ADA4571-2

Data Sheet

Rev. 0 | Page 12 of 13

Power Consumption

Worst case quiescent power occurs when the supply current runs at

the specified maximum of 14 mA and when the ADA4571-2 is

quiescent power of 77 mW.

to ground. The output voltages are protected against short circuits

to the VDDx pin or ground by current limitation within the given

time duration. Placing the device 180° rotated into the socket

may lead to damage if the supply current is not limited to 100 mA.

Offset of Signal Outputs

generated internally on chip. Offsets originate from matching

inaccuracies and other imperfections during the production

process. For tight tolerances, it is required to match the external

loads for VSINx and VCOSx to each other. For ESD and EMC

protection, the outputs contain a series resistance of 60 Ω. A

large output load resistance minimizes the influence of this

series resistance.

Signal Dependence on Air Gap Distance

The device measures the direction of the external magnetic

field within the x-y plane. This measurement result is widely

independent of the field strength, if it is greater than the specified

minimum value of 25 kA/m. Within a homogeneous field in the

x-y direction, the result is independent of the placement in the

z direction (air gap). The nominal z distance of the internal x-y

plane to the top surface of the plastic package is 0.400 mm.

DIAGNOSTICS

Broken Bond Wire Detection

The ADA4571-2 includes circuitry to detect broken bond wire

conditions between the AMR sensor and the instrumentation

amplifier. The detection circuitry consists of current sources and

window comparators placed on the signal connections between

the AMR sensor and the ASIC. The purpose of the current sources

is to pull the signal node outside of the normal operating region

in the event of an open bond wire between the AMR sensor and

the ASIC. The purpose of the window comparators is to detect

when the signal from the AMR sensor is outside of the normal

operating region. When the comparators detect that the signal

nodes are outside of the normal operating region, the circuit

pulls the VSINx and/or VCOSx node to ground to indicate the

fault to the host controller.

In addition to the active circuitry, there are applications

recommendations, such as the use of pull-up and pull-down

resistors, which detect broken bond wires by pulling nodes

outside of the defined operating regions. A broken bond wire at

VTEMPx, VCOSx, or VSINx interrupts the corresponding

outputs. To ensure that the output enters into a known state if

there is a broken bond wire on these pins, connect a 200 kΩ

pull-down resistor at these pins. Pulling these nodes outside of

the normal operating region signals a fault to the host controller.

Short-Circuit Condition to GNDx or VDDx

In the event of a short-circuit condition, the output voltages are

pulled to the GNDx pin or the VDDx pin.

Short Circuit Between Sine and Cosine Sensor Outputs

In the event of a short circuit between sensor outputs, the

device output voltages are tied to the output common-mode

voltage. A gross angular error is detected in the microcontroller.

100%

93%

LINEAR REGION

SHORT-CIRCUIT DIAGNOSTIC BAND (HIGH)

SHORT-CIRCUIT DIAGNOSTIC BAND (LOW)

7%

0%

Figure 16. Output Span Classification During Short-Circuit Diagnostic

Condition

Table 6. Diagnostic Cases

Fault Description

Output Conditions

Alert

Broken Bond Wire Between the

Internal MR Sensor and the ASIC

Broken bond wire detection is activated; the broken

channel(s), VSINx or VCOSx, are pulled to GNDx

Diagnostic region violation

Broken Bond Wire at the PDx Pin

Device remains functional

No alert

Broken Bond Wire at the GCx Pin

Gain control is activated

Possible change in output amplitude

Output Short Circuit to GNDx

Shorted channel is pulled to GNDx

Diagnostic region violation

Output Short Circuit to VDDx

Shorted channel is pulled to VDDx

Diagnostic region violation