®
RT8239A/B/C
High Efficiency, Main Power Supply Controller for Notebook Computers
General Description
The RT8239A/B/C is a dual step down, Switch Mode Power Supply (SMPS) controller which generates logic supply voltages for battery powered systems. It includes two Pulse Width Modulation (PWM) controllers adjustable from 2V to 5.5V and also two fixed 5V/3.3V linear regulators. One of the controllers (LDO5) provides automatic switch over to the BYP1 input connected to the main SMPS1 output for maximized efficiency. An optional external charge pump can be monitored through SECFB (RT8239B/C). Other features include on board power up sequencing, a power good output, internal softstart, and a soft discharge output that prevents negative voltage during shutdown.
A constant on-time PWM control scheme operates without sense resistors and assures fast load transient response while maintaining nearly constant switching frequency. To eliminate noise in audio applications, an ultrasonic mode is included, which maintains the switching frequency above 25kHz. Moreover, a diode emulation mode maximizes efficiency for light load applications. The SMPS1/SMPS2 switching frequency can be adjustable from 200kHz/233kHz to 400kHz/466kHz respectively.
The RT8239A/B/C is available in a WQFN-20L 3x3 package, and operates over an extended temperature range from −40°C to 85°C.
Features
z5.5V to 25V Input Voltage Range
z2V to 5.5V Output Voltage Range
zNo Current Sense Resistor Needed
z5V/3.3V Linear Regulators
z4700ppm/°C RDS(ON) Current Sensing
zInternal Current Limit Soft-Start and Soft Discharge Output
zBuilt In OVP/UVP/OCP
zSelectable Operation Mode with Switcher Enable Control (RT8239A)
zSECFB Input Maintains Charge Pump Voltage (RT8239B/C)
zPower Good Indicator (RT8239B/C includes SECFB)
zRoHS Compliant and Halogen Free
Applications
zNotebook computers
zSystem Power Supplies
z3- and 4- Cell Li+ Battery-Powered Device
Ordering Information
RT8239A/B/C
Package Type
QW : WQFN-20L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)
Pin Function With
A : ENM
B : SECFB
C : SECFB, Ultrasonic Mode
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.
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8239A/B/C-06 October 2012 |
www.richtek.com |
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1 |
RT8239A/B/C
Pin Configurations
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BYP1 BOOT1 UGATE1 PHASE1 LGATE1 |
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20 19 |
18 17 |
16 |
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FB1 |
1 |
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15 |
LDO3 |
ENTRIP1 |
2 |
GND |
14 |
LDO5 |
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TON |
3 |
13 |
ENM |
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ENTRIP2 |
4 |
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21 |
12 |
ENLDO |
FB2 |
5 |
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11 |
VIN |
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6 |
7 |
8 |
9 |
10 |
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PGOOD |
BOOT2 |
UGATE2 |
PHASE2 |
LGATE2 |
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RT8239A |
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Marking Information
RT8239A
JB= : Product Code
JB=YM YMDNN : Date Code
DNN
JB : Product Code
JB YM YMDNN : Date Code
DNN
RT8239C
JD= : Product Code
JD=YM YMDNN : Date Code
DNN
JD : Product Code
JD YM YMDNN : Date Code
DNN
(TOP VIEW)
WQFN-20L 3x3
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BYP1 BOOT1 UGATE1 PHASE1 LGATE1 |
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20 19 |
18 17 |
16 |
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FB1 |
1 |
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15 |
LDO3 |
ENTRIP1 |
2 |
GND |
14 |
LDO5 |
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TON |
3 |
13 |
SECFB |
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ENTRIP2 |
4 |
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21 |
12 |
ENLDO |
FB2 |
5 |
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11 |
VIN |
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6 |
7 |
8 |
9 |
10 |
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PGOOD |
BOOT2 |
UGATE2 |
PHASE2 |
LGATE2 |
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RT8239B/C |
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RT8239B
JC= : Product Code
JC=YM YMDNN : Date Code
DNN
JC : Product Code
JC YM YMDNN : Date Code
DNN
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8239A/B/C-06 October 2012 |
2 |
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RT8239A/B/C
Typical Application Circuit
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V |
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IN |
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5.5V to 25V |
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C1 |
R1 |
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RT8239A |
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C6 |
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10µF |
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11 |
VIN |
UGATE2 |
8 |
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N3 |
10µF |
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C2 |
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12 |
ENLDO |
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7 |
R5 |
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0.1µF |
BOOT2 |
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18 |
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N1 |
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UGATE1 |
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C7 |
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L2 |
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R2 |
19 |
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PHASE2 |
9 |
0.1µF |
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VOUT2 |
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BOOT1 |
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+ |
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C4 |
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LGATE2 |
10 |
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3.3V |
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L1 |
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N4 |
C8 |
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V |
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0.1µF |
17 |
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R6 |
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OUT1 |
+ |
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PHASE1 |
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5V |
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16 |
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6.5k |
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C3 |
N2 |
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LGATE1 |
FB2 |
5 |
R8 |
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R3 |
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R7 |
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100k |
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15k |
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4 |
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ENTRIP2 |
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10k |
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1 |
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FB1 |
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R9 |
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R4 |
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2 |
100k |
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RTON |
3 |
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ENTRIP1 |
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TON |
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10k |
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15 |
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20 |
BYP1 |
LDO3 |
C9 |
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3.3V Always On |
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C5 |
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4.7µF |
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1µF |
Chip Enable |
13 |
ENM |
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14 |
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LDO5 |
R10 |
C10 |
5V Always On |
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21 (Exposed Pad) GND |
PGOOD |
6 |
100k |
10µF |
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Figure 1. RT8239ANB Main Supply Typical Application Circuit
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8239A/B/C-06 October 2012 |
www.richtek.com |
3
RT8239A/B/C |
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V |
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IN |
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5.5V to 25V |
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C1 |
R1 |
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RT8239B/C |
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C6 |
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10µF |
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11 VIN |
UGATE2 8 |
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N3 |
10µF |
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C2 |
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12 ENLDO |
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7 |
R5 |
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0.1µF |
BOOT2 |
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18 UGATE1 |
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N1 |
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C7 |
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L2 |
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R2 |
19 |
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PHASE2 9 |
0.1µF |
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BOOT1 |
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+ |
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LGATE2 10 |
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L1 |
C4 |
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N4 |
C8 |
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VOUT1 |
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0.1µF |
17 PHASE1 |
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R6 |
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+ |
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5V |
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16 LGATE1 |
FB2 5 |
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6.5k |
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C3 |
N2 |
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R8 |
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R3 |
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R7 |
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100k |
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15k |
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ENTRIP2 4 |
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10k |
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1 |
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FB1 |
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R9 |
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R4 |
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2 |
100k |
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RTON |
3 TON |
ENTRIP1 |
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On |
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10k |
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20 BYP1 |
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Off |
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C5 |
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C11 |
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15 |
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1µF |
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LDO3 |
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3.3V Always On |
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C13 |
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0.1µF |
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C9 |
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0.1µF |
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C12 |
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4.7µF |
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LDO5 14 |
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5V Always On |
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0.1µF |
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R10 |
C10 |
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10µF |
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R11 |
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PGOOD 6 |
100k |
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C14 |
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200k |
13 SECFB |
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0.1µF |
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GND |
21 (Exposed Pad) |
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R12 |
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C15 |
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39k |
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VOUT2 3.3V
VCP
Figure 2. RT8239B/C NB Main Supply Typical Application Circuit
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8239A/B/C-06 October 2012 |
4 |
|
RT8239A/B/C
Functional Pin Description
Pin No. |
Pin Name |
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Pin Function |
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1 |
FB1 |
SMPS1 Feedback Input. Connect FB1 to a resistive voltage divider from SMPS1 |
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output to GND for adjustable output from 2V to 5.5V. |
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Channel 1 Enable and Current Limit Setting Input. Connect resistor to GND to set |
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2 |
ENTRIP1 |
the threshold for Channel 1 synchronous RDS(ON) sense. The GND-PHASE1 |
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current limit threshold is 1/10th the voltage seen at ENTRIP1 over a 0.5V to 3V |
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range. There is an internal 10μA current source from LDO5 to ENTRIP1. Leave |
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ENTRIP1 floating or drive it above 4.5V to shut down channel 1. |
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3 |
TON |
ON-Time/Frequency Adjustment Input. Connect to GND with 56kΩ to 100kΩ. |
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Channel 2 Enable and Current Limit Setting Input. Connect resistor to GND to set |
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4 |
ENTRIP2 |
the threshold for Channel 2 synchronous RDS(ON) sense. The GND-PHASE2 |
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current limit threshold is 1/10th the voltage seen at ENTRIP2 over a 0.5V to 3V |
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range. There is an internal 10μA current source from LDO5 to ENTRIP2. Leave |
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ENTRIP2 floating or drive it above 4.5V to shut down channel 2. |
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5 |
FB2 |
SMPS2 Feedback Input. Connect FB2 to a resistive voltage divider from SMPS2 |
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output to GND for adjustable output from 2V to 5.5V. |
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6 |
PGOOD |
Power Good Output for Channel 1 and Channel 2 (RT8239A). |
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Power Good Output for Channel 1, Channel 2 and SECFB (RT8239B/C). |
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7 |
BOOT2 |
Boost Flying Capacitor Connection for SMPS2. Connect to an external capacitor |
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according to the typical application circuits. |
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8 |
UGATE2 |
Upper Gate Driver Output for SMPS2. UGATE2 swings between PHASE2 and |
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BOOT2. |
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9 |
PHASE2 |
Switch Node for SMPS2. PHASE2 is the internal lower supply rail for the UGATE2 |
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high side gate driver. PHASE2 is also the current sense input for the SMPS2. |
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10 |
LGATE2 |
Lower Gate Drive Output for SMSP2. LGATE2 swings between GND and LDO5. |
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11 |
VIN |
Supply Input for LDO5. |
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Master Enable Input. LDO5/LDO3 is enabled if it is within logic high level and |
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12 |
ENLDO |
disabled if it is less than the logic low level. Leave ENLDO floating to default |
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enable LDO5/LDO3. |
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ENM |
Mode Selection with Enable Input. Pull up to LDO5 (Ultrasonic mode) or LDO3 |
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(RT8239A) |
(DEM) to turn on both switch Channels. Short to GND for shutdown. |
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Change Pump Feedback Pin. The SECFB is used to monitor the optional external |
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13 |
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charge pump. Connect a resistive divider from the change pump output to GND to |
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SECFB |
detect the output. If SECFB drops below its feedback threshold, an ultrasonic |
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pulse occurs to refresh the charge pump driven by LGATE1 or LGATE2. |
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(RT8239B/C) |
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If SECFB drops below its UV threshold, the switcher channels stop working and |
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enter into discharge-mode. Pull up to LDO5 or LDO3 to disable SECFB UVP |
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function. |
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5V Linear Regulator Output. LDO5 is the supply voltage for the low side MOSFET |
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14 |
LDO5 |
driver and also the analog supply voltage for the device. Bypass a minimum 4.7μF |
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ceramic capacitor to GND |
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15 |
LDO3 |
3.3V Linear Regulator Output. Bypass a minimum 4.7μF ceramic capacitor to |
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GND. |
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16 |
LGATE1 |
Lower Gate Driver Output for SMPS1. LGATE1 swings between GND and LDO5. |
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17 |
PHASE1 |
Switch Node SMPS1. PHASE1 is the internal lower supply rail for the UGATE1 |
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high side gate driver. PHASE1 is also the current sense input for the SMPS1. |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
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DS8239A/B/C-06 |
October 2012 |
|
www.richtek.com |
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5 |
RT8239A/B/C
Pin No. |
Pin Name |
Pin Function |
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18 |
UGATE1 |
Upper Gate Driver Output for SMPS1. UGATE1 swings between PHASE1 and |
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BOOT1. |
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19 |
BOOT1 |
Boost Flying Capacitor Connection for SMPS1. Connect to an external |
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capacitor according to the typical application circuits. |
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20 |
BYP1 |
Switch Over Source Voltage Input for LDO5. |
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21 (Exposed Pad) |
GND |
Analog Ground and Power Ground. The exposed pad must be soldered to a |
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large PCB and connected to GND for maximum power dissipation. |
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Function Block Diagram
BOOT1 |
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BOOT2 |
UGATE1 |
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UGATE2 |
PHASE1 |
LDO5 |
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LDO5 |
PHASE2 |
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SMPS1 |
SMPS2 |
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LGATE1 |
PWM |
PWM |
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LGATE2 |
Buck |
Buck |
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Controller |
Controller |
LDO5 |
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LDO5 |
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10µA |
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10µA |
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FB2 |
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FB1 |
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ENTRIP2 |
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ENTRIP1 |
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TON |
On Time |
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ENM (RT8239A) |
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Switch Over Threshold |
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SECFB (RT8239B/C) |
BYP1 |
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+ - |
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PGOOD |
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GND |
LDO5 |
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LDO5 |
REF |
LDO3 |
LDO3 |
VIN |
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Power-On |
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Sequence |
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ENLDO |
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Clear Fault Latch |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8239A/B/C-06 October 2012 |
6 |
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RT8239A/B/C |
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Absolute Maximum Ratings |
(Note 1) |
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z VIN, ENLDO to GND ------------------------------------------------------------------------------------------------------ |
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−0.3V to 30V |
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z BOOTx to PHASEx ------------------------------------------------------------------------------------------------------- |
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−0.3V to 6V |
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z ENTRIPx, FBx, TON, BYP1, PGOOD, LDO5, LDO3, ENM/SECFB to GND ------------------------------- |
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−0.3V to 6V |
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z PHASEx to GND |
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DC ----------------------------------------------------------------------------------------------------------------------------- |
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−0.3V to 30V |
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< 20ns ----------------------------------------------------------------------------------------------------------------------- |
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−8V to 38V |
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z UGATEx to PHASEx |
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DC ----------------------------------------------------------------------------------------------------------------------------- |
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−0.3V to 6V |
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< 20ns ----------------------------------------------------------------------------------------------------------------------- |
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−5V to 7.5V |
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z LGATEx to GND |
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DC ----------------------------------------------------------------------------------------------------------------------------- |
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−0.3V to 6V |
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< 20ns ----------------------------------------------------------------------------------------------------------------------- |
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−2.5V to 7.5V |
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z Power Dissipation, PD @ TA = 25°C |
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WQFN-20L 3x3 ------------------------------------------------------------------------------------------------------------ |
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3.33W |
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z Package Thermal Resistance |
(Note 2) |
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WQFN-20L 3x3, θJA ------------------------------------------------------------------------------------------------------- |
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30°C/W |
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WQFN-20L 3x3, θJC ------------------------------------------------------------------------------------------------------ |
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7.5°C/W |
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z Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- |
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260°C |
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z Junction Temperature ----------------------------------------------------------------------------------------------------- |
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150°C |
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z Storage Temperature Range -------------------------------------------------------------------------------------------- |
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−65°C to 150°C |
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z ESD Susceptibility (Note 3) |
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HBM (Human Body Model) ---------------------------------------------------------------------------------------------- |
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2kV |
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Recommended Operating Conditions |
(Note 4) |
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z Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- |
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5.5V to 25V |
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z Junction Temperature Range -------------------------------------------------------------------------------------------- |
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−40°C to 125°C |
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z Ambient Temperature Range -------------------------------------------------------------------------------------------- |
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−40°C to 85°C |
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Electrical Characteristics |
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(VIN = 12V, VENLDO = 5V, VENTRIPx = 2V, VBYP1 = 5V, No Load on LDO5, LDO3, TA = 25°C, unless otherwise specified) |
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Parameter |
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Symbol |
Test Conditions |
Min |
Typ |
Max |
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Unit |
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Input Supply |
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VIN Power On Reset |
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Rising Threshold |
-- |
5.1 |
5.5 |
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V |
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Falling Threshold |
3.5 |
-- |
4.5 |
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VIN Shutdown Current |
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IVIN_SHDN |
VENLDO = GND |
-- |
20 |
40 |
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μA |
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VIN Standby Supply Current |
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IVIN_SBY |
Both SMPS Off |
-- |
250 |
350 |
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Quiescent Power Consumption |
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IQ |
Both SMPSs on, FBx = 2.1V, |
-- |
5 |
7 |
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mW |
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BYP1 = 5V, ENM = 3.3V (RT8239A) |
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SMPS Output and FB Voltage |
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FBx Regulation Voltage |
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VFBx |
FBx, CCM Operation |
-- |
2 |
-- |
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V |
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FBx, DEM Operation |
1.98 |
2.006 |
2.03 |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
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DS8239A/B/C-06 October 2012 |
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www.richtek.com |
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7 |
RT8239A/B/C
Parameter |
Symbol |
Test Conditions |
Min |
Typ |
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Max |
Unit |
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Output Voltage Adjustable |
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SMPS1, SMPS2 |
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2 |
-- |
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5.5 |
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Range |
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V |
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SECFB Voltage |
VSECFB |
RT8239B |
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1.92 |
2 |
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2.08 |
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On-Time |
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On-Time Pulse Width |
tUGATEx |
VIN = 20V |
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VPHASE1 = 2V |
-- |
256 |
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-- |
ns |
RTON = 56kΩ |
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VPHASE2 = 2V |
-- |
220 |
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-- |
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Minimum Off-Time |
tLGATEx |
VFBx = 1.8V |
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-- |
-- |
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400 |
ns |
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Frequency Range |
fSMPS1 |
SMPS1 Operating Frequency |
200 |
-- |
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400 |
kHz |
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fSMPS2 |
SMPS2 Operating Frequency |
233 |
-- |
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466 |
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Ultrasonic Mode Frequency |
fASM |
RT8239C, VPHASEx = 50mV |
25 |
-- |
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-- |
kHz |
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Soft-Start |
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Soft-Start Time |
tSSx |
Zero to 200mV Current Limit Threshold |
-- |
2 |
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-- |
ms |
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from ENTRIPx Enable |
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Current Sense |
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Current Limit Current Source |
IENTRIPx |
VENTRIPx = 0.9V |
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9.4 |
10 |
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10.6 |
μA |
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Temperature Coefficient of |
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On The Basis of 25°C |
-- |
4700 |
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-- |
ppm/°C |
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IENTRIPx |
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Current Limit Adjustment |
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VENTRIPx = IENTRIPx x RENTRIPx |
0.5 |
-- |
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2.7 |
V |
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Range |
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Current Limit Threshold |
VENTRIPx |
GND − PHASEx, VENTRIPx = 2V |
180 |
200 |
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225 |
mV |
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Zero-Current Threshold |
VZC |
GND − PHASEx, FBx = 2.1V |
-- |
3 |
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-- |
mV |
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Internal Regulator and Reference |
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VBYP1 = 0V, ILDO5 < 100mA |
4.8 |
5 |
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5.2 |
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LDO5 Output Voltage |
VLDO5 |
VBYP1 = 0V, ILDO5 < 100mA , |
4.75 |
-- |
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5.25 |
V |
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6.5V < VIN < 25V |
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VBYP1 = 0V, ILDO5 < 50mA, |
4.75 |
-- |
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5.25 |
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5.5V < VIN < 25V |
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LDO5 Output Current |
ISHORT5 |
VBYP1 = 0V, VLDO5 = 4.5V |
-- |
225 |
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-- |
mA |
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5V Switchover Threshold |
VBYP1TH |
Falling Edge, Rising Edge with FB1 |
4.53 |
4.66 |
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4.79 |
V |
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Regulation Point |
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5V Switch RDS(ON) |
RBYPSW |
VBYP1 = 5V, ILDO5 = 50mA |
-- |
1.5 |
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3 |
Ω |
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LDO3 Output Voltage |
VLDO3 |
VBYP1 = 0V, ILDO3 < 100mA |
3.2 |
3.3 |
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3.46 |
V |
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VBYP1 = 5V, ILDO3 < 100mA |
3.2 |
3.3 |
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3.46 |
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LDO3 Output Current |
ISHORT3 |
VBYP1 = 0V, VLDO3 = 2.9V |
-- |
150 |
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-- |
mA |
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UVLO |
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LDO5 UVLO Threshold |
VUVLO5 |
Rising Edge |
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-- |
4.35 |
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4.5 |
V |
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Falling Edge |
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3.9 |
4.05 |
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4.2 |
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LDO3 UVLO Threshold |
VUVLO3 |
Both SMPS Off |
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-- |
2.2 |
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-- |
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Power Good |
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PGOOD Threshold |
VPGOOD |
PGOOD Detect, Rising edge with |
−14 |
−10 |
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−6 |
% |
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soft-start delay time. Hysteresis = 2.5% |
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PGOOD Propagation Delay |
tPD_PGOOD |
Falling Edge |
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-- |
5 |
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-- |
μs |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
||||||||
www.richtek.com |
|
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|
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DS8239A/B/C-06 |
October 2012 |
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8 |
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