RT34063A
DS34063A-07 September 2002
www.richtek.com
1
DC-to-DC Converter Control Circuits
General Description
The RT34063A Series is a monolithic control circuit
containing the primary functions required for DC-to-
DC converters.
These devices consist of an internal temperature
compensated reference, comparator, controlled duty
cycle oscillator with an active current limit circuit,
driver and high current output switch.
This series was specially designed to be
incorporated in Step-down and Step-up and
Voltage-inverting applications with a minimum
number of external components.
Ordering Information
RT34063A
Marking Information
Part Number
Marking
RT34063ACN
RT34063ACN
RT34063ACS
RT34063ACS
Features
Operation from 3.0V to 30V Input
Low Standby Current
Current Limiting
Internal Switch Current to 1.5A
Output Voltage Adjustable
Frequency Operation to 100KHz
Precision 2% Reference
Applications
Saver for Cellular Phones
DC-DC Converter Module
Pin Configurations
Part Number
Pin Configurations
RT34063ACN
(Plastic DIP-8)
RT34063ACS
(Plastic SOP-8)
TOP VIEW
Operating temperature range
C: Commercial standard
Package type
N : DIP-8
S : SOP-8
SC
SE
TC
GND
DRIVER
IPK
VCC
COMP
1
2
3
4
8
7
6
5
RT34063A
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DS34063A-07 September 2002
2
Absolute Maximum Ratings
Power Supply Voltage
30V
Feedback Input Voltage Range
-0.3 ~ +30V
Switch Collector Voltage
30V
Switch Emitter Voltage
30V
Switch Collector to Emitter Voltage
30V
Driver Collector Voltage
30V
Driver Collector Current (see Note 1)
100mA
Switch Current
1.5A
Power Dissipation, P
D
@ T
A
= 25
C
DIP-8
1.25W
SOP-8
0.625W
Package Thermal Resistance
DIP-8,
JA
100
C/W
SOP-8,
JA
160
C/W
Operating Junction Temperature
+125
C
Storage Temperature Range
-65 ~ +150
C
Note: 1. Maximum package power dissipation limits must be observed.
Electrical Characteristics
(VCC
= 5V, T
A
= 25
C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max Units
Oscillator
Frequency
V
PIN5
= 0V, C
T
= 1.0nF
26
38
48
kHz
Charge Current
I
CHG
5.0V
VCC
30V
25
36
43
A
Discharge Current
I
DISCHG
5.0V
VCC
30V
160
250
290
A
Discharge to Charge Current Ratio
Pin 7 to VCC
5.5
6.9
7.9
--
Current Limit Sense Voltage
V
LIMIT
I
CHG
= I
DISCHG
280
330
380
mV
Output Switch
Saturation Voltage, Darlington Connection
I
SW
= 1.0A, Pins1, 8 connected
--
1.0
1.3
V
Saturation Voltage, Darlington Connection
I
SW
= 1.0A, R
PIN8
= 82
to
VCC, Forced
20
--
0.45
0.7
V
DC Current Gain
I
SW
= 1.0A, V
CE
= 5.0V
50
75
--
--
Collector Off-state Current
V
CE
= 30V
--
0.01
100
A
Comparator
Threshold Voltage
1.225 1.25 1.275
V
Threshold Voltage Line Regulation
3.0V
VCC
30V
--
1.4
5.0
mV
Input Bias Current
I
BIAS
V
IN
= 0V
--
-20
-400
nA
Total Device
Supply Current
I
CC
VCC = 5.0V to 30V, C
T
= 1.0nF,
Pin7 = VCC, V
PIN5
>
V
TH
, Pin2
= GND, Remaining pins open
--
3.0
4.5
mA
RT34063A
DS34063A-07 September 2002
www.richtek.com
3
Function Block Diagram
Pin Description
Pin Name
Pin Function
SC
1.5A Switch Collector
SE
Darlington Switch Emitter
CT
Oscillator Timing Capacitor
GND
Power GND
COMP
Feedback Comparator Inverting Input
VCC
Power Supply Input
IPK
Highside Current Sense Input VCC-V
IPK
= 330mV
DRIVER
Driver Collector
1
8
COMP
SC
CT
S Q
R
Q2
Q1
100
I
PK
C
T
Oscillator
Comparator
1.25V
Reference
Regulator
2
3
4
5
6
7
SE
VCC
IPK
DRIVER
GND
+
_
RT34063A
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DS34063A-07 September 2002
4
Typical Operating Characteristics
Output Switch On-Off Time vs.
Oscillator Timing Capacitor
1
10
100
1000
0.01
0.1
1
10
CT, Oscilator Timing Capacitor (nF)
T
On
-
O
ff
,
O
u
tp
u
t
S
w
i
t
c
h
O
n
-O
ff
T
i
m
e
(
s
)
V
CC
= 5.0V
Pin 7 = V
CC
Pin 5 = GND
T
A
= 25
C
T
ON
T
OFF
Emitter Follower Configuration
Output Saturation Voltage vs. Emiter Current
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
0
0.3
0.6
0.9
1.2
1.5
IE, Emitter Current (A)
VCE,
Sa
t
u
r
a
t
i
o
n
V
o
l
t
a
g
e
(
V
)
.
V
CC
= 5.0V
Pin 1,7,8 = V
CC
Pin 3,5 = GND
T
A
= 25
C
Common Emiter Configuration Output Switch
Saturation Voltage vs. Collector Current
0.0
0.2
0.4
0.6
0.8
1.0
0
0.3
0.6
0.9
1.2
1.5
ICC, Collector Current (A)
VC
E,
Sat
u
r
a
t
i
on
Vol
t
a
g
e
(
V
)
.
V
CC
= 5.0V
Pin 7 = V
CC
Pin 2,3,5 = GND
T
A
= 25
C
Standyby Supply Current vs. Supply Voltage
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0
5
10
15
20
25
30
Supply Voltage (V)
I
C
C
,
S
u
ppl
y Cur
r
ent
(
m
A)
.
V
CC
= 5.0V
Pin 7 = V
CC
Pin 5 = 2.0V
Pin 2 = GND
T
A
= 25
C
Current Limit Sense Voltage vs. Temp.
200
220
240
260
280
300
320
340
360
380
400
-40
-20
0
20
40
60
80
Temperature ( C)
Cur
r
ent
Li
m
i
t
S
e
nse
V
o
l
t
ag
e (
m
V
)
.
V
CC
= 5.0V
I
CHARGE
= I
DISCHARGE
V
OUT
= 5.0V
Pin 1,8 = Open
Pin 7 = V
CC
C
T
= 1.0nF
Pin 5 = GND
T
A
= 25
C
Timing Capacitor Waveform
RT34063A
DS34063A-07 September 2002
www.richtek.com
5
I
C
vs. V
CE(Q1)
Curve
0
400
800
1200
1600
2000
0
160
320
480
640
800
V
CE
(mV)
I
C
(m
A
)
T
J
= -20
C
I
b
= 34mA
I
b
= 15mA
I
b
= 8mA
I
b
= 2.4mA
I
C
vs. V
CE(Q1)
Curve
0
400
800
1200
1600
2000
0
160
320
480
640
800
V
CE
(mV)
I
C
(m
A
)
T
J
= -10
C
I
b
= 34mA
I
b
= 15mA
I
b
= 8mA
I
b
= 2.4mA
I
C
vs. V
CE(Q1)
Curve
0
400
800
1200
1600
2000
0
160
320
480
640
800
V
CE
(mV)
I
C
(m
A
)
T
J
= 0
C
I
b
= 34mA
I
b
= 15mA
I
b
= 8mA
I
b
= 2.4mA
I
C
vs. V
CE(Q1)
Curve
0
400
800
1200
1600
2000
0
160
320
480
640
800
V
CE
(mV)
I
C
(m
A
)
T
J
= 25
C
I
b
= 34mA
I
b
= 15mA
I
b
= 8mA
I
b
= 2.4mA
I
C
vs. V
CE(Q1)
Curve
0
300
600
900
1200
1500
1800
0
160
320
480
640
800
V
CE
(mV)
I
C
(m
A
)
T
J
= 70
C
I
b
= 34mA
I
b
= 15mA
I
b
= 8mA
I
b
= 2.4mA
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