Datasheet

MAX15059 Evaluation Kit
Evaluates: MAX15059A/MAX15059B
_______________________________________________________________________________________ 3
*Default position.
Table 1. SHDN and Enable (JU2)
Table 3. RLIM (JU3)
Output-Voltage Programmability
The EV kit features a jumper to set the output
voltage (VOUT/APD) programmability. VOUT/APD is
programmed by connecting an external reference
voltage source to the CNTRL and SGND PCB
pads. Remove the shunt at jumper JU1 to use the
programmability feature and apply a reference voltage
< 1.2V to the CNTRL PCB pad. When the voltage
applied to the CNTRL pad is > 1.3V, the IC’s internal
reference is used. See Table 2 for jumper JU1 settings.
The output voltage at VOUT is set by resistors R1 and R2
to 70V when jumper JU1 is installed. To reconfigure the
output for a different voltage (VIN + 5V to 76V), select
a new surface-mount 0603 resistor for R1. Refer to the
Setting the Output Voltage section in the MAX15059 IC
data sheet for selecting the R1 value.
Current-Monitor Output (MOUT)
and APD Load Simulator
The MOUT PCB pad provides a current-monitor out-
put that sources a current equal to the APD current
in the MAX15059A and 1/5th the APD current in the
MAX15059B. An RC network comprised of resistor R3
and capacitor C7 provide a filter to the MOUT signal.
Capacitor C7 is not required in a typical design.
Additionally, resistors R8 and R9 set the APD load-
simulator circuit’s current for current-monitor step-
response measurements. Apply a 0 to 11V square-wave
signal to the APD_DRV PCB pad to simulate a 0 to 4mA
load. Use test point TP1 or TP2 to measure the APD load
current and TP3 as the SGND.
Clamp Input (CLAMP)
CLAMP provides a means for diode clamping the
volt age at MOUT; thus, V
MOUT
is limited to (V
CLAMP
+
0.6V). CLAMP can be connected to either an external
supply or BIAS (TP4). Leave CLAMP unconnected if
voltage clamping is not required.
Setting Fast Current-Limit
Threshold and ILIM
Resistor R5 sets the IC’s APD fast current-limit
threshold to 2.22mA. To reconfigure the circuit for
another current-limit threshold, replace resistor R5 and
use the following equation to calculate a new value for
the desired current:
( )
LIM
1.23V
R5(k ) 10 2.67k
I mA
 
 
Ω = × − Ω
 
 
 
 
 
 
where I
LIM
is the desired DC load current in milliamps.
Place a shunt on jumper JU3 to connect RLIM to SGND
and set the current-limit threshold to 4.6mA. See Table 3
for jumper JU3 settings.
The ILIM open-drain signal is available at the ILIM PCB
pad. During normal EV kit operation, resistor R6 pulls
up the ILIM pin to VIN. ILIM asserts low when the APD
current limit has been exceeded.
*Default position.
Table 2. Output-Voltage Programming (JU1)
*Default position.
**Apply a voltage > 1.3V to use the MAX15059 internal refer-
ence. The voltage should be 1.5V to VIN voltage. Refer to the
Adjusting the Feedback Set-Point/Reference Voltage section
in the MAX15059 IC data sheet for more information.
SHUNT
POSITION
SHDN PIN
EV KIT OPERATION
1-2*
Connected to
VIN
Enabled
2-3
Connected to
SGND
Disabled
SHUNT
POSITION
CNTRL PIN
OUTPUT-VOLTAGE
PROGRAMMING
Installed*
Connected to
VIN
Fixed output voltage:
Internal reference voltage
used.
Not installed
Connected to
external
reference
Programmable output
voltage: Apply an
external reference
voltage (< 1.2V) at
CNTRL PCB pad.
Not installed
Connected to
external
reference
Fixed output voltage:
Apply an external
reference voltage
(> 1.3V)** at CNTRL PCB
pad; internal reference
voltage used.
SHUNT POSITION CURRENT-LIMIT THRESHOLD
Installed Default setting of 4.6mA
Not installed* Programmed by R5