PTH12010LAH datasheet(19/27 Pages) TI

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t − Time − 20 ms/div

VTRK (1 V/div)

V01 (1 V/div)

V02 (1 V/div)

t − Time − 400 µs/div

VTRK (1 V/div)

V01 (1 V/div)

V02 (1 V/div)

MARGIN UP/DOWN CONTROLS

D %

Ror R =

499 - 99.8 kW

(2)

PTH12010W, PTH12010L

SLTS205E–JUNE 2003–REVISED APRIL 2006

Figure 17. Simultaneous Power Up with Auto-Track

Figure 18. Simultaneous Power Down with Auto-Track

Control

The PTH12060, PTH12010, PTH12020, and PTH12030 products incorporate Margin Up and Margin Down

control inputs. These controls allow the output voltage to be momentarily adjusted[1], either up or down, by a

nominal 5%. This provides a convenient method for dynamically testing the operation of the load circuit over its

supply margin or range. It can also be used to verify the function of supply voltage supervisors. The ±5% change

is applied to the adjusted output voltage, as set by the external resistor, RSET at the VO Adjust pin.

The 5% adjustment is made by pulling the appropriate margin control input directly to the GND terminal[2].A

low-leakage open-drain device, such as an N-channel MOSFET or P-channel JFET is recommended for this

purpose[3]. Adjustments of less than 5% can also be accommodated by adding series resistors to the control

inputs. The value of the resistor can be selected from Table 6, calculated using the following formula.

UP/DOWN ADJUST RESISTANCE CALCULATION

To reduce the margin adjustment to a value less than 5%, series resistors are required (See RD and RU in

Figure 19). For the same amount of adjustment, the resistor value calculated for RU and RD are the same. The

formula is as follows.

Where ∆% = The desired amount of margin adjust percent.

NOTES

1. The Margin Up and Margin Down controls were not intended to be activated simultaneously. If they are their

affects on the output voltage may not completely cancel, resulting in the possibility of a slightly higher error

in the output voltage set point.

2. The ground reference should be a direct connection to the module GND at pin 7 (pin 1 for the PTHxx050).

This will produce a more accurate adjustment at the load circuit terminals. The transistors Q1 and Q2 should

be located close to the regulator.

3. The Margin Up and Margin Down control inputs are not compatible with devices that source voltage. This

includes TTL logic. These are analog inputs and should only be controlled with a true open-drain device

(preferably a discrete MOSFET transistor). The device selected should have low off-state leakage current.

Each input sources 8 µA when grounded, and has an open-circuit voltage of 0.8 V.

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