ADT7411

Silicon Anomaly

ANOMALIES

Table 1. Averaging Function [er001]

Background

Averaging mode may output incorrect measurements before giving a final result.

Issue

Averaging mode enabled (for any channel) may output incorrect results.

Workaround

Disable the averaging function by setting C5 = 1 in the Control Configuration 2 register. The user may still accomplish

averaging by reading back 16 conversions and averaging all 16 readings to get a value that has reduced noise levels.

Related Issues

None.

Table 2. Round Robin (Fast Clock Mode Only) [er002]

Background

Issue

As the temperature of the device is ramped from cold to hot, irregular temperature and/or voltage measurements may

be obtained.

Workarounds

Enable slow clock mode by setting C0 = 0 in the Control Configuration 3 register.

Related Issues

None.

Table 3. Single Channel (Continuous Monitoring Mode Only) [er003]

Background

Changing a channel in single channel continuous monitoring mode during a conversion can result in data being

Issue

An error can be obtained where the data read back appears from the previous converted channel instead of the

current channel.

Workaround

Disable continuous monitoring before changing a channel. Once a channel is selected, turn monitoring on, wait for a

conversion and then turn monitoring off. Wait one conversion period to allow any in progress conversion to complete

before changing the channel; then take a measurement. The recommended list of steps are described in the

Workaround Steps for the er003 section.

Related Issues

None.

Workaround Steps for the er003

1. Enable single channel mode by setting C4 = 1 in the Control Configuration 2 register.

2. Set monitoring off (Set C0 = 0 in the Control Configuration 1 register).

3. Select a channel, for example, the channel for internal temperature (write 0x71 to Control Configuration 2 register).

4. Set monitoring on (Bit C0 = 1 in the Control Configuration 1 register).

5. Wait 2x the typical conversion time for the channel selected (depending on which one is being measured, the power supply [VDD]

or the analog input [AIN]) and 3x the typical conversion time for the temperature conversion.

6. Set monitoring off (Bit C0 = 0 in the Control Configuration 1 register).

7. Wait 1x the typical conversion time to allow any in progress conversion to complete before changing the channel.

8. Take a measurement.

9. Select the next channel (go back to Step 3).

Table 4. Software Reset (Round Robin Only) [er004]

Background

Erroneous results can be read if resetting the part repeatedly in round robin mode.

Issue

Resetting the part repeatedly by setting Bit C7 = 1 in Control Configuration 2, can cause all data registers to read back

00 after several software resets.

Workaround

Power down the part by setting Bit D7 (PD) = 1 in Control Configuration 1 and power up the part again by clearing

Bit D7 = 0 in Control Configuration 1, just before asserting the software reset bit in Control Configuration 2.

Related Issues

None.

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