View RN5RY202_44485.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

VFM STEP-UP DC/DC CONVERTER CONTROLLER
RN5RY202
NO.EA-042-0006
OUTLINE
The RN5RY202 Series are VFM (chopper) Control ICs for step-up DC/DC converter with an external power transistor featuring high output voltage accuracy and low supply current by CMOS process. Each of the RN5RY202 Series ICs consists of a voltage reference unit, an error amplifier, an oscillator, a VFM control circuit and feed back resistors. Output voltage is fixed at 2V in the IC. A low ripple, high efficiency step-up DC/DC converter can be constructed by simply adding an inductor, a diode, a capacitor, and a drive transistor and feed back resistors. Although the series have no CE pins unlike RN5RYxx1A, high voltage (VOUT=30V) can be also output by using external feed back resistors.
FEATURES
* Low Supply Current ............................................................................TYP. 3A * Low Temperature-Drift Coefficient of Output Voltage ...................TYP. 50ppm/C * High Accuracy Output Voltage .........................................................2.5% * Low Oscillation Start-up Voltage (no load) ......................................MAX. 0.8V * Any output voltage can be set with external resistors * Small Package SOT-23-5 (Mini-Mold)
APPLICATIONS
* Constant voltage power source for battery-powered instruments. * Constant power source for cameras, camcorders, pagers, and other hand-held communication tools. * Constant power source for devices that require higher voltages than battery voltages.
BLOCK DIAGRAM
VDD 2
Oscillator 3
VOUT 5
EXT
Output Buffer
- +
Vref
1
GND
1
RN5RY202
SELECTION GUIDE
In the RN5RY202 Series, the taping type for the ICs can be selected at the user's request. These selections can be made by designating the part number as shown below: RN5RY202 x - xx Part Number { ab c { d
Code a b 20. Designation of Output Voltage (VOUT) VOUT is fixed at 2.0V. 2 Designation of Packing Type : c A : Taping C : Antistatic bag (for Samples only) Designation of Taping Type :
Contents
d
Ex. TR, TL (refer to Taping Specifications ; TR type is prescribed as a standard.)
For example, Taping Type TR, is designated by Part Number RN5RY202A-TR.
PIN CONFIGURATION
* SOT-23-5
5 4
mark side
1
2
3
2
RN5RY202
PIN DESCRIPTION
Pin No. Symbol Description
1 2 3 4 5
GND VDD EXT NC VOUT
Ground Pin Input Pin External Transistor Drive Pin (CMOS Output) No Connection Internal Voltage Output Pin (fixed at 2V)
ABSOLUTE MAXIMUM RATINGS
Symbol Item Ratings Unit
VDD VOUT VEXT IEXT PD Topt Tstg Tsolder
Input Voltage Output Pin Voltage EXT Pin Output Voltage EXT Pin Output Current Power Dissipation Operating Temperature Storage Temperature Lead Temperature (Soldering)
12 12 -0.3 to VDD+0.3 50 150 -40 to +85 -55 to +125 260C 10s (Lead part)
V V V mA mW C C
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum ratings are threshold limit values that must not be exceeded even for an instant under any conditions. Moreover, such values for any two items must not be reached simultaneously. Operation above these absolute maximum ratings may cause degradation or permanent damage to the device. These are stress ratings only and do not necessarily imply functional operation below these limits.
3
RN5RY202
ELECTRICAL CHARACTERISTICS
* RN5RY202
Symbol Item Conditions MIN. TYP. MAX.
Topt=25C
Unit
VOUT VIN IDD1
Output Voltage Input Voltage Supply Current 1
VIN=VDD=1.9V
1.950
2.000
2.050 10
V V A
EXT No load, VDD=1.9V VOUT=1.9V, Test circuits1 EXT No load, VDD=1.9V VOUT=2.1V, Test circuits1 VDD=1.9V, VOUT=1.9V Test circuits2 VDD=1.9V, VOUT=1.9V EXT "H" side, Test circuits2 EXT No load, Test circuits2 IOUT=10mA -40CTopt85C VDD=1.9V, VOUT=1.9V VEXT=GND, Test circuits3 VDD=1.9V, VOUT=1.9V VEXT=1.9V, Test circuits4 VDD=2V, VOUT=10V Test circuits5 1.5 65
15
25
IDD2
Supply Curren 2
3
5
A
fosc
Duty Vstart VOUT Topt IEXTH
Maximum Oscillator Frequency
180
kHz
Oscillator Duty Cycle Oscillator Start-up Voltage Output Voltage Temperature Coefficient EXT "H" Output Current
75 0.7 50 0.8
% v ppm/C
-1.5
mA
IEXTL
EXT "L" Output Current
mA
RVSET
Voltage Set Resistor
2
M
4
RN5RY202
TEST CIRCUIT
GND VOUT A VDD EXT NC Oscilloscope A
GND VOUT VDD EXT NC
Test Circuit1
Test Circuit2
GND VOUT VDD EXT Oscilloscope NC Oscilloscope
GND VOUT VDD EXT NC
Test Circuit3
Test Circuit4
GND VOUT VDD EXT NC
A
Test Circuit5
5
RN5RY202
TYPICAL CHARACTERISTICS
1) Output Voltage vs. Output Current
2SK2054(NEC) 40 40 2SK1470(Sanyo)
Output Voltage VOUT(V)
35
Output Voltage VOUT(V)
0 20 40 60
35
30
30
25
25
20
20 0 20 40 60
Output Current IOUT(mA)
Output Current IOUT(mA)
2) Efficiency vs. Output Current
2SK2054(NEC) 80 70 80 70 2SK1470(Sanyo)
Efficiency (%)
Efficiency (%)
60 50 40 30 20 0 20 40 60
60 50 40 30 20 0 20 40 60
Output Current IOUT(mA)
Output Current IOUT(mA)
*) VIN=3.6V **) For test circuit details, see "TYPICAL APPLICATIONS".
6
RN5RY202
CHARACTERISTIC TEST CIRCUIT
L1 D1
VIN
VOUT
VDD
R1 RN5RY202
Q1
EXT
VOUT
+ (2V)
C
R2 GND
Components : Inductor (L1) Diode (D1) Capacitor (C) Transistor (Q1) Output voltage setting resistor (R1) Output voltage setting resistor (R2)
: CD54 (15H) : RB111C (Rohm) : 47F (Tantalum type) : 2SK2054 (NEC) or 2SK1470 (Sanyo) : 150k : 10k
TYPICAL APPLICATIONS
SD1 L1 R2 VDD C1 EXT R1 GND VOUT R3 C2
7
RN5RY202
NOTES ON EXTERNAL COMPONENTS * If input voltage is high enough, higher efficiency may be obtained by using MOSFET in the driver transistor, in which case no resistors and condensers are necessary. * Always keep the absolute maximum ratings (VDS and VCE) since spike voltage higher than output voltage may be applied to the driver transistor. We recommend that you use transistors with absolute maximum ratings more than twice of the output setting voltage. * Use capacitor with an allowable voltage which is at least one and a half times as much as the setting output voltage. * Use output voltage setting resistors with resistance much smaller than IC internal resistor (MIN. 2M). Be careful not to allow larger resistance, which will result in larger error in setting voltage. We recommend resistors up to several tens of k. * Select an inductor with small DC resistance and enough permissible current and less tendency to magnetic saturation. * Select a diode of a shot-key type with a faster switching speed. Also pay attention to current capacity. (Reference external components) * Inductor CD54, CD73, CD104 (Sumida) * Driver transistor 2SD1628 (Sanyo) 2SK1470 (Sanyo) 2SK1959 (NEC) 2SK2054 (NEC) * Diode RB111C (Rohm) D1FS4A (Shindengen) * Output condenser Tantalum type
8
RN5RY202
NOTES ON OUTPUT VOLTAGE SETTINGS
R2 VOUT RIC GND
I2 VOUT I3 2.0V
IIC R3
Output setting voltage is determined using the following formulas : I2=IIC+I3 ..........................................................................................(1) I3=2.0/R3 ........................................................................................(2) From (1) and (2) above, I2=IIC+2.0/R3 ..................................................................................(3) VOUT=2.0+R2 x I2............................................................................(4) By substituting (3) into the above formula VOUT=2.0+R2 x (IIC+2.0/R3) =2.0 x (1+R2/R3)+R2 x IIC ....................................................(5) The second term, R2 x IIC in the formula (5) above may cause a voltage setting error. Here, consider the formula in terms of IIC, IIC=2.0/RIC .....................................................................................(6) then R2 x IIC that causes the error will be as shown below : R2 x IIC=R2 x 2.0/RIC =2.0 x R2/RIC......................................................................(7) Thus, when R2<9

▲Up To Search▲

Price & Availability of RN5RY202

	To Download RN5RY202 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .