Richtek RT8204LGQW, RT8204LZQW Schematic [ru]
RT8204L
Single Synchronous Buck Controller
General Description
The RT8204L PWM controller provides high efficiency, excellent transient response, and high DC 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 RT8204L 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 buck conversion allows this device to directly step down high voltage batteries for the highest possible efficiency. The RT8204L is intended for CPU core, chipset, DRAM, or other low voltage supplies as low as 0.75V. The RT8204L is available in a WQFN-16L 3x3 package.
A built in LDO controller can drive an external N-MOSFET to provide a second output voltage from PWM output or other power source. The RT8204L can provide adjustable voltage down to 0.75V and maximum output voltage is dependen on the selected MOSFET. The internal 0.75V reference voltage with ±1.5% accuracy provides tight regulation of the output voltage. Other features such as independent enable control, open drain power good indicator, under voltage protection, and soft start make the RT8204L a system friendly power management solution for various applications.
Features
zPWM Controller
`Ultra High Efficiency
`Resistor Programmable Current Limit by Low Side RDS(ON) Sense (Lossless Limit)
`4700ppm/°C RDS(ON) Current Sensing
`Quick Load Step Response within 100ns
`1% VFB Accuracy Over Line and Load
`Adjustable 0.75V to 3.3V Output Range
`4.5V to 26V Battery Input Range
`Resistor Programmable Frequency
`Integrated Bootstrap Switch
`Over/Under Voltage Protection
`Voltage Ramp Soft-Start
`Power Good Indicator
zLDO Controller
`1.5% accuracy Over Line and Load
`Independent Enable and Power Good Indicator
`Drive N-MOSFETs within Rail to Rail Controller Voltage
`MLCC and POSCAP Stable
zRoHS Compliant and Halogen Free
Applications
zNotebook Computers
zCPU Core Supply
zChipset/RAM Supply as Low as 0.75V
Ordering Information
RT8204L 
Package Type
QW : WQFN-16L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free) Z : ECO (Ecological Element with
Halogen Free and Pb free)
Note :
Richtek products are :
`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes.
DS8204L-04 April 2011 |
www.richtek.com |
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1 |
RT8204L
Marking Information |
Pin Configurations |
RT8204LGQW |
(TOP VIEW) |
J8= : Product Code |
TON |
EN/DEM |
LEN |
BOOT |
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J8=YM |
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YMDNN : Data Code |
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DNN |
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16 |
15 |
14 |
13 |
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VOUT |
1 |
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12 |
UGATE |
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VDD |
2 |
GND |
11 |
PHASE |
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FB |
3 |
10 |
OC |
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PGOOD |
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17 |
VDDP |
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4 |
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9 |
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RT8204LZQW |
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5 |
6 |
7 |
8 |
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LPGOOD |
LFB |
LDRV |
LGATE |
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J8 |
: Product Code |
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YMDNN : Data Code |
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J8 YM |
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DNN |
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WQFN-16L 3x3 |
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Typical Application Circuit
VIN 4.5V to 26V
RTON
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16 |
VDDP |
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5V |
R2 |
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C1 |
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R1 |
2 |
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C2 |
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PGOOD |
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4 |
CCM/DEM |
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15 |
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LDO Enable |
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14 |
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LDO PGOOD |
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5 |
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R3 |
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V |
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DDP |
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17 (Exposed Pad) |
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* : |
Optional |
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RT8204L |
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R4 |
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C4 |
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13 |
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TON |
BOOT |
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C3 |
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V |
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VDDP |
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12 |
R5 |
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OUT1 |
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UGATE |
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Q1 |
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L1 |
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PHASE |
11 |
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VDD |
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LGATE |
8 |
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R6* |
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C8 |
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Q2 |
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R |
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OC |
10 |
ILIM |
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C5* |
R7 |
C6* |
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PGOOD |
FB |
3 |
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EN/DEM |
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R8 |
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C7* |
LEN |
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LPGOOD |
VOUT |
1 |
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LDRV |
7 |
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Q3 |
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C14 |
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R9 |
R10 |
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V |
OUT2 |
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R11 |
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GND |
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C10 |
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C11* |
C12 |
C13 |
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6 |
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LFB |
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R12 |
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C9 |
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www.richtek.com |
DS8204L-04 April 2011 |
2 |
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RT8204L
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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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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- |
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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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- |
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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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LEN |
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SS |
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0.75V VREF |
+ |
X1 |
LDRV |
SS Ramp |
- |
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LPGOOD |
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LFB |
- |
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90% VREF |
+ |
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50% VREF |
- |
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+ |
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LDO Controller
DS8204L-04 April 2011 |
www.richtek.com |
3
RT8204L
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 the PWM converter. |
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VOUT is an input of the PWM controller. |
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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 resistive voltage divider |
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from 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 |
LPGOOD |
Power Good Signal Open-Drain Output of the LDO Regulator. This pin will be |
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pulled high when the output voltage is within the target range. |
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6 |
LFB |
Feedback Input of LDO Regulator. This pin will be pulled high when the output |
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voltage is within the target range. |
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7 |
LDRV |
Drive Signal for LDO’s Path MOSFET. |
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8 |
LGATE |
Low Side N-MOSFET Gate-Drive Output for the PWM Controller. This pin |
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swings between GND to VDDP. |
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9 |
VDDP |
Gate Driver Supply for external MOSFETs. Bypass this pin to GND 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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LDO Enable Input with Internal Pull Low Resistor. LDO is enabled if LEN voltage |
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14 |
LEN |
is greater than the Logic High voltage level and disabled if LEN voltage is less |
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than the Logic Low voltage level. |
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PWM Enable and Operation Mode Selection Input. Connect to VDD for diode |
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15 |
EN/DEM |
emulation mode, connect GND for shutdown mode, and float the pin for CCM |
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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. |
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17 (Exposed Pad) |
GND |
Analog Ground and Power Ground. The exposed pad must be soldered to a |
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large PCB and connected to GND for maximum power dissipation. |
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www.richtek.com |
DS8204L-04 April 2011 |
4 |
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RT8204L |
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Absolute Maximum Ratings |
(Note 1) |
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z Input Voltage, TON to GND ------------------------------------------------------------------------------------------------ |
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–0.3V to 32V |
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z BOOT to PHASE ------------------------------------------------------------------------------------------------------------ |
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–0.3V to 6V |
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z UGATE to PHASE |
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DC ------------------------------------------------------------------------------------------------------------------------------- |
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–0.3V to 6V |
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< 20ns ------------------------------------------------------------------------------------------------------------------------- |
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−5V to 7.5V |
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z LGATE to GND |
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DC ------------------------------------------------------------------------------------------------------------------------------- |
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–0.3V to 6V |
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< 20ns ------------------------------------------------------------------------------------------------------------------------- |
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−2.5V to 7.5V |
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z PHASE to GND |
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DC ------------------------------------------------------------------------------------------------------------------------------- |
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–0.3V to 32V |
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< 20ns ------------------------------------------------------------------------------------------------------------------------- |
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−8V to 38V |
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z VDD, VDDP, VOUT, EN/DEM, LEN, LFB, FB, PGOOD, LPGOOD, LDRV to GND ------------------------- |
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–0.3V to 6V |
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z OC to GND -------------------------------------------------------------------------------------------------------------------- |
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–0.3V to 28V |
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z Power Dissipation, PD @ TA = 25°C |
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WQFN-16L 3x3 -------------------------------------------------------------------------------------------------------------- |
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1.471W |
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z Package Thermal Resistance (Note 2) |
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WQFN-16L 3x3, θJA --------------------------------------------------------------------------------------------------------- |
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68°C/W |
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WQFN-16L 3x3, θJC -------------------------------------------------------------------------------------------------------- |
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7.5°C/W |
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z Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------------- |
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260°C |
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z Junction Temperature ------------------------------------------------------------------------------------------------------- |
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150°C |
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z Storage Temperature Range |
---------------------------------------------------------------------------------------------- |
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–65°C to 150°C |
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z ESD Susceptibility (Note 3) |
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HBM (Human Body Mode) ------------------------------------------------------------------------------------------------ |
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2kV |
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MM (Machine Mode) -------------------------------------------------------------------------------------------------------- |
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200V |
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Recommended Operating Conditions (Note 4) |
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z Input Voltage, VIN ------------------------------------------------------------------------------------------------------------ |
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4.5V to 26V |
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z Supply Voltage, VDD, VDDP ------------------------------------------------------------------------------------------------ |
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4.5V to 5.5V |
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z Junction Temperature Range |
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−40°C to 125°C |
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z Ambient Temperature Range |
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−40°C to 85°C |
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Electrical Characteristics |
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(VDD = VDDP = 5V, VIN = 15V, VEN/DEM = VDD, RTON = 1MΩ, TA = 25°C, unless otherwise specified) |
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Parameter |
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Symbol |
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Test Conditions |
Min |
Typ |
Max |
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Unit |
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PWM Controller |
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Quiescent Current |
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IQ |
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VDD + VDDP, VFB = 0.8V, forced above |
-- |
-- |
1250 |
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μA |
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the regulation point |
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TON Operating Current |
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-- |
15 |
-- |
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μA |
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VDD + VDDP |
-- |
1 |
10 |
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Shutdown Current |
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ISHDN |
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TON |
-- |
1 |
5 |
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μA |
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VEN/DEM = 0V |
−10 |
−1 |
-- |
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FB Reference Voltage |
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VFB |
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VDD = 4.5V to 5.5V |
0.742 |
0.75 |
0.758 |
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V |
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To be continued |
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DS8204L-04 April 2011 |
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www.richtek.com |
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5 |
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RT8204L
Parameter |
Symbol |
Test Conditions |
Min |
Typ |
Max |
Unit |
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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 |
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VIN = 15V, VOUT = 1.25V, |
267 |
334 |
401 |
ns |
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RTON = 1MΩ |
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Minimum Off-Time |
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250 |
400 |
550 |
ns |
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VOUT Shutdown Discharge |
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EN/DEM = GND |
-- |
20 |
-- |
Ω |
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Resistance |
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Current Sensing |
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Current Limit Source Current |
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LGATE = High |
18 |
20 |
22 |
μA |
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Current Limiter Temperature |
TCICS |
On the basis of 25°C |
-- |
4700 |
-- |
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, VEN/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 Threshold |
VUVP |
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60 |
70 |
80 |
% |
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Over Voltage Protection |
VOVP |
With respect to error comparator |
110 |
115 |
120 |
% |
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Threshold |
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threshold |
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Over Voltage Fault Delay |
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FB forced above OV threshold |
-- |
20 |
-- |
μs |
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Under Voltage Lockout |
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Falling edge, PWM disabled below |
3.7 |
3.9 |
4.1 |
V |
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Threshold |
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this level |
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Under Voltage Lockout |
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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 |
-- |
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 |
-- |
ms |
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Thermal Shutdown |
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TSD_PWM |
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-- |
155 |
-- |
°C |
|
Thermal Shutdown Hysteresis |
TSD_PWM |
|
-- |
10 |
-- |
°C |
||
|
|
|
|
|
|
|
|
|
Driver On-Resistance |
|
|
|
|
|
|
||
UGATE Driver Source |
RUGATEsr |
BOOT to PHASE forced to 5V |
-- |
2 |
-- |
Ω |
||
UGATE Driver Sink |
|
RUGATEsk |
BOOT to PHASE forced to 5V |
-- |
1.5 |
-- |
Ω |
|
LGATE Driver Source |
RLGATEsr |
LGATE, High State |
-- |
1.5 |
-- |
Ω |
||
LGATE Driver Sink |
|
RLGATEsk |
LGATE, Low State |
-- |
0.7 |
-- |
Ω |
|
Dead Time |
|
|
LGATE Rising (VPHASE = 1.5V) |
-- |
30 |
-- |
ns |
|
|
|
UGATE Rising |
-- |
30 |
-- |
|||
|
|
|
|
|||||
Internal BOOT Charging Switch |
|
VDDP to BOOT, 10mA |
-- |
-- |
90 |
Ω |
||
On Resistance |
|
|
||||||
|
|
|
|
|
|
|
||
Logic I/O |
|
|
|
|
|
|
|
|
EN/DEM Input |
Logic-Low |
VIL |
EN/DEM Low |
-- |
-- |
0.8 |
V |
|
|
|
EN/DEM High |
2.9 |
-- |
-- |
|||
Threshold Voltage |
Logic-High |
VIH |
||||||
EN/DEM Float |
-- |
2 |
-- |
|
||||
|
|
|
|
|||||
|
To be continued |
|
|
www.richtek.com |
DS8204L-04 April 2011 |
6 |
|
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