Richtek RT8203GA, RT8203PA Schematic [ru]
RT8203
High-Efficiency, Quad Output, Main PowerControllers for Notebook Computers
General Description
The RT8203 dual step-down, Switch Mode Power Supply
(SMPS) controllers generate logic-supply voltages in
battery-powered systems. The RT8203 include two pulsewidth modulation (PWM) controllers, adjustable from 2V
to 5.5V or fixed at 5V a nd 3.3V . These devices feature two
linear regulators providing 5V and 3.3V always-on outputs.
Each linear regulator provides up to 100mA output current
with automatic linear regulator bootstrapping to the main
SMPS outputs. The RT8203 include on-board power-up
sequencing, a power good (PGOOD) output, internal softstart, and soft-shutdown output discharge that prevents
negative voltages on shutdown. Richtek's proprietary Mach-
PWMTM “instant-on” response, constant on-time PWM
control scheme operates without sense resistors and
provides 100ns response to load transients while
maintaining a relatively constant switching frequency . The
unique ultrasonic mode maintain s the switching frequency
above 25kHz, which eliminates noise in audio a pplications.
Other features include diode-emulation, which maximizes
efficiency in light-load applications, and fixed-frequency
PWM mode, which reduces RF interference in sensitive
applications. The RT8203 provides a pin-selectable
switching frequency, allowing either 200kHz/300kHz or
400kHz/500kHz operation of the 5V/3.3V SMPSs,
respectively . The RT8203 is available in SSOP-28 package.
Ordering Information
RT8203
Package Type
A : SSOP-28
Lead Plating System
P : Pb Free
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.
Features
zz
z No Current Sense Resistor Needed
zz
zz
z 1.5% Output V oltage Accura cy
zz
zz
z 3.3V and 5V 100mA Bootstra pped Linear Regulators
zz
zz
z Internal Soft-Start and Soft-Shutdown Output
zz
Discharge
zz
z Mach-PWM with 100ns Load Step Response
zz
zz
z 3.3V and 5V Fixed or Adjustable Outputs
zz
zz
z 7V to 24V Input Voltage Range
zz
zz
z Ultrasonic Mode Operation 25kHz (min.)
zz
zz
z Power Good (PGOOD) Signal
zz
zz
z Over Voltage Protection
zz
zz
z Under Voltage Protection
zz
zz
z Over Temperature Protection
zz
zz
z RoHS Compliant and 100% Lead (Pb)-Free
zz
Applications
z Notebook and Subnotebook Computers
z PDAs and Mobile Communication Devices
z 3- and 4-Cell Li+ Battery-Powered Devices
Pin Configurations
NC
PGOOD
ON3
ON5
ILIM3
EN
FB3
VREF
FB5
PRO
ILIM5
SKIP
TON
BOOT5
Supply
(TOP VIEW)
28
2
3
4
5
6
7
8
9
10
11
12
13
14
27
26
25
24
23
22
21
20
19
18
17
16
SSOP-28
15
SSOP-28
BOOT3
PHASE3
UGATE3
LDO3
LGATE3
GND
VOUT3
VOUT5
VIN
LGATE5
LDO5
VCC
UGATE5
PHASE5
DS8203-05 April 2011 www.richtek.com
1
RT8203
Typical Application Circuit
5V
ALWAYS ON
V
CC
V
OUT5
5V
C10
C1
4.7µF
+
C2
1µF
C3
1µF
C6
10µF
L1
AO4702
D3
R1
3.9
C5
0.1µF
Q1
C12
0.22µF
D1
BSC119N03
TABLE
BAT254
R3
2.2
C8
0.1µF
SEE
R2
47
17
5
11
20
14
16
15
19
13
21
8
9
23
VCC
ILIM3
ILIM5
VIN
BOOT5
UGATE5
PHASE5
LGATE5
TON
VOUT5
VREF
FB5
GND
18
LDO5
RT8203
V
IN
7V to 24V
3
ON3
4
ON5
25
LDO3 3.3V ALWAYS ON
PRO
BOOT3
UGATE3
PHASE3
LGATE3
VOUT3
SKIP
FB3
PGOOD
EN
NC
R6
1M
10
6
R4
2.2
28
26
27
24
BSC119N03
22
12
7
1
2
D2
BAT254
C9
0.1µF
V
CC
R5
100k
C4
4.7µF
Q2
AO4702
Q4Q3
V
REF
V
CC
ON
C7
10µF
L2
D4
Power-Good
INDICATOR
OFF
C11
V
OUT3
3.3V
Frequen cy-depe ndent Components
VOUT5 VOUT3
TON = VCC TON = GND TON = VCC TON = GND
f = 200kHz f = 400kHz f = 300kHz f = 500kHz
L1 = 7.6μH L1 = 5.6μH L2 = 4.7μH L2 = 3μH
C10 = 330μF C10 = 150μF C11 = 470μF C11 = 220μF
Figure 1. Fixed V oltage Regulator
DS8203-05 April 2011www.richtek.com
2
5V
ALWAYS ON
4.7µF
V
CC
V
OUT5
5V
C10
C13
0.1µF
C1
+
R7
15k
R8
10k
C2
1µF
C3
1µF
C6
10µF
L1
AO4702
D3
C12
0.22µF
R1
3.9
C5
0.1µF
Q1
BSC119N03
BAT254
D1
SEE
TABLE
R2
47
R3
2.2
C8
0.1µF
17
5
11
20
14
16
15
19
13
21
9
8
23
VCC
ILIM3
ILIM5
VIN
BOOT5
UGATE5
PHASE5
LGATE5
TON
VOUT5
FB5
VREF
GND
18
LDO5
RT8203
V
IN
7V to 24V
3
ON3
4
ON5
25
LDO3 3.3V ALWAYS ON
PRO
BOOT3
UGATE3
PHASE3
LGATE3
VOUT3
FB3
SKIP
PGOOD
EN
NC
R6
1M
10
6
R4
2.2
28
26
27
24
BSC119N03
22
7
12
1
2
D2
BAT254
C9
0.1µF
V
CC
100k
R5
C4
4.7µF
Q2
AO4702
Q4Q3
Power-Good
INDICATOR
C7
10µF
D4
L2
V
V
ON
REF
CC
OFF
R9
6.5k
R10
10k
RT8203
V
OUT3
3.3V
C11
C14
0.1µF
Frequen cy-depe ndent Components
VOUT5 VOUT3
TON = VCC TON = GND TON = VCC TON = GND
f = 200kHz f = 400kHz f = 300kHz f = 500kHz
L1 = 7.6μH L1 = 5.6μH L2 = 4.7μH L2 = 3μH
C10 = 330μF C10 = 150μF C11 = 470μF C11 = 220μF
Figure 2. Adjustable V oltage Regulator
DS8203-05 April 2011 www.richtek.com
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RT8203
Functional Pin Description
Pin No. Pin Name Pin Function
1 NC Connect to GND.
2 PGOOD
3 ON3
4 ON5
5 ILIM3
6 EN
7 FB3
8 VREF
9 FB5
10
11 ILIM5
PRO
Po wer Goo d O p en D rain Outpu t. PGO OD is pul le d low if either outp ut i s disa ble or is
more than 8.75% bel ow its normal val ue.
VOUT 3 Enabl e In put. T he 3.3V SMP S i s ena ble if ON 3 is greater than the on leve l
and disa bl e i f ON3 is less t han the off l evel . If ON 3 i s co nnec ted to V
SMPS starts after the 5V SMPS reached regul ation(delay start). Force ON3 below the
clear fault level to reset the fault latched.
VOUT5 Enable Input. The 5V SMPS is enable if ON5 is greater than the on level and
disab le i f ON 5 is le ss than the off level . If ON 5 is connec ted t o VRE F, the 5 V SMP S
starts after the 3.3V SMPS reached regulation(delay start). Force ON5 below the clear
fault level to reset the fault latched.
VOUT3 Current Limit Adjustment. The GND-PHASE3 current limit threshold defaults
to 100mV if ILIM3 is tied to VCC. In adjustable mode, the current limit threshold is 1/10
the voltage seen at ILIM3 over 0.5V to 3V range. The logic threshold for switch over to
100mV default value is approxi mately VCC − 1V.
Enable Control Input. The device enters its 15μA supply current shutdown mode if EN
is less than the EN input falling edge trip level and does not restart until EN is greater
than the E N input risin g edg e tr ip lev el. Co nnect E N to VI N for auto mat icall y star tu p.
EN can be connected to VIN through a resistive voltage divider to implement a
programmable undervoltage lockout.
VOUT3 Feedback Input. Connect FB3 to GND for fixed 3.3V operation. Connect FB3
to a resistive voltage divider from VOUT3 to GND to adjust the output from 2V to 5.5V.
2V Reference Output. Bypass to GND with a 0.22μF
up to 10 0μA f or ex terna l l oad s. Loa din g V REF degr a des FBx and V O UTx accu ra cy
according to the VREF load regulation error.
VOUT5 Feedback Input. Connect FB5 to GND for fixed 5V operation. Connect FB5 to
a resistive voltage divider from VOUT5 to GND to adjust the output from 2V to 5.5V.
Over Vo lta ge and Under Voltage Fault P rotecti on En able/Disa ble. Conn ect PRO to
VCC to disabl e Over Voltage and Under Voltage protection. Connect PRO to GND to
enable Ov er Voltage and Under Voltage protection.
VOUT5 Current Limit Adjustment. The GND − PHASE5 cu rrent limit threshold defaults
to 100mV if ILIM5 is tied to VCC. In adjustable mode, the current limit threshold is 1/10
the voltage seen at ILIM5 over 0.5V to 3V range. The logic threshold for switch over to
100mV default value is approxi mately VCC − 1V.
REF
capacitor. VRE F can source
(MIN)
, the 3.3V
12
13 TON
14 BOOT5
4
SKIP
Operation Mode Input Control. Connect SKIP to GND for diode-emulation mode
(DEM ) or to VCC fo r CCM m ode(f ixed frequency). Conn ect to VREF or flo ating for
ultrason ic mode.
Fr eque ncy S elec t Inp ut. C onne ct to V CC f or 200 k Hz/300k Hz ope ratio n an d to G ND
for 400kHz /500kHz operation (VOUT5/VOUT3 switching frequency respectively).
Bo ost Capac i tor Conn ec tio n for 5V S MP S. Co nnect an e xt ernal c eram ic c apac itor to
PHAS E5 and an exte rnal diode t o LDO5.
To be continued
DS8203-05 April 2011www.richtek.com
Pin No. Pin Name Pin Function
15 PHASE5
16 UGATE5
17 VCC
18 LDO5
19 LGATE5
20 VIN
21 VOUT5
22 VOUT3
23 GND Anal og and Pow er Ground.
24 LGATE3
25 LDO3
26 UGATE3
27 PHASE3
28 BOOT3
Inductor Connection for 5V SMPS. PHASE5 is the internal lower supply rail for the
UGATE5 high side gate driv er , and the current sense input for the 5V SMPS.
High Side N-MOSFET Floating Gate-Driver Output for VOUT5. Swings between
PH ASE5 a nd BOOT 5.
Analog Supply Voltage Input for the inter nal analog integrated circuit. Bypass to GND
with a 1μF cera mic capaci tor.
5V Linear Regulator Output. LDO5 is the gate driver supply for the external
MOSFETs. LDO5 can provide a total of 100mA, including the MOSFET gate-driver
requirements and external loads. If VOUT5 is greater than the LDO5 switchover
threshold, the LDO5 regulator shuts down and LDO5 pin connects to VOUT5 through
a 1. 4Ω switch. Bypass a 4.7μF ceramic capacitor to GND.
Low side N-MOSFET Gate-Drive Output for VOUT5. Swings between GND and
LDO5.
Power-Supply Input. VIN powers the LDO5/LDO3 linear regulators and is also used
for PWM contr ol circuits. Connect VI N to the batter y input or the AC adapte r output .
VOUT5 Sense Input . Connec t to the 5V outp ut. VO UT5 is an i nput to the PWM co nt ro l
circuit. It also serves as the 5V feedback input in fixed-voltage mode. If VOUT5 is
greater than the LDO5 switchover threshold, the LDO5 shuts down and LDO5
co nnect s to VOUT 5 through 1.4Ω switch .
VOUT3 Sense Input. Connect to the 3.3V output. VOUT3 is an input to the PWM
control circuit. It also serves as the 3.3V feedback input in fixed voltage mode. If
VOUT3 is greater than the LDO3 switchover threshold, the LDO3 shuts down and
LDO 3 connects to VOUT3 throug h 1.5Ω swi t ch.
Low side N-MOSFET Gate-Drive Output for VOUT3. Swings between GND and
LDO5.
3.3V Linear Regulator Output . LDO 3 can provide a total of 100mA to external loads. If
VOUT3 is greater than the LDO3 switchover threshold, the LDO3 regulator shuts
down and LDO3 pin connects to VOUT3 through a 1.5Ω switch. Bypass a 4.7μF
ceramic capacitor to GND.
High Side N-MOSFET Floating Gate-Driver Output for VOUT3. Swings between
PH ASE3 a nd BOOT 3.
Inductor Connection f or 3.3V SMPS. PHASE3 is the internal lower supply rail for the
UGATE3 high side gate driv er, and th e current sense inpu t fo r the 3.3V SMPS.
Boost Capacitor Con nec tion f or 3.3V SMPS. Connect an ext er nal ceramic capacitor to
PHASE3 and an external diode to LDO5.
RT8203
DS8203-05 April 2011 www.richtek.com
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RT8203
Function Block Diagram
BOOT3
UGATE3
PHASE3
LGATE3
ILIM3
FB3
VOUT3
Driver
Driver
VIN
U3 U5
VOUT3
L3 L5
PWM
Controller
VOUT5
PWM
Controller
Driver
Driver
PGOOD
GND
BOOT5
UGATE5
PHASE5
LGATE5
ILIM5
FB5
VOUT5
VOUTx
VREF
FBx
PRO
PGOOD
LDO3
ON3
ON5
EN
PRO
SS
(internal)
VIN
On-time
Compute
1.1xV
REF
0.7xV
REF
0.9xV
REF
EN3
LDO
(3V)
Power Sequence
+
GM
-
+
-
+
+
Logic
OV
UV
+
-
S2
2.93V
LDO5
+
Comp
S1
Latch
Thermal
Shutdown
1-SHOT
R
Ton
TRIG
Q
PWM Controller
Ton
QN
Detector
4.65V
25Khz
TRIG
QN
Min. Toff
1-SHOT
Detector
Current
Limit
+
-
2V
Reference
Zero
+
EN5
LDO
(5V)
+
+
-
LDO5
VCC
VREF
Ux
Lx
SKIP
PHASEx
ILIMx
DS8203-05 April 2011www.richtek.com
6
Absolute Maximum Ratings (Note 1)
RT8203
z Input Voltage, V
z BOOTx to GND ------------------------------------------------------------------------------------------------- −0.3V to 30V
z PHASEx to BOOTx-------------------------------------------------------------------------------------------- −6V to 0.3V
z PHASEx to GND------------------------------------------------------------------------------------------------ −1V to 25V
z VCC, LDOx, VOUTx, ONx, VREF, FBx, SKIP, PRO, PGOOD to GN D --------------------------- −0.3V to 6V
z UGATEx to PHASEx ------------------------------------------------------------------------------------------ −0.3V to (V
z ILIMx to GND ---------------------------------------------------------------------------------------------------- −0.3V to (V
z LGA TEx to G ND ------------------------------------------------------------------------------------------------ −0.3V to (V
z TO N to G ND------------------------------------------------------------------------------------------------------ −0.3V to 6V
z LDOx, VREF Short Circuit to GN D------------------------------------------------------------------------- Momentary
z LDOx Circuit (Internal Regulator) Continuous ----------------------------------------------------------- 100mA
z LDOx Circuit (Switchover to VOUTx) Continuous ------------------------------------------------------ 200mA
z Power Dissipation, P
, EN to GND ------------------------------------------------------------------------------ −0.3V to 25V
IN
@ TA = 25°C
D
BOOTx
CC
LDO5
SSOP-28 -------------------------------------------------------------------------------------------------------- 1.053W
z Package Thermal Resistance (Note 2)
SSOP-28, θJA---------------------------------------------------------------------------------------------------- 95°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
+ 0.3V)
+ 0.3V)
+ 0.3V)
Recommended Operating Conditions (Note 4)
z Input V oltage, V
z Control Voltage, V
z Junction T emperature Range--------------------------------------------------------------------------------- –10°C to 125°C
z Ambient T emperature Range--------------------------------------------------------------------------------- –10°C to 85°C
----------------------------------------------------------------------------------------------- 7V to 24V
IN
------------------------------------------------------------------------------------------- 5V ± 5%
CC
Electrical Characteristics
(VIN = 12V, No load on LDOx, VOUTx and VREF, ONx = VCC, VEN = 5V, TA = 25°C, unless Otherwise specification)
Parameter Symbol Test Conditions Min Typ Max Unit
Main SMPS Controllers
Input Voltage Range VIN LDO5 in regulation 7 -- 24 V
V
VOUT3 Output V oltage in Fixed
Mode
VOUT5 Output V oltage in Fixed
Mode
V
OUT3
V
OUT5
Output Voltage in Adj ustable Mode VIN = 7V to 24V, either SMPS 1.975 2.00 2.025 V
Output Voltage Adjust Range Either SMPS 2 -- 5.5 V
FBx Adjustable-Mode Threshold
Voltage
Dual-Mode comparator 0.12 -- 0.22 V
= 7V to 24V, FB3 = GND,
IN
= 5V
V
SKIP
= 8V to 24V, FB5 = GND,
V
IN
= 5V
V
SKIP
3.285 3.330 3.375 V
4.975 5.059 5.125 V
To be continued
DS8203-05 April 2011 www.richtek.com
7
RT8203
Parameter Symbol Test Conditions Min Typ Max Unit
DC Loa d Regul ation ΔV
Line R egula ti on ΔV
Curre nt-Limit Thresho ld
(P ositive, Default)
Curre nt-Limit Thresho ld
(P osit ive , Adjustable)
I
Zero-Current Threshold
Ei th er SMP S, V
LOAD
Ei th er SMP S, V
Ei th er SMP S, V
Ei th er SMP S, 7V < VIN <24V --- 0.005 -- %/V
LINE
= VCC, GND to PHASEx 90 100 110 mV
LIMx
V
= 0.5V, GND to PHASEx 40 50 60
ILIMx
V
= 1V, GN D to PHASEx 90 100 110
ILIMx
= 2V, GN D to PHASEx 185 200 215
V
ILIMx
SKIP = GND, I
= 5V, 0 to 5A -- −0.1 --
SKIP
= GND, 0 to 5A -- −1.5 --
SKIP
= 2V, 0 to 5A
SKIP
= VCC, GND − PH ASEx
LIMx
-- −1.7 --
-- 3 -- mV
%
mV
Soft-Start Ramp Time Zero to full limit -- 1.5 --- ms
5V SMPS -- 200 -- V
3.3V SMPS -- 3 00 - 5V SMPS -- 400 --
kHz
3.3V SMPS -- 5 00 - 25 -- --
REF
V
V
V
V
V
V
V
V
= 5.05V 1.854 2.060 2.265
OUT5
= 3.33V 0.821 0.912 1.003
OUT3
= 5.05V 0.876 1.030 1.184
OUT5
= 3.33V 0.467 0.546 0.625
OUT3
= 5.05V -- 92 --
OUT5
= 3.33V -- 88 --
OUT3
= 5.05V -- 84 --
OUT5
= 3.33V -- 80 --
OUT3
μs
%
Operating Frequency f
On-Time Pulse Width
Minimu m Off -time t
Ma x imu m Duty Cycle
= 5V ,
TON
V
= VCC
SKIP
OSC
V
TON
V
SKIP
= G ND
= VCC
SKIP = V
V
= 5V
TON
V
= G ND
TON
300 400 500 ns
OFF
V
= 5V
TON
V
= G ND
TON
Internal Regulator And Reference Voltage
LDO5 Output Voltage
ONx = GND, 7 V < V
0 < I
< 100mA (Note 5)
LDO5
< 24V,
IN
4.90 5.0 5.10 V
LDO 5 Short-Circuit Cu rrent LDO 5 = GND -- 3 50 - - mA
VCC Unde r-Vo lt age
Lockout Fault Threshold
LDO5 Bootstrap Switch
Threshold
LDO5 Bootstrap Switch
Resistance
LDO3 Output Voltage
LDO 5 to VOUT 5, V OUT5 = 5V -- 1.4 3.2 Ω
Falling edge of VCC,
hysteresis = 1%
Fall ing edge of VOUT5 , risi ng edge at
VOUT5 r egul ati on poi nt
ONx = GND, 7 V < V
0 < I
< 100mA (Note 5)
LDO3
< 24V,
IN
3.95 4.25 4.55 V
4.52 4.65 4.78 V
3.28 3.35 3.42 V
LDO 3 Short-Circuit Cu rrent LDO 3 = GND -- 1 75 - - mA
LDO3 Bootstrap Switch
Threshold
Fall ing edge of VOUT3 , risi ng edge at
VOUT3 r egul ati on poi nt
2.82 2.93 3.04 V
To be continued
DS8203-05 April 2011www.richtek.com
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