AMC7834 Datasheet, PDF (82/93 Pages) Texas Instruments – AMC7834 12-Bit Integrated Power-Amplifier Monitor and Control System with Temperature, Current and Voltage Supervision Capabilities

AMC7834
SLAS972B – NOVEMBER 2014 – REVISED MARCH 2016
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8.3 Initialization Set Up
8.3.1 Initialization Procedure
1. Supply all voltages (PAV_DD, AV_DD, DV_DD, IOV_DD, AV_CC, AV_SS) and clamp inputs (VCLAMP1 and VCLAMP2).
The AMC7834 does not require a specific supply sequencing.
2. A 250 µs POR delay occurs after a minimum AV_DD supply of 4.5 V has been applied. Do not attempt serial
communication during this time.
3. It is recommended to issue a hardware or software-reset.
4. Wait for completion of the reset operation (at least 250 µs for a hardware reset or at least 10 µs for a
software reset).
5. After reset, the following conditions are met:
– The device is in open-loop mode and all DAC data registers are set to all zeros.
– All DAC outputs are set to the clamp value regardless of the SLEEP1 and SLEEP2 pin levels.
– The PA_ON signal is set to the OFF state.
6. If not already done so, it is recommended to tie the SLEEP1 and SLEEP2 pins low.
7. Configure the AMC7834 without the DACs leaving clamp mode.
8. If the PA_ON control signal is enabled, switch the PA_ON signal to the ON state. By default, the AV_SS supply
must be present to enable the PA_ON signal to enter the ON state.
9. Release the DACs out of clamp mode.
10. Verify that the ADC has entered the READY state.
11. Issue an ADC trigger signal to initiate conversion of the monitoring inputs.
After initialization the AMC7834 allows switching between open-loop and closed-loop operation. However, before
switching between operating modes, it is strongly recommended to clamp the bipolar DAC outputs, stop the ADC
conversion cycle, and if applicable, switch the PA_ON signal to the OFF state. To resume operation follow steps
7 through 11 of the Initialization Procedure.
9 Power Supply Recommendations
The AMC7834 supply voltage ranges are specified in the Recommended Operating Conditions table.
10 Layout
10.1 Layout Guidelines
• All power supply pins should be bypassed to ground with a low-ESR ceramic bypass capacitor. The typical
recommended bypass capacitance has a value of 0.1 µF and is ceramic with a X7R or NP0 dielectric.
• A 4.7 µF capacitor is recommended between the REF_CMP pin and the AGND4 pin. A minimum capacitor
value of 470 nF is required to ensure stability.
• A high-quality ceramic capacitor, type NP0 or X7R, is recommended because of the optimal performance of
the capacitor across temperature and very-low dissipation factor.
• The digital and analog sections should have proper placement with respect to the digital pins and analog pins
of the AMC7834 device (see Figure 110). The separation of analog and digital blocks allows for better design
and practice as it ensures less coupling into neighboring blocks and minimizes the interaction between analog
and digital return currents.
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