Epson RTC-72421 A, RTC-72421 B, RTC-72423, RTC-72423 A Page, MQ - 162, 1. When ALE is used

RTC - 72421 / 72423

„Switching characteristics (AC characteristics)

1. When ALE is used

Write mode	( VDD=5 V ± 0.5 V,		RTC-72421;Ta=−	10 ° C to +70 ° C, RTC-72423;Ta=−40 ° C to +85 ° C )
Item		Symbol	Condition		Min.	Max.	Unit
CS1 set-up time		tSU(CS1)			1000
Address set-up time before ALE		tSU(A-ALE)			50
Address hold time after ALE		th(ALE-A)			50
ALE pulse width		tw(ALE)			80
ALE set-up time before write		tSU(ALE-W)			0
Write pulse width		tw(W)			120		ns
ALE set-up time after write		tSU(W-ALE)			50
Data input set-up time before write		tSU(D-W)			80
Data input hold time after write		th(W-D)			10
CS1 hold time		th(CS1)			1000
Write recovery time		trec(W)			200
Read mode	( VDD=5 V ± 0.5 V,		RTC-72421;Ta=−	10 ° C to +70 ° C, RTC-72423;Ta=−40 ° C to +85 ° C )
Item		Symbol	Condition		Min.	Max.	Unit
CS1 set-up time		tSU(CS1)			1000
Address set-up time before ALE		tSU(A-ALE)			50
Address hold time after ALE		th(ALE-A)			50
ALE pulse width		tw(ALE)			80
ALE set-up time before read		tSU(ALE-R)			0		ns
ALE set-up time after read		tSU(R-ALE)			50
Data output transfer time after read		tPZV(R-Q)	CL=150 pF			120
Data output floating transfer time after read		tPVZ(R-Q)			0	70
CS1 hold time		th(CS1)			1000
Read recovery time		trec(W)			200

(1) Write mode

CS1

A0 to A3

CS0

ALE

WR

D0 to D3

(Input)

	VIH2			VIH2
tsu(CS1)
	tsu(A-ALE)	th(ALE-A)	th(CS1)

VIH1VIH1

VIL1VIL1

tw(ALE)

VIH1 VIH1

VIL1		VIL1
tsu(ALE-W)	tw(W)	tsu(W-ALE)
VIH1		VIH1
VIL1		VIL1
	tsu(D-W)	th(W-D)
VIH1		VIH1
VIL1		VIL1

(2) Read mode

CS1

A0 to A3

CS0

ALE

RD

D0 to D3

(Input)

	VIH2			VIH2
tsu(CS1)			th(CS1)
	tsu(A-ALE)	th(ALE-A)

VIH1VIH1

VIL1VIL1

tw(ALE)

VIH1 VIH1

VIL1	VIL1
tsu(ALE-R)	tsu(R-ALE)
VIH1	VIH1
VIL1	VIL1
tpzv(R-Q)	tpvz(R-Q)
VIH1	VIH1
VIL1	VIL1

Page - 5 MQ - 162 - 03