®
RT8209A/B/C
Single Synchronous Buck Controller
General Description
The RT8209A/B/C PWM controller provides high efficiency, excellent transient response, and highDC output accuracy needed for stepping down high voltage batteries to generate low voltage CPU core, I/O, and chipset RAM supplies in notebook computers.
The constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency.
The RT8209A/B/C achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current mode PWMs. Efficiency is further enhanced by its ability to drive very large synchronous rectifier MOSFETs. The buck conversion allows this device to directly step down high voltage batteries for the highest possible efficiency. The RT8209A/B/C is intended for CPU core, chipset, DRAM, or other low voltage supplies as low as 0.75V. The RT8209A is in a WQFN-16L 3x3 package, the RT8209B is in a WQFN-14L 3.5x3.5 package and the RT8209C is available in a TSSOP-14 package.
Ordering Information
RT8209 
Package Type
QW : WQFN-16L 3x3 (W-Type) QW : WQFN-14L 3.5x3.5 (W-Type) C : TSSOP-14
Lead Plating System
G : Green (Halogen Free and Pb Free) Z : ECO (Ecological Element with
Halogen Free and Pb free)
A: WQFN-16L 3x3
B: WQFN-14L 3.5x3.5
C: TSSOP-14
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
zUltra-High Efficiency
zResistor Programmable Current Limit by Low Side RDS(ON) Sense (Lossless Limit)
zQuick Load Step Response within 100ns
z1% VFB Accuracy over Line and Load
z4.5V to 26V Battery Input Range
zResistor Programmable Frequency
zIntegrated Bootstrap Switch
zIntegrated Negative Current Limiter
zOver/Under Voltage Protection
z4 Steps Current Limit During Soft-Start
zPower Good Indicator
zRoHS Compliant and Halogen Free
Applications
zNotebook Computers
zSystem Power Supplies
zI/O Supplies
Marking Information
RT8209AGQW
FH= : Product Code
FH=YM YMDNN : Date Code
DNN
RT8209AZQW
FH : Product Code
FH YM YMDNN : Date Code
DNN
RT8209BGQW
A0= : Product Code
A0=YM YMDNN : Date Code
DNN
RT8209CGC
RT8209CGC : Product Code
RT8209C YMDNN : Date Code
GCYMDNN
Copyright ©2014 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8209A/B/C-07 January 2014 |
www.richtek.com |
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1 |
RT8209A/B/C
Pin Configurations
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TON |
EN/DEM |
NC |
BOOT |
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16 |
15 |
14 |
13 |
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VOUT |
1 |
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12 |
UGATE |
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VDD |
2 |
NC |
11 |
PHASE |
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FB |
3 |
10 |
CS |
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PGOOD |
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17 |
VDDP |
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4 |
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9 |
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5 |
6 |
7 |
8 |
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NC |
GND |
PGND |
LGATE |
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RT8209A (WQFN-16L 3x3) |
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(TOP VIEW)
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EN/DEM |
BOOT |
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TON |
1 |
14 |
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UGATE |
2 |
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13 |
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VOUT |
3 |
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12 |
PHASE |
VDD |
4 |
NC |
11 |
CS |
FB |
5 |
15 |
10 |
VDDP |
PGOOD |
6 |
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9 |
LGATE |
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7 |
8 |
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GND |
PGND |
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RT8209B (WQFN-14L 3.5x3.5) |
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EN/DEM |
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14 |
BOOT |
TON |
2 |
13 |
UGATE |
VOUT |
3 |
12 |
PHASE |
VDD |
4 |
11 |
CS |
FB |
5 |
10 |
VDDP |
PGOOD |
6 |
9 |
LGATE |
GND |
7 |
8 |
PGND |
RT8209C (TSSOP-14)
Typical Application Circuit |
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R |
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TON |
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V |
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250k |
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IN |
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4.5V to 26V |
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RT8209A/B/C |
R4 |
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C4 |
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0 |
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TON |
BOOT |
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10µF |
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C3 |
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VDDP |
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VDDP |
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R5 |
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Q1 |
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0 |
0.1µF |
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VOUT = 1.05V |
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R1 |
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UGATE |
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BSC119 L1 |
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N03S |
1µH |
* : Optional |
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R2 |
10 |
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PHASE |
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VDD |
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100k |
C2 |
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BSC119N03S |
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C1 |
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LGATE |
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Q2 |
R7* |
C5* |
C6* |
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1µF |
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220µF |
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R8 |
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PGOOD |
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PGOOD |
PGND |
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C7* |
12k |
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CS |
FB |
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R6 |
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R9 |
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18k |
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30k |
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CCM/DEM |
EN/DEM |
VOUT |
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GND |
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Functional Pin Description
Pin No. |
Pin Name |
Pin Function |
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RT8209A |
RT8209B/C |
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1 |
3 |
VOUT |
Output Voltage Pin. Connect to the output of PWM converter. |
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VOUT is an input of the PWM controller. |
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2 |
4 |
VDD |
Analog supply voltage input for the internal analog integrated |
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circuit. Bypass to GND with a 1μF ceramic capacitor. |
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3 |
5 |
FB |
Feedback Input Pin. Connect FB to a resistor voltage divider |
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from VOUT to GND to adjust VOUT from 0.75V to 3.3V |
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Power good signal open-drain output of PWM converter. This |
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4 |
6 |
PGOOD |
pin will be pulled high when the output voltage is within the |
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target range. |
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5, 14 |
RT8209B : |
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No internal connection. The exposed pad must be soldered to |
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NC |
a large PCB and connected to GND for maximum power |
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17 (Exposed pad) |
15 (Exposed pad) |
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dissipation. |
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Copyright ©2014 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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DS8209A/B/C-07 January 2014 |
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2
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RT8209A/B/C |
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Pin No. |
Pin Name |
Pin Function |
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RT8209A |
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RT8209B/C |
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6 |
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7 |
GND |
Analog Ground. |
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7 |
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8 |
PGND |
Power Ground. |
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8 |
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9 |
LGATE |
Low side N-MOSFET gate driver output for PWM. This pin |
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swings between GND and VDDP. |
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9 |
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10 |
VDDP |
VDDP is the gate driver supply for external MOSFETs. Bypass |
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to GND with a 1μF ceramic capacitor. |
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Over Current Trip Point Set Input. Connect resistor from this |
10 |
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11 |
CS |
pin to signal ground to set threshold for both over current and |
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negative over current limit. |
11 |
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12 |
PHASE |
The UGATE High Side Gate Driver Return. Also serves as |
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anode of over current comparator. |
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12 |
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13 |
UGATE |
High side N-MOSFET floating gate driver output for the PWM |
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converter. This pin swings between PHASE and BOOT. |
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13 |
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14 |
BOOT |
Bootstrap Capacitor Connection for PWM Converter. Connect |
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to an external ceramic capacitor to PHASE. |
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Enable/Diode Emulation Mode Control Input. Connect to VDD |
15 |
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1 |
EN/DEM |
for diode-emulation mode, connect to GND for shutdown and |
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floating the pin for CCM mode. |
16 |
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2 |
TON |
On Time/Frequency Adjustment Pin. Connect to PHASE |
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through a resistor. TON is an input for the PWM controller. |
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Function Block Diagram |
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TRIG |
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VOUT |
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On-time |
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Compute |
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BOOT |
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TON |
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1-SHOT |
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R |
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SS |
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+ |
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- |
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- |
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(internal) |
GM |
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+ |
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S |
Q |
DRV |
UGATE |
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+ |
- |
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Min. TOFF |
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PHASE |
VREF |
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Q |
TRIG |
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VDDP |
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Latch |
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1-SHOT |
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+ |
OV |
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125% VREF |
S1 |
Q |
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DRV |
LGATE |
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- |
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Latch |
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70% VREF |
+ |
UV |
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PGND |
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S1 |
Q |
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FB |
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PGOOD |
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- |
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- |
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Diode |
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90% VREF |
+ |
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Emulation |
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10µA |
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VDD |
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SS Timer |
Thermal |
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+ |
+ |
CS |
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Shutdown |
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GM |
GND |
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EN/DEM |
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- |
- |
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Copyright ©2014 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8209A/B/C-07 January 2014 |
www.richtek.com |
3
RT8209A/B/C
Absolute Maximum Ratings (Note 1)
z VDD, VDDP, VOUT, EN/DEM, FB, PGOOD, TON to GND------------------------------------------------------- |
−0.3V to 6V |
z BOOT to GND -------------------------------------------------------------------------------------------------------------- |
−0.3V to 38V |
z BOOT to PHASE ---------------------------------------------------------------------------------------------------------- |
−0.3V to 6V |
z PHASE to GND |
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DC ----------------------------------------------------------------------------------------------------------------------------- |
–0.3V to 32V |
< 20ns ----------------------------------------------------------------------------------------------------------------------- |
−8V to 38V |
z UGATE to PHASE |
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DC ----------------------------------------------------------------------------------------------------------------------------- |
−0.3V to 6V |
< 20ns ----------------------------------------------------------------------------------------------------------------------- |
−5V to 7.5V |
z CS to GND ------------------------------------------------------------------------------------------------------------------ |
−0.3V to 6V |
z LGATE to GND ------------------------------------------------------------------------------------------------------------- |
−0.3V to 6V |
z LGATE to GND |
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DC ----------------------------------------------------------------------------------------------------------------------------- |
−0.3V to 6V |
< 20ns ----------------------------------------------------------------------------------------------------------------------- |
−2.5V to 7.5V |
z PGND to GND -------------------------------------------------------------------------------------------------------------- |
–0.3V to 0.3V |
z Power Dissipation, PD @ TA = 25°C |
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WQFN−16L 3x3 ------------------------------------------------------------------------------------------------------------ |
1.471W |
WQFN−14L 3.5x3.5 ------------------------------------------------------------------------------------------------------- |
1.667W |
TSSOP-14------------------------------------------------------------------------------------------------------------------- |
0.741W |
z Package Thermal Resistance (Note 2) |
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WQFN−16L 3x3, θJA ------------------------------------------------------------------------------------------------------ |
68°C/W |
WQFN−16L 3x3, θJC ------------------------------------------------------------------------------------------------------ |
7.5°C/W |
WQFN−14L 3.5x3.5, θJA ------------------------------------------------------------------------------------------------- |
60°C/W |
WQFN−14L 3.5x3.5, θJC ------------------------------------------------------------------------------------------------- |
7.5°C/W |
TSSOP-14, θJA ------------------------------------------------------------------------------------------------------------- |
135°C/W |
z Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- |
260°C |
z Junction Temperature ----------------------------------------------------------------------------------------------------- |
150°C |
z Storage Temperature Range -------------------------------------------------------------------------------------------- |
−65°C to 150°C |
z ESD Susceptibility (Note 3) |
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HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- |
2kV |
MM (Machine Mode) ------------------------------------------------------------------------------------------------------ |
200V |
Recommended Operating Conditions |
(Note 4) |
z Input Voltage, VIN ---------------------------------------------------------------------------------------------------------- |
4.5V to 26V |
z Supply Voltage, VDD, VDDP ---------------------------------------------------------------------------------------------- |
4.5V to 5.5V |
z Junction Temperature Range -------------------------------------------------------------------------------------------- |
−40°C to 125°C |
z Ambient Temperature Range -------------------------------------------------------------------------------------------- |
−40°C to 85°C |
Copyright ©2014 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8209A/B/C-07 January 2014 |
4
RT8209A/B/C
Electrical Characteristics
(VIN = 15V, VDD = VDDP = 5V, TA = 25°C, unless otherwise specified)
Parameter |
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Symbol |
Test Conditions |
Min |
Typ |
Max |
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Unit |
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PWM Controller |
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Quiescent Supply Current |
IVDD |
VFB = 0.8V, EN/DEM = 5V |
-- |
500 |
800 |
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μA |
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IVDDP |
VFB = 0.8V, EN/DEM = 5V |
-- |
1 |
10 |
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Shutdown Current |
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ISHDN_VDD |
EN/DEM = 0V |
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-- |
1 |
10 |
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μA |
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ISHDN_VDDP |
EN/DEM = 0V |
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-- |
-- |
1 |
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FB Reference Voltage |
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VREF |
VDD = 4.5V to 5.5V |
0.742 |
0.750 |
0.758 |
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V |
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FB Input Bias Current |
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VFB = 0.75V |
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−1 |
0.1 |
1 |
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μA |
Output Voltage Range |
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VOUT |
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0.75 |
-- |
3.3 |
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V |
On Time |
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VPHASE = 12V, VOUT = 2.5V, |
336 |
420 |
504 |
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ns |
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RTON = 250kΩ |
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Minimum Off-Time |
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250 |
400 |
550 |
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ns |
VOUT Shutdown Discharge |
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EN/DEM = GND |
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-- |
20 |
-- |
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Ω |
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Resistance |
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Current Sensing |
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Current Limiter Source Current |
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CS to GND |
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9 |
10 |
11 |
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μA |
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Current Comparator Offset |
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−10 |
-- |
10 |
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mV |
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Zero Crossing Threshold |
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PHASE to GND, EN/DEM = 5V |
−10 |
-- |
5 |
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mV |
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Fault Protection |
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Current Limit Threshold |
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GND − PHASE, VCS = 50mV |
40 |
50 |
60 |
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mV |
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GND − PHASE, VCS = 200mV |
190 |
200 |
210 |
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Current Limit Setting Range |
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CS to GND |
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50 |
-- |
200 |
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mV |
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Output UV Threshold |
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UVP detect |
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60 |
70 |
80 |
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% |
OVP Threshold |
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VFB_OVP |
OVP detect |
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120 |
125 |
130 |
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% |
OV Fault Delay |
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FB forced above OV threshold |
-- |
20 |
-- |
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μs |
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VDD Under Voltage Lockout |
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Rising edge, PWM disabled below |
4.1 |
4.3 |
4.5 |
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V |
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this level |
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Threshold |
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Hysteresis |
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-- |
80 |
-- |
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mV |
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Current Limit Step Duration at |
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Each step |
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-- |
128 |
-- |
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clks |
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Soft-Start |
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UVP Blanking Time |
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From EN signal going high |
-- |
512 |
-- |
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clks |
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Thermal Shutdown |
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TSHDN |
Hysteresis = 10°C |
-- |
155 |
-- |
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°C |
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Driver On-Resistance |
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UGATE Drive Source |
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RUGATEsr |
VBOOT − VPHASE = 5V |
-- |
2 |
5 |
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Ω |
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UGATE Drive Sink |
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RUGATEsk |
VBOOT − VPHASE = 5V |
-- |
1 |
5 |
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Ω |
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LGATE Drive Source |
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RLGATEsr |
LGATE, High State |
-- |
1 |
5 |
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Ω |
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LGATE Drive Sink |
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RLGATEsk |
LGATE, Low State |
-- |
0.5 |
2.5 |
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Ω |
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UGATE Driver Source/Sink |
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VUGATE − VPHASE = 2.5V, |
-- |
1 |
-- |
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A |
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Current |
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VBOOT − VPHASE = 5V |
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LGATE Driver Source Current |
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VLGATE = 2.5V |
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-- |
1 |
-- |
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A |
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LGATE Driver Sink Current |
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VLGATE = 2.5V |
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-- |
3 |
-- |
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A |
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Dead Time |
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LGATE Rising (VPHASE = 1.5V) |
-- |
30 |
-- |
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ns |
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UGATE Rising |
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-- |
30 |
-- |
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Copyright ©2014 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
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DS8209A/B/C-07 January |
2014 |
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www.richtek.com |
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5
RT8209A/B/C
Parameter |
Symbol |
Test Conditions |
Min |
Typ |
Max |
Unit |
Internal BOOT Charging Switch |
|
VDDP to BOOT, 10mA |
-- |
-- |
80 |
Ω |
On Resistance |
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Logic I/O |
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EN/DEM Low |
-- |
-- |
0.8 |
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EN/DEM Logic Input Voltage |
|
EN/DEM High |
2.9 |
-- |
-- |
V |
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EN/DEM float |
-- |
2 |
-- |
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Logic Input Current |
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EN/DEM = VDD |
-- |
1 |
5 |
μA |
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EN/DEM = 0 |
−5 |
1 |
-- |
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PGOOD |
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VFB with respect to reference, |
87 |
90 |
93 |
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PGOOD from Low to High |
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PGOOD Threshold |
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VFB with respect to reference, |
-- |
125 |
-- |
% |
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PGOOD from High to Low |
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Hysteresis |
-- |
3 |
-- |
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Fault Propagation Delay |
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Falling edge, FB forced below |
-- |
2.5 |
-- |
μs |
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PGOOD trip threshold |
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Output Low Voltage |
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ISINK = 1mA |
-- |
-- |
0.4 |
V |
Leakage Current |
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High state, forced to 5V |
-- |
-- |
1 |
μA |
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 TA = 25°C on a high effective four layers thermal conductivity test board of JEDEC 51-7 thermal measurement standard. The case point of θJC is on the expose pad for the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Copyright ©2014 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8209A/B/C-07 January 2014 |
6
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