Controller. RT8202B Datasheet

RT8202B Datasheet PDF

Part RT8202B
Description Single Synchronous Buck Controller
Feature RT8202B; RT8202/A/B Single Synchronous Buck Controller General Description The RT8202/A/B PWM controller prov.
Manufacture Richtek
Datasheet
Download RT8202B Datasheet




RT8202B
®
RT8202/A/B
Single Synchronous Buck Controller
General Description
Features
The RT8202/A/B 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-onresponse to load transients while maintaining
a relatively constant switching frequency.
The RT8202/A/B 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 RT8202/A/B is intended for CPU
core, chipset, DRAM, or other low voltage supplies as
low as 0.75V. RT8202 is available in WQFN-16L 4x4,
RT8202A is available in WQFN-16L 3x3 and RT8202B is
available in WQFN-14L 3.5x3.5 packages.
Ultra-High Efficiency
Resistor Programmable Current Limit by Low Side
RDS(ON) Sense (Lossless Limit) or Sense Resistor
(High Accuracy)
Quick Load Step Response within 100ns
1% VOUT Accuracy over Line and Load
Adjustable 0.75V to 3.3V Output Range
4.5V to 26V Battery Input Range
Resistor Programmable Frequency
Over/Under Voltage Protection
2 Steps Current Limit During Soft-Start
Drives Large Synchronous-Rectifier FETs
Power Good Indicator
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Notebook Computers
CPU Core Supply
Chipset/RAM Supply as Low as 0.75V
Pin Configurations
Ordering Information
RT8202/A/B
(TOP VIEW)
Package Type
QW : WQFN-16L 4x4 (W-Type) (RT8202)
QW : WQFN-16L 3x3 (W-Type) (RT8202A)
QW : WQFN-14L 3.5x3.5 (W-Type) (RT8202B)
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.
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
16 15 14 13
VOUT
VDD
FB
PGOOD
1
2
3
4
GND
17
12 UGATE
11 PHASE
10 OC
9 VDDP
5678
WQFN-16L 4x4/WQFN-16L 3x3
TON
VOUT
VDD
FB
PGOOD
2
3
4
5
6
1 14
GND
15
78
13 UGATE
12 PHASE
11 OC
10 VDDP
9 LGATE
WQFN-14L 3.5x3.5
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8202/A/B-07 April 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



RT8202B
RT8202/A/B
Typical Application Circuit
VDDP
5V
PGOOD
CCM/DEM
C1
1µF
R2
51k
R1
10
C2
1µF
D1
BAT254
RT8202/A/B
TON
BOOT
VDDP
UGATE
VDD
PHASE
LGATE
PGOOD
OC
EN/DEM
GND
PGND
FB
VOUT
VIN
4.5V to 26V
R3
1M
R4
2.2
R5 0
R6 10k
C3
0.1µF
C4
10µF
Q1
AO4702 L1
2.4µH
VOUT
Q2
AO4702
R7 C7
220µF
C5 R8 C6
12k
C8
0.1µF
R9
20k
Figure 1. Output Voltage Setting for VOUT < 3.3V Application
VDDP
5V
PGOOD
CCM/DEM
C1
1µF
R2
51k
R1
10
C2
1µF
D1
BAT254
RT8202/A/B
TON
BOOT
VDDP
UGATE
VDD
PHASE
LGATE
PGOOD
OC
EN/DEM
GND
PGND
FB
VOUT
VIN
4.5V to 26V
R3
1M
R4
2.2
R5 0
R6 10k
C3
0.1µF
C4
10µF
Q1
AO4702 L1
2.4µH
VOUT
Q2
AO4702
R7 C7
220µF
C6
C5 R8
C8
0.1µF
R9
R10
VOUT FB
R11
Figure 2. Output Voltage Setting for VOUT > 3.3V Application
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8202/A/B-07 April 2014



RT8202B
RT8202/A/B
Functional Pin Description
Pin No.
RT8202/A RT8202B
Pin Name
Pin Function
1
3
VOUT
VOUT Sense Input. Connect to the output of PWM converter. VOUT
is an input of the PWM controller.
2
4
VDD
Analog Supply Voltage Input for the internal analog integrated circuit.
Bypass to GND with a 1F ceramic capacitor.
3 5 FB
4 6 PGOOD
5, 14
-- NC
6, 17
7, 15
(Exposed Pad) (Exposed Pad)
GND
7 8 PGND
8 9 LGATE
9 10 VDDP
VOUT Feedback Input. Connect FB to a resistor voltage divider from
VOUT to GND to adjust the output from 0.75V to 3.3V.
Power Good Signal Open-Drain Output of PWM Converter. This pin
will be pulled high when the output voltage is within the target range.
No Internal Connection.
Ground for Analog Circuitry. The exposed pad must be soldered to a
large PCB and connected to GND for maximum power dissipation.
Power Ground.
Low side N-MOSFET Gate-Drive Output for PWM. This pin swings
between GND and VDDP.
VDDP is the gate driver supply for the external MOSFETs. Bypass to
GND with a 1F ceramic capacitor.
10
11 OC
PWM Current Limit Setting and sense. Connect a resistor between
OC to PHASE for current limit setting.
Inductor Connection. This pin is not only the zero-current-sense input
11 12 PHASE for the PWM converter, but also the UGATE high side gate driver
return.
12
13
UGATE
High Side N-MOSFET Floating Gate-Driver Output for the PWM
converter. This pin swings between PHASE and BOOT.
13
14
BOOT
Boost Capacitor Connection for PWM Converter. Connect an external
ceramic capacitor to PHASE and an external diode to VDDP.
PWM Enable and Operation Mode Selection Input. Connect to VDD
15 1 EN/DEM for diode-emulation mode, connect to GND for shutdown mode and
floating the pin for CCM mode.
16
2
TON
VIN Sense Input. Connect to VIN through a resistor. TON is an input
of the PWM controller.
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8202/A/B-07 April 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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