®
R7735
High Performance Enhanced Quadruple Mode PWM
Flyback Controller
General Description
R7735 series is the successor of R7732/3 and fully compatible with most of SOT-23-6 / DIP-8 product so far in the market. It has enhanced quadruple mode PWM controller and owns excellent green power performance, especially under light load and no load conditions. It focuses on "easy to design" in different applications and it will save both design effort and external components.
Besides the general features shown in the Features section, R7735 covers wide protection options, such as internal Over Load Protection (OLP) and Over Voltage Protection (OVP) to eliminate the external protection circuits. Moreover, it also features Secondary Rectifier Short Protection (SRSP) and CS pin open protection. This protection will make the PSU design for reliability and safety easier.
R7735 is designed for power supply such as NB adaptor which is a very cost effective and compact design. The precise external OVP and Over Temperature Protection (OTP) can be implemented by very simple circuit. The start-up resistors can also be replaced by bleeding resistors to save power loss and component count.
Ordering Information
R7735
(B)* (* : See Version Table)
Package Type
E : SOT-23-6
N : DIP-8 (R7735G Only)
Lead Plating System
G : Green (Halogen Free and Pb Free)
R7735 Version (Refer to Version Table)
Note :
Richtek products are :
`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes.
Features
zNo Load Input Power Under 100mW
zAccurate Over Load Protection
zUVLO 9V/14V
zSoft Start Function
zCurrent Mode Control
zBuilt-in Slope Compensation
zInternal Leading Edge Blanking
zPWM Quadruple Mode for Green-Mode
zExcellent Green Power Performance
zCycle-by-Cycle Current Limit
zInternal Over Voltage Protection
zSecondary Rectifier Short Protection
zOpto-Coupler Short Protection
zFeedback Open-Loop Protection
zCS Pin Open Protection
zBuilt-in Jittering Frequency
zBuilt-in PRO Pin for External Arbitrary OVP/OTP
zSoft Driving for EMI Noise
zHigh Noise Immunity
zRoHS Compliant and Halogen Free
Application
zSwitching AC/DC Adaptor
zDVD Open Frame Power Supply
zSet-Top Box (STB)
zATX Standby Power
zTV/Monitor Standby Power
zPC Peripherals
zNB Adaptor
Marking Information
For marking information, contact our sales representative directly or through a Richtek distributor located in your area.
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
R7735-03 September 2012 |
www.richtek.com |
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1 |
R7735
Pin Configurations
(TOP VIEW)
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GND COMP NC |
PRO |
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GATE VDD CS |
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GND COMP PRO |
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SOT-23-6 |
GATE VDD |
NC |
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CS |
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DIP-8 |
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R7735 Version Table
Version |
R7735G |
R7735R |
R7735L |
R7735A |
R7735H |
Frequency |
65kHz |
65kHz |
65kHz |
65kHz |
100kHz |
OLP Delay Time |
56ms |
56ms |
56ms |
28ms |
36ms |
Internal OVP(27V) |
Auto Recovery |
Auto Recovery |
Latch |
Latch |
Auto Recovery |
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OLP & SRSP |
Auto Recovery |
Auto Recovery |
Auto Recovery |
Latch |
Auto Recovery |
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PRO Pin High |
Latch |
Auto Recovery |
Latch |
Latch |
Auto Recovery |
PRO Pin Low |
Auto Recovery |
Latch |
Latch |
Latch |
Latch |
*: VSRSP_TH : Secondary Rectifier Short Protection (SRSP) triggered threshold. R7735XGE : VSRSP_TH = 1.7V, X = G/R/L/A
R7735HGE(B) : VSRSP_TH = 2.6V
Typical Application Circuit
AC Mains (90V to 265V)
PRO |
VDD |
GATE |
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R7735 |
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COMP |
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CS |
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GND |
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NTC |
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Vo+
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+ |
Vo-
#
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# : See Application Information |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
R7735-03 September 2012 |
2 |
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R7735
Functional Pin Description
Pin No. |
Pin Name |
Pin Function |
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SOT-23-6 |
DIP-8 |
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1 |
8 |
GND |
Ground. |
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2 |
7 |
COMP |
Voltage Feedback. By connecting an opto-coupler to close control loop |
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3 |
5 |
PRO |
For External Arbitrary OVP or OTP. |
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4 |
4 |
CS |
Primary Current Sense. |
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5 |
2 |
VDD |
Power Supply. |
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6 |
1 |
GATE |
Gate Drive Output to Drive the External MOSFET. |
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-- |
3, 6 |
NC |
No Internal Connection. |
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Function Block Diagram
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VDD |
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VL_TH |
Auto |
Auto |
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IBIAS |
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+ |
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- |
Recovery |
Recovery |
OVP |
+ |
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PRO |
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27V |
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+ |
Latch |
Latch |
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- |
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- |
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VH_TH |
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Secondary Rectifier Short |
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POR |
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VSRSP_TH |
- |
& CS Open Protection |
Shutdown |
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+ |
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Logic |
UVLO |
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+ |
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Brownout |
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9V/14V |
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Sensing |
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- |
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COMP Open |
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Counter |
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Bias & |
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Sensing |
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Bandgap |
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OLP |
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Oscillator |
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Constant |
SS |
Dmax |
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Power |
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Soft Driver |
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S |
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- |
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Q |
GATE |
COMP |
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- |
R |
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+ |
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PWM |
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CS |
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Slope |
Comparator |
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Ramp |
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VCOMP |
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Quadruple Mode |
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VBURL |
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VBURH |
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LEB |
X3 |
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VDD |
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GND |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
|
R7735-03 September 2012 |
www.richtek.com |
3
R7735
Absolute Maximum Ratings (Note 1)
z Supply Input Voltage, VDD ----------------------------------------------------------------------------------------------- |
−0.3V to 30V |
z GATE Pin --------------------------------------------------------------------------------------------------------------------- |
−0.3V to 16.5V |
z PRO, COMP, CS Pin ------------------------------------------------------------------------------------------------------ |
−0.3V to 6.5V |
z IDD ------------------------------------------------------------------------------------------------------------------------------ |
10mA |
z Power Dissipation, PD @ TA = 25°C |
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SOT-23-6 -------------------------------------------------------------------------------------------------------------------- |
0.400W |
DIP-8-------------------------------------------------------------------------------------------------------------------------- |
0.714W |
z Package Thermal Resistance (Note 2) |
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SOT-23-6, θJA --------------------------------------------------------------------------------------------------------------- |
250°C/W |
DIP-8, θJA -------------------------------------------------------------------------------------------------------------------- |
140°C/W |
z Junction Temperature ------------------------------------------------------------------------------------------------------ |
150°C |
z Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------- |
260°C |
z Storage Temperature Range --------------------------------------------------------------------------------------------- |
−65°C to 150°C |
z ESD Susceptibility (Note 3) |
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HBM (Human Body Model) ----------------------------------------------------------------------------------------------- |
3kV |
MM (Machine Model) ------------------------------------------------------------------------------------------------------ |
250V |
Recommended Operating Conditions |
(Note 4) |
z Supply Input Voltage, VDD ----------------------------------------------------------------------------------------------- |
12V to 25V |
z Junction Temperature Range --------------------------------------------------------------------------------------------- |
−40°C to 125°C |
z Ambient Temperature Range --------------------------------------------------------------------------------------------- |
−40°C to 85°C |
Electrical Characteristics
(VDD = 15V, TA = 25°C, unless otherwise specified)
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Parameter |
Symbol |
Test Conditions |
Min |
Typ |
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Max |
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Unit |
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VDD Section |
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VDD Over Voltage Protection Level |
VOVP |
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26 |
27 |
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28 |
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V |
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VDD Zener Clamp |
VZ |
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29 |
-- |
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-- |
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V |
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On Threshold Voltage |
VTH_ON |
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13 |
14 |
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15 |
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V |
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Off Threshold Voltage |
VTH_OFF |
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8.5 |
9 |
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9.5 |
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V |
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VDD Holdup Mode Entry Point |
VDD_LOW |
VCOMP < 1.6V |
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9.5 |
10 |
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10.5 |
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V |
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VDD Holdup Mode Ending Point |
VDD_HIGH |
VCOMP < 1.6V |
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10 |
10.5 |
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11 |
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V |
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Latch-off Voltage |
VLH |
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4.5 |
5.5 |
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6.5 |
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V |
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Latched Reset Voltage |
VLH_RST |
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4 |
5 |
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6 |
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V |
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Start-up Current |
IDD_ST |
VDD = VTH_ON – 0.2V, |
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1 |
5 |
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10 |
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μA |
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TA= −40ºC to 100ºC |
(Note 5) |
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Operating Supply Current |
IDD_OP |
VDD= 15V, VCOMP = 2.5V, |
0.55 |
0.9 |
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1.6 |
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mA |
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GATE pin open |
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Latch-off Operating Current |
IDD_LH |
TA= −40ºC to 100ºC |
(Note 5) |
2 |
-- |
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8 |
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μA |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
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www.richtek.com |
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R7735-03 |
September 2012 |
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4 |
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R7735
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Parameter |
Symbol |
Test Conditions |
Min |
Typ |
Max |
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Unit |
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Oscillator Section |
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Normal PWM Frequency |
fOSC |
R7735G/R/L/A |
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60 |
65 |
70 |
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kHz |
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R7735H |
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92 |
100 |
108 |
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Frequency Reduction Mode |
fFR_MIN |
R7735G/R/L/A |
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18 |
22 |
-- |
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kHz |
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Minimum Frequency |
R7735H |
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-- |
25 |
-- |
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Maximum Duty Cycle |
DCYMAX |
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70 |
75 |
80 |
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PWM Frequency Jitter Range |
f |
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-- |
±6 |
-- |
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% |
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PWM Frequency Jitter Period |
TJIT |
For 65kHz |
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-- |
4 |
-- |
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Frequency Variation Versus |
fDV |
VDD= 12V to 25V |
-- |
-- |
2 |
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% |
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VDD Deviation |
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Frequency Variation Versus |
fDT |
TA= −30°C to 105°C |
-- |
-- |
5 |
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% |
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Temperature Deviation |
(Note 5) |
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COMP Input Section |
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Open-Loop Voltage |
VCOMP_OP |
COMP pin Open |
5.5 |
5.75 |
6 |
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V |
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COMP Open-Loop Protection |
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R7735G/R/L |
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45 |
56 |
65 |
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TOLP |
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R7735A |
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22 |
28 |
34 |
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Delay Time |
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R7735H |
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30 |
36 |
42 |
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Short Circuit Current |
IZERO |
VCOMP= 0V |
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0.15 |
0.29 |
0.45 |
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mA |
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Frequency Reduction Mode Entry |
VFR_ET |
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2.85 |
3 |
3.15 |
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V |
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Voltage |
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Frequency Reduction Mode |
VFR_ED |
R7735G/R/L/A |
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2.75 |
2.9 |
3.05 |
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V |
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Ending Voltage |
R7735H |
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2.65 |
2.8 |
2.95 |
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Current Sense Section |
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Initial Peak Current Limitation |
VCS_TH |
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0.68 |
0.7 |
0.72 |
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Offset |
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Maximum Clamping Current Limit |
VCS(MAX) |
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1.05 |
1.1 |
1.15 |
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V |
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Leading Edge Blanking Time |
tLEB |
(Note 6) |
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150 |
250 |
350 |
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Internal Propagation Delay Time |
tPD |
(Note 6) |
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-- |
100 |
-- |
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Minimum On Time |
tON(MIN) |
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250 |
350 |
450 |
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GATE Section |
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Rising Time |
tR |
VDD= 15V, CL= 1nF |
60 |
125 |
140 |
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Falling Time |
tF |
VDD= 15V, CL= 1nF |
25 |
40 |
65 |
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GATE Output Clamping Voltage |
VCLAMP |
VDD= 25V |
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12.1 |
14 |
15.9 |
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PRO Interface Section |
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Pull Low Threshold |
VL_TH |
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0.47 |
0.5 |
0.53 |
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V |
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Pull High Threshold |
VH_TH |
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3.5 |
3.8 |
4.1 |
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V |
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Internal Bias Current |
IBIAS |
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90 |
100 |
110 |
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μA |
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Pull High Sinking Current |
ISINK |
(Note 7) |
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0.7 |
-- |
1.4 |
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mA |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
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R7735-03 September 2012 |
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www.richtek.com |
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5 |
R7735
Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and 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 may affect device reliability.
Note 2. θJA is measured at TA = 25°C on a low effective thermal conductivity single-layer test board per JEDEC 51-3. Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. Guaranteed by design.
Note 6. Leading edge blanking time and internal propagation delay time are guaranteed by design.
Note 7. The sourcing current of PRO pin must be limited below 5mA. Otherwise it may cause permanent damage to the device.
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
R7735-03 September 2012 |
6 |
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