ADBMS2950BCCSZ datasheet(70/97 Pages) AD

70 / 97 page

ADBMS2950B

Data Sheet

Rev. 0 | Page 70 of 97

Figure 50. Internal ESD Protection Structures

Overvoltage Protection

To meet the accuracy specifications, the current and voltage

sense input signals must stay within the operating conditions

listed in the electrical characteristics of the ADCs under

differential and input-pin voltage range.

The absolute maximum ratings and the internal protection

structures allow to design an application circuitry that can

withstand various external stress conditions without the need

for external protection devices such as clamping or Zener

diodes. External diodes connected directly to the analog input

pins can even be unfavorable as their leakage current together

with the external source impedance may cause additional

measurement errors.

The analog voltage inputs (Vx, VBATx), VREF1P25 and OCA,

OCB can sink and source currents independent of whether the

ADBMS2950B is powered or unpowered. Currents can be

sourced by internal diode clamps from the GND pin and sunk

by internal diode clamps to the VREG pin. Even if the IC is

unpowered and the VREG pin is charged by clamping currents, it

consumes at least the sum of currents into V1 to V10, VBAT1,

VBAT2, VREF1P25, OCA, and OCB as specified in the Table 18

without the risk of violating the absolute maximum voltage

rating of any of those pins.

Sourcing currents, also independent of the power state of the

ADBMS2950B, must be limited below the absolute maximum

ratings of the pins and are not constrained by this sum of

currents maximum rating, but the power dissipation in the

internal diodes must be considered. As the currents into pins

must be limited by the application circuitry below the sum of

current maximum rating, it is also ensured that the power

dissipation is well-limited in the sourcing current condition.

CURRENT SENSE INPUTS

The current sense inputs I1 and I2 using the input pins I1A,

I1B, I2A, and I2B are internally connected to I1ADC, I2ADC,

OC1ADC, and OC2ADC. Identical external circuits must be

connected to S1A, I1A, I1B, S2A, I2A, and I2B with the circuit

input of S1A shorted to the circuit input of I1A and the circuit

input of S2A shorted to the circuit input of I2A leading to a

differential zero signal of I1A vs. S1A and I2A vs. S2A, see

Figure 51.

One side of the current sense resistor must be connected to PCB

GND to which also the RGND, SGND, and GND pins of the IC

are connected. It is recommended to connect the A-side (IxA,

SxA) of the shunt to GND and to BAT−.

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