MCP6V51-ESLASHMS datasheet(22/43 Pages) MICROCHIP

22 / 43 page

MCP6V51

DS20006136A-page 22

 2018 Microchip Technology Inc.

4.2

Other Functional Blocks

4.2.1

INPUT PROTECTION

The MCP6V51 can be operated on a single supply

voltage ranging from 4.5V to 45V, or in a split-supply

application (+/-2.25V to +/- 22.5V). The input common-

mode range extends below the negative rail,

VCML =VSS - 0.3V at 25°C, while maintaining high

CMRR (135 dB min. at 45VDD). The upper range of the

input common-mode is limited to VCMH =VDD -2.1V.

To ensure proper operation, these VCM limits, along

with any potential overvoltage/current conditions as

described in the following paragraphs, should be taken

into consideration.

4.2.1.1

Phase Reversal

The input devices are designed to not exhibit phase

inversion when the input pins exceed the supply

voltages. Figure 2-37 shows an input voltage

exceeding both supplies with no phase inversion.

4.2.1.2

Input Voltage Limits

In order to prevent damage and/or improper operation

of these amplifiers, the circuit must limit the voltages at

the input pins (see Section 1.1, Absolute Maximum

Ratings †). This requirement is independent of the

current limits discussed later on.

The ESD protection on the inputs can be depicted as

shown in Figure 4-4. This structure was chosen to

protect the input transistors against many (but not all)

overvoltage conditions and to minimize input bias

current (IB).

The input ESD diodes clamp the inputs when they try

to go more than one diode drop below VSS. They also

clamp any voltages well above VDD; their breakdown

voltage is high enough to allow normal operation but

not low enough to protect against slow overvoltage

(beyond VDD) events. Very fast ESD events (that meet

the specification) are limited so that damage can

largely be prevented.

FIGURE 4-4:

Simplified Analog Input ESD

Structures.

In addition, the input is protected by a pair of back-to-

back diodes across the amplifier’s inputs, which will

limit the voltage that can develop across the inputs to

about +/-1V.

In some applications, it may be necessary to prevent

excessive voltages from reaching the op amp inputs;

Figure 4-5 shows one approach of protecting these

inputs. D1 and D2 may be small-signal silicon diodes,

Schottky diodes for lower clamping voltages or

diode-connected FETs for low leakage.

FIGURE 4-5:

Protecting the Analog Inputs

against High Voltages.

4.2.1.3

Input Current Limits

In order to prevent damage and/or improper operation

of these amplifiers, the circuit must limit the currents

into the input pins (see Section 1.1, Absolute

Maximum

Ratings †).

This

requirement

independent of the voltage limits discussed previously.

Figure 4-6 shows one approach to protecting these

inputs. The R1 and R2 resistors limit the possible

current in or out of the input pins (and into D1 and D2).

Once the diode is forward biased, any current will flow

into the VDD supply line.

FIGURE 4-6:

Protecting the Analog Inputs

Against High Currents.

Bond

Pad

Bond

Pad

Bond

Pad

VDD

VIN+

VSS

Input

Stage

Bond

Pad

VIN-

VDD

VOUT

MCP6V51

VDD

VOUT

MCP6V51

min(R1 R2



VSS min V1 V2





–

10 mA

--------------------------------------------



min(R1 R2 



max V1 V2



 V

–

10 mA

------------------------------------------------



MCP6V51-E/MS Datasheet(PDF) 22 Page - Microchip Technology

MCP6V51-E/MS Datasheet(HTML) 22 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

Datasheet Download

Link URL