RICOH R1201x Technical data
R1201x SERIES
STEP-UP DC/DC CONVERTER FOR WHITE LED BACK LIGHT
NO.EA-207-120404
OUTLINE
The R1201x Series are PWM control type step-up DC/DC converter ICs with low supply current.
The R1201x is fully dedicated to drive White LEDs with constant current. Each of these ICs consists of an NMOS FET, a forward diode, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, a current limit circuit, an under voltage lockout circuit (UVLO), and an over-voltage protection circuit (OVP).
The R1201x can drive white LEDs in constant current with high efficiency by using an inductor, a resistor and capacitors as external components. A diode is built-in; therefore it is possible to drive up to 5 serial white LEDs without an external diode.
The LEDs current can be set by an external resistance value and can adjust the dimming of LEDs by CE pin according to the signal of PWM. Feedback voltage is 0.2V, therefore power loss by current setting resistance is small and efficiency is good. Maximum duty cycle is internally fixed, Typ. 91%. LEDs can be driven from low voltage. Protection circuits are the current limit of Lx peak current, the over voltage limit of output, and the under voltage lockout function. The oscillator frequency can be selected from 1MHz or 1.2MHz.
It is controllable the dimming of LEDs quickly when the PWM signal (between 200Hz to 300kHz) input to CE pin. If the CE pin input is "L" in the fixed time (Typ. 0.5ms), the IC becomes the standby mode and turns OFF LEDs.
FEATURES
• Supply Current ........................................................... |
Typ. 450μA (R1201xxx3A/4A) |
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Typ. 500μA (R1201xxx1A/2A) |
• Standby Current ......................................................... |
Max. 5μA |
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Input Voltage Range .................................................. |
1.8V to 5.5V |
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Feedback Voltage ...................................................... |
0.2V |
• Feedback Voltage Accuracy....................................... |
±10mV |
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Temperature-Drift Coefficient of Feedback Voltage ... |
±150ppm/°C |
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Oscillator Frequency .................................................. |
Typ. 1MHz, Typ. 1.2MHz |
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Maximum Duty Cycle ................................................. |
Typ. 91% |
• Switch ON Resistance ............................................... |
Typ. 1.35Ω |
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UVLO Detector Threshold.......................................... |
Typ. 1.6V |
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Lx Current Limit Protection ........................................ |
Typ. 700mA |
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OVP Detector Threshold............................................ |
Select from 9.5V, 14.0V, 18.5V, 20.6V, 21.6V |
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Switching Control ....................................................... |
PWM |
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LED dimming control.................................................. |
by external PWM signal (Frequency 200Hz to 300kHz) |
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Packages ................................................................... |
DFN1616-6 (Limited), SOT-23-6 |
• Ceramic capacitors are recommended...................... |
0.22μF (R1201x02xA/ 03xA/ 04xA) |
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1μF (R1201x05xA) |
APPLICATION
• White LED Backlight for portable equipment
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R1201x |
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BLOCK DIAGRAMS |
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VFB |
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VIN |
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LX |
VOUT |
Error Amp |
PWM Comp. |
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UVLO |
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R |
Q |
Switch |
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OVP |
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Control |
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S |
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Vref |
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PWM |
OSC |
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Control |
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Slope |
Current |
Current |
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Compensation |
Protect |
sense |
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EN |
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Σ |
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Shutdown |
Chip Enable |
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delay |
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CE |
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GND |
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SELECTION GUIDE
The OVP threshold voltage, and the package for the ICs can be selected at the user's request.
Product Name |
Package |
Quantity per Reel |
Pb Free |
Halogen Free |
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R1201LxxxA-TR |
DFN1616-6 (Limited) |
5,000 pcs |
Yes |
Yes |
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R1201NxxxA-TR-FE |
SOT-23-6 |
3,000 pcs |
Yes |
Yes |
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xxx: Designation of OVP detector threshold
(021)9.5V threshold of OVP, Frequency 1.2MHz
(031)14.0V threshold of OVP, Frequency 1.2MHz
(041)18.5V threshold of OVP, Frequency 1.2MHz
(051)20.6V threshold of OVP, Frequency 1.2MHz
(052) 21.6V threshold of OVP, Frequency 1.2MHz
(023) 9.5V threshold of OVP, Frequency 1MHz
(033) 14.0V threshold of OVP, Frequency 1MHz
(043) 18.5V threshold of OVP, Frequency 1MHz
(053) 20.6V threshold of OVP, Frequency 1MHz
(054) 21.6V threshold of OVP, Frequency 1MHz
As for R1201x052A/ 054A version, input voltage range is 1.8V to 4.5V.
The products scheduled to be discontinued (be sold to limited customer) : "Limited"
These products will be discontinued in the future. You can not select these products newly.
We will provide these products to the customer who has been using or has ordered them before. But we recommend changing to other products as soon as possible.
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R1201x
PIN CONFIGURATIONS
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• DFN1616-6 |
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Top View |
Bottom View |
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5 |
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6 |
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2 |
1 |
• SOT-23-6
6 5 4
(mark side)
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2 |
3 |
PIN DESCRIPTIONS
• DFN1616-6 (Limited)
Pin No |
Symbol |
Pin Description |
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1 |
CE |
Chip Enable Pin ("H" Active) |
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2 |
VFB |
Feedback Pin |
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3 |
Lx |
Switching Pin (Open Drain Output) |
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4 |
GND |
Ground Pin |
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VIN |
Input Pin |
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VOUT |
Output Pin |
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) Tab is GND level. (They are connected to the reverse side of this IC.)
The tab is better to be connected to the GND, but leaving it open is also acceptable.
• SOT-23-6
Pin No |
Symbol |
Pin Description |
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1 |
CE |
Chip Enable Pin ("H" Active) |
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VOUT |
Output Pin |
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3 |
VIN |
Input Pin |
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4 |
Lx |
Switching Pin (Open Drain Output) |
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5 |
GND |
Ground Pin |
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6 |
VFB |
Feedback Pin |
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R1201x
ABSOLUTE MAXIMUM RATINGS |
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GND=0V |
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Symbol |
Item |
Rating |
Unit |
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VIN |
VIN Pin Voltage |
−0.3 to 6.5 |
V |
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VCE |
CE Pin Voltage |
−0.3 to VIN+0.3 |
V |
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VFB |
VFB Pin Voltage |
−0.3 to VIN+0.3 |
V |
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VOUT |
VOUT Pin Voltage |
−0.3 to 25.0 |
V |
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VLX |
LX Pin Voltage |
−0.3 to 25.0 |
V |
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ILX |
LX Pin Current |
1000 |
mA |
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PD |
Power Dissipation (DFN1616-6) (Limited) |
640 |
mW |
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Power Dissipation (SOT-23-6) |
420 |
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Topt |
Operating Temperature Range |
−40 to 85 |
°C |
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Tstg |
Storage Temperature Range |
−55 to 125 |
°C |
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) For Power Dissipation, please refer to PACKAGE INFORMATION.
ABSOLUTE MAXIMUM RATINGS
Electronic and mechanical stress momentarily exceeded absolute maximum ratings may cause the permanent damages and may degrade the life time and safety for both device and system using the device in the field. The functional operation at or over these absolute maximum ratings is not assured.
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R1201x
ELECTRICAL CHARACTERISTICS
• R1201x |
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Topt=25°C |
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Symbol |
Item |
Conditions |
Min. |
Typ. |
Max. |
Unit |
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VIN |
Operating Input Voltage |
R1201xxx1A, R1201xxx3A |
1.8 |
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5.5 |
V |
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R1201x052A, R1201x054A |
1.8 |
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4.5 |
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IDD |
Supply Current |
VIN=Input voltage Max, |
R1201xxx1A/2A |
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0.5 |
1.0 |
mA |
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VFB=0V, Lx at no load |
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R1201xxx3A/4A |
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0.45 |
0.9 |
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Istandby |
Standby Current |
VIN=Input voltage Max, VCE=0V |
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1.0 |
5.0 |
μA |
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VUVLO1 |
UVLO Detector Threshold |
VIN falling |
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1.5 |
1.6 |
1.7 |
V |
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VUVLO2 |
UVLO Released Voltage |
VIN rising |
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VUVLO1 |
1.8 |
V |
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+0.1 |
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VCEH |
CE Input Voltage "H" |
VIN=Input voltage Max |
1.5 |
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V |
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VCEL |
CE Input Voltage "L" |
VIN=1.8V |
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0.5 |
V |
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RCE |
CE Pull Down Resistance |
VIN=3.6V |
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600 |
1200 |
2200 |
kΩ |
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VFB |
VFB Voltage Accuracy |
VIN=VCE=3.6V |
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0.19 |
0.20 |
0.21 |
V |
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VFB/ |
VFB Voltage Temperature |
VIN=VCE=3.6V, −40°C ≤ Topt ≤ 85°C |
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±150 |
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ppm |
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Topt |
Coefficient |
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IFB |
VFB Input Current |
VIN=Input voltage Max, VFB=0V or VIN |
−0.1 |
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0.1 |
μA |
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RON |
Switch ON Resistance |
VIN=3.6V, ILX=100mA |
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1.35 |
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Ω |
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ILXleak |
Switch Leakage Current |
VLX=24V |
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0 |
3.0 |
μA |
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ILXlim |
Switch Current Limit |
VIN=3.6V |
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400 |
700 |
1000 |
mA |
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Vf |
Diode Forward Voltage |
IDIODE=100mA |
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0.8 |
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V |
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IDIODEleak |
Diode Leakage Current |
VOUT=24V, VLX=0V |
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10 |
μA |
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fosc |
Oscillator Frequency |
VIN=3.6V, |
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R1201xxx1A/2A |
1.0 |
1.2 |
1.4 |
MHz |
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VOUT=VFB=0V |
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R1201xxx3A/4A |
0.83 |
1.0 |
1.17 |
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Maxduty |
Maximum Duty Cycle |
VIN=3.6V, VOUT=VFB=0V |
86 |
91 |
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R1201x021A/023A |
8.9 |
9.5 |
10.1 |
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VIN=3.6V, |
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R1201x031A/033A |
13.4 |
14.0 |
14.6 |
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VOVP1 |
OVP Detector Threshold |
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V |
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R1201x041A/043A |
17.9 |
18.5 |
19.1 |
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VOUT rising |
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R1201x051A/053A |
20.0 |
20.6 |
21.2 |
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R1201x052A/054A |
21.0 |
21.6 |
22.2 |
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VOVP1/ |
VOVP1 Voltage |
VIN=VCE=3.6V, −40°C ≤ Topt ≤ 85°C |
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±150 |
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Topt |
Temperature Coefficient |
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5
R1201x
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Symbol |
Item |
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Conditions |
Min. |
Typ. |
Max. |
Unit |
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R1201x021A/023A |
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VOVP1 |
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−0.5 |
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R1201x031A/033A |
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VOVP1 |
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−0.75 |
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VOVP2 |
OVP Released Voltage |
VIN=3.6V, |
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R1201x041A/043A |
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VOVP1 |
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V |
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VOUT falling |
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−1.0 |
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R1201x051A/053A |
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VOVP1 |
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−1.1 |
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R1201x052A/054A |
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VOVP1 |
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−1.15 |
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RECOMMENDED OPERATING CONDITIONS (ELECTRICAL CHARACTERISTICS) |
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All of electronic equipment should be designed that the mounted semiconductor devices operate within the recommended operating conditions. The semiconductor devices cannot operate normally over the recommended operating conditions, even if when they are used over such conditions by momentary electronic noise or surge. And the semiconductor devices may receive serious damage when they continue to operate over the recommended operating conditions.
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