Analog Devices ADSP-2186 Package, Assumptions, Total Power Dissipation = Pint + C × VDD2 × f

ENVIRONMENTAL CONDITIONS
Ambient Temperature Rating:
TAMB	= TCASE – (PD x θCA)
TCASE	= Case Temperature in °C
PD	= Power Dissipation in W
θCA	=	Thermal Resistance (Case-to-Ambient)
θJA	=	Thermal Resistance (Junction-to-Ambient)
θJC	=	Thermal Resistance (Junction-to-Case)
Package		uJA	uJC	uCA
TQFP		50°C/W	2°C/W	48°C/W

POWER DISSIPATION

To determine total power dissipation in a specific application, the following equation should be applied for each output:

C× VDD2 × f

C = load capacitance, f = output switching frequency.

Example

In an application where external data memory is used and no other outputs are active, power dissipation is calculated as follows:

Assumptions

•External data memory is accessed every cycle with 50% of the address pins switching.

•External data memory writes occur every other cycle with 50% of the data pins switching.

•Each address and data pin has a 10 pF total load at the pin.

•The application operates at VDD = 5.0 V and tCK = 30 ns.

Total Power Dissipation = PINT + (C × VDD2 × f)

PINT = internal power dissipation from Power vs. Frequency graph (Figure 8).

(C × VDD2 × f) is calculated for each output:

	# of		3 VDD2
	Pins	3 C			3f
Address, DMS	8	× 10 pF	× 52	V	× 33.3 MHz =	66.6 mW
Data Output, WR	9	× 10 pF	× 52	V	× 16.67 MHz = 37.5 mW
RD	1	× 10 pF	× 52	V	× 16.67 MHz =	4.2 mW
CLKOUT	1	× 10 pF	× 52	V	× 33.3 MHz =	8.3 mW
					116.6 mW

Total power dissipation for this example is PINT + 116.6 mW.

			ADSP-2186
	450	2186 POWER, INTERNAL1, 3, 4, 5
	425		VDD = 5.5V
	400		430mW
			370mW
– mW	375
	350	330mW	325mW
)
INT	325		VDD = 5.0V
(P	300		275mW
POWER
	275	245mW
	250		235mW
	225		VDD = 4.5V
			195mW
	200	175mW
	175
	150

	30	32	34	36	38	40	42
				1/fCK – MHz
	85		POWER, IDLE1, 2, 3, 5
							84mW
	80			76mW
	75	69mW			VDD = 5.5V
– mW	70
							67mW
	65			61mW
)
IDLE	60	56mW			VDD = 5.0V
(P	55						54mW
POWER				49mW
	50
		45mW			VDD = 4.5V
	45
	40
	35
	30	32	34	36	38	40	42
	30
				1/fCK – MHz

	70		POWER, IDLE n MODES3, 5
							67mW	IDLE
	65			61mW
mW	60		56mW
	55
n) –	50
IDLE
(P	45
POWER	35				32mW		34mW	IDLE (16)
	40
	30		30mW				32mW	IDLE (128)
					30mW
	25		28mW
	20	30	32	34	36	38	40	42
	28
				1/fCK – MHz

VALID FOR ALL TEMPERATURE GRADES.

1POWER REFLECTS DEVICE OPERATING WITH NO OUTPUT LOADS.

2IDLE REFERS TO ADSP-2186 STATE OF OPERATION DURING EXECUTION OF IDLE INSTRUCTION. DEASSERTED PINS ARE DRIVEN TO EITHER VDD OR GND.

3TYPICAL POWER DISSIPATION AT 5.0V VDD AND TA = 25°C EXCEPT WHERE SPECIFIED.

4IDD MEASUREMENT TAKEN WITH ALL INSTRUCTIONS EXECUTING FROM INTERNAL MEMORY. 50% OF THE INSTRUCTIONS ARE MULTIFUNCTION (TYPES 1, 4, 5, 12, 13, 14 30% ARE TYPE 2 AND TYPE 6, AND 20% ARE IDLE INSTRUCTIONS.

5SPECIFICATIONS AT 40MHz ARE PRELIMINARY AT THIS PRINTING.

Figure 8. Power vs. Frequency

REV. 0 –15–