SLVSHO1A March 2025 – December 2025 TPS1689
PRODUCTION DATA
The TPS1689x integrates a 10-bit, 460 KSPS SAR ADC preceded by an analog MUX. The following signals are available for sampling by the ADC:
VIN
VOUT
VIMON
VTEMP
VAUX
ADDR0
ADDR1
The ADC uses a 5kHz low-pass filter at the input to suppress high frequency noise (outside the ADC Nyquist bandwidth) and prevent aliasing.
The ADC also supports a high performance mode wherein the sampling rate is traded off in favor of improved DNL and INL. In this mode, the sampling rate is reduced to 270 KSPS. This mode can be selected by setting the ADC_HI_PERF bit in the DEVICE_CONFIG register.
During normal operation, the ADC automatically sequences the channels. The ADC channel sequencer manages MUX channel selection for sampling.
The ADDR0 and ADDR1 signals are sampled only at startup to decode the PMBus® target address.
The ADC implements background self-calibration to eliminate offset and gain errors inherent to the ADC.
The device also supports buffering of multiple samples of a selected parameter in RAM, which can be read by the host using the ADC_SAMPLE_BUF block read command. This allows the system designer to reconstruct the time domain profile/waveform of that parameter in a given interval. This can be useful during design/debugging by functioning like an in-built "digital oscilloscope". The ADC channel to sample for buffering and the decimation rate/sample skip count can be user configured using PMBus® writes to the ADC_CONFIG_2 register.
The TPS1689x can post-process raw ADC sampled data to compute the following derived parameters:
VIN Average
VIN Peak
VIN Min
VOUT Average
VOUT Min
IIN Average
IIN Peak
PIN
PIN Average
PIN Peak
EIN
Temperature Average
Temperature Peak
A single ADC sample can have higher errors due to internal noise. It is possible to improve the ADC SNR and the telemetry accuracy by averaging higher number of samples. The number of samples to be averaged is user-programmable using the PK_MIN_AVG register. The minimum, maximum, and average values can also be reset using the PK_MIN_AVG register.
The TPS1689x performs digital comparison on the ADC sampled data to detect the following system events.
VIN UV WARN
VIN UV FAULT
VIN OV WARN
VOUT PGOOD
IIN OC WARN
OT WARN
OT FAULT
PIN OP WARN
The results of the comparisons are reflected in the PMBus® status registers and can be configured to trigger other actions e.g. FET turn OFF (protection response) and FLT output assertion for faults, SMBA signal assertion for faults/warnings and Blackbox RAM/EEPROM update.