®
RT9992
5+2 CH DC/DC Converters for DV
General Description
Features
This is a 5+2 CH integrated PMIC for DV application. There
are 5 DC/DC converters : one synchronous step-up, one
selectable synchronous step-up/step-down, two
synchronous step-downs, and one WLED driver in either
asynchronous step-up or current source mode, selectable
by VOUT6 initial voltage. In addition, there are 2 LDO
regulators : one RTC LDO and one generic LDO. The
generic LDO can choose internal feedback loop for fixed
output 2.5V or external feedback loop for customized
output voltage. Both low voltage synchronous step-up
converters are with load disconnect function. All power
MOSFETs and compensation networks are integrated.
There is a power good indicator to monitor FB2, FB3, and
FB4 voltage status. CH1 to CH5 enabling can be controlled
flexibly : enabled independently or in preset sequences.
All Power MOSFETs Integrated
5 Channels with Internal Compensation
Flexible Enabling Control
Enabled Independently or in Preset Power On/
Off Sequences
CH2 Synchronous Converter in Step-Up or StepDown Mode Selectable by SEL Pin
Synchronous Step-Down DC/DC Converter
Up to 95% Efficiency
100% (max) Duty Cycle
Synchronous Step-Up DC/DC Converter
Adjustable Output Voltage
Up to 95% Efficiency
Asynchronous Step-Up Converter to Drive WLED,
Selectable Between Step-Up or Current Source
LED Open Protection (OVP6) in Step-Up Mode
PWM Dimming Control
Load Disconnect Function for CH1 and CH2
Synchronous Step-Up Converter
Fixed 2MHz Switching Frequency for CH1, CH2,
CH3, and CH4
Fixed 1MHz Switching Frequency for CH6
Generic LDO (CH5)
Output Voltage : Fixed 2.5V or Set by External
Feedback Network, Determined by FB5 Initial
Voltage
RTC LDO : Fixed Output Voltage 3.1V
Power Good Indicator to Monitor Output Voltage
Status of CH2, CH3, and CH4
32-Lead Package
RoHS Compliant and Halogen Free
Ordering Information
RT9992
Note :
Package Type
QW : WQFN-32L 4x4 (W-Type)
Lead Plating System
Z : ECO (Ecological Element with
Halogen Free and Pb free)
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.
Pin Configuration
(TOP VIEW)
EN1
LX1
PVDD1
BAT
RTCPWR
PVDD6
VDDM
FB6
Applications
32 31 30 29 28 27 26 25
FB1
PGOOD
FB5
VOUT5
PVDD5
EN5
SEQ
LX2
1
24
2
23
3
22
4
5
6
21
GND
20
33
19
7
18
8
17
VOUT6
LX6
EN6
PVDD3
LX3
EN3
FB3
FB4
CMOS DV
Gaming
Marking Information
ES : Product Code
PVDD2
VIN2
EN2
FB2
SEL
PVDD4
LX4
EN4
9 10 11 12 13 14 15 16
ES YM
DNN
YMDNN : Date Code
WQFN-32L 4x4
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9992-05 July 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
RT9992
Typical Application Circuit
For 2AA :
R10
100k
3.3V
2
C14
1µF
23
LX6
PVDD1
VBAT
30
VOUT6
5V
C3
10µF x 2
D4
24
C19
1µF
PGOOD
L1
2.2µH
31
LX1
C5
10µF
L6
10µH
VBAT
RT9992
R1
470k
FB1 1
C4
4.7pF
D1
R2
88.7k
D2
D3
R13
10
25
FB6
PVDD2
3.3V
C6
10µF*2
29 BAT
VBAT
C1
1µF
26 VDDM
C2
1µF
Chip Enable
VEN1234
VBAT
VBAT
VEN5
FB2
32
16
VBAT
5V
28
3.1V
C15
0.1µF
3.3V
C18
4.7pF
LX3
FB3
VBAT
C7
10µF
21
20
L3
2.2µH
1.8V
R5
470k
18
14
PVDD5
C10
33pF
15
VBAT
L4
2.2µH
C11
10µF
1.2V
C12
10µF
VOUT5
FB5
R12
180k
5V/3.3V
C8
10µF
R6
374k
FB4
3
L2
2.2µH
C9
10µF
LX4
4
R11
909k
PVDD3
PVDD4
5
10
LX2 8
RTCPWR
C16
1µF
3V
VIN2
PVDD6
SEL
C20
4.7pF
R4
150k
EN6
7 SEQ
13
12
EN4
6 EN5
27
R3
470k
EN1
11 EN2
19
EN3
22
C17
1µF
9
GND
17
33 (Exposed Pad)
R7
187k
C13
82pF
R8
374k
For above circuit, the power sequence is CH1 CH3 CH4 CH2, while CH5 remains independent.
For other power sequence combinations, refer to the power on/off sequence section in application information.
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is a registered trademark of Richtek Technology Corporation.
DS9992-05 July 2019
RT9992
For Li+ :
R10
100k
3.3V
2
13
VBAT
29
VBAT
C1
1µF
27
D5
5V
RT9992
PGOOD
SEL
BAT
VEN2
VEN3
VEN4
VEN5
R1
470k
FB1 1
9
FB2
VIN2
L2
2.2µH
3.3V
PVDD3
EN5
22 EN6
LX3
23 LX6
FB3
12
10
R9
470k
20
VBAT
C8
10µF
L3
2.2µH
1.8V
3.1V
18
14
FB5
RTCPWR
LX4
15
C15
0.1µF
5
3.3V
C16
1µF
2.5V
4
PVDD5
VOUT5
R5
470k
C10
33pF
R6
374k
PVDD4
28
C18
10pF
21
C9
10µF
7 SEQ
VBAT
R3
470k
R4
150k
24 VOUT6
3
VBAT
C6
10µF
C7
10µF
EN1
EN3
C4
4.7pF
R2
88.7k
VDDM
14 EN4
6
5V
C3
10µF x 2
PVDD2
11 EN2
19
VBAT
C5
10µF
30
LX2 8
32
L1
2.2µH
PVDD6
C2
1µF
VEN1
PVDD1
25 FB6
26
Chip Enable
LX1 31
FB4
GND
17
VBAT
C11
10µF
L4
2.2µH
C12
10µF
33 (Exposed Pad)
R7
187k
1.2V
C13
82pF
R8
374k
C17
1µF
For above circuit, all channels are independently enabled/disabled.
For other power sequence combinations, refer to the power on/off sequence section in application information.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9992-05 July 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3
RT9992
Channel
Table 1. Recommended Components for the Typical Application Circuit
CH3
Calculation
VOUT(V)
L3 (H)
R5 (k)
R6 (k)
C9 (F)
C10 (pF)
VOUT_CH3 = (1 + R5 / R6) x 0.8V
2.5
2.2
768
360
10
22
1.8
2.2
470
374
10
33
1.5
2.2
330
374
10
47
1.3
2.2
237
374
10
68
Channel
CH4
Calculation
VOUT_CH4 = (1 + R7 / R8) x 0.8V
V OUT (V)
L4 (H)
R7 (k)
R8 (k)
C12 (F)
C13 (pF)
2.5
2.2
768
360
10
22
1.8
2.2
470
374
10
33
1.5
2.2
330
374
10
47
1.3
2.2
237
374
10
68
1.2
2.2
187
374
10
82
1
2.2
23.2
93.1
10
47
1.2
2.2
187
374
10
82
1
2.2
23.2
93.1
10
47
Where C9, C12 are COUT,
C10, C13 are feedforward cap between output and FB
R5, R7 are the feedback resistor between output and FB
R6, R8 are the feedback resistor between GND and FB
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is a registered trademark of Richtek Technology Corporation.
DS9992-05 July 2019
RT9992
Functional Pin Description
Pin No.
1
Pin Name
FB1
Pin Function
Feedback input pin of CH1. High impedance in shutdown.
2
3
PGOOD
FB5
Power good indicator output pin (Open drain).
Feedback input pin of CH5. High impedance in shutdown.
4
5
VOUT5
PVDD5
Output pin for CH5. High impedance in shutdown.
Power input pin of CH5.
6
EN5
Enable pin of CH5.
7
SEQ
SEQ = H to use preset power on/off sequence. SEQ = L to independently
enable CH1 to 5. Logic state can’t be changed during operation.
8
LX2
Switch node of CH2. High impedance in shutdown.
9
PVDD2
Power input pin of CH2 in Step-Down or power output pin of CH2 in step-up.
10
11
VIN2
EN2
Power input node of CH2 in step-up.
Enable pin of CH2 or enable pin of preset On/Off sequence.
12
FB2
Feedback input pin of CH2. High impedance in shutdown.
13
SEL
Select pin to define CH2 in step-down (SEL = H) or step-up (SEL = L) mode.
Logic state can’t be changed during operation.
14
15
16
17
18
19
20
21
22
23
PVDD4
LX4
EN4
FB4
FB3
EN3
LX3
PVDD3
EN6
LX6
Power input pin of CH4.
Switch node of CH4. High impedance in shutdown.
Enable pin of CH4 or Select which preset On/Off sequence.
Feedback input pin of CH4. High impedance in shutdown.
Feedback input pin of CH3. High impedance in shutdown.
Enable pin of CH3 or select which preset On/Off sequence.
Switch node of CH3. High impedance in shutdown.
Power input pin of CH3.
Enable pin of CH6 and PWM dimming input signal pin.
Switch node of CH6 in step-up mode. High impedance in shutdown.
24
VOUT6
Sense pin for CH6 output voltage in step-up mode and CH6 mode selection
pin.
25
FB6
Feedback input pin of CH6 in step-up mode or current sink pin of CH6 in
current source mode.
26
VDDM
Internal control circuit power pin. That must connect to a bypass capacitor for
better noise rejection.
27
28
29
30
31
32
PVDD6
RTCPWR
BAT
PVDD1
LX1
EN1
Power input pin of CH6 N-MOSFET Driver.
RTC power output pin.
Battery power input pin and CH1 step-up power input node.
Power output pin of CH1.
Switch node of CH1. High impedance in shutdown.
Enable pin of CH1.
GND
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
33
(Exposed pad)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9992-05 July 2019
is a registered trademark of Richtek Technology Corporation.
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5
RT9992
Functional Block Diagram
PVDD6
BAT
VDDM
VDDI
VDDM
PGOOD
UVLO
Power
Good
FB2
FB3
LX6
VDDM
FB4
VDDM
PVDD1
Body
Diode
Control
CH6
Step-Up
+
Current Source
+
PWM Dimming
CH1
C-Mode
Step-Up
BAT
LX1
VOUT6
-
+
FB6
0.25V
REF
+
30mA
FB1
0.8V
REF
VDDM
PVDD2
EN6
Body
Diode
Control
VDDM
CH2
C-Mode
Step-Up
or
Step-Down
EN1
EN2
EN3
VIN2
LX2
Power ON/Off
Sequence Control
Logic Block
EN4
EN5
SEL
-
SEQ
+
FB2
0.8V
REF
VDDM
VDDI
RTC_LDO
w/Body Diode Control
RTCPWR
PVDD5
VOUT5
PVDD3
CH3
C-Mode
Step-Down
LX3
-
CH5
LDO
+
VDDM
FB3
0.8V
REF
PVDD4
int
ext
0.5V
REF
+
FB5
CH4
C-Mode
Step-Down
LX4
CH5
SEL
GND
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+
FB4
0.8V
REF
is a registered trademark of Richtek Technology Corporation.
DS9992-05 July 2019
RT9992
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage, VDDM ------------------------------------------------------------------------------------------LX1, LX2, LX3, LX4 -------------------------------------------------------------------------------------------------------< 20ns -----------------------------------------------------------------------------------------------------------------------LX6, VOUT6 ---------------------------------------------------------------------------------------------------------------< 20ns -----------------------------------------------------------------------------------------------------------------------Other Pins ------------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
−0.3V to 7V
−0.3V to 7V
−0.3V to 10V
−0.3V to 21V
−8V to 24V
−0.3V to 7V
WQFN−32L 4x4 -----------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
WQFN−32L 4x4, θJA -----------------------------------------------------------------------------------------------------WQFN−32L 4x4, θJC -----------------------------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3)
HBM (Human Body Mode) ----------------------------------------------------------------------------------------------
3.59W
Recommended Operating Conditions
27.8°C/W
7°C/W
150°C
260°C
−65°C to 150°C
2kV
(Note 4)
Supply Input Voltage VDDM -------------------------------------------------------------------------------------------- 2.7V to 5.5V
Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C
Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VDDM = 3.3V, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
For Bootstrap, First Rising
1.5
--
--
V
VBAT = 4.2V, VPVDD6 = 3V
--
7
12
A
VBAT = 4.2V, VPVDD6 < VBAT
--
--
1
A
IOFF
ENx = 0, VSEQ = 0V, SEL = 0V
--
1
10
A
IQ1
Non Switching, VEN1 = 3.3V,
VFB1 = 0.9V, VSEQ = 0V
--
--
800
A
IQ2
Non Switching, VEN2 = 3.3V,
VFB2 = 0.9V, VSEQ = 0V
--
--
800
A
IQ3
Non Switching, VEN3 = 3.3V,
VFB3 = 0.9V, VSEQ = 0V
--
--
800
A
Supply Voltage
VDDM Startup Voltage
Supply Current
Shutdown Supply Current into
BAT (including RTC LDO
quiescent current)
Shutdown Supply Current into
PVDD6
Shutdown Supply Current into
VDDM
CH1 (Synchronous Step-Up)
Supply Current into VDDM
CH2 (Synchronous Step-Up or
Step-Down) Supply Current
into VDDM
CH3 (Synchronous
Step-Down)
Supply Current into VDDM
VST
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RT9992
Parameter
Symbol
CH4 (Synchronous Step-Down)
IQ4
Supply Current into VDDM
CH6 (WLED) in Current Source Mode
IQ6c
Supply Current into VDDM
CH6 (WLED) in Asynchronous
Step-Up Mode Supply Current into
VDDM
Oscillator
CH1, 2, 3, 4 Operation Frequency
CH6 Operation Frequency
CH1 Maximum Duty Cycle (Step-Up)
CH2 Maximum Duty Cycle (Step-Up)
CH2 Maximum Duty Cycle
(Step-Down)
CH3 Maximum Duty Cycle
(Step-Down)
CH4 Maximum Duty Cycle
(Step-Down)
CH6 Maximum Duty Cycle (Step-Up)
IQ6b
Min
Typ
Max
Unit
Non Switching, VEN4 = 3.3V,
VFB4 = 0.9V, VSEQ = 0V
--
--
800
A
VEN6 = 3.3V, VOUT6 = 0V
--
--
600
Non switching, VEN6 = 3.3V,
VFB6 = 0.35V, VOUT6 = 1V
--
--
800
VFB1 = 0.7V
VFB2 = 0.7V
1800
900
80
80
2000
1000
83.5
83.5
2200
1100
87
87
kHz
kHz
%
%
VFB2 = 0.7V
--
--
100
%
VFB3 = 0.7V
--
--
100
%
VFB4 = 0.7V
--
--
100
%
VFB6 = 0.15V, VOUT6 = 1V
91
93
97
%
0.788
0.8
0.812
V
VOUT6 = 0V, Current Source
VOUT6 = 0V, VDDM = 3.3V,
Current Source
28.5
30
31.5
mA
--
--
0.6
V
VOUT6 = 1V. Step-Up
0.237
0.25
0.263
V
P-MOSFET, VPVDD1 = 3.3V
--
200
300
N-MOSFET, VPVDD1 = 3.3V
--
130
250
2.2
3
4
P-MOSFET, VPVDD2 = 3.3V
--
400
550
N-MOSFET, VPVDD2 = 3.3V
--
260
400
fOSC
fOSC6
Feedback and output Regulation Voltage
Feedback Regulation Voltage @ FB1,
FB2, FB3, and FB4
Sink Current into FB6 (CS mode)
Dropout Voltage @ FB6 (CS mode)
Feedback Regulation Voltage @ FB6
Test Conditions
VFB6
Power Switch
CH1 On Resistance of MOSFET
RDS(ON)
CH1 Current Limitation (Step-Up)
ILIM1
CH2 On Resistance of MOSFET
RDS(ON)
CH2 Current Limitation (Step-Down)
ILIM2_D
1
1.5
2
A
CH2 Current Limitation (Step-Up)
ILIM2_U
1.5
2.1
3
A
370
500
RDS(ON)
P-MOSFET, VPVDD3 = 3.3V
--
CH3 On Resistance of MOSFET
N-MOSFET, VPVDD3 = 3.3V
--
300
400
CH3 Current Limitation (Step-Down)
ILIM3
1
1.5
2
240
400
RDS(ON)
P-MOSFET, VPVDD4 = 3.3V
--
CH4 On Resistance of MOSFET
N-MOSFET, VPVDD4 = 3.3V
--
140
250
CH4 Current Limitation (Step-Down)
ILIM4
CH6 On Resistance of MOSFET
CH6 Current Limitation
RDS(ON)
ILIM6
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N-MOSFET
N-MOSFET
m
A
m
m
A
m
1.5
2
2.4
A
-0.6
0.75
0.8
1.1
1
A
is a registered trademark of Richtek Technology Corporation.
DS9992-05 July 2019
RT9992
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
5.9
6.15
6.4
V
18
19.5
21
V
Protection
Over Voltage Protection
PVDD1,PVDD2 (CH2 in Step-Up)
Over Voltage Protection @ VOUT6
VOVP6
Step-Up
Under Voltage Protection @ FB1,
FB2, FB3, FB4
VUVP1234
--
0.4
--
V
Under Voltage Protection @ FB5
VUVP5
--
0.3
--
V
5.9
6.15
6.4
V
2.4
2.7
VDDM Over Voltage Protection
VDDM Rising
VDDM UVLO Threshold
BAT UVLO Threshold
Protection Fault Delay
VDDM Falling
1.7
2.1
2.4
BAT Rising
1.3
1.4
1.5
BAT Falling
1.2
1.3
1.4
--
100
--
Except OVP1/2
V
V
ms
Control
EN1 to 6, SEL,
SEQ Threshold
Voltage
Logic-High
VIH
1.3
--
--
Logic-Low
VIL
--
--
0.4
EN1 to 5, SEL, SEQ Sink Current
--
1
6
A
EN6 Sink Current
--
4
20
A
--
32.7
--
ms
--
1.2
5
s
125
160
--
C
--
20
--
C
2.7
--
5.5
V
0.6
--
4.5
V
EN6 Low Time for Shutdown
V
tSHDN
EN6 High Time for CH6 Enable
Thermal Protection
Thermal Shutdown
TSD
Thermal Shutdown Hysteresis
TSD
CH5 LDO (COUT = 1F for Better Stability)
Input Voltage Range (PVDD5)
VPVDD5
Output Voltage Range
VOUT5
By external feedback
Feedback Regulation Voltage @
FB5
VFB5
Using external feedback loop
0.493
0.5
0.507
V
Regulated Output Voltage @
VOUT5
VREG5
Using internal feedback loop
2.45
2.5
2.55
V
(Note : before enabled, VFB5 >
0.8V. Then CH5 uses internal
feedback)
0.8
--
--
V
VPVDD5 = 3.3V
300
380
500
mA
IOUT = 100mA
60
100
120
mV
VFB5 = 0 to 0.5V
--
2.4
--
ms
IOUT = 10mA, VPVDD5 = 3.3V,
VOUT = 2.5V, 1kHz
--
55
--
db
FB5 Threshold to Select Internal
Feedback Network
Max Current Limit
ILIM5
Dropout Voltage
Soft-Start Time
tSS5
PSRR+
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
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RT9992
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
RTC LDO for RTCPWR (Keep On Once Bat Connect)
Input Voltage Range
VDDI
Max of BAT and PVDD6
--
--
5.5
V
Quiescent Current
Regulated Output Voltage @
RTCPWR
Max Output Current
(Current Limit)
IQ
VDDI = 4.2V
--
5
8
A
I OUT = 0mA
3.0
3.1
3.2
V
VDDI = 4.2V
60
105
200
mA
I OUT = 50mA
I OUT = 10mA
---
740
110
1000
200
mV
I OUT = 3mA
--
60
100
0.6
0.66
0.74
V
--
40
--
mV
For PGOOD Go Low
0.6
0.66
0.74
V
For PGOOD Go Low
-0.6
40
0.66
-0.74
mV
V
-13
40
14.4
-15.9
mV
ms
4
--
--
mA
Dropout Voltage
VDROP
Power Good Indicator
FB2 Regulation Threshold
For PGOOD Go Low
FB2 Hysteresis
FB3 Regulation Threshold
FB3 Hysteresis
FB4 Regulation Threshold
FB4 Hysteresis
PGOOD Rising Delay Time
PGOOD Sink Capability
Soft-Start Time
VDDM = 3.3V, VPGOOD = 0.5V
CH1 Soft-Start Time
tSS1
VFB1 = 0 to 0.8V
2.8
3.5
4.2
ms
CH2 Soft-Start Time
tSS2
VFB2 = 0 to 0.8V
2.8
3.5
4.2
ms
CH3 Soft-Start Time
tSS3
VFB3 = 0 to 0.8V
2.8
3.5
4.2
ms
CH4 Soft-Start Time
tSS4
VFB4 = 0 to 0.8V
2.8
3.5
4.2
ms
Note 1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
These are stress ratings only, and functional operation of the device at these or any other conditions beyond those
indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating
conditions may affect device reliability.
Note 2. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is
measured at the exposed pad of 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.
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RT9992
Typical Operating Characteristics
CH1 Step-Up Efficiency vs. Output Current
CH2 Step-Up Efficiency vs. Output Current
100
100
90
90
80
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
=
=
=
=
=
3.3V
3.6V
3.9V
4.2V
4.5V
Efficiency (%)
Efficiency (%)
80
40
30
20
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
40
30
VDDM = 3V, VOUT = 3.3V,
L = 2.2μH, COUT = 10μF x 2
10
0
0
10
100
1000
10
100
Output Current (mA)
1000
Output Current (mA)
CH2 Step-Down Efficiency vs. Output Current
CH3 Step-Down Efficiency vs. Output Current
100
100
90
90
80
80
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
40
=
=
=
=
=
=
=
3.4V
3.6V
3.9V
4.2V
4.5V
4.8V
5V
Efficiency (%)
Efficiency (%)
1.8V
2V
2.2V
2.5V
2.7V
3V
20
VDDM = 3V, VOUT = 5V,
L = 2.2μH, COUT = 10μF x 2
10
30
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
40
=
=
=
=
=
=
=
2.7V
3V
3.3V
3.6V
3.9V
4.2V
4.5V
30
20
20
10
10
VDDM = 3V, VOUT = 3.3V, L = 2.2μH, COUT = 10μF
VDDM = 3V, VOUT = 1.8V, L = 2.2μH, COUT = 10μF
0
0
10
100
10
1000
100
Output Current (mA)
CH6 Efficiency vs. Input Voltage
100
100
90
90
80
80
60
50
40
=
=
=
=
=
=
=
2V
2.5V
3V
3.3V
3.6V
4.2V
4.5V
Efficiency (%)
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
1000
Output Current (mA)
CH4 Step-Down Efficiency vs. Output Current
Efficiency (%)
=
=
=
=
=
=
30
20
70
60
50
40
30
20
10
VDDM = 3V, VOUT = 1V, L = 2.2μH, COUT = 10μF
0
VDDM = 3V, L = 10μH, COUT = 1μF,
IOUT = 4WLEDs, 25mA
10
0
10
100
Output Current (mA)
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1000
3.4
3.6
3.8
4
4.2
4.4
4.6
4.8
5
Input Voltage (V)
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RT9992
CH2 Step-Dwon Output Voltage vs. Output Current
5.20
3.310
5.15
3.305
5.10
3.300
Output Voltage (V)
Output Voltage (V)
CH1 Step-Up Output Voltage vs. Output Current
5.05
5.00
VBAT = 3V
VBAT = 4.5V
4.95
4.90
3.295
VBAT = 4.5V
VBAT = 5V
3.290
3.285
3.280
3.275
4.85
VOUT = 5V
VOUT = 3.3V
3.270
4.80
0
100
200
300
400
500
0
600
100
200
300
400
500
600
Output Current (mA)
Output Current (mA)
CH3 Step-Down Output Voltage vs. Output Current
CH4 Step-Down Output Voltage vs. Output Current
1.810
1.020
1.805
Output Voltage(V)
Output Voltage(V)
1.015
VBAT = 3V
VBAT = 4.5V
1.800
1.795
1.010
1.005
VBAT = 3V
VBAT = 4.5V
1.000
0.995
0.990
0.985
VOUT = 1.8V
1.790
VOUT = 1V
0.980
0
100
200
300
400
500
600
0
Output Current (mA)
150
300
450
600
750
900
Output Current (mA)
Power On Sequence Independently
CH5 LDO Output Voltage vs. Output Current
3.070
VOUT2
(5V/Div)
Output Voltage(V)
3.065
3.060
3.055
VOUT3
(2V/Div)
VBAT = 3.4V
VBAT = 4.5V
3.050
VOUT4
(1V/Div)
3.045
3.040
VOUT5
(2V/Div)
3.035
ADJ 3V, VOUT = 3V
VBAT = 3.7V, SEL = SEQ = Low
3.030
0
50
100
150
200
Time (50ms/Div)
Output Current (mA)
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RT9992
Power Off Sequence Independently
Power On Sequence 1
VOUT2
(5V/Div)
VOUT2
(5V/Div)
VOUT3
(2V/Div)
VOUT3
(2V/Div)
VOUT4
(1V/Div)
VOUT4
(1V/Div)
VOUT5
(2V/Div)
VOUT5
(2V/Div)
VBAT = 3.7V, SEL = SEQ = Low
Time (50ms/Div)
Time (5ms/Div)
Power Off Sequence 1
Power On Sequence 2
VOUT2
(5V/Div)
VOUT2
(5V/Div)
VOUT3
(2V/Div)
VOUT3
(2V/Div)
VOUT4
(1V/Div)
VOUT4
(1V/Div)
VOUT5
(2V/Div)
VBAT = 3.7V,
SEL = SEQ = EN3 = High, EN4 = Low, Turn on EN2
VBAT = 3.7V,
SEL = SEQ = EN3 = High, EN4 = Low, Turn on EN2
VOUT5
(2V/Div)
VBAT = 3.7V, SEL = SEQ = High,
EN3 = EN4 = EN5 = Low, Turn on EN2
Time (1ms/Div)
Time (5ms/Div)
Power Off Sequence 2
Power On Sequence 3
VOUT2
(5V/Div)
VOUT3
(2V/Div)
VOUT1
(5V/Div)
VOUT2
(5V/Div)
VOUT4
(1V/Div)
VOUT3
(2V/Div)
VOUT5
(2V/Div)
VBAT = 3.7V,
SEL = SEQ = High,
EN3 = EN4 = EN5 = Low, Turn on EN2
Time (1ms/Div)
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VOUT4
(1V/Div)
VBAT = 3.7V,
SEL = SEQ = EN3 = EN4 = High, Turn on EN2
Time (5ms/Div)
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RT9992
Power Off Sequence 3
Power On Sequence 4
VOUT1
(5V/Div)
VOUT2
(5V/Div)
VOUT1
(5V/Div)
VOUT2
(5V/Div)
VOUT3
(2V/Div)
VOUT3
(2V/Div)
VBAT = 3.7V,
VOUT4
(1V/Div)
VOUT4
(1V/Div)
SEL = SEQ = EN3 = EN4 = High, Turn on EN2
VBAT = 3.7V,
SEL = SEQ = EN4 = High, EN3 = Low, Turn on EN2
Time (1ms/Div)
Time (5ms/Div)
Power Off Sequence 4
CH1 Output Voltage Ripple
VOUT1
(5V/Div)
VOUT2
(5V/Div)
LX1
(2V/Div)
VOUT3
(2V/Div)
VOUT1ac
(5mV/Div)
VBAT = 3.7V,
VOUT4
(1V/Div)
VBAT = 3.7V, VOUT = 5V, IOUT = 400mA,
L = 2.2μH, COUT = 10μF x 2
SEL = SEQ = EN4 = High, EN3 = Low, Turn on EN2
Time (1ms/Div)
Time (500ns/Div)
CH2 Output Voltage Ripple
CH3 Output Voltage Ripple
LX2
(2V/Div)
LX3
(2V/Div)
VOUT2ac
(5mV/Div)
VOUT3ac
(5mV/Div)
VBAT = 3.7V, VOUT = 3.3V,
IOUT = 400mA, L = 2.2μH, COUT = 10μF
Time (500ns/Div)
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VDDM = PVDD6 = VOUT1 = 5V, VBAT = 3.7V,
VOUT = 1.8V, IOUT = 400mA, L = 2.2μH, COUT = 10μF
Time (500ns/Div)
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RT9992
CH4 Output Voltage Ripple
CH6 Output Voltage Ripple
LX4
(2V/Div)
LX6
(5V/Div)
VOUT4ac
(5mV/Div)
VOUT6ac
(50mV/Div)
VDDM = PVDD6 = VOUT1 = 5V, VBAT = 3.7V,
VOUT = 1V, IOUT = 400mA, L = 2.2μH, COUT = 10μF
VBAT = 1.8V, IOUT = 4WLEDs, L = 10μH, COUT = 1μF
Time (500ns/Div)
Time (500ns/Div)
CH1 Load Transient Response
CH2 Load Transient Response
IOUT
(200mA/Div)
IOUT
(200mA/Div)
VOUT1ac
(50mV/Div)
VOUT2ac
(50mV/Div)
VBAT = 3.7V, VOUT = 5V, IOUT = 50mA
to 250mA, L = 2.2μH, COUT = 10μF x 2
VBAT = 3.7V, VOUT = 3.3V, IOUT = 0mA
to 300mA, L = 2.2μH, COUT = 10μF
Time (1ms/Div)
Time (1ms/Div)
CH2 Load Transient Response
CH3 Load Transient Response
IOUT
(200mA/Div)
IOUT
(200mA/Div)
VOUT2ac
(50mV/Div)
VOUT3ac
(50mV/Div)
VBAT = 1.8V, VOUT = 3.3V, IOUT = 50mA
to 250mA, L = 2.2μH, COUT = 10μF x 2
Time (1ms/Div)
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VBAT = 3.7V, VOUT = 1.8V, IOUT = 0mA
to 300mA, L = 2.2μH, COUT = 10μF
Time (1ms/Div)
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RT9992
CH4 Load Transient Response
CH5 Load Transient Response
IOUT
(200mA/Div)
IOUT
(200mA/Div)
VOUT4ac
(50mV/Div)
VOUT5ac
(50mV/Div)
VBAT = 3.7V, VOUT = 1V, IOUT = 0mA to
300mA, L = 2.2μH, COUT = 10μF
Time (1ms/Div)
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ADJ = 3V, VBAT = 3.7V, VOUT = 3V,
IOUT = 0mA to 200mA, COUT = 1μF
Time (1ms/Div)
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RT9992
Application Information
The RT9992 includes the following four DC/DC converter
channels, two LDOs, and one WLED driver to build a
multiple-output power-supply system.
CH1 : Step-up synchronous current mode DC/DC converter
with internal power MOSFETs and compensation network.
The P-MOSFET body can be controlled to disconnect the
load.
CH2 : Selectable step-up or step-down synchronous
current mode DC/DC converter with internal power
MOSFETs and compensation network. The P-MOSFET
body can be controlled to disconnect the load.
CH3 : Step-down synchronous current mode DC/DC
converter with internal power MOSFETs and internal
compensation network.
CH4 : Step-down synchronous current mode DC/DC
converter with internal power MOSFETs and internal
compensation network.
CH5 : Generic LDO that provides either fixed 2.5V output
or adjustable output voltage via external feedback network,
depending on initial by FB5 voltage prior to becoming
The output voltage can be set by the following equation :
VOUT_CH1 = (1+R1/R2) x VFB1
where VFB1 is 0.8V typically.
CH2 : Synchronous Step-Up / Step-Down
Selectable DC/DC Converter
CH2 is a synchronous step-up / step-down selectable
converter for system I/O power.
Mode Setting
CH2 of the RT9992 features flexible step-up/step-down
topology setting for 2AA / Li-ion battery. If CH2 operates
in step-up mode, the SEL pin should be connected to
GND. If CH2 operates in step-down mode, the SEL pin
should be connected to VBAT. In addition, please note that
the logic state can not be changed during operation.
Table 2. CH2 Mode Setting
CH2 Operating
Mode
Step-Up
Connect the SEL pin to GND.
Step-Down
Connect the SEL pin to VBAT.
Connection
enabled.
CH6 : WLED driver operable in either current source mode
or asynchronous step-up mode with internal power
MOSFET and compensation network.
CH1 to CH4 operate in PWM mode with 2MHz, while
CH6 operates in step-up mode with 1MHz switching
frequency under moderate to heavy loading.
RTC_LDO : 3.1V output LDO with low quiescent current
and high output voltage accuracy.
Power Good Indicator : Monitors FB2, FB3, and FB4
status.
CH1 : Synchronous Step-Up DC/DC Converter
CH1 is a synchronous step-up converter for motor driver
power in DSC system. The converter operates at fixed
frequency and under PWM Current Mode. The converter
integrates internal MOSFETs, compensation network and
synchronous rectifier for up to 95% efficiency. It also
disconnects the load when CH1 is turned off. Connect
BAT to the power input node in front of CH1 inductor.
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Step-Up
The converter operates in fixed frequency PWM Mode,
Continuous Current Mode (CCM), and Discontinuous
Current Mode (DCM) with internal MOSFETs,
compensation network and synchronous rectifier for up
to 95% efficiency. In step-up mode, CH2 also disconnects
the load when it is turned off. Connect VIN2 to the power
input node in front of CH2 inductor.
Step-Down
The converter operates in fixed frequency PWM mode
and Continuous Current Mode (CCM) with internal
MOSFETs, compensation network and synchronous
rectifier for up to 95% efficiency. The CH2 step-down
converter can be operated at 100% maximum duty cycle
to extend the input operating voltage range. When the
input voltage is close to the output voltage, the converter
enters low dropout mode. In step-down mode, connect
the VIN2 pin to GND via a 470kΩ pull-down resistor.
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RT9992
The output voltage can be set by the following equation :
VOUT_CH2 = (1+R3/R4) x VFB2
where VFB2 is 0.8V typically
CH3 : Synchronous Step-Down DC/DC Converter
CH3 is suitable for DRAM power in DSC system. The
converter operates in fixed frequency PWM mode and
CCM with integrated internal MOSFETs and compensation
network. The CH3 step-down converter can be operated
at 100% maximum duty cycle to extend battery operating
voltage range. When the input voltage is close to the output
voltage, the converter enters low dropout mode with low
output ripple.
on the initial VOUT6 voltage level. In addition, if CH4 softstart does not finish, CH6 can not be turned on.
Table 3. CH6 WLED Setting
CH6 Operating Mode
VOUT6
Current Source
0.7V
Step-Up
where VFB3 is 0.8V typically.
When CH6 works in current source mode, it sinks an
accurate LED current modulated by EN6 high duty such
that it is easily dimmed from 0mA to 30mA. If CH6 works
in asynchronous step-up mode, it integrates asynchronous
step-up mode with an internal MOSFET and internal
compensation, and requires an external schottky diode
to output a voltage up to 19V. The LED current is set via
an external resistor and controlled via the PWM duty on
the EN6 pin. Regardless of the mode, holding EN6 low
for more than 32.7ms will turn off CH6.
CH4 : Synchronous Step-Down DC/DC Converter
CH6 WLED Current Dimming Control
CH4 is suitable for processor core power in DSC system.
The converter operates in fixed frequency PWM mode
and CCM with integrated internal MOSFETs and
compensation network. The CH4 step-down converter can
be operated at 100% maximum duty cycle to extend
battery operating voltage range. When the input voltage
is close to the output voltage, the converter enters low
dropout mode with low output ripple.
If CH6 is in asynchronous step-up mode, the WLED current
is set by an external resistor. And the dimming is
controlled by the duty of pulse width modulated signal on
the EN6 pin.
The output voltage can be set by the following equation :
VOUT_CH3 = (1 + R5 / R6) x VFB3
The output voltage can be set by the following equation :
VOUT_CH4 = (1+R7/R8) x VFB4
Where VFB4 is 0.8V typically.
CH5 : Generic LDO
The RT9992 provides a generic LDO with high output voltage
accuracy. The LDO outputs either a fixed 2.5V voltage or
an adjustable voltage with external feedback network,
depending on the initial FB5 voltage. The CH5 adjustable
output voltage can be set by the following equation :
VOUT_CH5 = (1+R11/R12) x VFB5
Where VFB5 is 0.5V typically.
CH6: WLED Driver
CH6 is a WLED driver that can operate in either current
source mode or asynchronous step-up mode, depending
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The average current through WLED can be set by the
following equations :
ILED (mA) = [250mV/R(Ω)] x Duty (%) ......for step-up mode
Or ILED (mA) = 30mA x Duty (%)....... for current source
mode
R : Current sense resistor from FB6 to GND.
Duty : PWM dimming via the EN6 pin. Dimming frequency
range is from 1kHz to 100kHz but 2kHz to 20kHz should
be avoided to prevent audio noise distraction.
VDDM Power Path
To support bootstrap function, the RT9992 includes a
power selection circuit which selects between BAT and
PVDD6 for the higher voltage to be used as the internal
node, VDDI, that connects to the external decoupling
capacitor at the VDDM pin. VDDM is the main power for
the RT9992 control circuit. VDDI is the power input for the
RTC LDO. To bootstrap VDDM, PVDD6 must connect to
the output of the first enabled low voltage synchronous
step-up channel (CH1 or CH2). Furthermore, PVDD6 also
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RT9992
provides power to the N-MOSFET driver in CH6. The
RT9992 includes UVLO circuits to check VDDM and BAT
voltage status.
diode control to avoid the RTCPWR node from back
charging into the input node VDDI.
Power Good
RTC LDO
The RT9992 provides a 3.1V output LDO for real time clock.
The LDO features low quiescent current (5μA) and high
output voltage accuracy. The RTC LDO is always on, even
when the system is shut down. For better stability, it is
recommended to connect a 0.1μF capacitor to the
RTCPWR pin. The RTC LDO includes pass transistor body
The RT9992 provides a power good indicator to monitor
FB2, FB3, and FB4 voltage status. After CH2, CH3, and
CH4 are turned on, if any one of them becomes lower
than 0.66V (typically), PGOOD will be pulled low. If all are
higher than 0.7V (typically), PGOOD will be released and
pulled high after 10ms.
Power On/Off Sequence
SEQ = 0 : CH1 to 5 are independently enabled by EN1 to EN5
SEQ = 1 : CH2 to 5, or CH1 to 4 is enabled in preset on/off sequence. The order is chosen by EN3 and EN4
SEQ
EN2
EN3
EN4
EN5
EN1
Power On Sequence
0
indept
indept
indept
indept
indept
independent
1
EN2345
1
0
X
indept
CH2
CH3
CH4
CH5
1
EN2345
0
0
0
indept
CH2
CH5
CH3
CH4
1
EN1234
1
1
indept
x
CH1
CH3
CH4
CH2
1
EN1234
0
1
indept
x
CH1
CH4
CH3
CH2
X : don't care but suggested to be LOW (0).
Sequence 1: SEQ is high, EN3 is high, EN4 is low.
Sequence 2 : SEQ is high, EN3 is low, EN4 is low, EN5
is low.
EN2 will turn on/off CH2 to CH5 in preset sequence. CH1
will be turned on by EN1 independently.
EN2 will turn on/off CH2 to CH5 in preset sequence. CH1
will be turned on by EN1 independently.
CH2 to CH5 Power On Sequence is :
CH2 to CH5 Power On Sequence is :
When EN2 goes high, CH2 will be turned on . 7ms after
CH2 is turned on, CH3 will be turned on. 7ms after CH3 is
turned on, CH4 will be turned on. 7ms after CH4 is turned
on, CH5 will be turned on.
When EN2 goes high, CH2 will be turned on . 7ms after
CH2 is turned on, CH5 will be turned on. About 1ms after
Ch5 is turned on, CH3 will be turned on. 7ms after CH3 is
turned on, CH4 will be turned on.
CH2 to CH5 Power-Off Sequence is :
CH2 to CH5 Power-Off Sequence is :
When EN2 goes low, CH5 will be turned off and VOUT5
will be internally discharged. When VOUT5 discharging
finishes, CH4 will turn off and internally discharge output
via LX4 pin. When FB4 < 0.1V, CH3 will turn off and
internally discharge output via LX3 pin. Likewise when
FB3 < 0.1V, CH2 will turn off and discharge output via LX2
pin. After FB2 < 0.1V, CH2 to 5 shutdown sequence will
be completed.
When EN2 goes low, CH4 will turn off first and internally
discharge output via LX4 pin. When FB4 < 0.1V, CH3 will
turn off and internally discharge output via LX3 pin. Likewise,
when FB3 < 0.1V, CH5 will turn off and VOUT5 will be
internally discharged. When VOUT5 discharging finishes,
CH2 will turn off and discharge output via LX2 pin. After
FB2 < 0.1V, CH2 to 5 shut down sequence will be
completed.
Power On/Off Sequence Example for CH2 to CH5
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RT9992
Table 4. CH2 to CH5 Power On/Off Sequence
EN3 to EN5 Setting
EN3 = H, EN4 = L, EN5 = X
EN3 = L, EN4 = L, EN5 = L
EN3 to EN5 Setting
EN3 = H, EN4 = L, EN5 = X
Power On Sequence
CH2→CH3→CH4→CH5
CH2→CH5→CH3→CH4
Power Off Sequence
CH5→CH4→CH3→CH2
EN3 = L, EN4 = L, EN5 = L
CH4→CH3→CH5→CH2
Timing Diagram for CH2 to CH5
Power On Sequence : CH2 Step-Down 3.3VCH3 Step-Down 1.8V CH4 Step-Down 1.2VCH5 LDO 2.5V
Power Off Sequence : CH5 LDO 2.5VCH4 Step-Down 1.2V CH3 Step-Down 1.8V CH2 Step-Down 3.3V
SEL = H, SEQ = H, EN3 = H, EN4 = L
VDDM
User Define
EN2
3.5ms
CH2 VOUT 3.3V
Wait until
FB2 < 0.1V
3.5ms
7ms
Wait until FB3 < 0.1V
3.5ms
CH3 VOUT 1.8V
7ms
2.4ms
CH4 VOUT 1.2V
Wait until FB4 < 0.1V
7ms
Wait until FB5 < 0.1V
CH5 VOUT 2.5V
Power On Sequence : CH2 Step-Down 3.3VCH5 LDO 2.5VCH3 Step-Down 1.8V CH4 Step-Down 1.2V
Power Off Sequence : CH4 Step-Down 1.2V CH3 Step-Down 1.8VCH5 LDO 2.5V CH2 Step-Down 3.3V
SEL = H, SEQ = H, EN3 = L, EN4 = L, EN5 = L
VDDM
User Define
EN2
3.5ms
CH2 VOUT 3.3V
CH5 LDO 2.5V
Wait until
FB2 < 0.1V
2.4ms
7ms
Wait until FB5 < 0.1V
3.5ms
8ms
3.5ms
CH3 VOUT 1.8V
Wait until FB3 < 0.1V
7ms
CH4 VOUT 1.2V
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Wait until FB4 < 0.1V
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RT9992
Power on/off sequence for CH1 to CH4
Sequence 4 : SEQ is high, EN3 is low, EN4 is high.
Sequence 3 : SEQ is high, EN3 is high, EN4 is high.
EN2 will turn on/off CH1 to CH4 in preset sequence. CH5
will be turned on by EN5 independently.
EN2 will turn on/off CH1 to CH4 in preset sequence. CH5
will be turned on by EN5 independently.
CH1 to CH4 Power On Sequence is :
When EN2 goes high, CH1 will be turned on. 7ms after
CH1 is turned on, CH3 will be turned on. 7ms after CH3 is
turned on, CH4 will be turned on. 7ms after CH4 is turned
on, CH2 will be turned on.
CH1 to CH4 Power-Off Sequence is :
CH1 to CH4 Power On Sequence is :
When EN2 goes high, CH1 will be turned on first. 7ms
after CH1 is turned on, CH4 will be turned on. 7ms after
CH4 is turned on, CH3 will be turned on. 7ms after CH3 is
turned on, CH2 will be turned on.
CH1 to CH4 Power Off Sequence is :
When EN2 goes low, CH2 will turn off first and internally
discharge output. When FB2 < 0.1V, CH3 will turn off and
internally discharge output via LX3 pin. When FB3 < 0.1V,
CH4 will turn off and internally discharge output via LX4
pin. Likewise when FB4 < 0.1V, CH1 will turn off and
internally discharge output via LX1 pin. After FB1 < 0.1V,
Ch1 to 4 shutdown sequence is completed.
When EN2 goes low, CH2 will turn off first and internally
discharge output. When FB2 < 0.1V, CH4 will turn off and
also internally discharge output via LX4 pin. When FB4 <
0.1V, CH3 will turn off and internally discharge output via
LX3 pin. Likewise, when FB3 < 0.1V, CH1 will turn off and
discharge output via LX1 pin. After FB1 < 0.1V, CH1 to 4
shutdown sequence will be completed.
Table 5. CH1 to CH4 Power On/Off Sequence
Enable Setting
EN3 = H, EN4 = H, EN1 = X
EN3 = L, EN4 = H, EN5 = X
Enable Setting
EN3 = H, EN4 = H, EN5 = X
Power On Sequence
CH1→CH3→CH4→CH2
CH1→CH4→CH3→CH2
Power Off Sequence
CH2→CH4→CH3→CH1
EN3 = L, EN4 = H, EN5 = X
CH2→CH3→CH4→CH1
Timing Diagram for CH1 to CH4
Power On Sequence : CH1 Step-Up 5V CH3 Step-Down 1.8V CH4 Step-Down 1.2V CH2 Step-Up 3.3V
Power Off Sequence : CH2 Step-Up 3.3V CH4 Step-Down 1.2VCH3 Step-Down 1.8V CH1 Step-Up 5V
SEL = L, SEQ = H, EN3 = H, EN4 = H
VDDM
User Define
EN2
3.5ms
CH1 VOUT 5V
CH3 VOUT 1.8V
Wait until
FB1 < 0.1V
3.5ms
7ms
Wait until FB3 < 0.1V
3.5ms
7ms
3.5ms
CH4 VOUT 1.2V
Wait until FB4 < 0.1V
7ms
Wait until FB2 < 0.1V
CH2 VOUT 3.3V
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9992-05 July 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
21
RT9992
Power On Sequence : CH1 Step-Up 5V CH4 Step-Down 1.2V CH3 Step-Down 1.8V CH2 Step-Up 3.3V
Power Off Sequence : CH2 Step-Up 3.3VCH3 Step-Down 1.8VCH4 Step-Down 1.2V CH1 Step-Up 5V
SEL = L, SEQ = H, EN3 = L, EN4 = H
VDDM
User Define
EN2
3.5ms
CH1 VOUT 5V
CH4 VOUT 1.2V
Wait until
FB1 < 0.1V
3.5ms
7ms
Wait until FB4 < 0.1V
3.5ms
7ms
Wait until FB3 < 0.1V
3.5ms
CH3 VOUT 1.8V
7ms
Wait until FB2 < 0.1V
CH2 VOUT 3.3V
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
PD(MAX) = (TJ(MAX) − TA) / θJA
where TJ(MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJA is the junction to ambient
thermal resistance.
For recommended operating condition specifications of
the RT9992, the maximum junction temperature is 125°C
and TA is the ambient temperature. The junction to ambient
thermal resistance, θJA, is layout dependent. For WQFN32L 4x4 packages, the thermal resistance, θJA, is 27.8°C/
W on a standard JEDEC 51-7 four-layer thermal test board.
The maximum power dissipation at TA = 25°C can be
calculated by the following formula :
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. For the RT9992 package, the derating
curve in Figure 1 allows the designer to see the effect of
rising ambient temperature on the maximum power
dissipation.
3.80
Maximum Power Dissipation (W)1
Thermal Considerations
Four Layer PCB
3.04
2.28
1.52
0.76
0.00
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 1. Derating Curve for the RT9992 Package
PD(MAX) = (125°C − 25°C ) / (27.8°C/W) = 3.59W for
WQFN-32L 4x4 package
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is a registered trademark of Richtek Technology Corporation.
DS9992-05 July 2019
RT9992
Layout Considerations
Place the feedback components as close as possible
to the FB pin and keep these components away from
the noisy devices.
For the best performance of the RT9992, the following
PCB layout guidelines must be strictly followed.
Place the input and output capacitors as close as
possible to the input and output pins respectively for
good filtering.
Connect the GND and Exposed Pad to a strong ground
plane for maximum thermal dissipation and noise
protection.
Keep the main power traces as wide and short as
possible.
The switching node area connected to LX and inductor
should be minimized for lower EMI.
Directly connect the output capacitors to the feedback
network of each channel to avoid bouncing caused by
parasitic resistance and inductance from the PCB trace.
LX should be connected to Inductor by wide and short
trace, keep sensitive compontents away from this trace
VOUT_CH1
GND
C1
GND
C5 VBAT
R13
VBAT
GND
C3
C2
D3
C15
VOUT_CH5
EN1
LX1
PVDD1
BAT
RTCPWR
PVDD6
VDDM
FB6
C4
R1
R12
R2
C18
C17
C16
GND
Input/Output capacitors must
be placed as close as possible
to the Input/Output pins.
C7
D1
C19
32 31 30 29 28 27 26 25
FB1
PGOOD
FB5
VOUT5
PVDD5
EN5
SEQ
LX2
L2
1
24
2
23
3
22
4
21
GND
5
6
20
19
33
7
18
8
17
VOUT6
LX6
EN6
PVDD3
LX3
EN3
FB3
FB4
9 10 11 12 13 14 15 16
PVDD2
VIN2
EN2
FB2
SEL
PVDD4
LX4
EN4
R11
D2
L1
VBAT
GND
L4
VBAT
L7
C8
L3
GND
C14
5V/3.3V
VOUT_CH3
R5
C10
C9
GND
R6
C12
R7
R8
C6
VOUT_CH2
C20
R3
VOUT_CH4 C13
C11
GND
R4
VBAT
Connect the Exposed Pad to a
ground plane.
Place the feedback components as close as possible
to the FB pin and keep away from noisy devices.
Figure 2. PCB Layout Guide
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DS9992-05 July 2019
is a registered trademark of Richtek Technology Corporation.
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23
RT9992
Table 6. Protection Action
Protection Type
VDDM
BAT
CH1 :
Boost
CH2 :
Boost
CH2 : Buck
CH3 : Buck
CH4 : Buck
CH5
CH6 Asyn
Boost
Thermal
Threshold(typical) Refer
to Electrical spec
Protection
Methods
UVLO
VDDM < 2.1V
No delay
Disable all channels
OVP
VDDM > 6.15V
100ms
IC shutdown
UVLO
VBAT < 1.3V
No delay
Disable all channels
Current Limit
N-MOSFET current > 3A
100ms
IC shutdown
PVDD1 UVP
VFB1 < 0.4V, or
VPVDD1 < VBAT0.8V or
VPVDD1 < 1.3V
100ms
IC shutdown
PVDD1 OVP
VPVDD1 > 6.15V
No delay
IC shutdown
Current Limit
100ms
IC shutdown
100ms
IC shutdown
PVDD2 OVP
N-MOSFET current > 2.1A
VFB2 < 0.4V, or
VPVDD2 < VIN2 0.8V or
VPVDD2 < 1.3V
VPVDD2 > 6.15V
No delay
IC shutdown
OCP
P-MOSFET current > 1.5A
100ms
IC shutdown
UVP
VFB2 < 0.4V
100ms
IC shutdown
OCP
P-MOSFET current > 1.5A
100ms
IC shutdown
UVP
VFB3 < 0.4V
100ms
IC shutdown
OCP
P-MOSFET current > 2A
100ms
IC shutdown
UVP
VFB4 < 0.4V
100ms
IC shutdown
Current Limit
UVP
P-MOSFET current > 0.38A
VFB5 < 0.3V
100ms
100ms
IC shutdown
IC shutdown
Current Limit
N-MOSFET current > 0.8A
Reset each cycle
OVP
Thermal
shutdown
VOUT6 > 19.5V
No delay
Temperature > 160C
No delay
PVDD2 UVP
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Delay Time
Shut down CH6 only
All channels stop
switching
is a registered trademark of Richtek Technology Corporation.
DS9992-05 July 2019
RT9992
Outline Dimension
1
1
2
2
DETAIL A
Pin #1 ID and Tie Bar Mark Options
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
0.700
0.800
0.028
0.031
A1
0.000
0.050
0.000
0.002
A3
0.175
0.250
0.007
0.010
b
0.150
0.250
0.006
0.010
D
3.900
4.100
0.154
0.161
D2
2.650
2.750
0.104
0.108
E
3.900
4.100
0.154
0.161
E2
2.650
2.750
0.104
0.108
e
L
0.400
0.300
0.016
0.400
0.012
0.016
W-Type 32L QFN 4x4 Package
Richtek Technology Corporation
14F, No. 8, Tai Yuen 1st Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot
assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be
accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
DS9992-05 July 2019
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