MAX186EVKIT-DIP Maxim Integrated, MAX186EVKIT-DIP Datasheet - Page 4

• Manufacturer Part Number: MAX186EVKIT-DIP
• Description: Data Conversion IC Development Tools Programmers, Development Systems
• Manufacturer: Maxim Integrated
• Series: MAX186, MAX188r

Specifications of MAX186EVKIT-DIP

• Interface Type: 4-Wire (SPI, Microwire, QSPI, TMS320)
• Factory Pack Quantity: 1

The MAX186 digital signals are available on the 8-pin
header located on the bottom edge of the board. This
header provides convenient connections for scope
probes or a ribbon cable.
The MAX186 performs conversions on demand or at
preset intervals. The conversion sequence does not
vary with the two methods. If the device is in shutdown
mode, a dummy conversion brings it out of shutdown,
and the program delays to allow the reference voltage
to settle. Then, as many as eight conversions are per-
formed to collect data for a complete line of the screen
display. Finally, if shutdown mode is enabled, another
dummy conversion returns the MAX186 to the proper
shutdown state.
The MAX186 has two shutdown levels. The FULL shut-
down mode completely disables the MAX186 reference
circuit and reduces supply current to 2µA. A delay of
300µs is required to activate from this shutdown state.
The delay must be greater when the external reference
compensation capacitor, C6, is installed. Be sure to set
the reference settling delay whenever the FULL shut-
down mode is used. Table 5 of the MAX186/MAX188
data sheet lists the reference settling times required for
different external capacitors.
The second shutdown level disables only the reference
output buffer. This drops the supply current to 30µA,
but requires a shorter delay (5µs with internal compen-
sation) between activation and conversion cycles. This
is referred to as the FAST shutdown mode.
On the MAX186 evaluation board, the
is programmed high so that it always enables the
MAX186 in normal operation. All modes are controlled
through software. In FAST or FULL shutdown mode, the
MAX186 is placed in shutdown between conversion
cycles and activated just before the conversions begin.
This reduces the average supply current but will
require a delay before the conversions. The
MAX186EVKIT Personal Computer Program section has
information on varying the delay and controlling the
shutdown mode.
MAX186 Evaluation System/Evaluation Kit
4
_______________________________________________________________________________________
Conversion Cycles
Shutdown Mode
SHDN
pin (P1.2),
Jumper JU2 is in series with the
MAX186. Opening this jumper floats the
abling the internal compensation of the reference
buffer. The external compensation capacitor, C6, is
supplied with the kit but not mounted on the PCB. If you
wish to use external compensation, cut the trace across
JU2 and mount the 22µF capacitor, C6. The reference
settling delay must be increased. See the MAX186/
MAX188 data sheet for descriptions of internal and
external reference compensation.
The MAX186 can be operated with an external refer-
ence voltage if the internal reference is disabled.
Connecting the REFADJ pin to V
internal reference. Soldering a short piece of wire
across jumper JU3 will make this connection. The 22µF
capacitor should also be soldered into location C6
when using an external voltage. The reference voltage
is then applied to the pad labeled VREF.
To use the MAX188, which requires an external refer-
ence, install C6 and connect the reference source to
the VREF pad.
Jumper JU1 facilitates monitoring the MAX186 supply
current in the shutdown modes. The jumper allows the
insertion of a current meter in series with the MAX186
V
cuit trace between the two holes marked JU1. Then sol-
der two short leads in each hole and connect the amme-
ter. A short piece of wire can be soldered across the
jumper location to restore normal connections.
Each of the eight inputs has a 300Ω resistor in series.
These optional resistors were included as current-limiting
devices for input overvoltage conditions. There is also an
optional 0.01µF capacitor on each of the inputs. This pro-
vides the low source impedance required when the
channel is the low side of a differential input pair. The
input capacitors are not required on channels used as
single-ended inputs. Refer to the Pseudo-Differential
Input section of the data sheet.
DD
supply. To monitor the current, cut the printed cir-
Reference Voltages
Evaluating External
DD
Analog Inputs
SHDN
will disable the
SHDN
pin of the
pin, dis-