Richtek RT8243AZQW, RT8243BZQW, RT8243CZQW Schematic [ru]

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®
RT8243A/B/C
High Efficiency, Main Power Supply Controller for Notebook Computers
General Description
The RT8243A/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 (RT8243B/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 RT8243A/B/C is available in a WQFN-20L 3x3
package, and operates over an extended temperature range
from −40°C to 85°C.
Features

5.5V to 25V Input Voltage Range


2V to 5.5V Output Voltage Range


No Current Sense Resistor Needed


5V/3.3V Linear Regulators


4700ppm/


Internal Current Limit Soft-Start and Soft Discharge

°°
°C R
°°
Current Sensing
DS(ON)
Output

Built In OVP/UVP/OCP


Selectable Operation Mode with Switcher Enable

Control (RT8243A)

SECFB Input Maintains Charge Pump Voltage

(RT8243B/C)

Power Good Indicator (RT8243B/C includes SECFB)


RoHS Compliant and Halogen Free

Applications
Notebook computers
System Power Supplies
3- and 4- Cell Li+ Battery-Powered Device
Ordering Information
RT8243A/B/C
Package Type QW : WQFN-20L 3x3 (W-Type)
Lead Plating System Z : ECO (Ecological Element with Halogen Free and Pb free)
Pin Function With A : ENM B : SECFB C : SECFB, Ultrasonic Mode
Note :
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.
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
©
DS8243A/B/C-07 November 2014 www.richtek.com
1
RT8243A/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
RT8243AZQW
8A : Product Code
8A YM
DNN
RT8243CZQW
0B YM
DNN
YMDNN : Date Code
0B : Product Code
YMDNN : Date Code
LGATE2
PHASE2 PHASE1
WQFN-20L 3x3
RT8243BZQW
7A YM
DNN
BOOT2
PGOOD
PHASE2
UGATE2
RT8243B/CRT8243A
7A : Product Code
YMDNN : Date Code
LGATE2
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
©
DS8243A/B/C-07 November 2014www.richtek.com
2
Typical Application Circuit
V
I
5
5
.
V
T
O
U
1
5
V
N
V
o
t
2
5
V
1
C
1
1
0
µ
F
N1
1
L
+
3
C
5
C
l
a
n
t
i
p
o
O
3
R
k
5
1
4
R 1
k
0
N2
Chip Enable
R
2
C
µ
.
1
0
2
R
4
C
.
1
0
R
TON
21 (Exposed Pad)
RT8243A/B/C
RT8243A
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
0
1
C
9
4
7
.
µ
F
C
0
1
R
k
0
0
1
1
4
7
.
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
1
0
F
µ
L
2
R
6
6
5
.
k
7
R
k
0
1
l
A
w
V
.
3
3
l
a
w
V
A
5 0 µ
F
V
O
U
T
+
C
8
O
s
y
a
n
s
y
O
2
3
.
3
V
n
Figure 1. RT8243A NB Main Supply Typical Application Circuit
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
©
DS8243A/B/C-07 November 2014 www.richtek.com
3
RT8243A/B/C
V
I
5
.
5
V
U
O
T
1
V
5
C
a
t
n
i
o
p
O
N
V
o
t
2
5
V
C
1
1
0
µ
F
N1
1
L
+
3
C
5
l
3
1
C
0
µ
1
.
1
C
1
0
.
µ
N2
3
R
k
5
1
4
R
k
0
1
F
4
F
C
V
CP
Figure 2. RT8243B/C NB Main Supply Typical Application Circuit
1
R
11
2
C
.
1
0
12
F
µ
18
2
R
4
C
.
0
19
F
µ
1
17
16
1
R
TON
3
20
1
1
C
0
1
.
F
µ
2
1
C
0
1
.
µ
F
1
1
R
2
0
0
k
5
1
13
2
1
R
9
k
3
VIN
ENLDO
UGATE1
BOOT1
PHASE1
LGATE1
FB1
TON
BYP1
SECFB
RT8243B/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
0
1
R
k
0
0
6
1
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
k
0
1
V
O
U
T
+
C
8
2
3
3
.
V
On
Off
n
O
s
y
a
l
w
A
V
.
3
3
F
n
s
O
y
l
a
w
V
A
C 4
5
1
0
7
.
µ
F
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
©
DS8243A/B/C-07 November 2014www.richtek.com
4
Functional Pin Description
Pin No. Pin Name Pin Function
RT8243A/B/C
1 FB1
2 ENTRIP1
3 TON ON-Time/Frequency Adjustment Input. Connect to GND with 56k to 100k.
4 ENTRIP2
5 FB2
6 PGOOD
7 BOOT2
8 UGATE2
9 PHASE2
SMPS1 Feedback Input. Connect FB1 to a resistive voltage divider from SMPS1 output to GND for adjustable output from 2V to 5.5V.
Channel 1 Enable and Current Limit Setting Input. Connect resistor to GND to set the threshold for Channel 1 synchronous R cur rent limit threshold is 1/10th the voltage seen at ENTRIP1 over a 0.5V to 3V range. There is an internal 10A current source from LD O5 to ENT RIP1. Leave ENTRIP1 floating or drive it above 4.5V to shut down channel 1.
Channel 2 Enable and Current Limit Setting Input. Connect resistor to GND to set the threshold for Channel 2 synchronous R cur rent limit threshold is 1/10th the voltage seen at ENTRIP2 over a 0.5V to 3V range. There is an internal 10A current source from LD O5 to ENT RIP2. Leave ENTRIP2 floating or drive it above 4.5V to shut down channel 2.
SMPS2 Feedback Input. Connect FB2 to a resistive voltage divider from SMPS2 output to GND for adjustable output from 2V to 5.5V.
Power Good Output for Channel 1 and Channel 2 (RT8243A).
Power Good Output for Channel 1, Channel 2 and SECFB (RT8243B/C).
Boost Flying Capacitor Connection for SMPS2. Connect to an external capacitor according to the typical application circuits.
Upper Gate Driver Output for SMPS2. UGATE2 swings between 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.
sense. The GND-PHASE1
DS(ON)
sense. The GND-PHASE2
DS(ON)
10 LGATE2 Lower Gate Drive Output for SMSP2. LGATE2 swings between GND and LDO5.
11 VIN Supply Input for LDO5.
Master Enable Input. LDO5/LDO3 is enabled if it is within logic high level and
12 ENLDO
ENM (RT8243A)
13
14 LDO5
15 LDO3
SECFB (RT8243B/C)
disabled if it is less than the logic low level. Leave ENLDO floating to default enable LDO5/LDO3.
Mode Selection 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 divider from the change pump output to GND to detect the output. If SECFB drops below its feedback threshold, an ultrasonic pulse occurs to refresh the charge pump driven by LGATE1 or LGATE2. If SECFB drops below its UV threshold, the switcher channels stop working and enter into discharge-mode. Pull up to LDO5 or LDO3 to disable SECFB UVP function.
5V Linear Regulator Output. LDO5 is the supply voltage for the low side MOSFET driver and also the analog supply voltage for the device. Bypass a minimum 4.7F ceramic capacitor to GND
3.3V Linear Regulator Output. Bypass a minimum 4.7F ceramic capacitor to GND.
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
DS8243A/B/C-07 November 2014 www.richtek.com
©
5
RT8243A/B/C
Pin No. Pin Name Pin Function
16 LGATE1
17 PHASE1
18 UGATE1
19 BOOT1
20 BYP1 Switch Over Source Voltage Input for LDO5.
21 (Exposed Pad) GND
Function Block Diagram
BOOT1
UGATE1
PHASE1
LGATE1
FB1
ENTRIP1
TON
BYP1
LDO5
LDO5
10µA
Switch Over Threshold
+
-
Lower Gate Driver Output for SMPS1. LGATE1 swings between GND and LDO5.
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 BOOT 1.
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.
BOOT2
UGATE2
PHASE2
LGATE2
FB2 ENTRIP2
ENM (RT8243A) SECFB (RT8243B/C)
PGOOD
SMPS1
PWM
Buck
Controller
On Time
SMPS2
PWM
Buck
Controller
LDO5
LDO5
10µA
GND
LDO5
LDO5
VIN
ENLDO
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
©
Power On
Sequence
Clear Fault Latch
REF
LDO3
LDO3
DS8243A/B/C-07 November 2014www.richtek.com
6
RT8243A/B/C
Absolute Maximum Ratings (Note 1)
VIN, ENLDO to GND ------------------------------------------------------------------------------------------------------ 0.3V to 30V
BOOTx to PHASEx
DC----------------------------------------------------------------------------------------------------------------------------- 0.3V to 6V
< 20ns ----------------------------------------------------------------------------------------------------------------------- 2.5V to 6.3V
ENTRIPx, FBx, TON, BYP1, PGOOD, LDO5, LDO3, ENM/SECFB to GND ------------------------------- 0.3V to 6V
PHASEx to GND
DC----------------------------------------------------------------------------------------------------------------------------- 0.3V to 30V
< 20ns ----------------------------------------------------------------------------------------------------------------------- 8V to 38V
UGATEx to PHASEx
DC----------------------------------------------------------------------------------------------------------------------------- 0.3V to 6V
< 20ns ----------------------------------------------------------------------------------------------------------------------- 5V to 7.5V
LGATEx to GND
DC----------------------------------------------------------------------------------------------------------------------------- 0.3V to 6V
< 20ns ----------------------------------------------------------------------------------------------------------------------- 2.5V to 7.5V
Power Dissipation, P
WQFN-20L 3x3 ------------------------------------------------------------------------------------------------------------ 3.33W
Package Thermal Resistance (Note 2)
WQFN-20L 3x3, θJA------------------------------------------------------------------------------------------------------- 30°C/W
WQFN-20L 3x3, θJC------------------------------------------------------------------------------------------------------ 7.5°C/W
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range -------------------------------------------------------------------------------------------- 65°C to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model)---------------------------------------------------------------------------------------------- 2kV
@ TA = 25°C
D
Recommended Operating Conditions (Note 4)
Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- 5.5V to 25V
Junction Temperature Range -------------------------------------------------------------------------------------------- 40°C to 125°C
Ambient Temperature Range -------------------------------------------------------------------------------------------- 40°C to 85°C
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
DS8243A/B/C-07 November 2014 www.richtek.com
©
7
RT8243A/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 Current
Quiescent Power Consumption
I
VIN_SHDN
I
VIN_SBY
I
Q
SMPS Output and FB Voltage
FBx Regulation Voltage
Output Voltage Adjustable Range
SECFB Voltage
V
FBx
SMPS1, SMPS2 2 -- 5.5
SECFB
V
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
RT8243C, V
Soft-Start
Soft-Start Time
t
SSx
Current Sense
Current Limit Current Source
Temperature Coefficient of I
ENTRIPx
Current Limit Adjustment Range
Current Limit Threshold
Zero-Current Threshold
I
ENTRIPx
V
ENTRIPx
V
ZC
Internal Regulator and Reference
LDO5 Output Voltage
V
LDO5
V
ENLDO
= GND
-- 20 40
A
Both SMPS Off -- 250 350
Both SMPSs on, FBx = 2.1V, BYP1 = 5V, ENM = 3.3V (RT8243A)
-- 5 7 mW
FBx, CCM Operation -- 2 --
V
FBx, DEM Operation 1.98 2.006 2.03
V
RT8243B 1.92 2 2.08
V R
IN
TON
FBx
= 20V
= 56k
= 1.8V
V
PHASE1
V
PHASE2
= 2V
= 2V
SMPS1 Operating Frequency 200 -- 400
SMPS2 Operating Frequency 233 -- 466
PHASEx
= 50mV
Zero to 200mV Current Limit Threshold from ENTRIPx Enable
V
ENTRIPx
= 0.9V
On The Basis of 25C
V
ENTRIPx
= I
ENTRIPx
GND  PHASEx, V
x R
ENTRIPx
ENTRIPx
= 2V
GND PHASEx, FBx = 2.1V
= 0V, I
V
BYP1
V
= 0V, I
BYP1
6.5V < V V
= 0V, I
BYP1
5.5V < V
< 25V
IN
< 25V
IN
LDO5
LDO5
LDO5
< 100mA
< 100mA ,
< 50mA,
-- 256 --
-- 220 --
ns
-- -- 400 ns
kHz
25 -- -- kHz
-- 2 -- ms
9.4 10 10.6
-- 4700 --
A
ppm/C
0.5 -- 2.7 V
180 200 225 mV
-- 3 -- mV
4.9 5 5.1
4.75 -- 5.25 V
4.75 -- 5.25
Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
8
©
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