Atmel ICE50, User Manual

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General Description
ICE50 User Guide 3-15
2523A–AVR–11/02
The ADC is built using analog multiplexers, programmable gain instrumentation amplifi-
ers and a 10-bit successive approximation A/D converter. This construction should have
the same performance as the actual part, but since the ADC is located on the POD as
an external construction the analog components will be more susceptible to ambient
noise and noise from switching IO lines.
Note:
Internal analog reference voltage is set to 2.5 volt when using the emulator. This
differs from part which uses 2.56 V. Due to this fact ADC conversions done by
the emulator using the internal analog reference voltage differ from the conver-
sions done in part.
All inputs to the ADC have serial current limiting resistors of 330
Ω
. This is to protect the
inputs of the ADC circuit when the emulator is switched off and the target power is
present. The outputs of the input multiplexers are clamped to V
CC
and GND and thus
when target V
CC
is present and the emulator power is turned off there will flow a current
of approximately (Vinput - 0.3V)/330
Ω
through each ADC input pin.
3.6 Power System
Description
The ICE50 needs external power in order to function. A switching power adapter is sup-
plied with the unit. The power adapter will accept input voltages in the range of 100VAC
to 240VAC and frequencies from 50Hz to 60Hz. This will cover most situations.
3.6.1 Power Supply Figure 3-22. Power Supply
The power supply delivered with ICE50 is dimensioned to meet the requirements of the
Emulator. If another power supply is used, it should supply a voltage between 9 and 15
VDC, and a minimum of 20W. It connects to the main unit through a standard connector
with 2.1 mm center tap. Ground is connected to the center tap.
3.6.2 ICE50 Power System The ICE50 has an internal power regulator designed to deliver regulated voltages for
use by the ICE itself. The power system is not designed to provide external power to the
target application.