Tool for Calculating Junction Temperature for Sync SRAM Products  
This calculator has three sections,  
   (1)   Description of Junction Temperature and Power Dissipation equations for ODT and Non ODT devices  
   (2)   Explanation of how to use this calculator (User Guide)  
   (3)   Power Dissipation & Junction Temperature Calculation (Power & Junction Temperature Calculator)  
Note:  This calculator is valid for all Standard Sync, NoBL, QDR II/II+/Xtreme and DDR II/II+/Xtreme SRAMs  
Reference Application Notes  
 
   AN4017 - Understanding Temperature Specifications: An Introduction
   AN42468 - On-Die Termination for QDRII+/DDRII+ SRAMs
 
Description of Junction Temperature and Power Dissipation equations for ODT and Non ODT devices  
Calculating Junction Temperature: TJ  =  Pd   θJA   +   TA
 
Note:  Refer to respective device datasheet for parameters used in the calculation below
Power Dissipation Calculation (Non ODT device)  
Pd   =  Core Power  +  I/O Switching Power
       =   VDD  IDD   +   α   f   CL   VDDQ2   N
                                                            (N - number of I/Os that are switching)

Power Dissipation Calculation (ODT device)  
Pd   =  Core Power  +  I/O Switching Power  +  ODT Power
       =   VDD  IDD   +   α   f   CL   VDDQ2   N   +   (5/16) [VDDQ2/ R ] NI/P
                                                (N - number of I/Os that are switching)  (NI/P - number of inputs with ODT)
                                                (R - R is the termination resistor divided by 2)
 
Note:   Please refer AN4017 and AN42468 for further Information and Derivation of the equations

Explanation of how to use this calculator (User Guide)  
To get the Power Dissipation for Non ODT device, user has to calculate Core Power followed by the I/O Switching Power.  
To get the Power Dissipation for ODT device, user has to calculate Core Power, I/O Switching Power and ODT Power sequentially in order.  
To calculate the Core Power Dissipation, user has to enter VDD and IDD. Then user has to press calculate button in the segment of the data entered, to obtain the Core Power Dissipation.  
To calculate the I/O Switching Power Dissipation, user has to enter α, f, CL, VDDQ and N. Then user has to press calculate button in the segment of the data entered, to obtain the I/O Switching Power Dissipation.  
If the device has ODT inputs then to calculate the ODT Power Dissipation, user has to enter NI/P and R. Then user has to press calculate button in the segment of the data entered, to achieve the ODT Power Dissipation.  
To calculate the Junction Temperature for respective device, user has to enter θJA and TA. Then user has to press calculate button in the segment of the data entered, to obtain the Junction Temperature for the desired device.  

Calculation of Power Dissipation and Junction Temperature  
Core Power Calculator  
To calculate the IDD for desired Frequency, Please refer Active Current Calculator
Enter VDD (V) 
Enter IDD (mA) 
    Calculated Core Power (mW) 
                                                              

I/O Switching Power Calculator  
Enter Activity Factor, α (0.5 for Sync, 1 for DDR/QDR) 
Enter Clock Frequency, f (MHz) 
    OR Enter Access Speed (ns) 
Enter Load Capacitance, CL (pf) 
Enter Number of switching I/Os
Enter VDDQ (V) 
    Calculated I/O Switching Power (mW) 
                                                             

ODT Power Calculator (for ODT device only)  
VDDQ (V) 
Enter Number of ODT Inputs NI/P  
Enter R (Ohm) 
    Calculated ODT Power (mW) 
                                                              

Junction Temperature Calculator  
Total Power Dissipation (Non ODT device)  (Pd) (mW) 
Total Power Dissipation (ODT device)  (Pd) (mW) 
Enter Thermal Resistance (Junction to Ambient), θJA (ºC/W) 
Enter Operating Temperature (Ambient Temp), TA (ºC) 
   Calculated Junction Temperature, TJ (Non ODT device) (ºC) 
   Calculated Junction Temperature, TJ (ODT device) (ºC) 
                                                             

Cypress Semiconductor