78M6612-IMR/F Maxim Integrated Products, 78M6612-IMR/F Datasheet - Page 73

• 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
3.13 Crystal Oscillator
The oscillator of the 78M6612 drives a standard 32.768 kHz watch crystal. The oscillator has been
designed specifically to handle these crystals and is compatible with their high impedance and limited
power handling capability. The oscillator power dissipation is very low to maximize the lifetime of any
battery backup device attached to VBAT.
Board layouts with minimum capacitance from XIN to XOUT will require less battery current. Good
layouts will have XIN and XOUT shielded from each other.
3.14 Flash Programming
Operational or test code can be programmed into the Flash memory using either an in-circuit emulator or
the Flash Programmer Module (TFP-1) available from Teridian. The Flash programming procedure uses
the E_RST, E_RXTX, and E_TCLK pins.
3.15 MPU Firmware Library
All application-specific MPU functions mentioned above under “Application Information” are available from
Teridian as a standard ANSI C library and as ANSI “C” source code. The code is available as part of the
Demonstration Kit for the 78M6612 IC. The Demonstration Kits come with the 78M6612 IC
preprogrammed with demo firmware mounted on a functional sample PCB (Demo Board). The Demo
Boards allow for quick and efficient evaluation of the IC without having to write firmware or having to
supply an in-circuit emulator (ICE).
3.16 Measurement Calibration
Once the 78M6612 Power and Energy Measurement device has been installed in a measurement
system, it is typically calibrated for tolerances of the current sensors, voltage dividers and signal
conditioning components. The device can be calibrated using the gain and phase adjustment factors
accessible to the CE. The gain adjustment is used to compensate for tolerances of components used for
signal conditioning, especially the resistive components. Phase adjustment is provided to compensate
for phase shifts introduced by certain types of current sensors.
Due to the flexibility of the MPU firmware, any calibration method, such as calibration based on energy, or
current and voltage can be implemented. It is also possible to implement segment-wise calibration
(depending on current range).
The 78M6612 supports common industry standard calibration techniques, such as single-point
(energy-only), multi-point (energy, Vrms, Irms), and auto-calibration.
Rev. 1.2
Since the oscillator is self-biasing, an external resistor must not be connected across
the crystal.
Figure 38: External Components for the Emulator Interface
62 Ω
62 Ω
62 Ω
62 Ω
V3P3D
V3P3D
62 Ω
62 Ω
22pF
22pF
LCD Segments
LCD Segments
22pF
22pF
(optional)
(optional)
22pF
22pF
ICE_E
ICE_E
E_RST
E_RST
E_RXTX
E_RXTX
E_TCLK
E_TCLK
78M6612
78M6612 Data Sheet
73