RT9971 - Richtek

RT9971
7 CH Power Management IC
General Description
Features
The RT9971 is a complete power supply solution for digital
still cameras and other hand held devices. The RT9971 is
a multi-channel power management IC including two stepup DC/DC converters, two step-down DC/DC converters,
one selectable step-up/step-down DC/DC converter, one
inverting DC/DC converter and one WLED driver.
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The RT9971 is designed to fulfill the applications for DSC
just as follows :
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CH1 is a synchronous step-up output for motor or DSC
system I/O power
CH2 is a selectable synchronous step-up/step-down
output for motor or DSC system I/O power
CH3 and CH4 are synchronous step-down outputs for DSP
core and memory power supply
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CH5 is a high voltage step-up output for CCD bias power
supply
CH6 is an inverting output for negative CCD bias power
supply
One Synchronous Step-Up or Step-Down
Selectable Convertor
Support 2AA or Li-ion Battery Applications
Preset On/Off Sequence
5 CHs with Internal Compensation
All Power Switches Integrated
Up to 95% Efficiency
100% (max) Duty Cycle for Step-Down Converter
Adjustable Output Voltage
LED PWM Dimming Control
LED Open Protection
Transformerless Inverting Converter for CCD
Fixed 1MHz Switching Frequency at CH1 to CH7
RTC_LDO/SW1 Selectable by CN Pin
40-Lead WQFN Package
RoHS Compliant and Halogen Free
Applications
Digital Still Camera
PDA
Portable Device
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CH7 is a high voltage step-up output for driving WLED
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For the CH2, the step-up or step-down converter, operation
mode can be selected by the SEL pin. Among all CHs,
there are 5 CHs with the built-in internal compensation.
The RT9971 also provides a transformerless inverting
Ordering Information
RT9971
Package Type
QW : WQFN-40L 5x5 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
converter for supplying the CCD power. For the
synchronous step-up and step down converters, the
efficiency can be up to 95%. The IC provides load
disconnection for CH 1 and CH 5. The IC has selectable
RTC_LDO/SW1 that can be determined by the CN pin.
The RT9971 is able to support Li-ion and 2AA battery
applications. The RT9971 provides WLED open protection,
current limit, thermal shutdown protection, over voltage
and under voltage protection to achieve complete
protection. The RT9971 is available in WQFN-40L 5x5
package.
DS9971-01 April 2011
Note :
Richtek products are :
}
RoHS compliant and compatible with the current require-
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Suitable for use in SnPb or Pb-free soldering processes.
ments of IPC/JEDEC J-STD-020.
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1
RT9971
Pin Configurations
EN134
LX2
LX1
EN2
COMP1
FB1
OK
VOUT1
FB2
COMP2
(TOP VIEW)
40 39 38 37 36 35 34 33 32 31
PVDD1
LX6
PVDD6
CP
CN
PNEG
FB6
1
30
2
29
3
28
4
27
5
6
26
GND
25
7
FB4 8
EN6 9
LX4 10
24
41
23
22
21
PVDD2
VDDM
CFB7
GND
LX7
LX5
VOUT7
FB3
EN7
LX3
PVDD4
EN5
SW5O
SW5I
FB5
VREF
SEL
RTC_R
RTC_PWR
PVDD3
11 12 13 14 15 16 17 18 19 20
WQFN-40L 5x5
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2
DS9971-01 April 2011
RT9971
Typical Application Circuit
For 2AA
3V3
L1
2.2µH
VBAT
VOUT_SW1
3.3V
C1
10µF
R19
50k
1
C27
10µF x 2
37
C2
4.7pF
R1
470k
R2
150k
C3
R3
560pF 39k
C4
10µF
VOUT_CH2
5V
3V3
L3
4.7µH
VOUT_CH3
2.5V
C9
10µF
R7
768k
34 FB2
33 COMP2
20 PVDD3
C10
22pF
C25
1µF
R11
1000k
R12
90.9k
VBAT
L6
10µH
VOUT_CH6
-7V
D4
C18
10µF/16V x 2
C17
1nF
FB6 7
R14
11.3k
VREF 16
C19
0.1µF
L7
10µH
VBAT
C26
1µF
LX7
23 FB3
C16
10µF/25V
15V
C15
1nF
21 LX3
R8
360k
26
WLED
D5
D1
VOUT7 24
C20
1µF/16V
D2
CFB7 28
3V3
VOUT_CH4
1.8V
C11
10uF
C12
10µF
VOUT_CH5
15V
R13
63.4k
C7
R6
560pF 39k
R5
88.7k
C8
10uF
LX6 2
PVDD2
C6
4.7pF
R4
470k
FB5 15
PVDD6 3
31 LX2
30
C14
10µF/25V
SW5O 13
SW5I 14
RT9971
38 COMP1
L2 2.2µH
VBAT
D3
FB1
36 OK
35 VOUT1
C5
10µFx2
LX5 25
PVDD1
C24
1µF
L5
10µH
29
VDDM
C22
10µF
VOUT_CH1
3V3
Q1
40 LX1
VBAT
C23
1µF
L4
4.7µH
11 PVDD4
RTC_R
C13
33pF
R9
470k
RTC_PWR
8
39
32
12
9
R10
374k
ON
OFF
FB4
EN2
EN134
EN5
EN6
17 SEL
22 EN7
VBAT
18
10 LX4
CP
19
R15
10
R16
10k
RTC 3.25V
4
CN 5
PNEG 6
GND
RTC Reset
C28
0.1µF
C29
1µF
27, Exposed Pad (41)
Note :
(1) SEL = High, CH2 is Step -Up, CN Connect to CAP
(2) VBAT = 1.8V to 3.2V
Timing Diagram
Power On Sequence : CH1 Step -Up 3.3V→ CH3 Step -Down 2.5V→ CH4 Step -Down 1.8V→ (CH2 Step -Up 5V and
SW1 3.3V)
Power Off Sequence : (CH2 Step -Up 5V and SW1 3.3V) → CH4 Step -Down 1.8V→ CH3 Step -Down 2.5V→ CH1
Step -Up 3.3V
VDDM
EN2, EN134
VOUT_CH1 3.3V
VOUT_CH3 2.5V
VOUT_CH4 1.8V
VOUT_SW1 3.3V
VOUT_CH2 5V
DS9971-01 April 2011
User define
3.5ms
3.5ms
3.5ms
3.5ms
3.5ms
IC shutdown
Wait until FB3 < 0.1V
Wait until FB4 < 0.1V
Wait until VOUT1 < 0.4V
Depends on loading
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3
RT9971
For Li-ion
VBAT C23
1µF
L1
2.2µH
VBAT
40 LX1
LX5 25
1 PVDD1
C1
10µF x 2
R1
470k
37
R2
88.7k
R3
39k
RTC 3.25V
36 OK
35 VOUT1
C21
0.22F
VBAT
or 5V
30
VOUT_CH2
3.3V
C4
10µF
C5
10µF
L2
4.7µH
VBAT
33 COMP2
20 PVDD3
L3
4.7µH
VOUT_CH3
2.5V
C9
10µF
34 FB2
C7
R6
2200pF 15k
R5
150k
C8
10µF
PVDD2
23 FB3
R12
90.9k
VBAT
L6
10µH
D4
R13
63.4k
FB6 7
R14
11.3k
VREF 16
C17
1nF
VOUT_CH6
-7V
C18
10µF/16V x 2
C19
0.1µF
L7
10µH
VBAT
C26
1µF
26
WLED
D5
D1
VOUT7 24
D2
C20
1µF/16V
CFB7 28
11
VBAT
L4
4.7µH
PVDD4
10 LX4
C13
33pF
R9
470k
R10
374k
C25
1µF
VOUT_CH5
15V
R11
1000k
LX6 2
LX7
R8
360k
VOUT_CH4
1.8V
C11
10µF
C12
10µF
PVDD6 3
21 LX3
C10
22pF
R7
768k
RT9971
C16
10uF/25V
15V
C15
1nF
FB5 15
31 LX2
C6
10pF
R4
470k
C14
10µF/25V
FB1
38 COMP1
VBAT
D3
SW5O 13
SW5I 14
C2
4.7pF
C3
560pF
C24
1µF
L5
10µH
29
VDDM
C22
10µF
VOUT_CH1
5V
VBAT
ON
8
39
32
12
9
17
22
OFF
RTC_R
RTC_PWR 19
CP
FB4
EN2
EN134
EN5
EN6
SEL
EN7
18
CN
PNEG
GND
RTC Reset
R15
10
R16
10k
RTC 3.25V
4
5
R18
10k
VBAT
6
27, Exposed Pad (41)
Note :
(1) SEL = Low, CH2 is Step -Down, CN Pull High
(2) VBAT = 2.7V to 4.2V
Timing Diagram
Power On Sequence : CH1 Step -Up 5V→CH3 Step -Down 2.5V→ CH4 Step -Down 1.8V→ CH2 Step -Down 3.3V
Power Off Sequence : CH2 Step -Down 3.3V→ CH4 Step -Down 1.8V→CH3 Step -Down 2.5V→CH1 Step -Up 5V
VDDM
EN2, EN134
V OUT_CH1 5V
V OUT_CH3 2.5V
V OUT_CH4 1.8V
V OUT_CH2 3.3V
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4
User define
3.5ms
3.5ms
3.5ms
3.5ms
IC shutdown
Wait until FB3 < 0.1V
Wait until FB4 < 0.1V
Wait until FB2 < 0.1V
DS9971-01 April 2011
RT9971
Table 1. Recommended Components for the Typical Application Circuit
Channel
CH3
Formula
VOUT_CH3 = (1+R7/R8) x 0.8
VOUT_CH3 (V)
2.5
1.8
1.5
1.3
1.2
1
L3 (µH)
4.7
4.7
4.7
4.7
4.7
4.7
R7 (kΩ)
768
470
330
237
187
23.2
R8 (kΩ)
360
374
374
374
374
93.1
C10 (pF)
22
33
47
68
82
47
C9 (µF)
10
10
10
10
10
10
Channel
CH4
Application
VOUT_CH4 = (1+R9/R10) x 0.8
V OUT_CH4 (V)
2.5
1.8
1.5
1.3
1.2
1
L4 (µH)
4.7
4.7
4.7
4.7
4.7
4.7
R9 (kΩ)
768
470
330
237
187
23.2
R10 (kΩ)
360
374
374
374
374
93.1
C13 (pF)
22
33
47
68
82
47
C12 (µF)
10
10
10
10
10
10
Channel
CH5
Formula
VOUT_CH5 = (1+R11/R12) x 1.25
VOUT_CH5 (V)
12
13
14
15
15.5
16
L5 (µH)
10
10
10
10
10
10
R11 (kΩ)
820
820
953
1000
820
886
R12 (kΩ)
95.3
86.6
93.1
90.9
71.5
75
C15 (pF)
1000
1000
1000
1000
1000
1000
C16 (µF)
10/16V
10/16V
10/25V
10/25V
10/25V
10/25V
Channel
Formula
CH6
V OUT_CH6 = (R13/R14) x (-1.25)
* R13+R14 <90k
VOUT_CH6 (V)
-6
-6.3
-7
-7.5
-8
L6 (µH)
10
10
10
10
10
R13 (kΩ)
57.6
69.8
63.4
68
68
R14 (kΩ)
12
13.7
11.3
11.3
10.5
C17 (pF)
1000
1000
1000
1000
1000
C18 (µF)
10 x 2pcs.
10 x 2pcs.
10 x 2pcs.
10 x 2pcs.
10 x 2pcs.
DS9971-01 April 2011
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5
RT9971
Functional Pin Description
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27,
41 (Exposed Pad)
28
29
Pin Name
PVDD1
LX6
PVDD6
CP
CN
PNEG
FB6
FB4
EN6
LX4
PVDD4
EN5
SW5O
SW5I
FB5
VREF
SEL
RTC_R
RTC_PWR
PVDD3
LX3
EN7
FB3
VOUT7
LX5
LX7
GND
CFB7
VDDM
30
PVDD2
31
32
33
34
LX2
EN134
COMP2
FB2
35
VOUT1
36
OK
37
38
39
40
FB1
COMP1
EN2
LX1
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6
Pin Function
Power Output of CH1.
Switch Node of CH6. High impedance in shutdown mode.
Power Input of CH6.
Charge Pump External Driver.
Charge Pump External Driver.
Negative Output of Charge Pump.
Feedback Input of CH6. High impedance in shutdown mode.
Feedback Input of CH4. High impedance in shutdown mode.
Enable Control Input of CH6.
Switch Node of CH4. High impedance in shutdown mode.
Power Input of CH4.
Enable Control Input of CH5.
Output of CH5 Load Disconnect.
Input of CH5 Load Disconnect.
Feedback Input of CH5. High impedance in shutdown mode.
1.25V Reference Output.
Li-ion or 2AA Select. Logic state can not be changed during operation.
RTC_Reset Output.
Power Input of RTC_Reset.
Power Input of CH3.
Switch Node of CH3. High impedance in shutdown mode.
Enable Control Input of CH7.
Feedback Input of CH3. High impedance in shutdown mode.
Sense Input for CH7 Output Voltage.
Switch Node of CH5. High impedance in shutdown mode.
Switch Node of CH7. High impedance in shutdown mode.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum thermal dissipation.
Feedback Input of CH7.
IC Analog Power Input.
Power Input of CH2 step-down converter, or power output of CH2 step-up
converter.
Switch Node of CH2. High impedance in shutdown mode.
Enable Control Input of CH1, CH3 and CH4.
Compensation of CH2. Pull to GND in shutdown mode.
Feedback input of CH2. High impedance in shutdown mode.
CN is set to low or floating : Sense Pin for CH1 Output Voltage. High impedance
in shutdown. CN is set to High: Output pin of RTC_LDO.
CN is set to low or floating : External Switch Control. High impedance in
shutdown. CN is set to High : Power input pin of RTC_LDO.
Feedback Input of CH1. High impedance in shutdown mode.
Compensation of CH1. Pull to GND in shutdown mode.
Enable Control Input of CH2.
Switch Node of CH1. High impedance in shutdown mode.
DS9971-01 April 2011
RT9971
Function Block Diagram
VDDM
LX5
PVDD1
CH5
C-Mode
Step-Up
PWM
CH1
C-Mode
Step-Up
LX1
+
FB5
1.25V
REF
SW5
SW5I
SW5O
0.8V
REF
PVDD6
CH6
C-Mode
Inverting
PVDD2
CH2
C-Mode
Step-Up or
Step-Down
LX6
FB6
+
-
LX7
COMP2
FB2
0.8V
REF
PVDD3
+
VDDM
0.25V
REF
Enable
Mode
Sequence
1.25V
REF
CH3
C-Mode
Step-Down
EN2
EN134
EN5
EN6
SEL
LX3
+
FB3
0.8V
REF
CP
CN
PNEG
OK
VOUT1
LX2
+
CH7
C-Mode
Step-Up
PWM
VOUT7
EN7
CFB7
VREF
COMP1
FB1
+
Negative
Charge
Pump
SW1
PVDD4
CH4
C-Mode
Step-Down
RTC
LDO
LX4
+
RTC_PWR
RTC_R
RTC
Reset
FB4
0.8V
REF
GND
Timing Diagram
CH5 and CH6 Timing Diagram
EN5
10ms
SW5I
Depends on loading
SW5O
(to CCD +)
Depends on loading
EN6
V OUT_CH6
(to CCD -)
DS9971-01 April 2011
10ms
Depends on loading
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7
RT9971
Absolute Maximum Ratings
(Note 1)
Supply Voltage, VDDM ------------------------------------------------------------------------------ −0.3V to 7V
Power Switch :
LX1, LX2, LX3, LX4 ---------------------------------------------------------------------------------- −0.3V to 6.5V
LX5, LX7, SW5I, SW5O, VOUT7 ---------------------------------------------------------------- −0.3V to 21V
LX6 ----------------------------------------------------------------------------------------------------- (PVDD6 − 14V) to (PVDD6 + 0.3V)
l The Other Pins -------------------------------------------------------------------------------------- −0.3V to 6.5V
l Power Dissipation, PD @ TA = 25°C
WQFN 40L 5x5 -------------------------------------------------------------------------------------- 2.778W
l Package Thermal Resistance (Note 2)
WQFN 40L 5x5, θJA --------------------------------------------------------------------------------- 36°C/W
WQFN 40L 5x5, θJC -------------------------------------------------------------------------------- 7°C/W
l Junction Temperature ------------------------------------------------------------------------------ 150°C
l Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------- 260°C
l Storage Temperature Range ---------------------------------------------------------------------- −65°C to 150°C
l ESD Susceptibility (Note 3)
HBM (Human Body Mode) ------------------------------------------------------------------------ 2kV
MM (Machine Mode) ------------------------------------------------------------------------------- 200V
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Recommended Operating Conditions
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(Note 4)
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
Supply Voltage
VDDM Operating Voltage
VDDM Startup Voltage
VDDM Over Voltage Protection
Supply Current
Shutdown Supply Current into VDDM
CH1 (Syn-Step-Up) : Supply Current
into VDDM
CH2 (Syn-Step-Up or Syn-Step-Down)
: Supply Current into VDDM
CH3 (Syn-Step-Down) :
Supply Current into VDDM
CH4 (Syn-Step-Down) :
Supply Current into VDDM
CH5 (Asyn-Step-Up) :
Supply Current into VDDM
CH6 (Inverting) + Charge pump :
Supply Current into VDDM
CH7 (WLED):
Supply Current into VDDM
Symbol
Test Condition
VDDM
VST
Min
Typ
Max
Unit
2.7
1.5
6
--6.25
5.5
-6.5
V
V
V
IOFF
All EN = 0, CN = 3.3V
--
5
10
µA
IQ1
Non Switching, EN134 = 3.3V
--
--
800
µA
IQ2
Non Switching, EN2 = 3.3V
--
--
800
µA
IQ3
Non Switching, EN134 = 3.3V
--
--
800
µA
IQ4
Non Switching, EN134 = 3.3V
--
--
800
µA
IQ5
Non Switching, EN5 = 3.3V
--
--
800
µA
IQ6
Non Switching, EN6 = 3.3V
PVDD6 = 3.3V
--
--
800
µA
IQ7
Non Switching, EN7 = 3.3V
--
--
800
µA
To be continued
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8
DS9971-01 April 2011
RT9971
Parameter
Oscillator
CH1,2,3,4, 5, 6, 7 Operating Frequency
Symbol
Test Condition
fOSC
Min
Typ
Max
Unit
900
1000
1100
kHz
CH1 Maximum Duty Cycle (Step-Up)
VFB1 = 0.7V
80
83
86
%
CH2 Maximum Duty Cycle (Step-Up)
CH2 Maximum Duty Cycle (Step-Down)
VFB2 = 0.7V
VFB2 = 0.7V
80
--
83
--
86
100
%
%
CH3 Maximum Duty Cycle (Step-Down)
VFB3 = 0.7V
--
--
100
%
CH4 Maximum Duty Cycle (Step-Down)
VFB4 = 0.7V
--
--
100
%
CH5 Maximum Duty Cycle (Step-Up)
VFB5 = 1.15V
91
94
97
%
CH6 Maximum Duty Cycle (Inverting)
VFB6 = 0.1V
91
94
97
%
CH7 Maximum Duty Cycle (WLED)
Feedback Regulation Voltage
Feedback Regulation Voltage @ FB1,
FB2, FB3, FB4
VFB7 = 0.15V
91
94
97
%
0.788
0.8
0.812
V
1.237
1.25
1.263
V
-15
0
15
mV
OK = 1V
0.237
50
0.25
--
0.263
--
V
µA
0µA < IREF < 200µA
1.237
--
1.25
--
1.263
10
V
mV
3.4
0.1
4.1
3.6
0.3
4.5
3.8
0.5
4.9
V
V
V
------
150
150
3
150
150
------
--------
1.5
3
200
200
1.5
200
200
--------
--
1.5
--
A
Feedback Regulation Voltage @ FB5
Feedback Regulation Voltage @ FB6
(Inverting)
Feedback Regulation Voltage @ CFB7
OK Sink Current
Reference
VREF Output Voltage
VREF Load Regulation
Negative Charge Pump
PVDD6 Low Threshold to Start Pump
PVDD6 Hysteresis Gap to Stop Pump
(PVDD6 − PNEG) Clamped Voltage
Power Switch
CH1 On Resistance of MOSFET
VREF
PVDD6 = 3.3V
RDS(ON)
P-MOSFET, PVDD1 = 3.3V
N-MOSFET, PVDD1 = 3.3V
CH1 Current Limitation (Step-Up)
CH2 On Resistance of MOSFET
RDS(ON)
P-MOSFET, PVDD2 = 3.3V
N-MOSFET, PVDD2 = 3.3V
CH2 Current Limitation (Step-Down)
CH2 Current Limitation (Step-Up)
CH3 On Resistance of MOSFET
R DS(ON)
P-MOSFET, PVDD3 = 3.3V
N-MOSFET, PVDD3 = 3.3V
CH3 Current Limitation (Step-Down)
CH4 On Resistance of MOSFET
R DS(ON)
P-MOSFET, PVDD4 = 3.3V
N-MOSFET, PVDD4 = 3.3V
CH4 Current Limitation (Step-Down)
mΩ
A
mΩ
A
A
mΩ
A
mΩ
CH5 Load Disconnect MOSFET
P-MOSFET, SW5I = 3.3V
--
0.5
--
Ω
CH5 On Resistance of MOSFET
N-MOSFET
--
0.5
--
Ω
CH5 Current Limitation
N-MOSFET
--
1.2
--
A
To be continued
DS9971-01 April 2011
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9
RT9971
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
CH6 On Resistance of MOSFET
P-MOSFET, PVDD6 = 3.3V
--
0.5
--
Ω
CH6 Current Limitation
P-MOSFET
--
1.5
--
A
CH7 On Resistance of MOSFET
N-MOSFET
--
1
--
Ω
CH7 Current Limitation
N-MOSFET
--
0.8
--
A
6
6.25
6.5
V
Under Voltage Protection of VOUT1
--
1.75
--
V
Over Voltage Protection of SW5I
18
--
21
V
Over Voltage Protection of VOUT7
12
--
16
V
0.35
0.4
0.45
V
Under Voltage Protection of FB2
(Step-Down)
--
0.4
--
V
Under Voltage Protection of FB3
--
0.4
--
V
Under Voltage Protection of FB4
--
0.4
--
V
Under Voltage Protection of FB5
--
0.8
--
V
Under Voltage Protection of FB6
--
0.4
--
V
Protection Fault Delay
--
100
--
ms
EN134, EN2, EN5, EN6, EN7 Input
High Level Threshold
1.3
--
--
V
EN134, EN2, EN5, EN6, EN7 Input
Low Level Threshold
--
--
0.4
V
EN134, EN2, EN5, EN6, EN7 Sink
Current
--
2
6
µA
SEL Input High Level Threshold
1.3
--
--
V
SEL Input Low Level Threshold
--
--
0.4
V
--
2
6
µA
125
160
--
°C
--
20
--
°C
1.57
1.6
1.63
V
--
16
--
mV
--
2
4
µA
35
55
75
ms
4
--
--
mA
Protection
Over Voltage Protection of PVDD1
and PVDD2
CH5 Load Disconnect UVP of SW5O
Control
SEL Sink Current
SEL = 3.3V
Thermal Protection
Thermal Shutdown
TSD
Thermal Shutdown Hysteresis
ΔTSD
RTC Reset
RTC_PWR Reset Threshold
Hysteresis
Standby Current
RTC_PWR = 3V
RTC_R Rising Delay Time
RTC_R Sink Capability
RTC_R = 0.5V,
RTC_PWR = 1.5V
To be continued
www.richtek.com
10
DS9971-01 April 2011
RT9971
Parameter
RTC LDO, CN = High
Input Voltage Range
Symbol
Test Condition
VIN
Standby Current
Min
Typ
Max
Unit
--
--
5.5
V
VIN = 4.2V
--
5
8
µA
Output Voltage
Maximum Output Current
VOUT
IOUT = 0mA
VIN = 4.2V
-60
3.25
--
3.3
--
V
mA
Dropout Voltage
VDROP
IOUT = 20mA
--
--
200
mV
Note 1. Stresses listed as the above “ Absolute Maximum Ratings” may cause permanent damage to the device. These
are for stress ratings. 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
for extended periods may remain possibility to affect device reliability.
Note 2. θJA is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test
board of JEDEC 51-7 thermal measurement standard. The case point of θJC is on the exposed pad for the WQFN
package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
DS9971-01 April 2011
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11
RT9971
Typical Operating Characteristics
CH1 Step-Up Efficiency vs. Output Current
100
90
90
80
80
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
40
=
=
=
=
=
=
3V
2.7V
2.5V
2.2V
2V
1.8V
Efficiency (%)
Efficiency (%)
CH1 Step-Up Efficiency vs. Output Current
100
30
20
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
40
30
VDDM = 5V, VOUT_CH1 = 5V,
L1 = 2.2µH, C1 = 10µFx2
10
0
0
10
100
1000
10
100
Output Current (mA)
CH2 Step-Down Efficiency vs. Output Current
100
100
90
90
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
=
=
=
=
=
=
80
3.4V
3V
2.7V
2.5V
2.2V
1.8V
Efficiency (%)
80
1000
Output Current (mA)
CH2 Step-Up Efficiency vs. Output Current
Efficiency (%)
4.5V
4.2V
3.9V
3.6V
3.3V
3V
20
VDDM = 3V, VOUT_CH1 = 3.3V,
L1 = 2.2µH, C1 = 10µFx2
10
40
30
20
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
40
=
=
=
=
=
=
3.4V
3.6V
3.9V
4.2V
4.5V
5V
30
20
VDDM = 3V, VOUT_CH2 = 5V,
L2 = 2.2µH, C5 = 10µFx2
10
VDDM = 5V, VOUT_CH2 = 3.3V,
L2 = 4.7µH, C5 = 10µF
10
0
0
10
100
1000
10
100
Output Current (mA)
1000
Output Current (mA)
CH3 Step-Down Efficiency vs. Output Current
CH4 Step-Down Efficiency vs. Output Current
100
100
90
90
80
80
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
40
=
=
=
=
=
=
=
2.7V
3V
3.3V
3.6V
3.9V
4.2V
4.5V
Efficiency (%)
Efficiency (%)
=
=
=
=
=
=
30
70
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
60
50
40
=
=
=
=
=
=
1.8V
2.5V
3V
3.3V
3.6V
4.5V
30
20
20
VDDM = 5V, VOUT_CH3 = 2.5V,
L3 = 4.7µH, C9 = 10µF
10
0
10
100
Output Current (mA)
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12
1000
VDDM = 3V, VOUT_CH4 = 1V,
L4 = 4.7µH, C12 = 10µF
10
0
10
100
1000
Output Current (mA)
DS9971-01 April 2011
RT9971
CH5 Step-Up Efficiency vs. Output Current
90
90
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
=
=
=
=
=
Inverting Efficiency (%)
100
80
Efficiency (%)
CH6 Inverting Efficiency vs. Output Current
100
4.5V
4.2V
3.9V
3.6V
3.4V
40
30
20
VDDM = 5V, VOUT_CH5 = 16V,
L5 = 10µH, C16 = 10µF
10
80
VBAT
VBAT
VBAT
VBAT
VBAT
70
60
50
=
=
=
=
=
3.4V
3.6V
3.9V
4.2V
4.5V
40
30
20
VDDM = 5V, VOUT_CH6 = -8V,
L6 = 10µH, C18 = 10µFx2
10
0
0
1
10
100
1
10
Output Current (mA)
100
Output Current (mA)
CH7 Efficiency vs. Input Voltage
CH1 Step-Up Output Voltage vs. Output Current
5.080
100
90
5.075
Output Voltage (V)
Efficiency (%)
80
70
60
50
40
30
20
VBAT = 3V
5.070
VBAT = 4.5V
5.065
5.060
5.055
10
VDDM = 5V
VDDM = 5V, L7 = 10µH, C20 = 1µF, IOUT = 25mA
5.050
0
3.4 3.5 3.6 3.7 3.8 3.9
4
0
4.1 4.2 4.3 4.4 4.5
100
200
300
400
500
600
Output Current (mA)
Input Voltage (V)
CH1 Step-Up Output Voltage vs. Output Current
CH2 Step-Down Output Voltage vs. Output Current
3.35
3.340
3.335
3.31
VBAT = 1.8V
3.29
VBAT = 4.5V
3.27
Output Voltage (V)
Output Voltage (V)
3.33
3.330
3.325
3.320
VBAT = 4.5V
VBAT = 5V
3.315
3.310
3.305
VDDM = 3V
3.25
VDDM = 5V
3.300
0
100
200
300
400
Output Current (mA)
DS9971-01 April 2011
500
600
0
100
200
300
400
500
600
Output Current (mA)
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13
RT9971
CH2 Step-Up Output Voltage vs. Output Current
CH3 Step-Down Output Voltage vs. Output Current
5.07
2.520
2.515
5.05
VBAT = 3.4V
5.04
Output Voltage (V)
Output Voltage (V)
5.06
5.03
2.510
VBAT = 3V
2.505
VBAT = 4.5V
2.500
2.495
VDDM = 3V
VDDM = 5V
5.02
2.490
0
100
200
300
400
500
600
0
100
Output Current (mA)
200
300
400
500
600
Output Current (mA)
CH4 Step-Down Output Voltage vs. Output Current
CH5 Step-Up Output Voltage vs. Output Current
1.015
16.3
1.013
16.2
1.009
1.007
1.005
1.003
VBAT = 3V
VBAT = 1.8V
VBAT = 4.5V
1.001
0.999
Output Voltage (V)
Output Voltage (V)
1.011
16.1
16.0
VBAT = 4.5V
VBAT = 3.4V
VBAT = 2.7V
15.9
15.8
0.997
VDDM = 3V
0.995
VDDM = 5V
15.7
0
100
200
300
400
500
0
600
Output Current (mA)
20
40
60
80
100
Output Current (mA)
CH6 Inverting Output Voltage vs. Output Current
Power On
Inverting Output Voltage (V)
-8
-8.05
VOUT_CH1
(5V/Div)
VOUT_CH2
(5V/Div)
-8.1
-8.15
VBAT = 4.5V
VBAT = 3.4V
VBAT = 2.7V
-8.2
VOUT_CH3
(2V/Div)
VOUT_CH4
(1V/Div)
-8.25
VDDM = 5V
VDDM = 5V, VBAT = 3.7V, SEL = Low
-8.3
0
20
40
60
80
100
Time (5ms/Div)
Output Current (mA)
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14
DS9971-01 April 2011
RT9971
Power Off
CH1 Output Voltage Ripple
VOUT_CH1
(5V/Div)
VOUT_CH2
(5V/Div)
LX1
(2V/Div)
VOUT_CH3
(2V/Div)
VOUT_CH1_ac
(20mV/Div)
VOUT_CH4
(1V/Div)
VDDM = 5V, VBAT = 3.7V, VOUT_CH1 = 5V,
IOUT = 400mA, L1 = 2.2μH, C1 = 10μFx2
VDDM = 5V, VBAT = 3.7V, SEL = Low
Time (1ms/Div)
Time (1μs/Div)
CH2 Output Voltage Ripple
CH3 Output Voltage Ripple
LX2
(2V/Div)
LX3
(2V/Div)
VOUT_CH2_ac
(10mV/Div)
VOUT_CH3_ac
(10mV/Div)
VDDM = 5V, VBAT = 3.7V, VOUT_CH3 = 2.5V,
IOUT = 300mA, L3 = 4.7μH, C9 = 10μF
VDDM = 5V, VBAT = 3.7V, VOUT_CH2 = 3.3V,
IOUT = 400mA, L2 = 4.7μH, C5 = 10μF
Time (1μs/Div)
Time (1μs/Div)
CH5 Output Voltage Ripple
CH6 Output Voltage Ripple
LX6
(10V/Div)
LX5
(10V/Div)
VOUT_CH6_ac
(10mV/Div)
VOUT_CH5_ac
(10mV/Div)
VDDM = 5V, VBAT = 3.7V, VOUT_CH5 = 16V,
IOUT = 30mA, L5 = 10μH, C16 = 10μF
Time (1μs/Div)
DS9971-01 April 2011
VDDM = 5V, VBAT = 3.7V, VOUT_CH6 = -8V,
IOUT = 50mA, L6 = 10μH, C18 = 10μFx2
Time (1μs/Div)
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15
RT9971
CH2 Load Transient Response
CH1 Load Transient Response
IOUT
(200mA/Div)
IOUT
(200mA/Div)
V OUT_CH1_ac
(100mV/Div)
V OUT_CH2_ac
(100mV/Div)
VDDM = 5V, VBAT = 3.7V, VOUT_CH2 = 3.3V,
IOUT = 0 to 300mA, L2 = 4.7μH, C5 = 10μF
VDDM = 3V, VBAT = 1.8V, VOUT_CH1 = 3.3V,
IOUT = 50mA to 250mA, L1 = 2.2μH, C1 = 10μFx2
Time (1ms/Div)
Time (1ms/Div)
CH3 Load Transient Response
CH4 Load Transient Response
IOUT
(200mA/Div)
IOUT
(200mA/Div)
V OUT_CH3_ac
(50mV/Div)
V OUT_CH4_ac
(50mV/Div)
VDDM = 3V, VBAT = 1.8V, VOUT_CH4 = 1V,
IOUT = 100mA to 300mA, L4 = 4.7μH, C12 = 10μF
VDDM = 5V, VBAT = 3V, VOUT_CH3 = 2.5V,
IOUT = 100mA to 300mA, L3 = 2.2μH, C9 = 10μF
Time (1ms/Div)
Time (1ms/Div)
CH5 Load Transient Response
CH6 Load Transient Response
IOUT
(20mA/Div)
IOUT
(20mA/Div)
V OUT_CH5_ac
(50mV/Div)
V OUT_CH6_ac
(50mV/Div)
VDDM = 5V, VBAT = 3.7V, VOUT_CH5 = 16V,
IOUT = 10mA to 30mA, L5 = 10μH, C16 = 10μF
Time (1ms/Div)
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16
VDDM = 5V, VBAT = 3.7V, VOUT_CH6 = -8V,
IOUT = 15mA to 50mA, L6 = 10μH, C18 = 10μFx2
Time (1ms/Div)
DS9971-01 April 2011
RT9971
Application information
The RT9971 includes the following seven DC/DC converter
CHs to build a multiple-output power-supply system.
The output voltage can be set by the following equation :
CH1 : Step-up synchronous current mode DC/DC converter
with internal power MOSFETs. The output voltage could
be load disconnected by a switch controller and an
external P-MOSFET.
Where VFB1 is 0.8V typically.
CH2 : Selectable step-up or step-down synchronous
current mode DC/DC converter with internal power
MOSFETs.
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 : Step-up asynchronous current mode DC/DC
converter with internal power MOSFET and internal
compensation network. The output voltage could be load
disconnected by an internal P-MOSFET.
CH6 : Inverting current mode DC/DC converter with internal
power P-MOSFET and internal compensation network.
CH7 : Current mode WLED driver with internal power
N-MOSFET and internal compensation network. This CH
also provides open LED protection.
SW1 : Load disconnect controller.
SW5 : Load disconnect switch for CH5
CH1 to CH7 operate in PWM mode with 1MHz constant
frequency under moderate to heavy loading.
RTC_LDO : Low quiescent current, high output voltage
accuracy LDO for Real Time Clock.
VOUT_CH1 = (1+R1/R2) x VFB1
SW1
SW1 is an open drain controller to drive an external
P-MOSFET and then functions as a load disconnect
switch for CH1. This switch features soft-start, Power On/
Off Sequence and under voltage protection functions. OK
is an open drain control pin. Once CH1, CH3, and CH4's
soft-start are finished, SW1 will be turned on. The OK pin
is slowly pulled low and controlled with soft-start to
suppress the inrush current. VOUT1 is used for SW1 softstart and under voltage protection.
CH2 : Synchronous Step-Up or Step-Down
Selectable DC/DC Converter
The CH2 is a synchronous step-up or step-down
selectable converter for motor or DSC system I/O power.
Mode setting
The CH2 of the RT9971 features flexible Step-up or Stepdown topology setting for either 1 x Li-ion or 2 x AA
application by the SEL pin. Please refer to “Electrical
Characteristics” for level of Logic-High or Logic-Low. When
the CH2 operates as a Step-up converter, the SEL must
be set at Logic-High. If the CH2 operates at Step-down
mode, the SEL must be set at Logic-Low. In addition,
please note that the logic state can not be changed during
operation.
Table 2. CH2 Mode Setting
CH2 Operating Mode
SEL
Step-up
Logic-High
Step-down
Logic-Low
RTC_Reset : Accurate voltage detector for RTC LDO.
CH1: Synchronous Step-Up DC/DC Converter
The CH1 is a synchronous step-up converter for motor or
DSC system I/O power. The converter operates at fixed
frequency and PWM Current Mode. The CH1 converter
integrates internal MOSFETs, compensation network and
synchronous rectifier for up to 95% efficiency.
DS9971-01 April 2011
Step-Up :
The converter operates at 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.
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17
RT9971
Step-Down :
The converter operates at 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. While the
input voltage is close to the output voltage, the converter
enters low dropout mode.
converter is inactive until the SW5 soft-start procedure is
finished. This feature provides load disconnect function
and effectively limits inrush current at start up.
The output voltage can be set by the following equation :
VOUT_CH5 = (1+R11/R12) x VFB5
Where VFB5 is 1.25V typically.
SW5
Where VFB2 is 0.8V typically.
SW5 is an internal switch enabled by EN5 and functions
as a load disconnection for CH5. This switch features softstart, Powe On Sequence, over voltage (for SW5I) and
under voltage (for SW5O) protection functions.
CH3 : Synchronous Step-Down DC/DC Converter
CH6 : INV DC/DC Converter
The converter operates at fixed frequency PWM mode,
CCM, integrated internal MOSFETs and compensation
network. The CH3 step-down converter can be operated
at 100% maximum duty cycle to extend the battery
operating voltage range. When the input voltage is close
to the output voltage, the converter could enter low dropout
mode with low output ripple.
This converter integrates an internal P-MOSFET and an
external schottky diode to provide CCD negative power
supply.
The output voltage can be set by the following equation :
VOUT_CH2 = (1+R4/R5) x VFB2
The output voltage can be set by the following equation :
VOUT_CH6 = (R13/R14) x (-VREF)
Where R13 and R14 are the feedback resisters connected
to FB6, VREF equals to 1.25V in typical.
The output voltage can be set by the following equation :
VOUT_CH3 = (1+R7/R8) x VFB3
Where VFB3 is 0.8V typically.
CH4 : Synchronous Step-Down DC/DC Converter
The converter operates at fixed frequency PWM mode,
CCM, 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 could enter low dropout mode with
low output ripple.
The output voltage can be set by the following equation :
Charge Pumps
The charge pump will be enabled while the PVDD6 voltage
is lower than 3.6V. This CH provides pump voltage to
enhance P-MOSFET gate driving capability. This function
is not necessary while battery is Li-ion type.
Reference Voltage
The RT9971 provides a precise 1.25V reference voltage
with souring capability of 100µA. Connect a 0.1µF ceramic
capacitor from the VREF pin to GND. Reference voltage
is enabled by connecting EN6 to logic high. Furthermore,
this reference voltage is internally pulled to GND at
shutdown.
VOUT_CH4 = (1+R9/R10) x VFB4
Where VFB4 is 0.8V typically.
CH5 : Step-Up DC/DC Converter
It integrates asynchronous step-up converter with an
internal N-MOSFET, internal compensation and an external
schottky diode to provide CCD positive power supply. The
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18
CH7 : WLED Driver
It is an asynchronous step-up converter with an internal
MOSFET, internal compensation and an external schottky
diode to drive up to 3 WLED. This CH also features PWM
dimming control from EN7 pin and open diode protection.
In addition, CH7 will be turned on until the CH4 soft-start
is finished.
DS9971-01 April 2011
RT9971
The current flows through WLED can be set by the following
equation :
I (mA) = [250mV/R(Ω)] x Duty (%)
R : Current sense resistor from CFB7 to GND.
Duty: PWM dimming by EN7 pin. Dimming frequency
range is from 30kHz to 100kHz.
Hold EN7 low for more than 64µs will turn off CH7.
RTC_Reset
The RT9971 provides an accurate voltage detector for
RTC_LDO voltage detection. It is used to detect whether
RTC_LDO output voltage is ready or not. Its power pin is
RTC_PWR and output pin is RTC_R. The output pin is an
open drain N-MOSFET and the sink capability is above
4mA. Once the RTC_PWR pin reaches 1.6V, it will count
for about 55ms, then the RTC_R will go high.
RTC_LDO
The RT9971 provides a LDO for real time clock. The LDO
function has features of low quiescent current (5µA) and
high output voltage accuracy since this LDO is running all
the time, even when the system is shutdown. In addition,
LDO share “OK” and “VOUT1” pin with SW1 and the
function is decided by “CN” pin. Following table is used
to select LDO or SW1.
and CH2 (Note A) will be shutdown. After that, CH4 will be
turned off and internally pulled low to wait for the completion
of CH4's shutdown. And then, CH3 will be turned off and
internally pulled low to wait for CH3's shutdown completion.
Then, CH1 will be turned off and internally pulled low
(Note B) to wait for CH1's shutdown completion. Finally,
the whole IC will be shutdown (if EN2, EN5, EN6 and EN7
already go low).
Note A : If CH2 is configured as a step -up, then the CH2
will not be internally pulled low and the completion of
shutdown will not be checked.
Note B : CH1 is configured as a step -up, so the CH1 will
not be internally pulled low and the completion of shutdown
will not be checked.
Table 4. Power On/Off Sequence
Power On
Sequence
Power Off
Sequence
CH1 -> CH3 -> CH4 -> (SW1 and CH2)
(SW1 and CH2) -> CH4 -> CH3 -> CH1
Thermal Considerations
Function
CN
RTC_LDO
Logic-High
For continuous operation, do not exceed absolute
maximum operation junction temperature. The maximum
power dissipation depends on the thermal resistance of
IC package, PCB layout, the rate of surroundings airflow
and temperature difference between junction to ambient.
The maximum power dissipation can be calculated by
following formula :
SW1
Logic-Low
PD(MAX) = (TJ(MAX) − TA ) / θJA
Table 3. RTC_LDO and SW1 Setting
Power On/Off Sequence
Where T J(MAX) is the maximum operation junction
temperature, TA is the ambient temperature and the θJA is
The Power On Sequence is :
the junction to ambient thermal resistance.
While EN134 goes high, CH1 will be turned on to wait for
the completion of CH1's soft-start. After that, CH3 will be
turned on to wait for the completion of CH3's soft-start.
And then, CH4 will be turned on to wait for the completion
of CH4's soft-start. Then,SW1 will be turn on and CH2 is
allowed to be turn on by EN2 at any time. Finally, SW1
soft-start will be completed.
The Power-Off Sequence is :
For recommended operating conditions specification of
RT9971, The maximum junction temperature is 125°C.
The junction to ambient thermal resistance θJA is layout
dependent. For WQFN-40L 5x5 packages, the thermal
resistance θJA is 36°C/W on the standard JEDEC 51-7
four layers thermal test board. The maximum power
dissipation at TA = 25°C can be calculated by following
formula :
At first, while EN134 goes low, (SW1 is shutdown and
internally pull low, CH2 must be turned off by EN2) SW1
PD(MAX = (125°C −25°C) / (36°C/W ) = 2.778W for
WQFN-40L 5x5 packages
DS9971-01 April 2011
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19
RT9971
Layout Considerations
Maximum Power Dissipation (W)
The maximum power dissipation depends on operating
ambient temperature for fixed T J(MAX) and thermal
resistance θJA. For RT9971 packages, the Figure 1 of
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
For the best performance of the RT9971, the following
PCB layout guidelines must be strictly followed.
Four Layers PCB
}
Place the input and output capacitors as close as
possible to the input and output pins respectively for
good filtering.
}
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.
}
Place the feedback components as close as possible
to the FB pin and keep these components away from
the noisy devices.
}
Place the compensative components as close as
possible to the COMP pin and keep these components
away from the noisy devices.
}
Connect the GND and Exposed Pad to a strong ground
plane for maximum thermal dissipation and noise
protection.
WQFN-40L 5x5
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 1. Derating Curves for RT9971 Packages
Place the feedback and compensation
components as close as possible to the FB and
COMP pin and keep away from noisy devices.
LX should be connected to inductor by
wide and short trace, keep sensitive
components away from this trace.
V OUT_CH2
VOUT_CH1
GND
C2 R1
GND
VBAT
GND
C6 R4
C5
C3
C7
R3
R2
C21
R5
R6
C1
4
27
5
26
GND
24
8
23
41
9
21
11 12 13 14 15 16 17 18 19 20
VOUT_CH5
GND
R16
R12
PVDD2
VDDM
CFB7
GND
LX7
LX5
VOUT7
FB3
EN7
LX3
R15
VBAT
D1
C23
D5
L7
WLED+
VBAT
C20
C26
L5
C24
D3
VBAT
GND
C14
R8
R7
C10
L3
GND
V OUT_CH3
C9
C8
C15 R11
VBAT
VBAT
GND
22
10
C11
C16
VOUT_CH4
25
7
L4
C12
EN1234
LX2
28
RTC_PWR
PVDD3
R9
R10
29
3
GND
C13
2
6
D2
C4
30
SEL
RTC_R
C19
WLED-
40 39 38 37 36 35 34 33 32 31
FB5
VREF
C18
L2
1
PVDD4
VOUT_CH6
L6
PVDD1
LX6
D4
PVDD6
C25
VBAT CP
CN
C17
PNEG
R13
FB6
R14
FB4
EN6
LX4
COMP2
LX1
SYS_R
C22
EN5
SW5O
SW5I
Input/Output
capacitors must
be placed as close
as possible to the
Input/Output pins.
COMP1
FB1
OK
VOUT1
FB2
L1
GND
Connect the Exposed Pad
to a ground plane.
Figure 2. PCB Layout Guide
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20
DS9971-01 April 2011
RT9971
Protection
type
V DDM
CH1
Step-Up
CH2
Step-Up
Table 5. Protection Items
Threshold (typical)
Refer to Electrical
Protection methods
spec.
VDDM > 6.25V
Automatic reset at VDDM < 6V
100ms
VDDM power
reset
Current
Limit
N-MOSFET current >
3A
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
100ms
cycle
VDDM power
reset
PVDD1
OVP
PVDD1 > 6.25V
N-MOSFET off, P-MOSFET off. No-delay
VDDM power
reset
Current
Limit
N-MOSFET current >
3A
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
100ms
cycle
VDDM power
reset
PVDD2
OVP
PVDD2 > 6.25V
N-MOSFET off, P-MOSFET off. No-delay
VDDM power
reset
P-MOSFET current >
1.5A
CH3
Current
Step-Down Limit
P-MOSFET current >
1.5A
CH4
Current
Step-Down Limit
P-MOSFET current >
1.5A
CH7
WLED
SW 1
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
100ms
cycle
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
100ms
cycle
N-MOSFET off, P-MOSFET off.
Automatic reset at next clock
100ms
cycle
VD DM power reset
VDDM power
reset
VDDM power
reset
Current
Limit
N-MOSFET current >
1.2A
N-MOSFET off. Automatic reset
100ms
at next clock cycle
VDDM power
reset
Current
Limit
P-MOSFET current >
1.5A
P-MOSFET off. Automatic reset
100ms
at next clock cycle
Current
Limit
N-MOSFET current >
0.8A
N-MOSFET off. Automatic reset Not
at next clock cycle
Applicable
OVP
VOUT7 > 14V
Shutdown CH7
Not
Applicable
UVP
VOUT1 < 1.75V after
SW1 soft start end
Automatic reset at
VOUT1 > 1.75V
100ms
OVP
SW5I > 18V
N-MOSFET off
No-delay
UVP
SW5O < 0.4V after
SW5 soft start end
Automatic reset at
SW5O > 0.4V
100ms
Thermal
shutdown
Temperature > 160°C All channels stop switching
VDDM power
reset
Automatic reset
at next clock
cycle
Reset by toggling
EN7
VDDM power
reset
VDDM power
reset
VDDM power
reset
Temperature <
140°C
VDDM power
reset
SW 5
Thermal
Reset method
OVP
CH2
Current
Step-Down Limit
CH5
Asyn
Step-Up
CH6
Inverting
IC
Shutdown
Delay time
No-delay
CH2
UVP
Step-Down
FB2 < 0.4V after CH2
soft start end
N-MOSFET off, P-MOSFET off.
100ms
Automatic reset at FB2 > 0.4V
CH3
UVP
Step-Down
CH4
UVP
Step-Down
FB3 < 0.4V after CH3
soft start end
FB4 < 0.4V after CH4
soft start end
FB5 < 0.8V after CH5
soft start end
N-MOSFET off, P-MOSFET off.
100ms
Automatic reset at FB3 > 0.4V
N-MOSFET off, P-MOSFET off.
100ms
Automatic reset at FB4 > 0.4V
N-MOSFET off.
No-delay
FB6 > 0.4V
P-MOSFET off.
No-delay
CH5
UVP
CH6
UVP
DS9971-01 April 2011
VDDM
reset
VDDM
reset
VDDM
reset
VDDM
reset
power
power
power
power
www.richtek.com
21
RT9971
Outline Dimension
D
SEE DETAIL A
D2
L
1
E2
E
e
b
1
1
2
2
DETAIL A
Pin #1 ID and Tie Bar Mark Options
A
A3
A1
Symbol
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
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
4.950
5.050
0.195
0.199
D2
3.250
3.500
0.128
0.138
E
4.950
5.050
0.195
0.199
E2
3.250
3.500
0.128
0.138
e
L
0.400
0.350
0.016
0.450
0.014
0.018
W-Type 40L QFN 5x5 Package
Richtek Technology Corporation
Richtek Technology Corporation
Headquarter
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
5F, No. 95, Minchiuan Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)86672399 Fax: (8862)86672377
Email: [email protected]
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit
design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be
guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
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22
DS9971-01 April 2011