richtek RT8239A, RT8239B, RT8239C Datasheet
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 soft-
start, 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
zz
z 5.5V to 25V Input Voltage Range
zz
zz
z 2V to 5.5V Output Voltage Range
zz
zz
z No Current Sense Resistor Needed
zz
zz
z 5V/3.3V Linear Regulators
zz
zz
z 4700ppm/
zz
zz
z Internal Current Limit Soft-Start and Soft Discharge
zz
°°
°C R
°°
Current Sensing
DS(ON)
Output
zz
z Built In OVP/UVP/OCP
zz
zz
z Selectable Operation Mode with Switcher Enable
zz
Control (RT8239A)
zz
z SECFB Input Maintains Charge Pump Voltage
zz
(RT8239B/C)
zz
z Power Good Indicator (RT8239B/C includes SECFB)
zz
zz
z RoHS Compliant and Halogen Free
zz
Applications
z Notebook computers
z System Power Supplies
z 3- 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 require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
DS8239A/B/C-04 April 2011 www.richtek.com
1
RT8239A/B/C
Pin Configurations
BYP1
BOOT1
1
FB1
TON
FB2
2
3
GND
4
ENTRIP1
ENTRIP2
UGATE1
(TOP VIEW)
LGATE1
17181920
16
15
LDO3
14
LDO5
13
ENM
12
21
9876
ENLDO
115
VIN
10
FB1
ENTRIP1
TON
ENTRIP2
FB2
BYP1
BOOT1
PHASE1
UGATE1
LGATE1
17181920
16
1
2
3
GND
4
15
LDO3
14
LDO5
13
SECFB
12
21
9876
ENLDO
115
VIN
10
BOOT2
PGOOD
UGATE2
Marking Information
RT8239A
JB= : Product Code
JB=YM
DNN
JB YM
DNN
RT8239C
YMDNN : Date Code
JB : Product Code
YMDNN : Date Code
LGATE2
PHASE2 PHASE1
WQFN-20L 3x3
RT8239B
JC=YM
DNN
JC YM
DNN
BOOT2
PGOOD
PHASE2
UGATE2
RT8239B/CRT8239A
JC= : Product Code
YMDNN : Date Code
JC : Product Code
YMDNN : Date Code
LGATE2
2
JD=YM
DNN
JD YM
DNN
JD= : Product Code
YMDNN : Date Code
JD : Product Code
YMDNN : Date Code
DS8239A/B/C-04 April 2011www.richtek.com
Typical Application Circuit
V
N
5
.
V
O
T
U
1
V
5
I
5
o
V
t
2
5
V
1
C
1
1
0
µ
F
N1
1
L
+
3
R
1
k
5
4
R
k
0
1
N2
Chip Enable
3
C
5
C
µ
F
1
R
2
C
.
µ
1
0
2
R
4
C
.
0
1
R
TON
21 (Exposed Pad)
RT8239A/B/C
RT8239A
BOOT2
FB2
LDO3
LDO5
8
7
9
10
5
4
2
15
14
6
N3
R
5
C
7
0
1
.
µ
F
N4
8
R
k
0
0
1
9
R
k
0
1
0
C
9
4
7
.
µ
F
C
0
1
R
k
0
0
1
1
1
0
11
VIN
12
F
F
µ
18
19
17
16
1
3
20
13
ENLDO
UGATE1
BOOT1
PHASE1
LGATE1
FB1
TON
BYP1
ENM
GND
UGATE2
PHASE2
LGATE2
ENTRIP2
ENTRIP1
PGOOD
C
6
µ
1
0
F
L
2
R
6
5
6
.
k
7
R
k
0
1
l
w
A
.
V
3
3
l
a
w
V
A
5
0
µ
F
V
O
U
2
+
C
y
s
a
O
s
y
T
3
3
V
.
8
n
O
n
Figure 1. RT8239A NB Main Supply Typical Application Circuit
DS8239A/B/C-04 April 2011 www.richtek.com
3
RT8239A/B/C
V
N
5
.
V
O
T
U
1
V
5
C
µ
1
I
5
o
V
t
5
V
2
C
1
µ
1
F
0
N1
L
1
+
3
C
5
F
3
1
C
0
1
.
µ
1
C
1
µ
.
0
N2
3
R
5
1
k
4
R
k
0
1
F
4
F
C
V
CP
Figure 2. RT8239B/C NB Main Supply Typical Application Circuit
1
R
11
2
C
.
1
0
12
µ
F
18
2
R
4
C
.
0
19
1
F
µ
17
16
1
R
TON
3
20
1
1
C
1
0
.
µ
F
2
1
C
.
0
1
µ
F
1
R
1
2
0
0
k
5
1
13
2
1
R
9
3
k
VIN
ENLDO
UGATE1
BOOT1
PHASE1
LGATE1
FB1
TON
BYP1
SECFB
RT8239B/C
ENTRIP2
ENTRIP1
UGATE2
BOOT2
PHASE2
LGATE2
FB2
LDO3
LDO5
PGOOD
GND
8
R
7
9
5
C
0
10
5
4
2
15
C
9
4
7
.
µ
14
1
0
R
k
0
1
6
0
21 (Exposed Pad)
C
6
1
0
µ
N3
7
1
µ
.
F
L
N4
8
R
k
0
0
1
9
R
k
0
0
1
F
2
R
6
6
5
.
k
7
R
0
1
k
V
O
U
T
+
C
2
3
V
.
3
8
On
Off
O
n
s
y
a
l
w
A
.
3
3
V
F
s
n
O
y
a
l
w
5
A
C
1
1
0
V
0
µ
F
DS8239A/B/C-04 April 2011www.richtek.com
4
Functional Pin Description
Pin No. Pin Name Pin Function
1 FB1
2 ENTRIP1
3 TON ON-Time/Freque ncy Adjustment Input. Connect to GND with 56kΩ to 100kΩ.
4 ENTRIP2
5 FB2
6 PGOOD
7 BOOT 2
8 U GAT E2
9 PHASE2
10 LGATE2 Lower Gate Drive Outp ut f or SMSP2. LGATE2 swings between GND and LDO5.
11 VIN Supply Input for LDO5.
12 ENLDO
ENM
(RT8239A)
13
SECFB
(RT8239B/C)
14 LDO5
15 LDO3
16 LGATE1 Lower Gate Driver Output for SMPS1. LGATE1 swing s between GND and LDO5.
17 PHASE1
18 UGAT E1
SMPS1 Feedba ck Input. Connect FB1 to a resisti ve voltage divider fro m SMPS1
output to GND for adjustable out put from 2V to 5.5V.
Channel 1 Enable and Current Limit Settin g In pu t. Connect resistor to GND to set
the threshold for Channel 1 synchronous R
current limit threshold is 1/10th the voltage seen at ENTRIP1 over a 0.5V t o 3 V
range. There is an internal 10μA current sour ce from LDO5 to ENTRIP1. Leave
ENTRIP1 f loating or drive it above 4.5V to shut down channel 1.
Channel 2 Enable and Current Limit Settin g In pu t. Connect resistor to GND to set
the threshold for Channel 2 synchronous R
current limit threshold is 1/10th the voltage seen at ENTRIP2 over a 0.5V t o 3 V
range. There is an internal 10μA current sour ce from LDO5 to ENTRIP2. Leave
ENTRIP2 f loating or drive it above 4.5V to shut down channel 2.
SMPS2 Feedba ck Input. Connect FB2 to a resisti ve voltage divider fro m SMPS2
output to GND for adjustable out put from 2V to 5.5V.
Power Good Output for Channel 1 and Channel 2 (RT 8239A).
Power Good Output for Channel 1, Channel 2 and SECFB (RT82 39B/C).
Boost Flying Capacitor Connection for SMPS2. Connect to an external capacitor
accordin g to the typical application circuits.
Upper Gate Driver Output for SM PS2. UGATE2 swings betwee n PHASE2 and
BOOT2.
Switch Node for SMPS2. PHASE2 is the internal lower supply rail for the UGATE2
high side gate driver. PHASE2 is also the current sense input for the SMPS2.
Mast er Enable Input. LDO5/LDO3 is en abled if it is within logic high level and
disab led if it is less than the logic lo w level.
Mode Selectio n with Enable Input. Pull up to LDO5 (Ultrasonic mode ) or LDO3
(DEM) to turn on both switch Channels. Short to GND for shutdown.
Change Pump Feedback Pin. The SECFB is used to monitor the optional external
charge pump . Connect a resistive di vider from the chang e p ump output to GND to
detect the output. If SECFB d rops below its f eedback threshold, an ultra sonic
pulse occurs to re fresh the charge p ump driven by LGATE1 or LGATE2.
If SECFB drops bel ow its UV threshol d, the switcher channels stop working and
enter into discharge-mode. Pull up to LDO5 or LDO3 to disabl e SECFB UVP
function.
5V Linear Regulator Output. LDO5 is the supply voltage for th e low side MOSFET
driver and also the analog s upply voltage for the device. Bypass a min im um 4.7μF
ceramic capacitor to GND
3.3V Linear Regulat or Output. Bypass a minimum 4.7μF ceramic cap aci tor to
GND.
Switch Node SMPS1. PHASE1 is the internal lower supply rail for the UGATE1
high side gate driver. PHASE1 is also the current sense input for the SMPS1.
Upper Gate Driver Output for SMPS1. UGATE1 swings between PHASE1 and
BOOT1.
RT8239A/B/C
sense. The GND-PHASE1
DS(ON)
sense. The GND-PHASE2
DS(ON)
To be continued
DS8239A/B/C-04 April 2011 www.richtek.com
5
RT8239A/B/C
Pin N o. Pin N ame Pin F unction
19 BOOT1
20 BYP1 Switch Over Source Voltage Input for LDO5.
21 (Exposed Pad) GND
Function Block Diagram
Boost Flying Capacitor Connection for SMPS1. Connect to an external
capacitor according to the typical application circuits.
Analog Ground and Power Ground. The exposed pad must be soldered to a
large PCB and connected to GND for maximum power dissipation.
BOOT1
UGATE1
PHASE1
LGATE1
FB1
ENTRIP1
TON
BYP1
LDO5
LDO5
SMPS1
10µA
-
Controller
On Time
+
LDO5
Switch Over Threshold
LDO5
PWM
Buck
SMPS2
PWM
Buck
Controller
REF
LDO5
LDO3
BOOT2
UGATE2
PHASE2
LDO5
LGATE2
10µA
FB2
ENTRIP2
ENM (RT8239A)
SECFB (RT8239B/C)
PGOOD
GND
LDO3
VIN
ENLDO
Power-On
Sequence
Clear Fault Latch
DS8239A/B/C-04 April 2011www.richtek.com
6
RT8239A/B/C
Absolute Maximum Ratings (Note 1)
z VIN, ENLDO to GND ------------------------------------------------------------------------------------------------------ −0.3V to 30V
z BOOTx to PHASEx ------------------------------------------------------------------------------------------------------- −0.3V to 6V
z ENTRIPx, FBx, TON, BYP1, PGOOD, LDO5, LDO3, ENM/SECFB to GND ------------------------------- −0.3V to 6V
z PHASEx to GND
DC----------------------------------------------------------------------------------------------------------------------------- −0.3V to 30V
< 20ns ----------------------------------------------------------------------------------------------------------------------- −8V to 38V
z UGATEx to PHASEx
DC----------------------------------------------------------------------------------------------------------------------------- −0.3V to 6V
< 20ns ----------------------------------------------------------------------------------------------------------------------- −5V to 7.5V
z LGATEx to GND
DC----------------------------------------------------------------------------------------------------------------------------- −0.3V to 6V
< 20ns ----------------------------------------------------------------------------------------------------------------------- −2.5V to 7.5V
z Power Dissipation, P
WQFN-20L 3x3 ------------------------------------------------------------------------------------------------------------ 1.471W
z Package Thermal Resistance (Note 2)
WQFN-20L 3x3, θJA------------------------------------------------------------------------------------------------------- 68°C/W
WQFN-20L 3x3, θJC------------------------------------------------------------------------------------------------------ 7.5°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)
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 200V
@ TA = 25°C
D
Recommended Operating Conditions (Note 4)
z Supply Input Voltage, V
z Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C
z Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C
------------------------------------------------------------------------------------------------ 5.5V to 25V
IN
DS8239A/B/C-04 April 2011 www.richtek.com
7
RT8239A/B/C
Electrical Characteristics
(VIN = 12V, V
Parameter Symbol Test Conditions Min Typ Max Unit
Input Supply
VIN Power On Reset
ENLDO
= 5V, V
ENTRIPx
= 2V, V
= 5V, No Load on LDO5, LDO3, T
BYP1
= 25°C, unless otherwise specified)
A
Rising Threshold -- 5.1 5.5
Falling Threshold 3.5 -- 4.5
V
VIN Shutdown Current
VIN Standby Supply
Curr ent
Quiescent Power
Consumption
I
VIN_SHDN
I
VIN_SBY
I
Q
SMPS Output and FB Voltage
FBx Regulation Voltage
Outp ut Voltage
Adjustable Range
SECFB Voltage
V
FBx
SMPS1, SMPS2 2 -- 5.5
V
SECFB
On Time
ON-Time Pulse Width
Minimum Off-Time
Frequency Range
Ultrasonic Mode
Frequency
t
UGATEx
t
LGATEx
f
SMPS1
f
SMPS2
f
ASM
V
RT8239C, V
Soft-Start
Soft-Start Time
t
SSx
Current Sens e
Curr ent Limit Current
Source
Temperature Coefficient
of I
ENTRIPx
Current Limit Adjustment
Range
Curr ent Limit Threshold
Zero-Current Threshold
I
ENTRIPx
V
ENTRIPx
V
GND − PHASEx, FBx = 2.1V
ZC
Internal Regulator and Reference
LDO5 Output Voltage
V
LDO5
V
ENLDO
= GND
-- 20 40
μA
Both SMPS Off -- 25 0 350
Both SMPSs on, FBx = 2.1V,
BYP1 = 5V, ENM = 3.3V (RT8239A)
-- 5 7 mW
FBx, CCM Operation -- 2 --
V
FBx, DEM Ope ration 1.98 2.006 2.03
V
RT8239B 1 .92 2 2.08
V
R
IN
TON
FBx
= 20V
= 56kΩ
= 1.8V
V
PHASE1
V
PHASE2
= 2V
= 2V
SMPS1 Opera tin g Frequency 200 -- 400
-- 256 -ns
-- 220 --
-- -- 400 ns
kHz
SMPS2 Opera tin g Frequency 233 -- 466
PHASEx
= 50m V
Zero to 200mV Current Limit Threshold
from ENTRIPx Enable
V
ENTRIPx
= 0.9V
On Th e Basis of 25°C
V
ENTRIPx
GND − PHASEx, V
= I
ENTRIPx
x R
ENTRIPx
ENTRIPx
= 2V
25 -- -- kHz
-- 2 -- ms
9.4 10 10.6
-- 4700 --
μA
ppm/°C
0.5 -- 2.7 V
180 200 225 mV
-- 3 -- mV
V
= 0V, I
BYP1
V
= 0V, I
BYP1
6.5V < V
= 0V, I
V
BYP1
5.5V < V
< 25V
IN
< 25V
IN
LDO5
LDO5
LDO5
< 100mA
< 100mA ,
< 50mA,
4.8 5 5.2
4.75 -- 5.25
4.75 -- 5.25
V
To be continued
DS8239A/B/C-04 April 2011www.richtek.com
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