IDT79R4640100DU View Datasheet(PDF) - Integrated Device Technology

Part Name

Description

Manufacturer

IDT79R4640100DU

LOW-COST EMBEDDED ORION™ RISC MICROPROCESSOR

Integrated Device Technology 

R4640/RV4640

COMMERCIAL/INDUSTRIAL TEMPERATURE RANGE

WAIT instruction finishes the W pipe-stage (i.e. the SysAd

bus is not idle), the WAIT is treated as a NOP.

Once the CPU is in Standby Mode, any interrupt,

including the internally generated timer interrupt, will

cause the CPU to exit Standby Mode.

Mode bit

0

4s:1

7:5

8

10:9

11

12

Description

Reserved (must be zero)

Writeback data rate:

32-bit

0→W

1 → WWx

2 → WWxx

3 → WxWx

4 → WWxxx

5 → WWxxxx

6 → WxxWxx

7 → WWxxxxxx

8 → WxxxWxxx

9-15 reserved

Clock multiplier:

0→2

1→3

2→4

3→5

4→6

5→7

6→8

7 reserved

0 → Little endian

1 → Big endian

00 → R4000 compatible

01 → reserved

10 → pipelined writes

11 → write re-issue

Disable the timer interrupt on Int[5]

Must be 1

Thermal Considerations

The R4640 utilizes special packaging techniques to

improve the thermal properties of high-speed processors.

The RV4640 is packaged using cavity-up packaging in a

128-pin thermally enhanced PQFP package (“DU”) with a

drop-in heat spreader, for devices with low peak power.

The R4640 also utilizes the MQUAD package for higher

power consumption devices (the “MU” package), which is

an all-aluminum package with the die attached to a

normal copper lead frame mounted to the aluminum

casing.

Due to the heat-spreading effect of the aluminum, the

MQUAD package allows for an efficient thermal transfer

between the die and the case. The aluminum offers less

internal resistance from one end of the package to the

other, reducing the temperature gradient across the

package and therefore presenting a greater area for

convection and conduction to the PCB for a given temper-

ature. Even nominal amounts of air flow will dramatically

reduce the junction temperature of the die, resulting in

cooler operation. The MQUAD package is pin and socket

compatible with the 128-pin PQFP package.

The R4640 is guaranteed in a case temperature

range of 0° to +85° C. The type of package, speed

(power) of the device, and air flow conditions affect the

equivalent ambient temperature conditions that will meet

this specification.

The equivalent allowable ambient temperature, TA,

can be calculated using the thermal resistance from case

to ambient (∅CA) of the given package. The following

equation relates ambient and case temperatures:

TA = TC - P * ∅CA

where P is the maximum power consumption at hot

temperature, calculated by using the maximum ICC speci-

fication for the device.

Typical values for ∅CA at various air flows are shown

in Table 6.

14:13

Output driver strength:

10 → 100% strength (fastest)

11 → 83% strength

00 → 67% strength

01 → 50% strength (slowest)

255:15 Must be zero

Table 5: Boot-time mode stream

∅CA

Airflow (ft/min) 0 200 400 600 800 1000

128 PQFP (DU) 21 13 10 9

8

7

128 MQUAD (MU) 21 13 10 9

8

7

Table 6: Thermal Resistance (∅CA) at Various Airflows

Note that the R4640 implements advanced power

management to substantially reduce the average power

dissipation of the device. This operation is described in

the IDT79R4640/ IDT79R4650 RISC Processor Hardware

User’s Manual.

10

Share Link: