Hercules Series, Page 6

Part No. 98–002 Rev. 1.1

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Application Notes

Signal Characteristics: Per table on page 5.

Input Signals:

Enable_L: This input signal is used to enable the

output of the converter when activated (active Low).

The signal is referenced to the output side (–Sense).

Enable_L does not require an external pull-up resistor.

If an external pull-up is used it should be tied to +5V.

To minimize start-up problems it is recommended that

Enable_L be driven from an open-drain configured FET.

Voltage Adjust: The output voltage of the converter

shall be adjustable as specified in the table on page 3.

The voltage adjust pin sources 1 mA current. The

adjustment shall be done using an external voltage

source or a resistor connected between the Voltage

Adjust pin and the – Sense pin. See below for output

voltage adjustment application information.

Current Share: When two or more converters are

connected in parallel, their current share pins must be

connected together to allow proper load sharing.

Sync: When two or more converters from the same

manufacturer are connected in parallel, their sync pins

may be connected together to synchronize their

operating frequencies. When two or more converters

from different manufacturers are connected in parallel

their sync pins must NOT be connected together.

Output Signals:

MODOK_L: MODOK_L shall be asserted to indicate

that the output voltage is in regulation. When two or

more converters are operating in parallel a failed

converter may or may not de-assert its MODOK_L

signal.

OTW_L: OTW_L shall be asserted to indicate that the

converter temperature is too high and that the converter

is about to shut down. OTW_L will be asserted a

minimum of 500 msec before the converter shuts down

due to an overtemperature condition. The output of this

signal is the open drain of a FET. The output is current

limited to 8-15 mA and may be used to drive an external

LED directly.

Output Voltage Adjustment:

Voltage Programming: A voltage may be applied

between the Voltage Adjust pin (pin 5) and the – Sense

pin (pin 1) to adjust the output voltage up or down from

the nominal output voltage by a maximum of

±10%.

The trim voltage for the GPH1V5-40 and GPH1V5-60

is:

0.30

For the GPH2V2-40 and GPH2V2-60 the output voltage

may be trimmed to +15% , - 10%. The trim voltage for

these two units is:

= ——————

+ 1.0V

0.44

The trim voltage for the GPH3V3-40 and GPH3V3-60 is:

0.66

The trim voltage for the GPH5V0-30 and GPH5V0-40

is:

1.0

Resistor Programming: A resistor may be connected

between the Voltage Adjust pin (pin 5) and the

– SENSE pin (pin 1) to adjust the output voltage up or

down from the nominal output voltage by a maximum

of +/- 10 %. The GPH2V2-40, -60 may be adjusted

+15 %, -10 %. The value of the trim resistor is for a

single converter or for multiple paralleled converters

with separate trim resistors on each of their Voltage

Adjust pins.

Although not recommended, the Voltage Adjust pins for

N paralleled converters may be tied together. In this

For the GPH1V5-40 and GPH1V5-60, the trim resistor

value in Kohms for these two units is:

Ω

0.30

The resistor value in Kohms for the GPH2V2-40 and

GPH2V2-60 is:

Ω

0.44

The resistor value in Kohms for the GPH3V3-40 and

GPH3V3-60 is:

Ω

0.66