RT34063A
DC/DC Converter Control Circuits
General Description
Features
The RT34063A Series is a monolithic control circuit
containing the primary functions required for DC/DC
converters.
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Operation from 3.0V to 30V Input
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Low Standby Current
Current Limiting
Internal Switch Current to 1.5A
Output Voltage Adjustable
Frequency Operation to 100kHz
Precision 2% Reference
RoHS Compliant and 100% Lead (Pb)-Free
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.
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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.
Applications
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Saver for Cellular Phones
DC/DC Converter Module
Ordering Information
Pin Configurations
RT34063A
Package Type
N : DIP-8
S : SOP-8
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commercial Standard)
Note :
(TOP VIEW)
SC
8
DRIVER
SE
2
7
IPK
TC
3
6
VCC
GND
4
5
COMP
Richtek Pb-free and Green products are :
`
RoHS compliant and compatible with the current require-
DIP-8 / SOP-8
ments of IPC/JEDEC J-STD-020.
`
Suitable for use in SnPb or Pb-free soldering processes.
`
100%matte tin (Sn) plating.
Functional Pin Description
Pin Name
Pin Function
SC
1.5A Switch Collector.
SE
Darlington Switch Emitter.
TC
Oscillator Timing Capacitor.
GND
Power GND.
COMP
Feedback Comparator Inverting Input.
VCC
Power Supply Input.
IPK
High side Current Sense Input VCC-VIPK = 330mV.
DRIVER
Driver Collector.
DS34063A-14 November 2007
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1
RT34063A
Function Block Diagram
DRIVER
8
1
S Q
SC
Q2
R
Q1
IPK
100
7
2
SE
3
TC
IPK
CT
Oscillator
VCC
6
Comparator
+
-
COMP
1.25V
Reference
Regulator
5
4
GND
Typical Application Circuit
L
170µH
8
180
1
S
Q
R
2
7
RSC
0.22
VIN
CT
CT
OSC
6
+
12V
IPK
+
-
100µF
5
COMP
1N5819
3
1.25V
Ref
1500pF
4
Optional Filter
1.0µH
R2
47K
330µF
+
+
R1
2.2K
VOUT
VOUT
28V/175mA
CO
100µF
Figure 1. Step-up Converter
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DS34063A-14 November 2007
RT34063A
8
VOUT
VIN
7
2
6
3
5
4
+
1
(a) External NPN Switch
8
+
7
VOUT
R
1
2
R
0 for
Constant VIN
VIN
6
3
5
4
(b) External NPN Saturated Switch (See Note)
Figure 2. External Current Boost Connections for IC Peak Greater than 1.5A
Note: If the output switch is driven into hard saturation (non-Darlington configuration) at low switch currents ( ≤ 300mA) and high
driver currents ( ≥ 30mA), it may take up to 2.0μs to come out of saturation. This condition will shorten the off time at
frequencies ≥ 30kHz, and is magnified at high temperature. This condition does not occur with a Darlington configuration,
since the output switch cannot saturate. If a non-Darlington configuration is used, the following output drive condition is
recommended.
DS34063A-14 November 2007
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RT34063A
8
1
S
Q
Q2
R
Q1
7
RSC
0.33
VIN
6
+
25V
IPK
CT
OSC
+
-
100µF
5
COMP
2 1N5819
CT
L
220µH
3
1.25V
Ref
470pF
4
Optional Filter
1.0µH
R2
470µF
+
+
R1
1.2K
3.6K
VOUT
VOUT
5.0V/500mA
CO
100µF
Figure 3. Step-down Converter
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DS34063A-14 November 2007
RT34063A
8
1
2
6
3
5
4
VOUT
+
VIN
7
(a) External NPN Switch
8
VIN
7
2
6
3
5
4
VOUT
+
1
(b) External PNP Saturated Switch
Figure 4. External Current Boost Connections for IC Peak Greater than 1.5A
DS34063A-14 November 2007
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RT34063A
8
180
1
S
Q
Q2
R
Q1
2
7
VIN
IPK
CT
OSC
6
+
4.5V to 6.0V
RSC
0.24
+
-
100µF
COMP
88µH
L
1N5819
3
1.25V
Ref
1500pF
5
4
Optional Filter
1.0µH
R2
VOUT
-12V/100mA
CO
1000µF
100µF
+
953
+
R1
8.2K
VOUT
Figure 5. Voltage Inverting Converter
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DS34063A-14 November 2007
RT34063A
8
1
2
7
VOUT
6
3
5
4
+
VIN
(a) External NPN Switch
8
1
VOUT
2
6
3
5
4
+
7
VIN
(b) External PNP Saturated Switch
Figure 6. External Current Boost Connections for Peak Greater than 1.5A
DS34063A-14 November 2007
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RT34063A
Design Formula Table
Calculation
Step-up
ton/toff
VOUT + VF − VIN (MIN)
VIN (MIN) − VSAT
(ton + toff)
1
f
1
f
1
f
toff
ton + toff
ton
+1
toff
ton + toff
ton
+1
toff
ton + toff
ton
+1
toff
ton
(ton + toff ) − toff
(ton + toff ) − toff
(ton + toff ) − toff
CT
4.0 × 10−5 ton
4.0 × 10−5 ton
4.0 × 10−5 ton
Ipk (SWITCH)
⎞
⎛ ton
2 IOUT (MAX) ⎜
+ 1⎟
off
t
⎠
⎝
2 IOUT (MAX)
⎞
⎛ ton
2 IOUT(MAX) ⎜
+ 1⎟
off
t
⎠
⎝
RSC
0.3/Ipk (SWITCH)
0.3/Ipk (SWITCH)
0.3/Ipk (SWITCH)
L (min)
⎛ (VIN(MIN) − VSAT ) ⎞
⎜⎜ Ipk(SWITCH) ⎟⎟ton(MAX )
⎝
⎠
⎛ (VIN(MIN) − VSAT ) ⎞
⎜⎜ Ipk(SWITCH ) ⎟⎟ ton(MAX )
⎝
⎠
⎛ (VIN(MIN) − VSAT ) ⎞
⎜⎜ Ipk(SWITCH ) ⎟⎟ton(MAX )
⎝
⎠
9
CO
Step-down
Voltage-Inverting
VOUT + VF
VIN (MIN) − VSAT − VOUT
Ipk (SWITCH )( ton + toff )
8 Vripple(pp )
IOUT ton
Vripple (pp)
VSAT
: Saturation voltage of the output switch.
VF
: Forward voltage drop of the output rectifier.
V OUT + V F
V IN − V SAT
9
IOUT ton
Vripple (pp)
The following power supply characteristics must be chosen:
VIN
: Nominal input voltage.
VOUT
: Desired output voltage VOUT = 1.25(1+
IOUT
: Desired output current.
f
: Minimum desired output switching frequency at the selected values of Vin and IO.
Vripple(pp)
: Desired peak-to-peak output ripple voltage. In practice, the calculated capacitor value needs to be increased
due to its equivalent series resistance and board layout. The ripple voltage should be kept to a low value
since it directly affects the line and load regulation.
R2
)
R1
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DS34063A-14 November 2007
RT34063A
Absolute Maximum Ratings
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(Note 1)
Power Supply Voltage -------------------------------------------------------------------------------------------------Feedback Input Voltage Range --------------------------------------------------------------------------------------Switch Collector Voltage ----------------------------------------------------------------------------------------------Switch Emitter Voltage ------------------------------------------------------------------------------------------------Switch Collector to Emitter Voltage --------------------------------------------------------------------------------Driver Collector Voltage ------------------------------------------------------------------------------------------------Driver Collector Current (see Note) ----------------------------------------------------------------------------------Switch Current -----------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
DIP-8 ----------------------------------------------------------------------------------------------------------------------SOP-8 ---------------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
DIP-8, θJA -----------------------------------------------------------------------------------------------------------------SOP-8, θJA ---------------------------------------------------------------------------------------------------------------Junction Temperature --------------------------------------------------------------------------------------------------Storage Temperature Range ------------------------------------------------------------------------------------------Note:Maximum package power dissipation limits must be observed.
Recommended Operating Conditions
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30V
−0.3 to +30V
30V
30V
30V
30V
100mA
1.5A
1.25W
0.625W
100°C/W
160°C/W
150°C
65 to +150°C
(Note 3)
Power Supply Input Voltage Range ---------------------------------------------------------------------------------- 3V to 30V
Junction Temperature Range ------------------------------------------------------------------------------------------ −40°C to 125°C
Ambient Temperature Range ------------------------------------------------------------------------------------------ −40°C to 85°C
Electrical Characteristics
(VCC = 5V, TA = 25° C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
VPIN5 = 0V, CT = 1.0nF
26
38
48
kHz
Oscillator
Frequency
Charge Current
ICHG
5.0V ≤ VCC ≤ 30V
25
36
43
μA
Discharge Current
IDISCHG 5.0V ≤ VCC ≤ 30V
160
250
290
μA
Pin 7 to VCC
5.5
6.9
7.9
--
ICHG = I DISCHG
280
330
380
mV
Discharge to Charge Current
Ratio
Current Limit Sense Voltage
V LIM
Output Switch
Saturation Voltage, Darlington
Connection
ISW = 1.0A, Pins1, 8 connected
--
1.0
1.3
V
Saturation Voltage, Darlington
Connection
ISW = 1.0A, RPIN8 = 82Ω to VCC,
Forced β ≅ 20
--
0.45
0.7
V
DC Current Gain
ISW = 1.0A, V CE = 5.0V
50
75
--
--
Collector Off-state Current
V CE = 30V
--
0.01
100
μA
To be continued
DS34063A-14 November 2007
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RT34063A
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
1.225
1.25
1.275
V
3.0V ≤ VCC ≤ 30V
--
1.4
5.0
mV
IBIAS
VIN = 0V
--
−20
−400
nA
ICC
VCC = 5.0V to 30V, CT = 1.0nF,
Pin7 = VCC, VPIN5 > VTH, Pin2 = GND,
Remaining pins open
--
3.0
4.5
mA
Comparator
Threshold Voltage
Threshold Voltage Line
Regulation
Input Bias Current
Total Device
Supply Current
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended
periods may remain possibility to affect device reliability.
Note 2. θJA is measured in the natural convection at T A = 25°C on a low effective thermal conductivity test board of
JEDEC 51-3 thermal measurement standard.
Note 3. The device is not guaranteed to function outside its operating conditions.
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DS34063A-14 November 2007
RT34063A
T On-Off , Output Switch On-Off Time (us)
Typical Operating Characteristics
Output Switch On-Off Time vs.
Oscillator Timing Capacitor
Timing Capacitor Waveform
1000
VCC = 5.0V
Pin 7 = VCC
Pin 5 = GND
TA = 25°C
100
10
VOUT = 5.0V
Pin 1,8 = Open, Pin 7 = VCC
CT = 1.0nF ,Pin 5 = GND
TA = 25°C
1
0.01
0.1
1
Time (10μs/Div)
10
Common Emiter Configuration Output Switch
Saturation Voltage vs. Collector Current
A
1.7
1.0
1.6
VCE, Saturation Voltage (V)
A
Emitter Follower Configuration
Output Saturation Voltage vs. Emiter Current
VCE, Saturation Voltage (V)
TC, Oscilator Timing Capacitor (nF)
1.5
1.4
1.3
1.2
VCC = 5.0V
Pin 1,7,8 = VCC
Pin 3,5 = GND
TA = 25°C
1.1
0.8
0.6
0.4
VCC = 5.0V
Pin 7 = VCC
Pin 2,3,5 = GND
TA = 25°C
0.2
0.0
1
0
0.3
0.6
0.9
1.2
0
1.5
0.3
IE, Emitter Current (A)
Standyby Supply Current vs. Supply Voltage
3.0
2.5
2.0
1.5
VCC = 5.0V
Pin 7 = VCC
Pin 5 = 2.0V
Pin 2 = GND
TA = 25°C
0.5
0.0
0
5
10
15
20
Supply Voltage (V)
DS34063A-14 November 2007
0.9
1.2
1.5
25
Current Limit Sense Voltage vs. Temperature
Current Limit Sense Voltage (mV) .
ICC, Supply Current (mA) .
3.5
1.0
0.6
ICC, Collector Current (A)
30
400
380
360
340
320
300
280
260
240
VCC = 5.0V
ICHARGE = IDISCHARGE
220
200
-40
-20
0
20
40
60
80
Temperature (°C)
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RT34063A
IC vs. VCE(Q1) Curve
IC vs. VCE(Q1) Curve
2000
2000
TJ = -20°C
TJ = -10°C
Ib = 34mA
1600
1200
Ib = 15mA
800
Ib = 8mA
I C (mA)
I C (mA)
1600
Ib = 34mA
1200
Ib = 15mA
800
Ib = 8mA
400
400
Ib = 2.4mA
Ib = 2.4mA
0
0
0
160
320
480
640
0
800
160
320
640
800
VCE (mV)
VCE (mV)
IC vs. VCE(Q1) Curve
IC vs. VCE(Q1) Curve
2000
2000
TJ = 0°C
TJ = 25°C
Ib = 34mA
Ib = 34mA
1600
1200
Ib = 15mA
800
Ib = 8mA
I C (mA)
1600
I C (mA)
480
Ib = 15mA
1200
Ib = 8mA
800
400
400
Ib= 2.4mA
Ib = 2.4mA
0
0
0
160
320
480
640
800
VCE (mV)
0
160
320
480
640
800
VCE (mV)
IC vs. VCE(Q1) Curve
1800
TJ = 70°C
Ib = 34mA
1500
Ib = 15mA
I C (mA)
1200
Ib = 8mA
900
600
Ib = 2.4mA
300
0
0
160
320
480
640
800
VCE (mV)
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DS34063A-14 November 2007
RT34063A
Outline Dimension
A
B
E
J
C
L
I
D
F
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
9.068
9.627
0.357
0.379
B
6.198
6.604
0.244
0.260
C
3.556
4.318
0.140
0.170
D
0.356
0.559
0.014
0.022
E
1.397
1.651
0.055
0.065
F
2.337
2.743
0.092
0.108
I
3.048
3.556
0.120
0.140
J
7.366
8.255
0.290
0.325
L
0.381
0.015
8-Lead DIP Plastic Package
DS34063A-14 November 2007
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RT34063A
H
A
M
J
B
F
C
I
D
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
4.801
5.004
0.189
0.197
B
3.810
3.988
0.150
0.157
C
1.346
1.753
0.053
0.069
D
0.330
0.508
0.013
0.020
F
1.194
1.346
0.047
0.053
H
0.170
0.254
0.007
0.010
I
0.050
0.254
0.002
0.010
J
5.791
6.200
0.228
0.244
M
0.400
1.270
0.016
0.050
8-Lead SOP Plastic Package
Richtek Technology Corporation
Richtek Technology Corporation
Headquarter
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
8F, No. 137, Lane 235, Paochiao Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)89191466 Fax: (8862)89191465
Email: marketing@richtek.com
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design,
specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed
by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
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DS34063A-14 November 2007