Datasheet, Volume 1 91
Electrical Specifications
7.11.2 DC Characteristics

The PECI interface operates at a nominal voltage set by VCCIO. The DC electrical

specifications shown in Table 7-10 are used with devices normally operating from a

VCCIO interface supply. VCCIO nominal levels will vary between processor families. All

PECI devices will operate at the VCCIO level determined by the processor installed in the

system. For specific nominal VCCIO levels, refer to Table 7-5.

Notes:
1. VCCIO supplies the PECI interface. PECI behavior does not affect VCCIO min/max specifications.
2. The leakage specification applies to powered devices on the PECI bus.
3. The PECI buffer internal pull up resistance measured at 0.75*VCCIO.
7.11.3 Input Device Hysteresis

The input buffers in both client and host models must use a Schmitt-triggered input

design for improved noise immunity. Use Figure 7-2 as a guide for input buffer design.

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Table 7-10. PECI DC Electrical Limits

Symbol Definition and Conditions Min Max Units N otes1
Rup Output resistance 15 45 3
Vin Input Voltage Range -0.15 VCCIO V
Vhysteresis Hysteresis 0.1 * VCCIO N/A V
VnNegative-Edge Threshold Voltage 0.275 * VCCIO 0.500 * VCCIO V
VpPositive-Edge Threshold Voltage 0.550 * VCCIO 0.725 * VCCIO V
Cbus Bus Capacitance per Node N/A 10 pF
Cpad Pad Capacitance 0.7 1.8 pF
Ileak000 leakage current at 0V 0.6 mA
Ileak025 leakage current at 0.25*VCCIO —0.4mA
Ileak050 leakage current at 0.50*VCCIO —0.2mA
Ileak075 leakage current at 0.75*VCCIO —0.13mA
Ileak100 leakage current at VCCIO —0.10mA

Figure 7-2. Input Device Hysteresis

Minimum VP
Maximum VP
Minimum VN
Maximum VN

PECI High Range

PECI Low Range

Valid Input

Signal Range

Minimum

Hysteresis

VTTD

PECI Ground