EP4SE360F35I4 Datasheet, PDF (428/432 Pages) Altera Corporation – This section provides a complete overview of all features relating to the Stratix IV device family, which is the most architecturlly advanced

13–4
Chapter 13: Power Management in Stratix IV Devices
Temperature Sensing Diode
Temperature Sensing Diode
The Stratix IV TSD uses the characteristics of a PN junction diode to determine die
temperature. Knowing the junction temperature is crucial for thermal management.
Historically, junction temperature is calculated using ambient or case temperature,
junction-to-ambient (ja) or junction to-case (jc) thermal resistance, and device power
consumption. Stratix IV devices can either monitor its die temperature with the
internal TSD with built-in ADC circuitry or the external TSD with an external
temperature sensor. This allows you to control the air flow to the device.
You can use the Stratix IV internal TSD in two different modes of operation—
power-up mode and user mode. For power-up mode, the internal TSD reads the die’s
temperature during configuration if the ALTTEMP_SENSE megafunction is enabled
in your design. The ALTTEMP_SENSE megafunction allows temperature sensing
during device user mode by asserting the clken signal to the internal TSD circuitry. To
reduce device static power, disable the internal TSD with built-in ADC circuitry when
not in use.
f For more information about using the ALTTEMP_SENSE megafunction, refer to the
Thermal Sensor (ALTTEMP_SENSE) Megafunction User Guide.
The external temperature sensor steers bias current through the Stratix IV external
TSD, which measures forward voltage and converts this reading to temperature in the
form of an 8-bit signed number (7 bits plus sign). The 8-bit output represents the
junction temperature of the Stratix IV device and can be used for intelligent power
management.
External Pin Connections
The Stratix IV external TSD requires two pins for voltage reference. Figure 13–1 shows
how to connect the external TSD with an external temperature sensor device. As an
example, external temperature sensing devices, such as MAX1619, MAX1617A,
MAX6627, and ADT 7411, can be connected to the two external TSD pins for
temperature reading.
Figure 13–1. TSD External Pin Connections in Stratix IV Devices
External TSD
TEMPDIODEP
Stratix IV Device
TEMPDIODEN
External
Temperature
Sensor
f For more information about the external TSD specification, refer to the DC and
Switching Characteristics for Stratix IV Devices chapter.
Stratix IV Device Handbook
Volume 1
February 2011 Altera Corporation