CA3277E View Datasheet(PDF) - Intersil
Part Name
Description
Manufacturer
CA3277E Datasheet PDF : 8 Pages
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CA3277
IGN IN
R1
220Ω IGN IN CA3277
C1
0.1µF
IGNITION
COMP
L1
150µH
6V
BATT
UNREG
SUPPLY IN
330Ω
C2
200µF
(VBATT -2.9V)
DATA
COMP
DATA IN
I
CUR OUT
CURRENT
AMP
OVR-TEMP
SHTDWN
OVR-VOLT
SHTDWN
LOW VOLT
SHTDWN
BANDGAP
REF
OUT2
ENABLE
CUR DATA IGN
EN
IN OUT OUT (OUT2)
ERROR AMP FB
AND OUTPUT
CONTROL
ERROR AMP FB
AND OUTPUT
CONTROL
OUT2
C5
0.1µF
OUT1
C7
0.1µF
LOW VOLT
RESET
GND
R5
CRST RESET 47KΩ
+5V
DISPLAY OR
CONTROL
OUTPUT
TO
OUT2
R4
22kΩ
TDO
C3
0.47µF
RDI SENSE CONTROL
IN
OUT
5V MICROCONTROLLER
C4
0.01µF
RESET VDD
VSS
C6
22µF
+5V ENABLE
SWITCHED
OUTPUT
+5V
STANDBY
C8
OUTPUT
100µF
+5V
CMOS
MEMORY
BUS
NOTE: DATA IN and CUR OUT are remote/host Serial Data Communication Buffers. Typical Remote Source
Impedance for DATA IN is 1kΩ. Typical Remote Load for CUR OUT is 250Ω.
FIGURE 1. TYPICAL APPLICATION CIRCUIT OF THE CA3277 DUAL 5V REGULATOR WITH MICROCONTROLLER AND SERIAL
DATA BUFFER INTERFACE TO A REMOTE HOST
Applications
Other functions of the CA3277 include a Data Comparator
and Current Multiplier for use as interface buffers to transfer
serial data at higher level logic to and from a remote host
microcontroller. The OUT1 5V Standby Supply provides
power to the local microcontroller which interfaces to the
CA3277 interface buffers at a 5V logic level. As shown in
Figure 1, the DATA IN input of the Data Comparator receives
serial data referenced to the BATT voltage level. The output
of the Data Comparator is 5V CMOS compatible logic and is
connected to the RDI (remote data input) terminal of the
microcontroller. The TDO (data out) output of the microcon-
troller is connected to the Current Multiplier input of the
CA3277.
Current Multiplier - The Current Multiplier, with internal cir-
cuitry shown in Figure 2, receives data from the
microcontroller in the form of an open drain or gate switched
output driving a 22KΩ resistor load in series to the Current
Input at pin 10 (CUR IN). The input stage of the Current Mul-
tiplier is a current mirror amplifier which is internally
connected to the 5V regulated OUT1 voltage source. The
output stage of the Current Multiplier is a current mirror
amplifier referenced to GND and has an open collector
Current Output at pin 9 (CUR OUT), with a minimum drive
capability of 35mA. The Current Multiplier output load is
normally connected via resistive loading to the BATT voltage
supply level. As such, the microcontroller transmits data out
(TDO output) to the input of the CA3277 Current Multiplier
which amplifies and translates the signal back to the voltage
reference level of the BATT power supply input. When
driving a similar remote CA3277, the voltage drop from the
BATT input line switches the Data Comparator which
provides serial data to the RDI input of the remote microcon-
troller. The nominal current gain of the Current Multiplier is
100X.
The application use of the Current Multiplier is not limited to
digital serial data transfer. The Current Multiplier is an
independent function and is open to use for other purposes,
including linear signal amplification, sensor output amplifica-
tion and current controlled threshold switching. The current
output terminal, CUR OUT may be externally load-
connected to OUT1, OUT2, BATT or any other power supply
level up to the maximum ratings given for the BATT input
terminal. It is important to note that some applied uses of the
Current Multiplier may contribute significant on-chip power
dissipation. A nominal current mirror input drive of 200µA will
provide sufficient drive to switch a 250Ω resistor load at the
input of the data comparator. As such, the quiescent OFF
condition of the Data comparator should be in the High state.
7-42
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