RT34063A
DC-to-DC Converter Control Circuits
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.
RT34063A
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Package type |
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N : DIP-8 |
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S : SOP-8 |
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Operating temperature range |
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C: Commercial standard |
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Marking Information |
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Part Number |
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Marking |
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RT34063ACN |
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RT34063ACN |
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RT34063ACS |
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RT34063ACS |
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Features
zOperation from 3.0V to 30V Input
zLow Standby Current
zCurrent Limiting
zInternal Switch Current to 1.5A
zOutput Voltage Adjustable
zFrequency Operation to 100KHz
zPrecision 2% Reference
Applications
zSaver for Cellular Phones
zDC-DC Converter Module
Pin Configurations
Part Number |
Pin Configurations |
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RT34063ACN |
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TOP VIEW |
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(Plastic DIP-8) |
SC |
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DRIVER |
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1 |
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8 |
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SE |
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IPK |
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2 |
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7 |
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RT34063ACS |
TC |
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VCC |
3 |
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6 |
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(Plastic SOP-8) |
GND |
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COMP |
4 |
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5 |
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DS34063A-06 May 2001 |
www.richtek-ic.com.tw |
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1 |
RT34063A
Absolute Maximum Ratings
z Power Supply Voltage |
30V |
zFeedback Input Voltage Range -0.3 ~ +30V
zSwitch Collector Voltage 30V
zSwitch Emitter Voltage30V
zSwitch Collector to Emitter Voltage 30V
zDriver Collector Voltage30V
z Driver Collector Current (see Note 1) |
100mA |
zSwitch Current1.5A
zPower Dissipation, PD @ TA = 25°C
DIP-81.25W SOP-8
0.625W
•Package Thermal Resistance
DIP-8, θJA 100°C/W
SOP-8, θJA 160°C/W
zOperating Junction Temperature Range-40 ~ +125°C
zStorage Temperature Range-65 ~ +150°C
Note: 1. Maximum package power dissipation limits must be observed.
Electrical Characteristics
(VCC = 5V, TA = 25°C, unless otherwise specified)
Parameter |
Symbol |
Test Conditions |
Min |
Typ |
Max |
Units |
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Oscillator |
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Frequency |
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VPIN5 = 0V, CT = 1.0nF |
26 |
38 |
48 |
kHz |
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Charge Current |
ICHG |
5.0V ≤ VCC ≤ 30V |
25 |
36 |
43 |
µA |
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Discharge Current |
IDISCHG |
5.0V ≤ VCC ≤ 30V |
160 |
250 |
290 |
µA |
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Discharge to Charge Current Ratio |
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Pin 7 to VCC |
5.5 |
6.9 |
7.9 |
-- |
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Current Limit Sense Voltage |
VLIMIT |
ICHG = IDISCHG |
280 |
330 |
380 |
mV |
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Output Switch |
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Saturation Voltage, Darlington Connection |
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ISW = 1.0A, Pins1, 8 connected |
-- |
1.0 |
1.3 |
V |
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Saturation Voltage, Darlington Connection |
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ISW = 1.0A, RPIN8 = 82Ω to |
-- |
0.45 |
0.7 |
V |
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VCC, Forced β 20 |
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DC Current Gain |
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ISW = 1.0A, VCE = 5.0V |
50 |
75 |
-- |
-- |
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Collector Off-state Current |
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VCE = 30V |
-- |
0.01 |
100 |
µA |
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Comparator |
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Threshold Voltage |
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1.225 |
1.25 |
1.275 |
V |
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Threshold Voltage Line Regulation |
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3.0V ≤ VCC ≤ 30V |
-- |
1.4 |
5.0 |
mV |
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Input Bias Current |
IBIAS |
VIN = 0V |
-- |
-20 |
-400 |
nA |
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Total Device |
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Supply Current |
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VCC = 5.0V to 30V, CT = 1.0nF, |
-- |
3.0 |
4.5 |
mA |
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ICC |
Pin7 = VCC, VPIN5 > VTH, Pin2 |
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= GND, Remaining pins open |
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www.richtek-ic.com.tw |
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DS34063A-06 May 2001 |
2
RT34063A
Function Block Diagram
DRIVER 8 |
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SC |
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S Q |
Q2 |
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R |
Q1 |
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7 |
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100 |
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IPK |
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2 |
SE |
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IPK |
CT |
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Oscillator |
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VCC 6
Comparator
+ _
COMP 5
3 CT
1.25V Reference Regulator
4 GND
Pin Description
Pin Name |
Pin Function |
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SC |
1.5A Switch Collector |
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SE |
Darlington Switch Emitter |
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CT |
Oscillator Timing Capacitor |
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GND |
Power GND |
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COMP |
Feedback Comparator Inverting Input |
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VCC |
Power Supply Input |
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IPK |
Highside Current Sense Input VCC-VIPK = 330mV |
DRIVER |
Driver Collector |
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DS34063A-06 May 2001 |
www.richtek-ic.com.tw |
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3 |
RT34063A
Typical Application Circuit
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170 H |
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8 |
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L |
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1 |
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180 |
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S Q |
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R |
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7 |
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2 |
1N5819 |
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RSC |
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IPK |
CT |
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0.22 |
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CT |
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6 |
OSC |
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VIN |
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3 |
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12V |
+100 F |
+ |
Comp. |
1.25V |
1500pF |
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Ref |
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5 |
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4 |
Optional Filter |
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R2 |
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1.0 H |
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VOUT |
VOUT |
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R1 |
47k |
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330 F |
+CO 28V/175mA |
+ |
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100 F |
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2.2k |
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Fig.1 Step-up Converter
www.richtek-ic.com.tw |
DS34063A-06 May 2001 |
4
RT34063A
8 |
VOUT |
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1 |
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+ |
7 |
2 |
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6 |
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VIN |
3 |
5 |
4 |
Fig.2a External NPN Switch
8 |
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R |
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1 |
VOUT |
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+ |
7 |
2 |
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R→0 for |
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6 |
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Constant VIN |
VIN |
3 |
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5 |
4 |
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Fig.2b External NPN Saturated Switch (See Note)
Fig.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 2.0 s 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 nonDarlington configuration is used, the following output drive condition is recommended.
DS34063A-06 May 2001 |
www.richtek-ic.com.tw |
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