Richtek RT8205LGQW, RT8205LZQW, RT8205MGQW, RT8205MZQW Schematic [ru]
High Efficiency, Main Power Supply Controller
for Notebook Computer
RT8205L/M
General Description
The RT8205L/M is a dual step-down, switch mode power
supply controller generating logic-supply voltages in
battery powered systems. It includes two Pulse-Width
Modulation (PWM) controllers adjustable from 2V to 5.5V,
and also features fixed 5V/3.3V linear regulators. Each
linear regulator provides up to 100mA output current with
automatic linear regulator bootstrapping to the PWM
outputs. An optional external charge pump can be
monitored through SECFB (RT8205M). The RT8205L/M
includes on-board power up sequencing, a power good
output, internal soft-start, and internal soft-discharge
output that prevents negative voltage during shutdown.
The constant on-time PWM control scheme operates
without sense resistors and provides 100ns response to
load transient response while maintaining nearly constant
switching frequency. To eliminate noise in audio
applications, an ultrasonic mode is included, which
maintains the switching frequency above 25kHz. Moreover,
the diode-emulation mode maximizes efficiency for light
load applications. The RT8205L/M is available in a
WQFN-24L 4x4 package.
Ordering Information
RT8205
Package Type
QW : WQFN-24L 4x4 (W-Type)
Features
zz
z Constant On-time Control with 100ns Load Step
zz
Response
zz
z Wide Input Voltage Range : 6V to 25V
zz
zz
z Dual Adjustable Outputs from 2V to 5.5V
zz
zz
z Secondary Feedback Input Maintains Charge Pump
zz
V oltage (RT8205M)
zz
z Fixed 3.3V and 5V LDO Output : 100mA
zz
zz
z 2V Reference Voltage
zz
zz
z Frequency Selectable via TONSEL Setting
zz
zz
z 4700ppm/
zz
zz
z Programmable Current Limit Combined with
zz
°°
°C R
°°
Current Sensing
DS(ON)
Enable Control
zz
z Selectable PWM, DEM, or Ultrasonic Mode
zz
zz
z Internal Soft-Start and Soft-Discharge
zz
zz
z High Efficiency up to 97%
zz
zz
z 5mW Quiescent Power Dissipation
zz
zz
z Thermal Shutdown
zz
zz
z RoHS Compliant and Halogen Free
zz
Applications
z Notebook and Sub-Notebook Computers
z 3-Cell and 4-Cell Li+ Battery-Powered Devices
Lead Plating System
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)
Pin Function
L : Default
M : With SECFB
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.
DS8205L/M-05 June 2011 www.richtek.com
1
RT8205L/M
Marking Information
EM= : Product Code
EM=YM
DNN
EM YM
DNN
Pin Configurations
ENTRIP1
TONSEL
ENTRIP2
YMDNN : Date Code
EM : Product Code
YMDNN : Date Code
VOUT1
1
2
FB1
3
REF
4
5
FB2
6
78910 1211
PGOOD
BOOT1
21 20 1924 2223
GND
UGATE1
25
RT8205MGQWRT8205LGQW
EN= : Product Code
EN=YM
YMDNN : Date Code
DNN
RT8205MZQWRT8205LZQW
EN : Product Code
EN YM
YMDNN : Date Code
DNN
(TOP VIEW)
LGATE1
PHASE1
18
NC
17
VREG5
16
VIN
15
GND
14
SKIPSEL
13
EN
ENTRIP1
FB1
REF
TONSEL
FB2
ENTRIP2
VOUT1
1
2
3
4
5
6
78910 1211
PGOOD
BOOT1
21 20 1924 2223
GND
UGATE1
PHASE1
25
LGATE1
18
17
16
15
14
13
SECFB
VREG5
VIN
GND
SKIPSEL
EN
VOUT2
VREG3
BOOT2
PHASE2
UGATE2
WQFN-24L 4x4
RT8205L
VOUT2
VREG3
LGATE2
BOOT2
LGATE2
PHASE2
UGATE2
WQFN-24L 4x4
RT8205M
DS8205L/M-05 June 2011www.richtek.com
2
Typical Application Circuit
1
C
1
0
µ
F
o
ON
R
R
T
O
O
B
C
2
0
.
F
1
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1
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2
2
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L
1
6
8
.
µ
V
O
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1
T
5
V
C
3
2
2
0
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8
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1
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R
5
C
4
R
1
2
k
1
5
R
1
3
k
1
0
F
P
W
OFF
RT8205L/M
V
N
I
5
2
o
t
V
6
8
R
3
.
9
16
C
1
0
0
.
F
1
µ
0
4
21
0
1
22
VIN
UGATE1
BOOT1
RT8205L
UGATE2
BOOT2
PHASE2
LGATE2
GND
20
19
24
PHASE1
LGATE1
VOUT1
VOUT2
FB2
ENTRIP1
ENTRIP2
2
FB1
3
4
14
13
REF
TONSEL
SKIPSEL
EN
5
F
GND
VREG5
PGOOD
VREG3
R
0
1
10
9
11
0
R
0
B
O
O
T
2
C
0
12
15
7
5
R
1
M
L
I
I
1
k
0
1
6
5
R
2
M
L
I
I
k
0
5
1
25 (Exposed Pad)
17
C
9
F
µ
.
7
4
23
8
6
1
C
F
µ
.
7
4
Q2
BSC119
N03S
1
1
µ
1
F
.
Q4
BSC119
N03S
V
5
R
6
0
k
0
1
P
G
3
.
3
3
1
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2
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4
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7
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0
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7
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2
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4
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5
k
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1
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3
3
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2
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0
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1
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0
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V
N
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2
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6
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BSC119
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H
V
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V
5
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3
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2
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9
1
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6
R
5
BSC119
C
4
8
C
1
R
1
2
k
1
5
R
1
F
µ
3
1
0
k
C
6
µ
F
1
.
0
8
C
1
.
0
µ
F
Q3
N03S
2
D
4
D
A
B
0
D
1
D
3
2
5
T
4
CP
ON
OFF
R
3
.
9
16
0
C
1
0
.
1
F
µ
R
0
4
R
O
O
1
T
B
C
2
.
1
F
µ
21
0
22
20
19
24
2
C
5
0
µ
F
1
.
VIN
UGATE1
BOOT1
PHASE1
LGATE1
VOUT1
FB1
RT8205M
UGATE2
BOOT2
PHASE2
LGATE2
GND
VOUT2
FB2
ENTRIP1
ENTRIP2
GND
VREG5
7
C
F
µ
.
1
0
PGOOD
R
6
0
0
k
2
18
SECFB
R
7
k
9
3
13
EN
VREG3
REF
TONSEL
SKIPSEL
R
0
1
10
9
11
0
R
0
O
2
T
O
B
C
0
12
15
7
5
R
L
I
I
1
M
0
5
1
1
6
k
R
L
I
I
2
M
k
0
5
1
25 (Exposed Pad)
17
C
9
F
µ
.
7
4
23
8
C
6
1
.
7
4
F
µ
3
C
5
1
µ
2
2
.
0
4
14
Q2
BSC119
N03S
1
1
µ
F
1
.
Q4
BSC119
N03S
V
5
R
6
k
0
0
1
P
3
V
2V
G
.
3
REF
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r
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3
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1
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1
4
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V
.
3
3
F
µ
C
2
1
C
2
0
0
.
1
F
µ
DS8205L/M-05 June 2011 www.richtek.com
3
RT8205L/M
Functional Pin Description
Pin No. Pin Name Pin Function
Channel 1 Enable and Current Limit Setting Input. Connect a resistor to GND to
set the threshold for channel 1 synchronous R
1 ENTRIP1
2 FB1
3 REF
4 TON SEL
5 FB2
6 ENTRIP2
7 VOUT2
8 VREG3 3.3V Linear Regulator Output.
9 BOOT2
10 UGATE2
11 PHASE2
12 LGATE2
13 EN
14 SKIPSEL
15,
25 (Exposed Pad)
16 VIN Supply Input for 5V/3.3V LDO and Feed Forward On Time Circuitry.
17 VREG5
GND
current limit threshold is 1/10th the voltage seen at ENTRIP1 over a 0.515V to 3V
range. There is an internal 10μA current source from VREG5 to ENTRIP1. Leave
ENTRIP1 floating or drive it above 4.5V to shutdown channel 1.
SMPS1 Feedback Input. Connect FB1 to a resistive voltage divider from VOUT1
to GND to adjust output from 2V to 5.5V.
2V Reference Output. Bypass to GND with a minimum 0.22μF capacitor. REF
can source up to 100μA for external loads. Loading REF degrades FBx and
output accuracy according to the REF load regulation error.
Frequency Selectable Input for VOUT1/VOUT2 respectively.
400kHz/500kHz : Connect to VREG5 or VREG3
300kHz/375kHz : Connect to REF
200kHz/250kHz : Connect to GND
SMPS2 Feedback Input. Connect FB2 to a resistive voltage divider from VOUT2
to GND to adjust output from 2V to 5.5V.
Channel 2 Enable and Current Limit Setting Input. Connect a resistor to GND to
set the threshold for channel 2 synchronous R
current limit threshold is 1/10th the voltage seen at ENTRIP2 over a 0.515V to 3V
range. There is an internal 10μA current source from VREG5 to ENTRIP2. Leave
ENTRIP2 floating or drive it above 4.5V to shutdown channel 1.
Bypass Pin for SMPS2. Connect to the SMPS2 output to bypass efficient power
for VREG3 pin. VOUT2 is also for the SMPS2 output soft-discharge.
Boost Flying Capacitor Connection for SMPS2. Connect to an external capacitor
according to the typical application circuits.
Upper Gate Driver Output for SMPS2. UGATE2 swings between PHASE2 and
BOOT2.
Switch Node for SMPS2. PHASE2 is the internal lower supply rail for the
UGATE2 high side gate driver. PHASE2 is also the current sense input for the
SMPS 2.
Lower Gate Drive Output for SMPS2. LGATE2 swings between GND and
VREG 5.
Master Enable Input. The REF/VREG5/VREG3 are enabled if it is within logic
high level and disabled if it is less than the logic low level.
Operation Mode Selectable Input.
Connect to VREG5 or VREG3 : Ultrasonic Mode
Connect to REF : DEM Mode
Connect to GND : PWM Mode
Ground for SMPS Controller. The exposed pad must be soldered to a large PCB
and connected to GND for maximum power dissipation.
5V Linear Regulator Output. VREG5 is also the supply voltage for the lower gate
driver and analog supply voltage for the device.
sense. The GND − PHASE1
DS(ON)
sense. The GND − PHASE2
DS(ON)
T o be continued
DS8205L/M-05 June 2011www.richtek.com
4
RT8205L/M
Pin No. Pin Name Pin Function
NC
(RT8205L)
18
SECF B
(RT8205M)
19 LGATE1 Lower Gate Drive Output for SMPS1. L GATE1 swings b etween GND and VREG5.
20 PHAS E1
21 UGATE1 Upper Gate Driver Output for SMPS1. UGATE1 swings between PHASE1 and BOOT1.
22 BOOT1
23 PGOOD Po wer Good Output for Channel 1 and Channel 2. (Logical AND)
24 VOUT1
Function Block Diagram
No Int ernal Co nnection.
Charge Pump Co ntrol Pin . The SECFB is used to mon itor the opt ional external 14V
cha rge pump. Connect a resistive voltage d ivi der from the 14 V charge pump ou tput to
GND to detect the output. If SECFB drops below the threshold volt age, LGATE1 will
provide 33kHz switching frequency for the ch arge pump. This will refresh t he ext ernal
cha rge pump driven by LGATE1 without o ver disc harging the output voltage.
Switch Node for SMPS1. PHASE1 is the internal lower supply rail for the UGATE1 high
side gate driver. PHASE1 is also the current sense input for the SMPS1.
Boost Flying Ca pacito r Conne ction f or SMPS1. Conne ct t o an external capa ci tor
according to the typical application circuits.
Bypass Pin for SMPS1. Connect to the SMPS1 output to bypass efficient power for
VREG5 pin. VOUT1 is also f or the SMPS1 output s oft-discharge.
TONSEL SKIPSEL
BOOT1
UGATE1
PHASE1
LGATE1
FB1
ENTRIP1
EN
VOUT1
VREG5
VREG5
VREG5
SW5 Threshold
Power-On
Sequence
Clear Fault Latch
VREG5
SMPS1
PWM Buck
Controller
Thermal
Shutdown
SMPS2
PWM Buck
Controller
SW3 Threshold
REF
VREG5
VREG3
VREG5
BOOT2
UGATE2
PHASE2
LGATE2
VOUT2
FB2
ENTRIP2
PGOOD
GND
VREG3
VIN
REF
DS8205L/M-05 June 2011 www.richtek.com
5
RT8205L/M
Absolute Maximum Ratings (Note 1)
z VIN, EN to GND ----------------------------------------------------------------------------------------------- −0.3V to 30V
z PHASEx to GND
DC---------------------------------------------------------------------------------------------------------------- −0.3V to 30V
< 20ns ----------------------------------------------------------------------------------------------------------- −8V to 38V
z BOOTx to PHASEx ------------------------------------------------------------------------------------------ −0.3V to 6V
z ENTRIPx, SKIPSEL, TONSEL, PGOOD to GND ------------------------------------------------------ −0.3V to 6V
z VREG5, VREG3, FBx , VOUTx, SECFB, REF to GND ---------------------------------------------- −0.3V to 6V
z UGATEx to PHASEx
DC---------------------------------------------------------------------------------------------------------------- −0.3V to (VREG5 + 0.3V)
< 20ns ----------------------------------------------------------------------------------------------------------- −5V to 7.5V
z LGATEx to GND
DC---------------------------------------------------------------------------------------------------------------- −0.3V to (VREG5 + 0.3V)
< 20ns ----------------------------------------------------------------------------------------------------------- −2.5V to 7.5V
z Power Dissipation, P
WQFN-24L-4x4 ------------------------------------------------------------------------------------------------ 1.923W
z Package Thermal Resistance (Note 2)
WQFN-24L-4x4, θJA------------------------------------------------------------------------------------------ 52°C/W
WQFN-24L-4x4, θJC------------------------------------------------------------------------------------------ 7°C/W
z Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------ 260°C
z Junction Temperature ---------------------------------------------------------------------------------------- 150°C
z Storage Temperature Range -------------------------------------------------------------------------------- −65°C to 150°C
z ESD Susceptibility (Note 3)
HBM (Human Body Mode) ---------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ----------------------------------------------------------------------------------------- 200V
@ TA = 25°C
D
Recommended Operating Conditions (Note 4)
z Supply Input Voltage, V
z Junction Temperature Range ------------------------------------------------------------------------------- −40°C to 125°C
z Ambient Temperature Range ------------------------------------------------------------------------------- −40°C to 85°C
----------------------------------------------------------------------------------- 6V to 25V
IN
DS8205L/M-05 June 2011www.richtek.com
6
Electrical Characteristics
(VIN = 12V, VEN = 5V, V
Parameter Symbol Test Conditions Min Typ Max Unit
Input Supply
ENTRIP1
= V
ENTRIP2
= 2V, No Load, T
= 25°C, unless otherwise specified)
A
RT8205L/M
VIN Standby Current I
VIN Shutdown Supply
Current
Quiescent Power
Consumption
VIN_SBY
I
VIN_SHDN
P
VIN
+P
PVCC
SMPS Output and FB Voltage
FBx Volt age V
SECFB Voltage V
Output Voltage Adjust
Range
V
Dischar ge
OUTx
Curr ent
FB x
SECFB
V
OU Tx
V
On-Time
On-Time Pulse Width tON
VIN = 6V to 25V, ENTRIPx = GND -- 200 -- μA
V
= 6V to 25V,
IN
ENTRIPx = EN = GND
Both SMPS On, V
SKIPSEL = REF, V
= 3.3V (Note 5)
V
OUT2
= 2.1V,
FBx
OUT1
= 5V,
-- 20 40 μA
-- 5 7 mW
DEM Mode 1.975 2 2.025
PWM Mode (Note 6) -- 2 --
V
Ultrasonic Mode -- 2.032 --
1.92 2 2.08 V
SMPS1, SMPS2 2 -- 5.5 V
= 0.5V, V
OUTx
TONSEL = G ND
TONSEL = REF
TONSEL =
VREG 5
ENTRIPx
= 0V 10 45 -- mA
V
= 5.05V ( 200kHz) 189 5 210 5 2315
OUT1
= 3.33V (250kHz) 999 1110 1221
V
OUT2
V
= 5.05V ( 300kHz) 122 7 140 3 1579
OUT1
= 3.33V (375kHz) 647 740 833
V
OUT2
V
= 5.05V ( 400kHz) 895 105 2 1209
OUT1
= 3.33V (500kHz) 475 555 635
V
OUT2
ns
Minimum Off-Time t
Ultrasonic Mode
Frequency
FBx = 1.9V 200 300 400 ns
OFF
SKIPSEL = VREG5 or VREG3 22 33 -- kHz
Soft-Start
Soft-Start Time t
Internal Soft-Start -- 2 -- ms
SSx
Current Sen se
ENTRIPx Source
Curr ent
I
ENTRIPx
V
ENTRIPx
= 0.9V 9.4 10 10.6 μA
ENTRIPx Current
Temperature
TC
IENTRIPx
In Comparison w ith 25°C ( Note 6) -- 4700 -- ppm/°C
Coefficient
ENTRIPx Adjustment
Range
Curr ent Limit
Threshold
Zero-Current
Threshold
V
ENTRIPx
GND − PHASEx, V
= I
ENTRIPx
x R
ENTRIPx
ENTRIPx
0.515 -- 3 V
= 2V 180 200 220 mV
GND − PHASEx in DEM -- 3 -- mV
T o be continued
DS8205L/M-05 June 2011 www.richtek.com
7
RT8205L/M
Parameter Symbol Test Conditions Min Typ Max Unit
Internal Regulator and Reference
V
OUT1
V
VREG5 Output Voltage V
VREG3 Output Voltage V
VREG5 Output Current I
VREG3 Output Current I
VREG5 Switchover
Threshold to V
OUT1
VREG3 Switchover
Threshold to V
OUT2
VREGx Switchover Equivalent
Resistance
REF Output Voltage V
VREG5
VREG3
V
VREG5
V
VREG3
V
SW5
V
SW3
R
VREGx to V
SWx
No External Load 1.98 2 2.02 V
REF
OUT1
I
VREG5
V
OUT1
I
VREG5
V
OUT2
V
OUT2
I
VREG3
V
OUT2
I
VREG3
VREG5
VREG3
V
OUT1
V
OUT1
V
OUT2
V
OUT2
REF Load Regulation 0 < I
= GND, I
= GND, 6.5V < VIN < 25V,
< 100mA
= GND, 5.5V < VIN < 25V,
< 50mA
= GND, I
= GND, 6.5V < VIN < 25V,
< 100mA
= GND, 5.5V < VIN < 25V,
< 50mA
= 4.5V, V
= 3V, V
Rising Edge 4.6 4.75 4.9
Falling Edge 4.3 4.4 4.5
Rising Edge 2.975 3.125 3.25
Falling Edge 2.775 2.875 2.975
OUTx
< 100μA -- 10 -- mV
LOAD
< 100mA 4.8 5 5.2
VREG5
4.75 5 5.25
4.75 5 5.25
< 100mA 3.2 3.33 3.46
VREG3
3.13 3.33 3.5
3.13 3.33 3.5
= GND 100 175 250 mA
OUT1
= GND 100 175 250 mA
OUT2
, 10mA -- 1.5 3 Ω
V
V
V
V
REF Sink Current REF in Regulation 5 -- -- μA
UVLO
VREG5 Under Voltage
Lockout Threshold
VREG3 Under Voltage
Lockout Threshold
SMPSx off -- 2.5 -- V
Rising Edge -- 4.20 4.35
V
Falling Edge 3.7 3.9 4.1
Power Good
PGOOD Detect, FBx Falling Edge 82 85 88
PGOOD Threshold
Hysteresis, Rising Edge with SS
Delay Time
-- 6 --
%
PGOOD Propagation Delay Falling Edge, 50mV Overdrive -- 10 -- μs
PGOOD Leakage Current High State, Forced to 5.5V -- -- 1 μA
PGOOD Output Low Voltage I
= 4mA -- -- 0.3 V
SINK
Fault Detection
Over Voltage Protection Trip
Threshold
Over Voltage Protection
Propagation Delay
Under Voltage Protection Trip
Threshold
UVP Shutdown Blanking Time t
V
FB_OVP
FBx = 2.35V -- 5 -- μs
V
FB_UVP
SHDN_ UVP
OVP Detect, FBx Rising Edge 109 112 116 %
UVP Detect, FBx Falling Edge 49 52 56 %
From ENTRIPx Enable -- 5 -- ms
T o be continued
DS8205L/M-05 June 2011www.richtek.com
8
Parameter Symbol Test Conditions Min Typ Max Unit
Thermal Shutdown
RT8205L/M
Thermal Shutdown T
Thermal Shutdown
Hysteresis
SHDN
-- 10 -- °C
Logic Input
SKIPSEL Input Voltage
EN Threshold
Voltage
Logic-High VIH 1 -- --
Logic-Low V
ENTRI Px
IL
EN Voltage VEN
EN Current IEN
Input Leakage Current
Internal BOOT Switch
Internal Boost Switch
On-Resistance
Power MOSFET Drive rs
-- 150 -- °C
Low Level (PWM Mode) -- -- 0.8
REF Level (DEM Mode) 1.8 -- 2.3
V
High Level (Ultrasonic Mode) 2.7 -- --
Low Level (SMPS Off) -- -- 0.25
On Level (SMPS On) 0.515 -- 3 ENTRIPx Input Voltage V
V
High Level (SMPS Off) 4.5 -- --
V
-- -- 0.4
Floating, Default Enable 2.4 3.3 4.2
V
= 0.2V, Source 1.5 3 5
EN
V
= 5V, Sink -- 3 8
EN
V
OUT1
V
OUT1
V
OUT1
V
TONSEL
V
SECFB
/ V
/ V
/ V
= 0V or 5V −1 -- 1
= 200kHz / 250kHz -- -- 0.8
OUT2
= 300kHz / 375kHz 1.8 -- 2.3 TONSEL Setting Voltage
OUT2
= 400kHz / 500kHz 2.7 -- --
OUT2
, V
SKIPSEL
= 0V or 5V −1 -- 1
V
μA
V
μA
VREG5 to BOOTx, 10mA -- 40 80 Ω
UGATEx On-Resistance
UGATEx, High State,
BOOTx to PHASEx F orced to 5V
UGATEx, Low State,
BOOTx to PHASEx F orced to 5V
-- 4 8
Ω
-- 1.5 4
LGATEx, High State -- 4 8
LGATEx On-Resistance
Ω
LGATEx, Low State -- 1.5 4
LGATEx Rising -- 30 --
Dead Time
ns
UGATEx Rising -- 40 --
DS8205L/M-05 June 2011 www.richtek.com
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