PC8374L datasheet(123/239 Pages) NSC

123 / 239 page

7.0 Glue Functions (Continued)

Revision 1.1

123

www.national.com

7.2.4

Main Power Good

This function generates the PWRGD_3V signal, indicating that the Main power supply voltage is valid. The PWRGD_3V sig-

nal indicates to system components that their input power supplies are valid. PWRGD_3V is de-asserted immediately when

SLP_S3 is asserted or PWRGD_PS is de-asserted. It is asserted with tPSD delay after PWRGD_PS is asserted. Figure 24

shows a simplified diagram of the circuit that generates the PWRGD_3V signal.

Figure 24. PWRGD_3V Generation (Simpliﬁed Diagram)

For the AC characteristics, see “Main Power Good” on page 234.

7.2.5

Power Distribution Control

This function generates the BKFD_CUT and the LATCHED_BF_CUT power distribution control signals.

An active low BKFD_CUT signal is generated when the Main power supply voltage is valid (PWRGD_PS = high) and the

system is not in one of the S3 to S5 sleep states (SLP_S3 = high).

The LATCHED_BF_CUT signal is generated from BKFD_CUT and SLP_S5 as follows:

● Rising edge of BKFD_CUT while the system is not in S5 sleep state (SLP_S5 = high) sets LATCHED_BF_CUT to

high.

● Falling edge of BKFD_CUT while the system is not in S5 sleep state (SLP_S5 = high) resets LATCHED_BF_CUT to

low.

● When the system is in S5 sleep state (SLP_S5 = low), LATCHED_BF_CUT is reset to low.

Figure 25 shows a simplified diagram of the circuit that generates the BKFD_CUT and the LATCHED_BF_CUT signals.

Table 47. Resume Reset Circuit DC Characteristics

Symbol

Parameter

Conditions

Min

Max

Unit

VTRIP

VSB5 Threshold Level

VSB3 = 3.3V ±10%

4.05

4.5

ZOFF

Output Impedance at VSB3 Off

1. Not tested. Guaranteed by characterization.

VSB3 = 0V,

VSB5 =5V ±10%

710

Ω

PWRGD_PS

PWRGD_3V

Detector

tPSD

Delay

Reset

R-S Flip-Flop

Set

SLP_S3

Winbond Electronics Corp. Advanced PC Product Center

PC8374L Datasheet(PDF) 123 Page - National Semiconductor (TI)

PC8374L Datasheet(HTML) 123 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL