Richtek RT9903PQV Schematic [ru]
Preliminary
RT9903
5 Channel DC/DC Converters IC
with High-Efficiency Step-up
General Description
The RT9903 is a complete power-supply solution for digital
still cameras and other hand-held devices. It integrates a
high-efficiency fours step-up DC-DC converte
rs and a
charge pump.
The two Step-up DC-DC converters (CH1,CH2) accept
inputs from 1.5V to 5.5V and regulate a resistor-
adjustable output up to 17V. One Step-up DC-DC
converter (CH3) can be regarded as white LED Driver,
which reference voltage is 0.2V and have OVP function.
One step-up DC-DC converter (CH4) regulate a resistor-
adjustable output up 5V. An adjustable operating
frequency (up to 1.4MHz) is utilized to get optimum size,
cost, and efficiency.
The feature of the charge pump (CH5) is to deliver few
current to CCD negative voltage.
RT9903 is available in VQFN-24L 4x4 package. Each
DC-DC converters have independent shutdown inputs.
Applications
z Digital Still Camera
z PDAs
z Portable Device
Features
zz
T wo step-up DC-DC Converters (CH1, CH2)
z
zz
``
`HV Internal Switches
``
``
`50mA Load Current
``
zz
z One Step-up DC-DC Converter (CH3)
zz
``
`0.2V Reference Voltage
``
``
`HV Internal Switches
``
``
`LED Brightness Dimming Control
``
``
`Over Voltage Protection
``
zz
z One Step-up DC-DC Converter (CH4)
zz
``
`External Switches
``
``
`External Current Limit Setting
``
zz
z Step-up Charge Pump (CH5) for CCD Negative
zz
Voltage
``
`HV Internal Switches
``
zz
z Up to 1.4MHz Switching Frequency
zz
μμ
zz
z 1
μA Supply Current in Shutdown Mode
zz
μμ
zz
z External Compensation Network for All Converters
zz
zz
z Programm able Soft Start Function (CH1, CH2, CH3,
zz
CH4)
zz
z Independent Ena ble Pin to Shutdown Each Channel
zz
zz
z 24-Lead VQFN Package
zz
zz
z RoHS Compliant and 100% Lead (Pb)-Free
zz
Pin Configurations
Ordering Information
(TOP VIEW)
RT9903
Package Type
QV : VQFN-24L 4x4 (V-Type)
Operating Temperature Range
P : Pb Free with Commercial Standard
Note :
RichTek Pb-free 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.
`100% matte tin (Sn) plating.
Marking Information
For marking information, contact our sales representative
CX
INCD
FB_CP
RT
EXT4
CS4
LX2
COMP2
24 2223
1
2
3
4
5
6
7
8910 12
FB4
COMP4
VQFN-24L 4x4
FB2
21 20 19
GND
FB3
11
COMP3 AGND
FB1
LX3
COMP1
18
LX1
17
VDD
16
PGND
15
EN4
14
EN2
13
EN1
EN3
directly or through a RichTek distributor located in your
area, otherwise visit our website for detail.
DS9903-04 November 2005 www.richtek.com
1
RT9903
Typical Application Circuit
2-AA Battery 1.8V to 3.2V
Preliminary
WLED
(12V)
3.3V_Motor
C5 to C8
10uFx4
VBATT
R15
R5
1.2k
C10
4.7nF
10
300k
130k
R2
R3
C11
500pF
C3
10uF10uF
SS0520
Chip Enable
R6
C12
6.8nF
C1
10uF
D1
SS0520
C2
1uF
C4
D2
C9
1nF
R7
C13
56nF
R1
VBATT
L2
4.7uH
Q1
Si2302
R8
2.7k1.2k2.2k
C14
4.7nF
L1
4.7uH
R4
10k
11
4
21
16
9
6
5
7
13
14
12
15
19
23
10
8
VDD
LX3
RT
AGND
PGND
FB3
CS4
EXT4
FB4
EN1
EN2
EN3
EN4
COMP1
COMP2
COMP3
COMP4
17
RT9903
C15
4.7uF
FB-CP
LX1
FB1
LX2
FB2
INCD
CX
18
20
24
22
2
1
3
C16
10uF
C24
68nF
VBATT
C19
10uF
L3
4.7uH
SS0520
L4
4.7uH
SS0520
SS0520
D6
SS0520
VCC
3.3V
D3
R9
2.2M
D4
R11
5.1M
R12
360k
D5
R10
200k
R13
750k
R14
330k
1uF
C27
C17
1nF
C21 to C23
10uFx3
C20
1nF
+12V (+LCD)
C18
10uF
+15V (+CCD)
-7.5V (-CCD)
C25 to C26
10uFx2
DS9903-04 November 2005www.richtek.com
2
WLED
(12V)
3.3V_Motor
C5 to C8
10uFx4
1.2k
4.7nF
VBATT
R15
10
R5
C10
R2
300k
R3
130k
C11
500pF
C2
1uF
C3
10uF10uF
SS0520
Chip Enable
R6
2.2k
C12
6.8nF
C1
10uF
D1
SS0520
C4
D2
C9
1nF
R7
1.2k
C13
56nF
R1
VBATT
L2
4.7uH
Q1
Si2302
R8
2.7k
C14
4.7nF
L1
4.7uH
R4
10k
11
4
21
16
9
6
5
7
13
14
12
15
19
23
10
8
Preliminary
V_3.3V
17
VDD
LX3
RT
AGND
PGND
FB3
RT9903
CS4
EXT4
FB4
EN1
EN2
EN3
EN4
COMP1
COMP2
COMP3
COMP4
C15
4.7uF
FB-CP
LX1
FB1
LX2
FB2
INCD
CX
18
20
24
22
2
1
3
C16
10uF
C24
68nF
C19
10uF
L3
4.7uH
VBATT
SS0520
VCC
3.3V
D3
SS0520
R9
2.2M
L4
4.7uH
D4
SS0520
R11
5.1M
R12
360k
D5
SS0520
D6
R10
200k
R13
750k
R14
330k
C27
1uF
C17
1nF
C20
1nF
+12V (+LCD)
C18
10uF
C21 to C23
10uFx3
C28
C25 to C26
10uFx2
RT9903
+15V (+CCD)
-7.5V (-CCD)
Function Block Diagram
CX
Charge Pump
Thermal
Protection
PGND (Exposed Pad)
Oscillator
+
-
RT
Soft
Start
VDD
AGND
COMP1
COMP3
EN1
CH1
V-Mode
Step-Up
PWM
CH3
C-Mode
Step-Up
PWM
EN3
LX1
LX3
-
FB3
+
+
V
FB1
V
REF
0.2V
REF
1V
COMP4
COMP2
LX2 FB2 FBCPINCD
EN2
CH2
V-Mode
Step-Up
PWM
CH4
C-Mode
Step-Up
PWM
10uA
CS4
EXT4
EN4
+
+
-
FB4
DS9903-04 November 2005 www.richtek.com
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RT9903
Preliminary
Functional Pin Description
Pin Number Pin Name Pin Function
1 CX Charge Pump External Driver Pin
2 INCD Charge Pump Input Pin
3 FB_CP Charge Pump Feedback Pin
4 RT Frequency Setting Resistor Connection Pin
5 EXT4 CH4 External Power Switch
6 CS4 CH4 Current Sense Input Pin
7 FB4 CH4 Feedback Input
8 COMP4 CH4 Feedback Compensation Pin
9 FB3 CH3 Feedback Input
10 COMP3 CH3 Feedback Compensation Pin
11 LX3 CH3 Switch Node
12 EN3 CH3 Enable Input Pin
13 EN1 CH1 Enable Input Pin
14 EN2 CH2 Enable Input Pin
15 EN4 CH4 Enable Input Pin
16
17 VDD Power Input Pin
18 LX1 CH1 Switch Node
19 COMP1 CH1 Feedback Compensation Pin
20 FB1 CH1 Feedback Input
21 AGND Analog Ground
22 FB2 CH2 Feedback Input
23 COMP2 CH2 Feedback Compensation Pin
24 LX2 CH2 Switch Node
Exposed Pad GND Exposed pad should be soldered to PCB board and connected to GND.
PGND Power Ground
DS9903-04 November 2005www.richtek.com
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Preliminary
Absolute Maximum Ratings (Note 1)
RT9903
z Supply Input Voltage (V
z LX1, LX2, LX3 Pins, INCD Pin---------------------------------------------------------------------------------------- −0.3V to 20V
z Other I/O Pin Voltage ---------------------------------------------------------------------------------------------------
z Power Dissipation, P
) --------------------------------------------------------------------------------------------- −0.3 to 7V
DD
@ T
D
= 25°C
A
−0.3V to 7V
VQFN-24L 4x4 ------------------------------------------------------------------------------------------------------------ 1.923W
z Package Thermal Resistance (Note 3)
VQFN-24L 4x4, θJA------------------------------------------------------------------------------------------------------- 52°C/W
z Lead Temperature (Soldering, 10 sec.) ---------------------------------------------------------------------------- 260°C
z Operation Temperature Range --------------------------------------------------------------------------------------- −40°C to 85°C
z Junction Temperature Range ----------------------------------------------------------------------------------------- 0°C to 125°C
z Storage Temperature Range ------------------------------------------------------------------------------------------ −65°C to 150°C
Recommended Operating Conditions (Note 2)
z Maximum Output Voltage Setting ( V
z Dimming Control Frequency Range, CH3 ------------------------------------------------------------------------- 200Hz to 900Hz
OUT1
and V
) ---------------------------------------------------------- 17V
OUT2
Electrical Characteristics
(VDD =3.3V, TA = 25°C, unless otherwise specification)
Parameter Symbol Test Condition Min Typ Max Units
Supply Voltage
VDD Operating Voltage V
VDD Start-up Voltage VDD Pin Voltage 1.5 -- -- V
VDD Over Voltage Protection V
Supply Current
Shutdown Supply Current I
CH1 DC/DC Converter Supply
Current
CH2 DC/DC Converter & Charge
Pump Supply Current
CH3 DC/DC Converter Supply
Current
CH4 DC/DC Converter Supply
Current
VDD Pin Voltage 2.4 -- 5.5 V
VDD
DD(OVP)
OFF
I
VDD1
I
VDD2
I
VDD3
I
VDD4
VDD Pin Voltage 6 -- -- V
VDD = 3.6V, V
=3.6V,
V
VDD
= V
V
FB1
V
EN1
V
EN3
V
VDD
V
FB2
V
EN1
V
EN3
V
VDD
V
FB3
V
EN1
V
EN3
V
VDD
V
FB4
V
EN1
V
EN3
REF
= 3.3V, V
= 0V, V
= 3.6V,
= V
REF
= 0V, V
= 0V, V
= 3.6V,
= V
REF
= 0V, V
= 3.3V, V
= 3.6V,
= V
REF
= 0V, V
= 0V, V
EN1 to 4
+ 0.15V
EN4
+ 0.15V
EN2
EN4
+ 0.15V
EN2
+ 0.15V
EN2
EN4
= 0V -- 0.01 1 μA
EN2
= 0V,
-- 200 250 μA
= 0V
= 3.3V,
-- 210 260 μA
= 0V
= 0V,
= 0V
EN4
= 0V,
-- 250 300 μA
-- 200 250 μA
= 3.3V
To be continued
DS9903-04 November 2005 www.richtek.com
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