78M6612-IMR/F Maxim Integrated Products, 78M6612-IMR/F Datasheet - Page 11

• Manufacturer Part Number: 78M6612-IMR/F
• Description: IC POWER MEASUREMENT AC 68-QFN
• Manufacturer: Maxim Integrated Products

Specifications of 78M6612-IMR/F

• Mounting Style: SMD/SMT
• Package / Case: QFN-68
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS_6612_001
rising edge after the last mux state of its sequence, the mux will wait one additional CK32 cycle before
beginning a new frame. At the beginning of this cycle, the value of CROSS will be updated according to
the CHOP_E bits. The extra CK32 cycle allows time for the chopped VREF to settle. During this cycle,
MUXSYNC is held high. The leading edge of muxsync initiates a pass through the CE program
sequence. The beginning of the sequence is the serial readout of the four RTM words.
reverse state, CROSS is held high. In the chop state, CROSS is toggled near the end of each Mux
cycle in a SUM cycle.
The internal bias voltage VBIAS (typically 1.6 V) is used by the ADC when measuring the temperature
and battery monitor signals.
1.2.5 Temperature Sensor
The 78M6612 includes an on-chip temperature sensor implemented as a bandgap reference. It is used
1.2.6 Battery Monitor
The battery voltage is measured by the ADC during alternative multiplexer frames if the BME (Battery
Measure Enable) bit in the I/O RAM is set. While BME is set, an on-chip 45 kΩ load resistor is applied to
the battery, and a scaled fraction of the battery voltage is applied to the ADC input. After each alternative
MUX frame, the result of the ADC conversion is available at CE DRAM address 07. BME is ignored and
assumed zero when system power is not available (V1 < VBIAS). See
details regarding the ADC LSB size and the conversion accuracy.
1.2.7 Functional Description
The AFE functions as a data acquisition system, controlled by the MPU. The main signals (IA, VA, IB,
VB) are sampled and the ADC counts obtained are stored in CE DRAM where they can be accessed by
the CE and, if necessary, by the MPU. Alternate multiplexer cycles are initiated less frequently by the
MPU to gather access to the slow temperature and battery signals.
Rev. 1.2
CHOP_E
Frame, as described above. It is desirable that CROSS take on alternate values at the beginning of each
Mux cycle. For this reason, if chop state is selected, CROSS will not toggle at the end of the last Mux
to determine the die temperature The MPU may request an alternate multiplexer cycle containing the
temperature sensor output by asserting MUX_ALT.
The primary use of the temperature data is to determine the magnitude of compensation required to
offset the thermal drift in the system (see
has 3 states: positive, reverse, and chop. In the positive state, CROSS is held low. In the
V A
VB
IA
IB
TEMP
VBAT
MUX_ALT
EQU
CHOP_E
MUX_DIV
CTRL
MUX
MUX
MUX
Figure 3: AFE Block Diagram
CROSS
CK32
Section 3.3 Temperature
VREF_CAL
VREF_DIS
VBIAS
VREF
VREF
FIR_DONE
FIR_START
V3P3A
VBIAS
+
VREF
-
CONVERTER
ADC_E
Compensation).
∆Σ ADC
4.9MHz
Section 5.4.4 Battery Monitor
FIR_LEN
78M6612 Data Sheet
FIR
for
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