MAX8515EVKIT Maxim Integrated, MAX8515EVKIT Datasheet - Page 2

• Manufacturer Part Number: MAX8515EVKIT
• Description: Voltage & Current References Evaluation Kit for the MAX8515 MAX8515A
• Manufacturer: Maxim Integrated

Specifications of MAX8515EVKIT

• Product: Voltage References
• Topology: Shunt References
• Output Voltage: 0.2 V to 18 V
• Initial Accuracy: 0.5 %
• Shunt Current (max): 20 mA
• Series Vref - Input Voltage (max): 30 V

4) Connect the 8VDC power supply to the VIN pad.
5) In the following sequence, turn on the VREF, VIN,
6) Slowly raise output voltage VOUT above 0.8V (iso-
7) The VC output voltage goes to logic low when
The MAX8515 EV kit circuit simplifies the evaluation of
the MAX8515A shunt regulator in a voltage-regulation
circuit and the MAX8515 shunt regulator in an OVP cir-
cuit used in isolated DC-to-DC converters. Galvanic
isolation is achieved by the shunt regulator’s ability to
drive an optocoupler that separates the circuit’s supply
voltage and feedback inputs from the output shunt
stage grounds.
The voltage-regulation circuit is set to regulate at 0.8V
and provides an isolated voltage-feedback signal. PC
board pads are provided for adding resistors and
capacitors for loop compensation. The OVP threshold
is set to 1V and provides an isolated logic signal. Both
circuits’ thresholds can be reconfigured to as low as
0.6V by replacing their respective feedback resistors.
The MAX8515 EV kit is designed to operate from a volt-
age supply connected across the VIN and GND pads
on the EV kit. The input voltage source supplies the iso-
lated voltage-feedback circuit and the OVP circuit on
the EV kit. The EV kit operates from a nominal input
voltage of 8V and has a range of 6V to 10V. The input
voltage is nominally set to 8V by current-limiting resis-
tors R1 and R8 that limit the optocoupler shunting cur-
rent under 10mA. The EV kit’s operational voltage is
dependent on the application and can be adjusted in
the 1.8V to 18V range by replacing current-limiting
resistors R1, R5, R8, and R9 and selecting them to limit
the current to under 10mA.
The MAX8515 EV kit also requires an input voltage ref-
erence at the VREF pad. The voltage applied at VREF
determines the voltage at the VC and OVP signal out-
put pads during board operation.
The isolated voltage-regulation feedback circuit and
the OVP circuit on the EV kit are configured to monitor a
single output from a DC-to-DC converter. The voltage
output from the DC-to-DC converter must be connected
across the VOUT and GND pads of the EV kit.
MAX8515 Evaluation Kit
2
Connect the supply ground to the GND pad.
and VOUT power supplies.
lated voltage-feedback circuit threshold) and then
above 1V (OVP circuit threshold).
VOUT is higher than 0.8V and the OVP output goes
to logic low when VOUT is higher than 1V.
_______________________________________________________________________________________
Detailed Description
Input Voltages
Output
The top circuit on the EV kit board features the
MAX8515A shunt regulator in a 5-pin SC70 package
and has an initial accuracy of ±0.5%. The voltage-regu-
lation circuit is set for an output-regulation threshold of
0.8V that is set by feedback resistors R3 and R4.
The voltage-regulation threshold can be adjusted to a
minimum of 0.6V by replacing feedback resistors R3
and R4 and using the following equation:
where V
By default, the voltage-regulation circuit functions as an
OVP circuit and requires the installation of compensa-
tion components R2, C2, C3, and C11 to function as a
voltage-regulation circuit. These components are appli-
cation dependent and may require verification in the
lab. Refer to the Optical Feedback section in the
MAX8515 data sheet to select the proper compensa-
tion components.
When the voltage at the VOUT pad rises above the set
threshold, the shunt regulator sinks current to drive the
optocoupler and generates a voltage signal at the VC
pad. Connect VC to the primary side of the DC-to-DC
converter’s voltage control stage.
The bottom circuit on the EV kit board features the
MAX8515 shunt regulator in a 5-pin SOT23 package
and has an initial accuracy of ±1%. The OVP circuit has
an OVP threshold of 1V that is set by feedback resistors
R11 and R12.
The overvoltage threshold can be adjusted to a mini-
mum of 0.6V by replacing feedback resistors R11 and
R12 and using the following equation:
where V
When the voltage at the VOUT pad rises above the set
threshold, the shunt regulator sinks current to drive the
optocoupler and generates a logic-low signal at the
OVP pad. Connect OVP to the primary side of the con-
verter’s control stage.
FB
FB
V
V
THRESHOLD
= 0.6V.
= 0.6V.
THRESHOLD
Voltage-Regulation Circuit
= V
= V
FB
Overprotection Circuit
FB
✕
✕
((R11 / R12) +1)
((R3 / R4) +1)
(Bottom Circuit)
(Top Circuit)