HMC701LP6CE Datasheet, PDF (21/46 Pages) Hittite Microwave Corporation – 8 GHz 16-Bit Fractional-N Synthesizer

v03.0709
HMC701LP6CE
8 GHz 16-Bit Fractional-N Synthesizer
11
Temperature Sensor
The HMC701LP6CE features a built in temperature sensor which may be used as a general purpose temperature
sensor.
The temperature sensor is enabled via tsens_spi_enable (Reg1Eh=1 Table 40) and when enabled draws 2 mA.
The temperature sensor features a built in 3-bit quantizer that allows the temperature to be read in register tsens_
temperature (Reg21h Table 43). The temperature sensor data converter is not clocked. Updates to the temperature
sensor register are made by strobbing register tsens_spi_strobe (Reg00h<3> Table 11). The 3-bit quantizer operates
over a -40°C to +100°C range as follows:
Tn = floor {(Temperature +40) / 17.5 where Tn is the decimal value of register tsens_temperature}
(EQ 7)
7
6
5
4
3
2
1
0
-40 -20
0
20
40
60
TEMPERATURE (°C)
80
100
Figure 19. Typical Temperature Sensor Quantizer output
Temperature sensor slope is 17.5 mV/lsb. Absolute tolerances on the temperature sensor thresholds may vary by up
to ±10°C worst case.
Nominal temperature is given by:
(EQ 8)
Charge Pump & Phase Frequency Detector (PFD)
The Phase Frequency Detector or PFD has two inputs, one from the reference path divider and one from the VCO path
divider. The PFD compares the phase of the VCO path signal with that of the reference path signal and controls the
charge pump output current as a linear function of the phase difference between the two signals. The output current
varies linearly over a full ±2π radians input phase difference.
PFD Functions
phase_sel (Reg05h<0> Table 16) inverts the phase detector, polarity for use with an inverting opamp or negative
slope VCO.
upout_en in Reg05h<1> Table 16 allows masking of the PFD up output, which effectively prevents
the charge pump from pumping up.
dnout_en in Reg05h<2> Table 16 allows masking of the PFD down output, which effectively prevents
the charge pump from pumping down.
Charge Pump Tri-State
De-asserting both upout_en and dnout_en effectively tri-states the charge pump while leaving all other functions
operating internally.
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