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dc2023afa

DEMO MANUAL DC2023A

Sequencing Output Channels

The LTM2987 has been pre-programmed to different

TON_DELAY values for each channel. The TON_DELAY

parameterisappliedtoeachdevicerelativetoitsrespective

CONTROL pin. When multiple demo boards are connected

together, all CONTROL pins are wire OR’d. Therefore the

TON delays are enforced relative to one edge. The same

applies to TOFF_DELAY values. When the CONTROL

switch is set to the OFF position, all rails will power down

sequentially based on each of the device’s TOFF_DELAY

values. Figure 6 shows an oscilloscope screen capture of

common Demo BoarD operations

Figure 6. Sequencing Output Channels with DC2023A Using TON_DELAY and TOFF_DELAY

Figure 8. TOFF_DELAY Configuration

Figure 7. TON_DELAY Configuration

three output rails sequencing up and down in response

to the CONTROL pin.

Each channel has an LED which visually indicates if the

channel has power. When the CONTROL pin is switched

on and off, you will observe the relative on/off timing of

the 16 channels.

For the LTM2987, the TON_DELAY and TOFF_DELAY

values extend to 13.1 seconds, providing very long on

and off sequencing of power supply rails.

LTM2987 Datasheet(PDF) 8 Page - Linear Technology