AFE032 datasheet(62/77 Pages) TI1

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AFE032

SBOS669A – AUGUST 2013 – REVISED DECEMBER 2013

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Current Overload

The maximum output current allowed from the power amplifier (PA) can be programmed with the external RSET

resistor connected between PA_ISET (pin 26) and ground. The PA goes to current limit state if a fault condition

occurs, causing the PA to source or sink more current than its programmed limit value. IFLAG_INT (bit 7 in the

REG_AFE_STATUS register) is set to '1' if the PA goes to current limit state for more than 16,384 DAC_CLK

cycles.

Setting the IFLAG mask bit of the REG_FLAG_CTL register prevents a fault condition from commanding the

active-low, open-drain interrupt pin (INT). Note that the PA still goes to a current limit state to protect the device

and the IFLAG_INT bit is still set to '1'.

CAUTION

ENPAICLN and ENPAICLP (bits 1 and 0 of the REG_PA_CURRENT_CFG register,

respectively) allow the current limit protection circuitry to be enabled or disabled. By

default, the current limit protection circuitry is enabled and protects the device from

damage during current overload events only if the ENPAICLN and ENPAICLP bits

remain in their default states. Disabling these bits can potentially damage the device in

an current overload event.

Thermal Overload

The device contains internal PA thermal shutdown protection circuitry that automatically disables the PA output

stage if the junction temperature exceeds +165°C.

Note that the thermal shutdown protection circuitry only operates if a fault condition causes thermal overload

(that is, forces the junction temperature to exceed +165°C) and the Disable TLIM bit (bit 0 in the

REG_DAC/HPF/LPF/PA_CTL register) remains in the default state of '0'. The device thermal shutdown

protection circuitry allows the PA to resume normal operation only when the junction temperature falls below

+150°C. The TFLAG_INT bit remains set to '1' even after the device returns to normal operation. The

TFLAG_INT bit can be reset to '0' by performing a read operation on the REG_AFE_STATUS register.

Setting the TFLAG mask bit of the REG_FLAG_CTL register prevents a thermal overload event from

commanding the active-low, open-drain interrupt pin (INT). Note that the internal PA thermal shutdown protection

circuitry still disables the PA output stage automatically (provided that a thermal overload condition occurs and

the Disable TLIM bit is in set to '0') and the TFLAG_INT bit is still set to '1'.

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