MAX5003EVKIT データシートの表示（PDF） - Maxim Integrated

部品番号

コンポーネント説明

一致するリスト

MAX5003EVKIT

MAX5003 Evaluation Kit

Maxim Integrated 

MAX5003 Evaluation Kit

LVL position disconnects the R1-R2 resistor-divider

from the MAX5003’s FB pin, as required for isolated

operation). Turn the power supply back on and verify

that the output voltage is still +5V. Note that for the iso-

lated configuration, the output ground and the input

ground may differ by as much as 500V. Do not oper-

ate switches SW1 and SW2 when power is applied

to the EV kit because the controller can be dam-

aged.

Nonisolated Level-Shifted Feedback

To configure the MAX5003 EV kit for operation in a sys-

tem in which the negative terminal of the input power

supply is at a more negative potential than the negative

terminal of the output power supply (for example, in a

-48V input to +5V output application), first turn off the

power supply and cut the JU1 PC board trace. Set the

SW1 switch to the NON position, and set the SW2

switch to the LVL position. Locate parts R18, R19, and

Q1 (directly above jumper JU1 on the PC board).

Solder the following parts into the R18, R19, and Q1

locations: R18 = 36.5kΩ ±1% resistor (1206), R19 =

12.4kΩ ±1% resistor (1206), and Q1 = 60V 2N2907-

type PNP transistor (SOT23). Note that the initial DC

output voltage accuracy and the temperature variation

will be degraded in this configuration. Do not operate

switches SW1 and SW2 when power is applied to

the EV kit because the controller can be damaged.

Undervoltage Lockout

and Shutdown

The MAX5003 EV kit is configured to go into undervolt-

age lockout when VIN drops below 32V. The MAX5003

does not have a shutdown pin, but the undervoltage

lockout state is equivalent to a shutdown state. The

MAX5003 EV kit contains a shutdown function consist-

ing of an NPN switching transistor (Q2) that can pull the

VINDIV pin to ground. To place the MAX5003 in under-

voltage lockout, drive the SHDN pad with a +5V logic-

high signal to turn on transistor Q2. For normal opera-

tion, the SHDN pad can be connected to ground or left

unconnected. Note that the logic-high signal used to

drive the SHDN pad is referenced to the negative side

of the input supply. For more details regarding under-

voltage lockout, refer to the MAX5003 data sheet.

Current Limiting

The MAX5003 EV kit has a current-limiting feature

implemented by current-sense resistor R9. The

MAX5003 turns off switching FET N1 when the voltage

at the CS pin reaches 100mV. Since R9 is a 0.11Ω

resistor, this limits the current in the transformer primary

to 0.91A peak, which corresponds to a typical output

short-circuit current of 4.5A. R10, a 100Ω resistor, is

connected between the current-sense resistor and the

CS pin to enable current-sense blanking after N1 is

turned on, as described in the MAX5003 data sheet.

Layout Considerations

The MAX5003 EV kit layout is optimized for fast switch-

ing and high currents. The input and output power and

ground traces must both be as short and wide as pos-

sible to minimize unwanted parasitic inductance. This

board was not designed per UL spacing specifications.

_______________________________________________________________________________________ 3

Share Link: