LTM4677 datasheet(55/110 Pages) AD

55 / 110 page

LTC3888-1

Rev. 0

For more information www.analog.com

will range from 220µs to 320µs, not including basic oscil-

lator tolerances. For software-based output changes (e.g.,

margining), this algorithmic delay begins when the STOP

bit is received on the serial bus. An example of this mini-

mum turn on/off delay and step-wise output control can

be seen in Figure 33, where TON_DELAY = 0s.

To effectively implement tracking and sequencing between

rails controlled by ADI digital power products, two signals

should be shared between all controlling ICs: SHARE_CLK

and RUN (CONTROL pin on LTC297x products). This

facilitates synchronized rail sequencing on or off based

on shared input supply state (VIN_ON threshold), external

hardware control (RUN pin), or PMBus commands (pos-

sibly using global addressing).

Figure 33 shows an example of output supply sequencing

using TON_DELAY.

Conventional coincident and ratiometric tracking can also

be emulated by setting equivalent turn-on/off delays and

appropriate rates as shown in Figure 34 and Figure 35.

APPLICATIONS INFORMATION

Figure 30. Time-Based VOUT Turn-On with Servo

DAC VOLTAGE

ERROR (NOT

TO SCALE)

TIME DELAY OF

<1S, TYPICAL

SERVO MODE

ENABLED

FINAL OUTPUT

VOLTAGE REACHED

TON_MAX_FAULT_LIMIT

SOFT-START

@ VOUT_TRANSITION_RATE

TIME

388812 F30

TON_DELAY

VOUT

PGOOD

VOUT_UV_FAULT_LIMIT

RUN

HYSTERESIS

(NOT TO SCALE)

Figure 31. Time-Based VOUT Turn-Off

SOFT-OFF

@ VOUT_TRANSITION_RATE

TOFF_DELAY

TIME

388812 F31

VOUT

RUN

Figure 32. Example of Fixed LTC3888-1 Processing Delay

and Soft-Start

Figure 33. LTC3888-1 Time-Based Supply Sequencing

388812 F32

VOUT

(0.5V/DIV)

RUN

(5V/DIV)

200µs/DIV

388812 F33

VOUT2

VOUT3

VOUT4

VOUT1

100ms/DIV

0.5V/DIV

Figure 34. LTC3888-1 Time-Based Coincident Supply Ramping

Figure 35. LTC3888-1 Time-Based Ratiometric Supply Ramping

388812 F34

100ms/DIV

VOUT2

VOUT3

VOUT4

VOUT1

0.5V/DIV

388812 F35

100ms/DIV

VOUT2

VOUT3

VOUT4

VOUT1

0.5V/DIV

LTM4677 Datasheet(PDF) 55 Page - Analog Devices

LTM4677 Datasheet(HTML) 55 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL