Electronics
Semiconductor Division
RC4190
Micropower Switching Regulator
Features
•
•
•
•
•
High efficiency – 85% typical
Low quiescent current – 215
µ
A
Adjustable output – 1.3V to 30V
High switch current – 200 mA
Bandgap reference – 1.31V
•
•
•
•
•
Accurate oscillator frequency –
±
10%
Remote shutdown capability
Low battery detection circuitry
Low component count
8-lead packages including small outline (SO-8)
Description
The RC4190 monolithic IC is a low power switch mode reg-
ulator intended for miniature power supply applications.
This DC-to-DC converter IC provides all of the active com-
ponents needed to create supplies for micropower circuits
(load power up to 400 mW, or up to 10W with an external
power transistor). Contained internally are an oscillator,
switch, reference, comparator, and logic, plus a discharged
battery detection circuit.
Application areas include on-card circuits where a non-standard
voltage supply is needed, or in battery operated instruments
where an RC4190 can be used to extend battery lifetime.
These regulators can achieve up to 85% efficiency in most
applications while operating over a wide supply voltage
range, 2.2V to 30V, at a very low quiescent current drain of
215
µ
A.
The standard application circuit requires just seven external
components for step-up operation: an inductor, a steering
diode, three resistors, a low value timing capacitor, and an
electrolytic filter capacitor. The combination of simple appli-
cation circuit, low supply current, and small package make
the RC4190 adaptable to a wide range of miniature power
supply applications.
The RC4190 is most suited for single ended step-up
(V
OUT
> V
IN
) circuits because the NPN internal switch tran-
sistor is referenced to ground. It is complemented by another
Raytheon micropower switching regulator, the RC4391,
which is dedicated to step-down (V
OUT
< V
IN
) and inverting
V
OUT
= –V
IN
) applications. Between the two devices the
ability to create all three basic switching regulator configura-
tions is assured. Refer to the RC4391 data sheet for step-
down and inverting applications.
With some optional external components the application
circuit can be designed to signal a display when the battery
has decayed below a predetermined level, or designed to
signal a display at one level and then shut itself off after the
battery decays to a second level. See the applications section
for these and other unique circuits.
The RC4190 micropower switching regulator series consists
of three devices, each with slightly different specifications.
The RM4190 has a 1.5% maximum output voltage tolerance,
0.2% maximum line regulation, and operation to 30V. The
RC4190 has a 5.0% maximum output voltage tolerance,
0.5% maximum line regulation, and operation to 24V. Other
specifications are identical. Each type is available in plastic
and ceramic DIPs, or SO-8 packages.
Block Diagram
4190
LBR
LBD
C2
Q2
C
X
OSC
C1
+1.31V
1.31V
REF
V
FB
Gnd
Q1
+1.2V
L
X
BIAS
I
C
+V
S
65-3464-01
Rev. 1.0.0
RAYTHEON [ RAYTHEON COMPANY ]
