2.13.2 Temperature Monitor

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Unless otherwise noted, temperature monitor performance is specified with a 2N3904 diode-connected bipolar transistor from National Semiconductor or Infineon Technologies, nominal power supply voltages, with the output measured using the internal voltage reference with the internal ADC in 12-bit mode and 62.5 Ksps. After digital compensation. Unless otherwise noted, the specifications pertain to conditions where the SmartFusion cSoC and the sensing diode are at the same temperature.

Table 2-94. Temperature Monitor Performance Specifications
Specification	Test Conditions	Min.	Typical	Max.	Units
Input diode temperature range	—	–55	—	150	°C
Input diode temperature range	—	233.2	—	378.15	K
Temperature sensitivity	—	—	2.5	—	mV/K
Intercept	Extrapolated to 0K	—	0	—	V
Input referred temperature offset error	At 25 °C (298.15K)	—	±1	1.5	°C
Input referred temperature offset error	At –55ºC to +125ºC	—	—	2	°C
Gain error	Slope of BFSL vs. 2.5 mV/K	—	±1	2.5	% nom.
Overall accuracy	Peak error from ideal transfer function	—	±2	±3	°C
Overall accuracy	At –55ºC to +125ºC	—	—	±5	°C
Input referred noise	At 25 °C (298.15K) – no output averaging	—	4	—	°C rms
Input referred noise	At –55ºC to +125ºC	—	—	6.5	°C rms
Output current	Idle mode	—	100	—	µA
Output current	Final measurement phases	—	10	—	µA
Analog settling time	Measured to 0.1% of final value, (with ADC load)
	From TM_STB (High)	5	—	—	µs
	From ADC_START (High)	5	—	105	µs
AT parasitic capacitance	—	—	—	500	pF
Power supply rejection ratio	DC (0–10 KHz)	1.2	0.7	—	°C/V
Input referred temperature sensitivity error	Variation due to device temperature (–40 °C to +100 °C). External temperature sensor held constant.	—	0.005	0.008	°C/°C
Temperature monitor (TM) operational power supply current requirements (per temperature monitor instance, not including ADC or VAREFx)	VCC33A	—	200	—	µA
	VCC33AP	—	150	—	µA
	VCC15A	—	50	—	µA

Note: All results are based on averaging over 64 samples.

Figure 2-51. Temperature Error Versus External Capacitance