MAX5974AEVKIT Maxim Integrated, MAX5974AEVKIT Datasheet - Page 4

• Manufacturer Part Number: MAX5974AEVKIT
• Description: Power Management IC Development Tools
• Manufacturer: Maxim Integrated
• Type: PWM Controllersr
• Series: MAX5974A, MAX5974B, MAX5974C, MAX5974Dr

Specifications of MAX5974AEVKIT

• Product: Evaluation Kits
• Tool Is For Evaluation Of: MAX5974A
• Input Voltage: - 30 V to - 57 V
• Output Voltage: 5 V
• Output Current: 4.7 A

MAX5974A Evaluation Kit
• MAX5974A EV kit
• IEEE 802.3af/at-compliant PSE and Category 5e
• -48V, 1A-capable DC power supply
• Voltmeter
The EV kit is fully assembled and tested. Follow the
steps below to verify board operation. Caution: Do not
turn on the power supply until all connections are
completed.
1) Use one of the following methods to power the EV kit:
2) Activate the PSE power supply or turn on the external
3) Using a voltmeter, verify that the EV kit provides
The MAX5974A EV kit is a fully assembled and tested
surface-mount circuit board that evaluates the MAX5974A
active-clamped, spread-spectrum, current-mode PWM
controller. The EV kit features a powered Ethernet port, a
data-only Ethernet port, and a MAX5969B IEEE 802.3af/
at-compliant network PD interface-controller IC.
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Detailed Description of Hardware
Ethernet network cable
DC power supply.
approximately +5V across the +5V and GND PCB pads.
GND is galvanically isolated from the EV kit’s input VDD
and VSS pads.
• If network connectivity is required: Connect a
• If network connectivity is not required:
Category 5e Ethernet network cable from the EV
kit input port RJ45 MagJack connector (RJ45) to
the corresponding PSE Ethernet LAN connection
to provide power to the EV kit. A modular RJ45
jack (J1) provides an interface with the Ethernet
data signals only.
Connect a -48V DC power supply between the
VDD and VSS pads on the EV kit. Connect the
power-supply positive terminal to the VDD pad
and the negative terminal to the VSS pad.
Hardware Connections
Required Equipment
Quick Start
The EV kit is a galvanically isolated 25W DC-DC converter
using the active-clamped, current-mode PWM controller
in a forward, coupled-inductor feedback topology. The EV
kit receives power from an IEEE 802.3af/at-compliant PSE
and a UTP cable connected to the EV kit’s RJ45 MagJack.
The EV kit uses a 1 x 1Gb RJ45 MagJack and two diode-
bridge power rectifiers (D1, D2) to separate the -57V DC
power sent by the PSE. The EV kit accepts power from
an endspan or midspan PSE network configuration. The
EV kit also provides an RJ45 jack (J1) for interfacing to
the Ethernet data signals. PCB pads VDD and VSS are
available for powering the EV kit if network connectivity
is not required.
The EV kit output voltage is configured for +5V and
provides up to 4.7A output current while achieving up to
92% efficiency. Transformer T1 provides up to +1650V
galvanic isolation for the output. Transformer T2 is used
for providing the operating voltage at the device’s IN
input and for coupled-inductor feedback control for
setting the output voltage using resistors R3, R11, and
R49. Current-sense resistors R21 and R25 limit the peak
current through transistor N3 and primary transformer
T1. PCB pad D11 is available for clamping the IC IN
input when driving the EN input using an external source.
Capacitor C17 and transistor N4 form a clamping
network that protects transformer T1 against saturation,
due to reverse current, by monitoring the voltage across
the device’s CS input during auxiliary driver N4’s off time.
The EV kit also demonstrates the full PD functionality of the
device, such as PD detection signature, PD classification
signature, in-rush current control, and UVLO. Resistors
R14 and R4 set the PD detection signature and the PD
classification signature, respectively.
The EV kit circuit accepts power from a wall-adapter DC
power source. When a +37V to +57V wall-adapter power
source is applied at the PWR+ and PWR- PCB pads, it
takes precedence over the PSE source, allowing the wall
adapter to power the EV kit circuit. When applying a valid
voltage source between the PWR+ and PWR- PCB pads,
the MAX5696B’s internal isolation switch disconnects
VSS from RTN, which allows the wall adapter to supply
power to the EV kit.