RT8202L/M
Single Synchronous Buck Controller
General Description
The RT8202L/M PWM controller provides the high efficiency, excellent transient response, and highDC output accuracy needed for stepping down high voltage batteries to generate low voltage CPU core, I/O, and chipset RAM supplies in notebook computers.
The constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency.
The RT8202L/M achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current mode PWMs. Efficiency is further enhanced by its ability to drive very large synchronous rectifier MOSFETs. The RT8202L is available in a WQFN-16L 4x4 package and the RT8202M is available in a WQFN-16L 3x3 package.
Features
zUltra-High Efficiency
zResistor Programmable Current Limit by Low Side RDS(ON) Sense (Lossless Limit)
z4700ppm/°C RDS(ON) Current Sensing
zQuick Load Step Response within 100ns
z1% VFB Accuracy over Line and Load
zAdjustable 0.75V to 3.3V Output Voltage Range
z3V to 26V Battery Input Voltage Range
zResistor Programmable Frequency
zIntegrated Bootstrap Switch
zOver Voltage Protection
zUnder Voltage Protection
zVoltage Ramp Soft-Start
zBuilt In Soft Discharge Output
zPower Good Indicator
zRoHS Compliant and 100% Halogen Free
Ordering Information |
Applications |
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z Notebook Computers |
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RT8202L/M |
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Package Type |
z CPU Core Supply |
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z Chipset/RAM Supply as Low as 0.75V |
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QW : WQFN-16L 4x4 (W-Type) |
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QW : WQFN-16L 3x3 (W-Type) |
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Lead Plating System |
Pin Configurations |
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G : Green (Halogen Free and Pb Free) |
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(TOP VIEW) |
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Z : ECO (Ecological Element with |
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Halogen Free and Pb free) |
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TON |
EN/DEM |
NC |
BOOT |
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L : WQFN-16L 4x4 |
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M : WQFN-16L 3x3 |
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Note : |
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16 |
15 |
14 |
13 |
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VOUT |
1 |
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12 |
UGATE |
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Richtek products are : |
VDD |
2 |
GND |
11 |
PHASE |
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` RoHS compliant and compatible with the current require- |
FB |
3 |
10 |
OC |
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17 |
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ments of IPC/JEDEC J-STD-020. |
PGOOD |
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9 |
VDDP |
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` Suitable for use in SnPb or Pb-free soldering processes. |
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6 |
7 |
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NC |
GND |
PGND |
LGATE |
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WQFN-16L 4x4 (RT8202L)/ |
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WQFN-16L 3x3 (RT8202M) |
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DS8202L/M-04 April 2011 |
www.richtek.com |
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RT8202L/M
Marking Information
RT8202LGQW |
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RT8202MGQW |
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EK= : Product Code |
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JJ= : Product Code |
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EK=YM |
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YMDNN : Date Code |
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JJ=YM |
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YMDNN : Date Code |
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DNN |
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DNN |
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RT8202LZQW |
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RT8202MZQW |
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EK : Product Code |
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JJ : Product Code |
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EK YM |
YMDNN : Date Code |
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JJ YM |
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YMDNN : Date Code |
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DNN |
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DNN |
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Typical Application Circuit
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RT8202L/M |
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16 |
TON |
BOOT |
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9 |
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V |
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VDDP |
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DDP |
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UGATE |
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5V |
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R2 |
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C1 |
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PHASE |
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2 |
VDD |
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C2 |
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R1 |
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LGATE |
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PGOOD |
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4 |
PGOOD |
OC |
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CCM/DEM |
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15 |
EN/DEM |
FB |
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6 , 17 (Exposed Pad) |
GND |
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7 |
PGND |
VOUT |
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* Optional |
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V |
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IN |
26V |
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3V to |
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R |
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TON |
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C4 |
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13 |
R3 |
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V |
12 |
R4 |
C3 |
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OUT |
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Q1 |
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L1 |
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11 |
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8 |
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Q2 |
R5* |
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C8 |
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R |
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10 |
ILIM |
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C5* |
R6 |
C6* |
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3 |
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C7* |
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R7 |
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1 |
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www.richtek.com |
DS8202L/M-04 April 2011 |
2 |
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RT8202L/M
Function Block Diagram
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TRIG |
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VOUT |
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On-time |
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Compute |
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TON |
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1-SHOT |
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R |
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+ |
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- Comp |
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BOOT |
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SS (Internal) |
+ |
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PWM |
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GM |
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+ |
S |
Q |
DRV |
UGATE |
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- |
- |
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PHASE |
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Min. TOFF |
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Q |
TRIG |
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+ |
OV |
Latch |
1-SHOT |
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VDDP |
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115% VREF |
S1 |
Q |
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DRV |
LGATE |
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Latch |
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FB |
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UV |
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PGND |
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S1 |
Q |
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Diode |
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70% VREF |
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- |
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Emulation |
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90% VREF |
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+ |
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20µA |
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SS Ramp |
Thermal |
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VDD |
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+ |
OC |
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Shutdown |
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GND |
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- |
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EN/DEM |
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PGOOD |
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DS8202L/M-04 April 2011 |
www.richtek.com |
3
RT8202L/M
Functional Pin Description
Pin No. |
Pin Name |
Pin Function |
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1 |
VOUT |
Output Voltage Sense Pin. Connect this pin to the output of PWM converter. |
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VOUT is also for the output soft discharge when shutdown. |
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2 |
VDD |
Analog Supply Voltage Input for Internal Analog Integrated Circuit. Bypass this |
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pin to GND with a 1μF ceramic capacitor. |
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3 |
FB |
Feedback Input of PWM Controller. Connect FB to a resistor voltage divider from |
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VOUT to GND to adjust the output voltage from 0.75V to 3.3V. |
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4 |
PGOOD |
Power Good Signal Open-Drain Output of PWM Controller. This pin will be |
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pulled high when the output voltage is within the target range. |
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5, 14 |
NC |
No Internal Connection. |
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6, |
GND |
Analog Ground. The exposed pad must be soldered to a large PCB and |
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17 (Exposed Pad) |
connected to GND for maximum power dissipation. |
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7 |
PGND |
Power Ground. |
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8 |
LGATE |
Low Side N-MOSFET Gate-Drive Output for PWM. This pin swings between |
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PGND to VDDP. |
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9 |
VDDP |
Gate Driver Supply for External MOSFETs. Bypass this pin to PGND with a 1μF |
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ceramic capacitor. |
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10 |
OC |
PWM Current Limit Setting and Sense. Connect a resistor between OC to |
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PHASE for current limit setting. |
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11 |
PHASE |
Inductor Connection. This pin is not only the zero-current-sense input for the |
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PWM converter, but also the UGATE high side gate driver return. |
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12 |
UGATE |
High Side N-MOSFET Floating Gate-Driver Output for PWM controller. This pin |
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swings between PHASE and BOOT. |
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13 |
BOOT |
Boost Capacitor connection for PWM Controller. Connect an external ceramic |
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capacitor from this pin to PHASE. |
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PWM Enable and Operation Mode Selection Input. Connect this pin to VDD for |
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15 |
EN/DEM |
diode-emulation mode, connect this pin to GND for shutdown mode and floating |
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the pin for CCM mode. |
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16 |
TON |
On Time/Frequency Adjustment Pin. Connect this pin to VIN through a resistor. |
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TON is an input of the PWM controller. |
www.richtek.com |
DS8202L/M-04 April 2011 |
4 |
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RT8202L/M |
Absolute Maximum Ratings (Note 1) |
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z Input Voltage, TON to GND ------------------------------------------------------------------------------------------------ |
–0.3V to 32V |
z BOOT to PHASE ------------------------------------------------------------------------------------------------------------ |
–0.3V to 6V |
z UGATE to PHASE |
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DC ------------------------------------------------------------------------------------------------------------------------------- |
–0.3V to 6V |
< 20ns ------------------------------------------------------------------------------------------------------------------------- |
−5V to 7.5V |
z LGATEx to GND |
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DC ------------------------------------------------------------------------------------------------------------------------------- |
–0.3V to 6V |
< 20ns ------------------------------------------------------------------------------------------------------------------------- |
−2.5V to 7.5V |
z PHASE to GND |
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DC ------------------------------------------------------------------------------------------------------------------------------- |
–0.3V to 32V |
< 20ns ------------------------------------------------------------------------------------------------------------------------- |
−8V to 38V |
z PGND to GND ---------------------------------------------------------------------------------------------------------------- |
–0.3V to 0.3V |
z VDD, VDDP, VOUT, EN/DEM, FB, PGOOD to GND ---------------------------------------------------------------- |
–0.3V to 6V |
z OC to GND -------------------------------------------------------------------------------------------------------------------- |
–0.3V to 28V |
z Power Dissipation, PD @ TA = 25°C |
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WQFN-16L 3x3 -------------------------------------------------------------------------------------------------------------- |
1.471W |
WQFN-16L 4x4 -------------------------------------------------------------------------------------------------------------- |
1.852W |
z Package Thermal Resistance (Note 2) |
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WQFN-16L 3x3, θJA --------------------------------------------------------------------------------------------------------- |
68°C/W |
WQFN-16L 3x3, θJC -------------------------------------------------------------------------------------------------------- |
7.5°C/W |
WQFN-16L 4x4, θJA --------------------------------------------------------------------------------------------------------- |
54°C/W |
WQFN-16L 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) |
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HBM (Human Body Mode) ------------------------------------------------------------------------------------------------ |
2kV |
MM (Machine Mode) -------------------------------------------------------------------------------------------------------- |
200V |
Recommended Operating Conditions |
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z Input Voltage, VIN ------------------------------------------------------------------------------------------------------------ |
3V to 26V |
z Supply Voltage, VDD, VDDP ------------------------------------------------------------------------------------------------ |
4.5V to 5.5V |
z Junction Temperature Range --------------------------------------------------------------------------------------------- |
−40°C to 125°C |
z Ambient Temperature Range --------------------------------------------------------------------------------------------- |
−40°C to 85°C |
DS8202L/M-04 April 2011 |
www.richtek.com |
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5 |
RT8202L/M
Electrical Characteristics
(VDD = VDDP = 5V, VIN = 15V, VEN/DEM = VDD, RTON = 1MΩ, TA = 25°C, unless otherwise specified)
Parameter |
Symbol |
Test Conditions |
Min |
Typ |
Max |
Unit |
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Quiescent Current |
IQ |
IVDD + IVDDP, VFB = 0.8V, forced |
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1250 |
μA |
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above the regulation point |
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TON Operating Current |
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-- |
15 |
-- |
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IVDD + IVDDP |
-- |
1 |
10 |
μA |
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Shutdown Current |
ISHDN |
ITON |
-- |
1 |
5 |
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EN/DEM = 0V |
−10 |
−1 |
-- |
μA |
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FB Reference Voltage |
VFB |
VDD = 4.5V to 5.5V |
0.742 |
0.75 |
0.758 |
V |
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FB Input Bias Current |
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VFB = 0.75V |
−1 |
0.1 |
1 |
μA |
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Output Voltage Range |
VOUT |
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0.75 |
-- |
3.3 |
V |
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On-Time |
tON |
VIN = 15V, VOUT = 1.25V |
267 |
334 |
401 |
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Minimum Off-Time |
tOFF |
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250 |
400 |
550 |
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VOUT Shutdown Discharge |
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EN/DEM = GND, VOUT = 0.5V |
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20 |
-- |
Ω |
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Resistance |
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Current Sensing |
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Current Limit Source |
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LGATE = High |
18 |
20 |
22 |
μA |
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Current |
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Current Limiter Temperature |
TCICS |
On the basis of 25°C |
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4700 |
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ppm/°C |
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Coefficient |
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Current Comparator Offset |
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GND to OC |
−10 |
-- |
10 |
mV |
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Voltage |
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Zero Crossing Threshold |
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PHASE to GND, EN/DEM = 5V |
−10 |
-- |
5 |
mV |
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Voltage |
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Fault Protection |
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Current Limit Sense Voltage |
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GND − PHASE, RILIM = 10kΩ |
170 |
200 |
230 |
mV |
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Output Under Voltage |
VUVP |
UVP detect, FB falling edge |
60 |
70 |
80 |
% |
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Threshold |
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Over Voltage Protection |
VOVP |
OVP detect, FB rising edge |
110 |
115 |
120 |
% |
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Threshold |
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Over Voltage Fault Delay |
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FB forced above over voltage |
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20 |
-- |
μs |
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threshold |
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Under Voltage Lockout |
VUVLO |
Falling edge, PWM disabled below |
3.7 |
3.9 |
4.1 |
V |
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Threshold |
this level |
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Under Voltage Lockout |
VUVLO |
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-- |
150 |
-- |
mV |
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Hysteresis |
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Soft-Start Ramp Time |
tSS |
From EN high to internal VREF |
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1.5 |
-- |
ms |
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reaches 0.71V (0Æ95%) |
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Under Voltage Blank Time |
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From EN signal going high |
-- |
4.5 |
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Thermal Shutdown |
TSD |
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-- |
155 |
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°C |
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Thermal Shutdown |
TSD |
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-- |
10 |
-- |
°C |
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Hysteresis |
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Driver On-Resistance |
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UGATE Driver Source |
RUGATEsr |
UGATE, High State, BOOT to PHASE |
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2 |
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Ω |
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forced to 5V |
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UGATE Driver Sink |
RUGATEsk |
UGATE, Low State, BOOT to PHASE |
-- |
1.5 |
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Ω |
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forced to 5V |
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To be continued |
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www.richtek.com |
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DS8202L/M-04 |
April 2011 |
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