71m6515h Maxim Integrated Products, Inc., 71m6515h Datasheet - Page 20

• Manufacturer Part Number: 71m6515h
• Description: 71m6515h Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

The SSI timing is shown in Figure 12.
Reset Mode
When RESETZ is pulled low or when VFLT < V3P3/2, all activity (i.e. sampling of analog signals, CE, generation of digital
outputs) in the chip stops while the analog circuits are active. The exceptions are the oscillator and RTC module, which
continue to run. Additionally, all I/O Register bits are cleared. As long as VFLT > V3P3/2, the internal 2.5V regulator will
continue to provide power to the digital section.
Once initiated, the reset mode will persist until the reset timer times out. This will occur in 4100 cycles of the real time clock
after RESETZ goes high, at which time the 71M6515H will begin executing its preboot and boot sequences.
Power Fault Circuit
The power fault comparator compares the voltage at the VFLT pin to V3P3/2. The comparator output internally enables the
battery backup protection for oscillator, RTC and RAM during the power fail mode.
Voltage Reference
The internal voltage reference of the 71M6515H is calibrated at 25°C during device manufacture. The 71M6515H is given
additional temperature-related calibrations which further compensate its ADC gain and allow it to achieve 10PPM/°C over
±60°C temperature range.
Temperature Sensor
The device includes an on-chip temperature sensor for determining the temperature of the bandgap reference. The primary
use of the temperature data is to determine the magnitude of compensation required to offset thermal drift in the system. The
temperature sensor is read once per accumulation interval.
Temperature measurement can be implemented with the following steps:
Temperature Compensation for Energy Measurements
TEMP_NOM is one of the calibration parameters that must be loaded by the host in order to enable temperature measurement
and thereby temperature compensation.
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SSDATA (Output)
SCLK (Output)
1)
2)
3)
T
SFR (Output)
MUX_STATE
=
At a known temperature T
Read the DELTA_T register at the known temperature. The obtained value should be <±0.1°C.
The temperature T (in °C) at any environment can be obtained by reading the DELTA_T register and applying the
following formula:
T
N
+
DELTA
10
If SSI_CKGATE =1
_ T
N
Figure 12: SSI Timing (SSI_FPOL = SSI_RDYPOL = 0)
, read the TEMP_RAW register and write the value into TEMP_NOM register.
31
© 2005-2008 TERIDIAN Semiconductor Corporation
30
SSI_BEG
16
Temperature Compensation
Fault and Reset Behavior
15
If 16bit fields
1
0
31
30
SSI_BEG+1
16
15
If 32bit fields
Energy Meter IC
1
0
31
If SSI_CKGATE =1
DATA SHEET
71M6515H
SSI_END
1
0
MARCH 2008
V1.4