F1950 datasheet(21/23 Pages) RENESAS

21 / 23 page

6 Bit Digital Step Attenuator

1 MHz to 4000 MHz

Glitch-FreeTM, Digital Step Attenuator

Rev 2, July 2017

IDTF1912NCGI

Datasheet

APPLICATIONS INFORMATION

F1912 Digital Pin Voltage & Resistance Values (pins not connected)

The following table lists the resistance between various pins and ground when no DC power is applied. When

the device is powered up with +5 Volts DC these same pins should have the measured voltage to ground.

Name

DC voltage

(volts)

Resistance

(ohms)

VMODE

2.5V

100 kΩ pullup resistor

to internally regulated

2.5 V

3, 4, 5

DATA, CLK, LE

2.5V

100 kΩ pullup resistor

to internally regulated

2.5 V

Logic Voltage applied before Power Supply

Due to on-chip ESD protection circuitry, the VDD supply voltage is required to be present before the logic

voltages can be applied to the logic pins (VMODE, DATA, LE, CLK, D[5:0]). If in the application this is not

possible, then a series resistor of 3kΩ needs to be added in line with each of the logic pins, D0-D3. The other

logic pins (VMODE, DATA, LE, CLK, D4, D5) already have a significant resistor value per the Bill Of Material

(BOM). This resistor limits the current into the logic pin to a safe level when VDD is not present. The resistor

should be placed close to the device to minimize the impact on switching speed due to stray PCB parasitics.

F1950 Datasheet(PDF) 21 Page - Renesas Technology Corp