ADA4522-4ARZ-R7 datasheet(30/48 Pages) AD

30 / 48 page

Data Sheet

ADA4522-1/ADA4522-

2/ADA4522-4

analog.com

Rev I 30 of 48

Also, take note to include the power dissipation of all channels of the amplifier when calculating the total power

dissipation for the ADA4522-1/ADA4522-2/ADA4522-4.

The thermal shutdown circuitry does not guarantee the device to be free of permanent damage if the junction

temperature exceeds 150°C. However, the internal thermal shutdown function may help avoid permanent damage

or reduce the degree of damage. Each amplifier channel has thermal shutdown circuitry, composed of a temperature

sensor with hysteresis.

As soon as the junction temperature reaches 190°C, the thermal shutdown circuitry shuts down the amplifier. Note

that either one of the two thermal shutdown circuitries is activated; this activation disables the channel. When the

amplifier is disabled, the output becomes open state and the quiescent current of the channel decreases to 0.1 mA.

When the junction temperature cools down to 160°C, the thermal shutdown circuitry enables the amplifier and the

quiescent current increases to its typical value.

When overheating in the die is caused by an undesirable excess amount of output current, the thermal shutdown

circuit repeats its function. The junction temperature keeps increasing until it reaches 190°C and one of the channels

is disabled. Then, the junction temperature cools down until it reaches 160°C, and the channel is enabled again. The

process then repeats.

Input Protection

When either input of the ADA4522-1/ADA4522-2/ADA4522-4 exceeds one of the supply rails by more than 300 mV, the

ESD diodes mentioned in the On-Chip Input EMI Filter and Clamp Circuit section become forward-biased and large

amounts of current begin to flow through them. Without current limiting, this excessive fault current causes

permanent damage to the device. If the inputs are expected to be subject to overvoltage conditions, insert a resistor

in series with each input to limit the input current to ±10 mA maximum. However, consider the resistor thermal noise

effect on the entire circuit.

At a ±15 V supply voltage, the broadband voltage noise of the ADA4522-1/ADA4522-2/ADA4522-4 is approximately 5.8

nV/√Hz (at unity gain), and a 1 kΩ resistor has a thermal noise of 4 nV/√Hz. Adding a 1 kΩ resistor increases the total

noise to 7 nV/√Hz.

Single-Supply and Rail-to-Rail Output

The ADA4522-1/ADA4522-2/ADA4522-4 are single-supply amplifiers, where their input voltage range includes the

lower supply rail. This feature is ideal for applications where the input common-mode voltage is at the lower supply

rail, for example, ground sensing. Conversely, the amplifier output is rail to rail. Figure 73 shows the input and output

waveforms of the ADA4522-1/ADA4522-2/ADA4522-4 configured as a unity-gain buffer with a supply voltage of ±15 V.

With an input voltage of ±15 V, the low output voltage tracks the input voltage, whereas the high output swing

clamps/ distorts when the input goes out of the input voltage range (−15 V ≤ IVR ≤ +13.5 V). However, the device does

not exhibit phase reversal.

ADA4522-4ARZ-R7 Datasheet(PDF) 30 Page - Analog Devices