Richtek RT9912AGQW Schematic [ru]
RT9912A
Multi-Channel Power Management IC for Portable Device
General Description
The RT9912A is a multi-channel power management IC
providing power conversion and system power ma nagement functions for one or two alkaline battery powered
portable handheld device.
The RT9912A integrates one high efficiency synchronous
buck regulator, one high efficiency boost regulator, one
linear regulator and one adjustable voltage detector for
reset function.
Ordering Information
RT9912A
Package Type
QW : WQFN-24L 4x4 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
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.
Marking Information
For marking information, contact our sales re presentative
directly or through a Richtek distributor located in your
area.
Features
zz
300mA Sync. Step Down Converter for V
z
zz
zz
z 300mA Sync. Step Up Converter for IO and Memory
zz
zz
z High Efficiency Up to 92%
zz
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z Low Dropout Linear Regulator
zz
zz
z Adjustable Voltage Detector for Reset Function
zz
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z Current Limit Protection
zz
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z Thermal Shutdown Protection
zz
zz
z Low Operation Current Consumption
zz
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z Small 24-Lead WQFN Package
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z RoHS Compliant and Halogen Free
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CORE
Applications
z DSC
z Portable Multimedia Player
z GPS
Pin Configurations
(TOP VIEW)
GND
CT
18
FB4
17
VDD4
16
RESET
15
ENBUK
14
25
11
VDD3
13
FB3
VDD1
FB1
ENSW
PSW
NC
ENBST
VOUT1
24 2223
1
2
3
4
5
6
7
LX1
VBAT
21 20 19
GND
8 9 10 12
LX2
FB2
PGND2
PVDD2 PGND1
VDD2
VOUT3
WQFN-24L 4x4
DS9912A-01 April 2011 www.richtek.com
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RT9912A
Typical Application Circuit
V
BAT
VDD3
VDD3V3_IO
C1
1uF
22
14
C3
1uF
17
C2
V
C4
1nF
OUT2
1uF
R4
120k
18
20
16
15
R3
1M
19, Exposed Pad (25)
1
3
6
VDD1
VBAT
VDD3
VDD4
FB4
CT
GND
RESET
ENSW
ENBUK
ENBST
RT9912A
VOUT1
LX1
FB1
PSW
VOUT3
FB3
PGND1
PGND2
PVDD2
VDD2
LX2
FB2
24
23
2
4
12
13
21
8
10
11
9
7
L1
D1
L2 4.7uH
4.7uH
10uF
R5
590k
R6
390k
R7
1.6M
R8
330k
C5
120k
C8
1nF
C12
1uF
C10
100pF
R1
1.2M
R2
C6
2.2pF
C9
4.7uF
C11
10uF
C13
22nF
V
OUT3
3V
VDD2
V
OUT2
1.8V
C7
22uF
Q1
C16
22uF
V
OUT1
3.3V
VDD3V3_IO
Power ON Sequence : V
VDD3V3_IO
→
VDD3V3_IO V
OUT2
ENBUK
ENBST
V
OUT2
PSW
V
OUT3
→
OUT3
DS9912A-01 April 2011www.richtek.com
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Function Block Diagram
RT9912A
VDD1
VBAT
FB1
ENBST
ENSW
ENBUK
FB2
VDD2
VDD3
VDD1
CH1
Syn-Boost
PFM
CH1
Power
Ready
VDD3
PVDD1
PGND1
PVDD1
PGND1
CH2
Syn-Buck
PFM
CH3
LDO
Regulator
ENLDO
LDOOK
FB3
PVDD2
PGND2
PVDD2
PGND2
VOUT1
LX1
PGND1
PSW
PVDD2
LX2
PGND2
VOUT3
FB3
GND
VDD4
FB4
VDD4
CH4
Reset
Reset
Signal
Delay
RESET
CT
Thermal Protection
DS9912A-01 April 2011 www.richtek.com
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RT9912A
Functional Pin Description
Pin No. Pin Na me Pi n Fun cti o n
1 VDD1 CH1 Power Input Pin.
2 FB1 CH1 Feedback Input Pin.
3 ENSW Load Disconnect Enable Pin.
4 PSW Load Disconnect P-MOSFET Gate Drive Pin.
5 NC No Internal Connection. This pin must be floating.
6 ENBST Boost Enable Pin.
7 FB2 CH2 Feedback Input.
8 PGND2 Power Ground for CH2.
9 LX2 CH2 Switch Node.
10 PVDD2 CH2 Power Input Pin.
11 VDD2 CH2 Power Input Pin for Analog.
12 VOUT3 CH3 Output Voltage.
13 FB3 CH3 Feedback Input.
14 VDD3 CH3 Power Input Pin.
15 ENBUK BUCK Enable Pin.
16 RESET Reset Pulse Output, N egative Pulse.
17 VDD4 CH4 Power Input Pin.
18 FB4 CH4 Feedback Input.
19,
Exposed Pad (25)
20 CT
21 PGND1 Power Ground for CH1.
22 VBAT
23 LX1 CH1 Switch Node.
24 VOUT1 CH1 Output Voltage.
GND
Analog Ground. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
External Delay Adjust Pin.
Battery Power Input Pin.
DS9912A-01 April 2011www.richtek.com
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Absolute Maximum Ratings (Note 1)
T
RT9912A
z Supply Voltage, V
z LX1 and LX2 Pin Switch V oltage ---------------------------------------------------------------------------------------- −0.3V to 6.5V
z Other I/O Pin Voltage------------------------------------------------------------------------------------------------------ −0.3V to 6.5V
z Power Dissipation, P
, V
DD1
DD2
@ TA = 25°C
D
, V
DD3
, V
DD4
, PV
-------------------------------------------------------------------- −0.3V to 6.5V
DD2
WQFN-24L 4x4 ------------------------------------------------------------------------------------------------------------- 1.852W
z Package Thermal Resistance (Note 2)
WQF N-24L 4x4, θJA-------------------------------------------------------------------------------------------------------- 54°C/W
WQFN-24L 4x4, θJC------------------------------------------------------------------------------------------------------- 7°C/W
z Junction T emperature------------------------------------------------------------------------------------------------------ 150°C
z Lead T e mperature (Soldering, 10 sec.)-------------------------------------------------------------------------------- 260 °C
z Storage T emperature Range --------------------------------------------------------------------------------------------- −65°C to 150°C
z ESD Susceptibility (Note 3)
HBM (Human Body Mode) ----------------------------------------------------------------------------------------------- 2kV
MM (Ma chine Mode)------------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions (Note 4)
z Supply Input Voltage, V
z Junction T emperature Range---------------------------------------------------------------------------------------------
z Ambient T emperature Range---------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------- 1.7V to 5V
BAT
−40°C to 125°C
−40°C to 85°C
Electrical Characteristics
(V
= V
= V
DD1
DD2
DD3
= V
Parameter Symbol Test Condition Min Typ Max Units
Supply Voltage
Minimum Operating Input Voltage RL = 3kΩ -- -- 1.7 V
Minimum Startup Voltage (Boost) V
VDD1 Operating Voltage V
VDD2 Operating Voltage V
VDD3 Operating Voltage V
VDD4 Operating Voltage V
VDD1 Over Voltage Protection 5.1 6 6.5 V
Supply Current
Shutdown Supply Current I
Boost Supply Current I
Buck Supply Current I
DD4
= 3.3V, T
= 25°C, unless otherwise specified)
A
RL = 3kΩ -- 0.8 1.1 V
S
1.7 -- 5 V
DD1
VDD2, PVDD2 Pin Voltage 1.7 -- 5 V
DD2
2.5 -- 5 V
DD3
1.5 -- 5 V
DD4
OFF
VDD1
V
V
V
V
V
V
ENBST
= 0V = V
DD4
= 3.3V, V
DD1
ENBST
OUT1
= V
DD2
= V
ENSW
= V
ENSW
= 3.3V
DD3
DD3
FB1
= V
= 0V
= 0.9V
= 3.3V
= 0V
DD4
-- -- 10 uA
-- 45 70 uA
(no switching)
V
VDD2
= 3.3V, V
DD2
ENBST
= V
DD1
= V
DD3
V
V
FB2
ENSW
= V
= 0.9V
= 0V
= 0V
DD4
-- 85 140 uA
(no switching)
To be continued
DS9912A-01 April 2011 www.richtek.com
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