using a range
of high-speed operation amplifiers (e.g., from Maxim). The PCB layout
supports the optional on-board generation of a -5V power supply for
the amplifier, again using Maxim components. An optional Maxim quad
switch can be used to translate the I/O and RST signal voltages to
EIA-232 levels, where the power is supplied by the connected serial
port. The PCB layout is suitable for both single and double sided
boards. With the double-sided version, a GND plane helps to improve
the high-frequency characteristics of the circuit. With the
single-sided version, a few additional GND wire-connections have to be
made.


Suggested possible components:

Operation Amplifier:

  Option 1A (1:1, 1 GHz, 1100 V/µs, 560 ohm & 0 ohm):

    MAX4223ESA

  Option 1B (1:1, 780 MHz, 4200 V/µs, low impedance output, no resistors):

    MAX4200ESA

  Option 1C (1:1, 780 MHz, 4200 V/µs, 50 ohm output, no resistors):

    MAX4201ESA

  Option 1D (1:2, 400 MHz, 1200 V/µs, 2x 600 ohm)

    MAX4112ESA

  Option 1E (1:8, 270 MHz, 1800 V/µs, 500 ohm & 69 ohm)

    MAX4113ESA

  also:

    2 SMD power supply bypass ceramic capacitors 0.01 to 0.1 µF
    2 SMD power supply bypass ceramic capacitors 1000 pF or 10 nF (nearest IC)

Voltage Converter:

  Option 2A (125 kHz):

    MAX870EUK (code ABZN)

  Option 2B (35 kHz):

    MAX829EUK (code AABJ)

  also:

    3 SMD tantalum capacitors, low ESR, e.g. 4.7 or 10 µF

RS232 Converter (quad switch):

    MAX314CSE

  also:

    4 SMD diodes (+5 V, +10V, and -10V power supply polarity protection)

Other components:

  1 SMD GND current measurement resistor (e.g., 10 ohm)
  1 SMD smartcard VCC bypass capacitor 0.1 µF
  1 SMD smartcard VCC bypass ceramic capacitor 1000 pF
  1 smartcard adapter (38.1 mm = 1.5 in between opposing pins)
  1 photoresist PCB, 0.8 mm thickness (!), double sided, 60 x 190 mm

IC component data sheets:

  http://www.maxim-ic.com/

The first four prototype PCBs were produced in 2000-07 for Markus
Kuhn by

  Cambridge Circuit Co. Ltd
  4 Winship Road, Milton
  Cambridge CB4 6BQ
  http://www.cambridge-circuit.co.uk/