ADA4830-2BCPZ-R2 datasheet(13/22 Pages) AD

13 / 22 page

Data Sheet

ADA4830-1/ADA4830-2

Rev. C | Page 13 of 22

THEORY OF OPERATION

CORE AMPLIFIER

At the core of the ADA4830-1 and ADA4830-2 are high speed,

rail-to-rail op amps that are built on a 0.35 µm CMOS process.

Together with the core amplifier, the ADA4830-1 and ADA4830-2

combine four highly matched on-chip resistors into a difference

amplifier function. Common-mode range extension at its inputs

is achieved by employing a resistive attenuator. The closed-loop

differential to single-ended gain of the video channel is internally

fixed at 0.50 V/V (−6 dB) to ensure compatibility with video

decoders whose input range is constrained to 1 V p-p or less.

The transfer function of the ADA4830-1 and ADA4830-2 is

REF

INN

INP

OUT

−

where:

VOUT is the voltage at the output pin, VOUT.

VINP and VINN are the input voltages at the INP and INN pins,

respectively.

VREF is the voltage at the VREF pin.

OVERVOLTAGE (SHORT-TO-BATTERY)

PROTECTION

Robust inputs guarantee that sensitive internal circuitry is not

subjected to extreme voltages or currents during a stressful event. A

short-to-battery condition usually consists of a voltage on either

input (or both inputs) that is significantly higher than the power

supply voltage of the amplifier. Duration may vary from a short

transient to a continuous fault.

The ADA4830-1 and ADA4830-2 can withstand voltages of up

to 18 V on the inputs. Critical internal nodes are protected from

exposure to high voltages by circuitry that clamps the inputs at a

safe level and limits internal currents. This protection is available

whether the device is enabled or disabled, even when the supply

voltage is removed.

SHORT-TO-BATTERY OUTPUT FLAG

The short-to-battery output flag (STB pin) is functionally

independent of the short-to-battery protection. Its purpose is

to indicate an overvoltage condition on either input. Because

protection is provided passively, it is always available; the flag

merely indicates the presence or absence of a fault condition.

ESD PROTECTION

All pins on the ADA4830-1 and ADA4830-2 are protected with

internal ESD protection structures connected to the power supply

pins (+VS and GND). These structures provide protection during

the handling and manufacturing process.

The inputs (INN and INP) of the ADA4830-1 and ADA4830-2

can be exposed to dc voltages well above the supply voltage;

therefore, conventional ESD structure protection cannot be used.

The ADA4830-1 and ADA4830-2 employ Analog Devices, Inc.,

proprietary ESD devices at the input pins (INN, INP) to allow

for a wide common-mode voltage range and ESD protection

well beyond the handling and manufacturing requirements.

The inputs of the ADA4830-1 and ADA4830-2 are ESD protected

to survive ±8 kV human body model (HBM)

POWER SUPPLY PINS (ADA4830-2)

As indicated in the Absolute Maximum Ratings section, the voltage

difference between the +VS1 and +VS2 pins of the ADA4830-2

cannot exceed 0.5 V. To ensure compliance with the Absolute

Maximum Ratings, it is recommended that these supply pins be

connected together to the same power supply source.

ADA4830-2BCPZ-R2 データシート(PDF) 13 Page - Analog Devices

ADA4830-2BCPZ-R2 データシート(HTML) 13 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

データシートダウンロード