English
Language : 

LC87F1A32A Datasheet, PDF (11/26 Pages) Sanyo Semicon Device – CMOS IC FROM 32K byte, RAM 2048K byte on-chip 8-bit 1-chip Microcontroller with Full-Speed USB
LC87F1A32A
USB Reference Power Option
When a voltage 4.4 to 5.5V is supplied to VDD1 and the internal USB reference voltage circuit is activated, the
reference voltage for USB port output is generated. The active/inactive state of reference voltage circuit can be switched
by the option select. The procedure for marking the option selection is described below.
(1)
(2)
(3)
(4)
Option select
USB Regulator
USE
USE
USE
NONUSE
USB Regulator at HOLD mode
USE
NONUSE
NONUSE
NONUSE
USB Regulator at HALT mode
USE
NONUSE
USE
NONUSE
Reference voltage circuit
state
Normal state
HOLD mode
active
active
active
inactive
active
inactive
inactive
inactive
HALT mode
active
inactive
active
inactive
When the USB reference voltage circuit is made inactive, the level of the reference voltage for USB port output is
equal to VDD1.
Selection (2) or (3) can be used to set the reference voltage circuit inactive in HOLD or HALT mode.
When the reference voltage circuit is activated, the current drain increase by approximately 100A compared with
when the reference voltage circuit is inactive.
Example 1: VDD1=VDD2=3.3V
Inactivating the reference voltage circuit (selection (4)).
Connecting VDD3 to VDD1 and VDD2.
LSI
P70
Power supply
3.3V
For backup
VDD1
D+
VDD2
D-
VDD3
UFILT
VSS1 VSS2 VSS3
1.5k
27 to 33
To USB connector
5pF
0
2.2F
Example 2: VDD1=VDD2=5.0V
Activating the reference voltage circuit (selection (1)).
Isolating VDD3 from VDD1 and VDD2, and connecting capacitor between VDD3 and VSS.
LSI
P70
Power supply
5V
For backup
VDD1
D+
D-
VDD2
2.2F
VDD3
UFILT
0.1µF
VSS1 VSS2 VSS3
1.5k
27 to 33
To USB connector
5pF
0
2.2F
No.A0704-11/26