AD8364ACPZ-R2 datasheet(20/44 Pages) AD

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AD8364

Data Sheet

Rev. C | Page 20 of 44

TEMPERATURE SENSOR INTERFACE

The AD8364 provides a temperature sensor output capable of

driving about 1.6 mA. A 330 Ω-equivalent internal resistance is

connected from TEMP to COMR to provide current sink

capability. The temperature scaling factor of the output voltage is

approximately 2 mV/°C. The typical absolute voltage at 25°C is

about 620 mV.

TEMP

VPSR

INTERNAL

VPTAT

Ω

COMR

350

Ω

Figure 53. TEMP Interface Simplified Schematic

VREF INTERFACE

An internal voltage reference is provided to the user at Pin VREF.

The VREF voltage is a temperature stable 2.5 V reference that

can drive about 18 mA. An 830 Ω equivalent internal resistance

is connected from VREF to ACOM for 3 mA sink capability.

VREF

VPSR

INTERNAL

VOLTAGE

Ω

1.465k

Ω

COMR

900

Ω

Figure 54. VREF Interface Simplified Schematic

POWER-DOWN INTERFACE

The operating and stand-by currents for the AD8364 at 25°C are

approximately 70 mA and 500 µA, respectively. The PWDN pin

is connected to an internal resistor divider made with two 42 kΩ

resistors. The divider voltage is applied to the base of an NPN

transistor to force a power-down condition when the device is

active. Typically when PWDN is pulled greater than 2 V, the

device is powered down. Figure 46 and Figure 47 show typical

response times for various RF input levels. The output reaches

to within 0.1 dB of the steady-state value in about 1.6 µs; the

reference voltage is available to full accuracy in a much shorter

time. This wake-up response vary depending on the input

coupling means and the capacitances CDEC[A, B], CHP[A, B],

and CLP[A, B].

PWDN

42k

Ω

42k

Ω

COMR

POWER DOWN

SIGNAL

Figure 55. PWDN Interface Simplified Schematic

VST[A, B] INTERFACE

The VST[A, B] interface has a high input impedance of 72 kΩ.

The voltage at VST[A, B] is converted to an internal current

used to steer the VGA gain. The VGA attenuation control is

set to 20 dB/V.

GAIN ADJUST

1.35

µA/dB

VST[A, B]

18.5k

Ω

ACOM

36k

Ω

36k

Ω

Figure 56. VST[A, B] Interface Simplified Schematic

AD8364ACPZ-R2 Datasheet(PDF) 20 Page - Analog Devices

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