MAX15500_11 Datasheet, PDF (16/28 Pages) Maxim Integrated Products – Industrial Analog Current/ Voltage-Output Conditioners

Industrial Analog Current/
Voltage-Output Conditioners
_Detailed Description
The MAX15500/MAX15501 output a programmable cur-
rent up to Q24mA or a voltage up to Q12V proportional to
a control signal at AIN. The devices operate from a dual
15V to 32.5V supply. The control voltage applied at AIN
is typically supplied by an external DAC with an output
voltage range of 0 to 4.096V for the MAX15500 and 0
to 2.5V for the MAX15501. The MAX15500/MAX15501
are capable of both unipolar and bipolar current and
voltage outputs. In current mode, the devices produce
currents of -1.2mA to +24mA or -24mA to +24mA. In
voltage mode, the devices produce voltages of -0.3V
to +6V, -0.6V to +12V, or Q12V. To allow for overrange
and underrange capability in unipolar mode, the transfer
function of the MAX15500/MAX15501 is offset such that
when the voltage at AIN is 5% of full scale, IOUT is 0mA
and VOUT is 0V. Once VAIN attains full scale, VOUT or
IOUT becomes full scale +5% or +20% depending on
the state of FSMODE. The MAX15500/MAX15501 are
protected against overcurrent and short-circuit condi-
tions when OUT goes to ground or a voltage up to
Q32.5V. The devices also monitor for overtemperature
and supply brownout conditions. The supply brownout
threshold is programmable between ±10V and ±24V in
2V increments.
The MAX15500/MAX15501 are programmed through an
SPI interface with daisy-chain capability. A device ready
logic output (READY) and two device select inputs (CS1
and CS2) facilitate a daisy-chain arrangement for multiple
Table 1. Output Values for FSMODE =
DVDD, Unipolar 5% Overrange
OUTPUT RANGE
0 to 20mA
(4mA to 20mA)
0 to 5V
0 to 10V
OUTPUT VALUES
VAIN = 5%FS
VAIN = FS
0mA
21mA
0V
5.25V
0V
10.5V
device applications. The MAX15500/MAX15501 provide
extensive error reporting of short-circuit, open-circuit,
brownout, and overtemperature conditions through the
SPI interface and an additional open-drain interrupt
output (ERROR). The MAX15500/MAX15501 include an
analog 0 to 3V output (MON) to monitor the load condi-
tion at OUT.
Analog Section
The MAX15500/MAX15501 support two output modes:
current and voltage. Each mode has different full-scale
output values depending on the state of FSMODE as
detailed in Tables 1 to 4 and Figures 1 and 2. Use the
device configuration register in Table 6 to select the
desired voltage or current output range.
Startup
During startup, the MAX15500/MAX15501 output is set
to zero and all register bits are set to zero. The devices
remain in standby mode until they are configured
through the SPI interface.
Input Voltage Range
The input voltage full-scale level is selectable between
2.5V and 4.096V using logic input FSSEL. The MAX15500
is specified for a 0 to 4.096V input voltage range, while
the MAX15501 is specified for a 0 to 2.500V input volt-
age range. Connect FSSEL to DVDD to set the input
range to 0 to 4.096V for the MAX15500. Connect FSSEL
to DGND to set the input range to 0 to 2.500V for the
MAX15501.
Table 3. Output Values for FSMODE =
DVDD, Bipolar 5% Overrange
OUTPUT RANGE
Q20mA
Q10V
OUTPUT VALUES
VAIN = 0V
VAIN = FS
-21mA
+21mA
-10.5V
+10.5V
Table 2. Output Values for FSMODE =
DGND, Unipolar 20% Overrange
OUTPUT RANGE
OUTPUT VALUES
VAIN = 5%FS
VAIN = FS
0 to 20mA
(4mA to 20mA)
0mA
24mA
0 to 5V
0V
6V
0 to 10V
0V
12V
Table 4. Output Values for FSMODE =
DGND, Bipolar 20% Overrange
OUTPUT RANGE
OUTPUT VALUES
VAIN = 0V
VAIN = FS
Q20mA
-24mA
+24mA
Q10V
-12V
+12V
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