CS8183
http://onsemi.com
6
V
IN1
V
OUT1
NC
NC
GND
GND
NC
NC
V
OUT2
V
IN2
NC
NC
GND
GND
NC
NC
V
ADJ1
V
REF
/
ENABLE1
V
REF
/
ENABLE2
V
ADJ2
C2
20 mF
V
OUT
400 mA
B+
V
REF
C1
2.0 mF
Figure 13. 400 mA Loading
400 mA Output Capability
Normally regulator outputs cannot be combined to
increase capability. This can cause damage to an IC because
of mismatches in the output drivers. The tight tolerances in
tracking of the CS8183 allow their outputs to be combined
for increased performance. Figure 13 shows the circuit
connections needed to perform this function.
APPLICATION NOTES
Switched Application
The CS8183 has been designed for use in systems where
the reference voltage on the V
REF
/ENABLE pin is
continuously on. Typically, the current into the
V
REF
/ENABLE pin will be less than 1.0 mA when the
voltage on the V
IN
pin (usually the ignition line) has been
switched out (V
IN
can be at high impedance or at ground.)
Reference Figure 14.
V
OUT
GND
GND
Adj
V
IN
GND
GND
V
REF
/
ENABLE
V
OUT
V
REF
5.0 V
V
BAT
C1
1.0 mF
Ignition
Switch
< 1.0 mA
CS8183
Figure 14.
C2
10 mF
External Capacitors
Output capacitors for the CS8183 are required for
stability. Without them, the regulator outputs will oscillate.
Actual size and type may vary depending upon the
application load and temperature range. Capacitor effective
series resistance (ESR) is also a factor in the IC stability.
Worst−case is determined at the minimum ambient
temperature and maximum load expected.
The output capacitors can be increased in size to any
desired value above the minimum. One possible purpose of
this would be to maintain the output voltage during brief
conditions of negative input transients that might be
characteristic of a particular system.
The capacitors must also be rated at all ambient
temperatures expected in the system. To maintain regulator
stability down to −40°C, a capacitor rated at that temperature
must be used.
More information on capacitor selection for SMART
REGULATOR®s is available in the SMART REGULATOR
application note, “Compensation for Linear Regulators.”
Calculating Power Dissipation in a Dual Output Linear
Regulator
The maximum power dissipation for a dual output
regulator (Figure 15) is:
PD(max) +
{
V
IN
(max) * V
OUT1
(min)
}
I
OUT1
(max)
)
{
V
IN
(max) * V
OUT2
(min)
}
I
OUT2
(max2)
(1)
) V
IN
(max)I
Q
where:
V
IN(max)
is the maximum input voltage,
V
OUT1(min)
is the minimum output voltage from V
OUT1
,
V
OUT2(min)
is the minimum output voltage from V
OUT2
,
