LTC6994HS6-1-TRMPBF Ver la hoja de datos (PDF) - Analog Devices

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LTC6994HS6-1-TRMPBF

TimerBlox: Delay Block/Debouncer

Analog Devices 

LTC6994-1/LTC6994-2

APPLICATIONS INFORMATION

Power Supply Current

The Electrical Characteristics table specifies the supply

current while the part is idle (waiting for an input transi-

tion). IS(IDLE) varies with the programmed tDELAY and the

supply voltage, as described by the equations in Table 2,

valid for both the LTC6994-1 and LTC6994-2.

Table 2. Approximate Idle Supply Current Equations

CONDITION

TYPICAL IS(IDLE)

NDIV ≤ 64

( ) V + • NDIV • 7pF + 4pF

tDELAY

V+

+ 500kΩ + 2.2 •ISET + 50µA

NDIV ≥ 512

V+

• NDIV •

tDELAY

7pF

+

V+

500kΩ

+

1.8

• ISET

+

50µA

When an input transition starts the delay timing circuity,

the instantaneous supply current increases to IS(ACTIVE).

IS(ACTIVE) = IS(IDLE) + ∆IS(ACTIVE)

∆IS(ACTIVE) can be estimated using the equations in Table 3,

assuming a periodic input with frequency fIN. The equa-

tions assume the input pulse width is greater than tDELAY;

otherwise, the output will not transition (and the increase

in supply current will be less).

Table 3. Active Increase in Supply Current

CONDITION

NDIV ≤ 64

NDIV ≥ 512

DEVICE

LTC6994-1

LTC6994-2

Either Version

TYPICAL ∆IS(ACTIVE)*

fIN • V+ • (NDIV • 5pF + 18pF + CLOAD)

fIN • V+ • (NDIV • 10pF + 22pF + CLOAD)

fIN • V+ • CLOAD

*Ignoring resistive loads (assumes RLOAD = ∞)

Figures 14 and 15 show how the supply current increases

from IS(IDLE) as the input frequency increases. At higher

NDIV settings, the increase in active current is smaller.

250 V+ = 3.3V

INPUT PULSE WIDTH = 1.1 • tDELAY

200

÷1, RSET = 50k

150

÷8, RSET = 50k

÷1, RSET = 100k

100

÷1, RSET = 800k

50

CLOAD = 5pF

RLOAD = ∞

0

“IDLE” 0.2

0.4

0.6

fIN • tDELAY

0.8 1.0

699412 F14

Figure 14. IS(ACTIVE) vs Input Frequency, LTC6994-1

250 V+ = 3.3V

fIN < 1/(2 • tDELAY) TO ALLOW RISING AND

FALLING DELAYS TO REACH THE OUTPUT

200

÷1, RSET = 50k

150

÷8, RSET = 50k

100

÷1, RSET = 100k

÷1, RSET = 800k

50

CLOAD = 5pF

RLOAD = ∞

0

“IDLE” 0.1

0.2

0.3

fIN • tDELAY

0.4 0.5

699412 F15

Figure 15. IS(ACTIVE) vs Input Frequency, LTC6994-2

Rev. C

20

For more information www.analog.com

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