BA6129AF-E2 Rohm Semiconductor, BA6129AF-E2 Datasheet - Page 6

• Manufacturer Part Number: BA6129AF-E2
• Description: IC RESET W/BATT BACKUP SOP8 TR
• Manufacturer: Rohm Semiconductor
• Type: Battery Backup Circuitr

Specifications of BA6129AF-E2

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active Low
• Voltage - Threshold: 3.5V
• Operating Temperature: -20°C ~ 75°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Reset Timeout: -

•
These ICs have two distinct functions, a logic output function and a power supply switching function.
The logic output circuit consists of the following:
(1) Reset output (NPN Tr open collector)
(2) CS output
(3) CSB output (NPN Tr open collector + pull-up resistor)
The power supply switching circuit consists of a PNP
power transistor and an SBD (Schottky barrier diode).
The normal power supply V
power supply (V
ing circuit. When the PNP power transistor is turned on
and off, the IC power is switched from the normal
power supply to the battery backup power supply, and
vice versa.
The power supply voltage detection circuit consists of a
standard voltage source V
parator. The power supply V
resistance. When the power supply voltage drops
below the detection voltage (BA6129AF: V
when V
6
Memory ICs
Circuit operation
CC
drops and V
BAT
(PNP Tr open collector + pull-down resistor)
) are both connected to the switch-
S
V
V
RESET
CS
CSB
+ 0.1Vtyp. when V
CC
O
REF
CC
CC
and the battery backup
is detected using a split
and a hysteresis com-
S
= 3.5Vtyp.
CC
Fig. 2 Timing chart
rises;
BA6162 / F: V
0.1Vtyp. when V
the CS signal (CS-Low, CSB-High) are output by the
logic output function, and the SRAM (or other memory
device) is switched to backup mode.
If the power supply V
the switching voltage (BA6129AF and BA6162 / F: V
3.3Vtyp. when V
rises), the SBD develops a forward bias because the
PNP power transistor is off. The power supply output
V
power supply (V
When the normal power supply V
process is reversed.
O
switches from the power supply V
BA6129AF / BA6162 / BA6162F
(BA6129AF) (BA6162 / F)
5V
V
V
OV
V
V
OV
V
V
V
V
V
V
S
S
B
O (Vcc)
O (BAT)
RESH
RESL
CSH
CSL
CSBH
CSBL
BAT
= 4.2Vtyp. when V
[3.5V
CC
CC
).
[
[
[
rises), the Reset signal (Low) and
[3.3V
[
[
[
Typ.
[5V—V
[3V—V
drops, V
V
GND]
V
CC
GND]
GND]
V
CC
] [4.2V
CC
O
Typ.
]
]
]
drops further and goes below
SAT1
SAT2
]
Typ.
]
]
B
]
+ 0.1Vtyp. when V
CC
CC
rises, the above
CC
drops, and V
to the battery
S
B
CC
+
=