Final Datasheet Rev 1.0
July 21, 2017
Semtech
Proprietary & Confidential
When any of the above sensing modes are commanded, the information returned on the DATA pin will be amended with the
system measurement results. This will consist of eight bits of data following the Status Values and a “0” bit. The sequence will be
as follows:
CLK: R Page Addr
Sensing
Command
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ANY
↑ Sample Param. Conv. Complete ↑ ↓ Output Data ↓
DATA: High-Z 0 S7 S6 S5 S4 S3 S2 S1 S0 0 D7 D6 D5 D4 D3 D2 D1 D0 0 High-Z
Figure 4: Sensing Communication Protocol
The switch depends on the CLK to make its data conversion, so it is required that the CLK continue to be driven until the output
data is received.
The requested measurement is sampled during the “0” bit at the beginning of the status bit stream. The converted signal is
complete at the end of the “0” bit following the status bit stream, with the transfer of the converted data commencing afterward.
For temporally-accurate measurements to be made, the microcontroller must comprehend the delay between the start of the
Reset / Preamble / Address / Command sequence and the sampling period. The timing of the sample will be entirely dependent
on the CLK timing presented to the device.
Continuous Sample Mode
The device supports a continuous sample mode whereby a continuous series of samples is provided without having to send
another command. By continuing to send a series of “1” bits on the CLK pin, the microcontroller will be provided a continuous
series of converted samples of the selected type, 8 bits long, and separated by a “0” transmission. By utilizing this feature, the
microcontroller may sample waveforms and use the data for numerical analysis to gain insight into the health of the load, the
quality of the supply voltage, compute power factor, frequency, distortion, etc. Samples following the first conversion will be
taken at the end of the D3 bit transmission of the prior sampled data.
Status Values
The (S7…S0) field received using the DATA pin provides the status of the switch before the command has been executed. Each of
the status bits is generated by the switch in the following way:
• For zero: the DATA pin is pulsed for first 2 clock pulses matching the protocol (the pulses corresponding to the Zero
signal).
• For one: the DATA pin duplicates the signal available at the CLK pin (the pulses corresponding to the One signal).
The following status values are defined:
Table 4: Status Bits
S7 Power Transfer Mode Enabled
S6 Inrush Mode Enabled
S5 Dithering Enabled
S4 Over Temperature Warning
S3 Over-Temperature Shutdown
S2 Inrush Over-Current Shutdown
S1 Over-Current Shutdown
S0 Switch State
Data Values
The DATA (D7, D6…D0) field is used to provide the acquired value of the system parameter requested by the Command Sequence
if there is data to be returned by that command. The data will be transmitted with the MSB first.
For Continuous Sample Mode, drive 9 “1” bits
(D7-D0, 0) for each additional conversion desired
