Intel Pentium D 830 HH80551PG0802MN Data Sheet

31

In most cases, termination resistors are not required as these are integrated into the processor 
silicon. See 

 for details on which GTL+ signals do not include on-die termination.

Valid high and low levels are determined by the input buffers by comparing with a reference 
voltage called GTLREF. 

 lists the GTLREF specifications. The GTL+ reference voltage 

(GTLREF) must be generated on the motherboard using high precision voltage divider circuits. 

V

IL

Input Low Voltage

—

—

0.3

V

V

IH

Input High Voltage

0.9

—

—

V

V

IL

Input Low Voltage

—

—

0.24

V

1

1.

These parameters are not tested and are based on design simulations.

V

IH

Input High Voltage

0.96

—

—

V

-

1.

Unless otherwise noted, all specifications in this table apply to all processor frequencies.

GTLREF_PU

GTLREF pull up resistor

124 * 0.99

124

124 * 1.01

Ω

2

2.

GTLREF is to be generated from V

TT

 by a voltage divider of 1% resistors (one divider for each GTLREF land). 

GTLREF_PD

GTLREF pull down resistor

210 * 0.99

210

210 * 1.01

Ω

R

PULLUP

On die pullup for 
BOOTSELECT signal

500

-

5000

Ω

3

3.

These pull-ups are to V

TT

.

R

TT

 

60

Ω Platform Termination 

Resistance

41

50

58

Ω

4

4.

R

TT

 is the on-die termination resistance measured at V

TT

/2 of the GTL+ output driver. The IMPSEL pin is used to select a

50

Ω or 60Ω buffer and R

TT

 value. 

50

Ω Platform Termination 

Resistance

37

45

52

Ω

COMP[1:0]

60

Ω Platform COMP 

Resistance

59.8

60.4

61

Ω

5

5.

COMP resistance must be provided on the system board with 1% resistors. COMP[1:0] resistors are to V

SS

. COMP[3:2]

resistors are to V

SS

. 

50

Ω Platform COMP 

Resistance

49.9 * 0.99

49.9

49.9 * 1.01

Ω

COMP[3:2]

60

Ω Platform COMP 

Resistance

59.8

60.4

61

Ω

50

Ω Platform COMP 

Resistance

49.9 * 0.99

49.9

49.9 * 1.01

Ω