RT5800
2.1MHz, 3 CHs, Step-Down Converter with I
2
C Interface
General Description
The RT5800 is a multi-phase, programmable power
management IC, integrated with four high efficient,
synchronous step-down converter cores. The RT5800
can be 2 + 2 and 2 + 1 + 1 output by OTP. It also
features wide output voltage range and the capability to
configure the corresponding power stages, which make
the device optimized to meet power management
requirements for low-power processors, such as core
power for CPUs and GPUs. The RT5800 supports
many programmable functions including voltage level,
slew rate of voltage change, and slew rate of soft-start
via an I
2
C interface capable of operating up to 3.4MHz.
The RT5800 also supports remote-sense function to
get accurate output voltage at large loading. Moreover,
the device has interrupt and fault-detection function to
report error status. The RT5800 is available in a
WQFN-30L 4.5x5 (FC) package.
Features
FMEA Compliant PinOut
2 + 2 / 2 + 1 + 1 Phase Output
Input Supply Voltage Range : 3V to 6V
I
2
C Programmable Output Voltage : 0.3V to 1.85V
Maximum Output Current : 5.5A per Phase
Output Remote Sense for High Accuracy
Fast Transient Response
Selectable Automatic Phase Shielding and
Power Saving Mode Enables Higher Light Load
Efficiency
Dynamic
Voltage
Scaling
(DVS)
Programmable Slew Rate for Each Output
Programmable Soft-Start Function
Interrupt Function and Fault Detection
Watchdog Function
Input Under-Voltage Lockout (UVLO)
Cycle-by-Cycle Current Limit
Output Under-Voltage Protection
Over-Temperature Protection
WQFN-30L 4.5x5 (FC)
with
Applications
Automotive Systems
Simplified Application Circuit
AVIN
V
IN
PVIN1
C
IN
PVIN2
PVIN3
PVIN4
EN
I C Signal
2
VOUT1
LX1
LX4
RTN1
VOUT2
RT5800
LX2
RTN2
VOUT3
LX3
RTN3
PGND
AGND
L3
V
OUT3
C
OUT3
L2
V
OUT2
C
OUT2
L1
L4
V
OUT1
C
OUT1
SCL
SDA
VSELA
Signal Input
Signal Output
WDOG_RST
INT
VIO
AVIN_FILT
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5800-00
November 2019
www.richtek.com
1
RT5800
Ordering Information
RT5800
-
-
Code Version
Operation Phase
21 : program to 2 + 1 + 1 phase operation
22 : program to 2 + 2 phase operation
Package Type
QWF : WQFN-30L 4.5x5 (FC)
Lead Plating System
G : Green (Halogen Free and Pb Free)
PVIN4
NC
LX4
PGND
LX1
NC
PVIN1
1
2
3
4
5
6
7
Pin Configuration
(TOP VIEW)
VOUT2
RTN2
AVIN
SDA
24
VIO
30
29
28
EN
27
26
25
SCL
23
INT
22
21
20
PVIN2
NC
LX2
PGND
LX3
NC
PVIN3
Note :
Richtek products are :
PGND
31
19
18
17
16
RoHS compliant and compatible with the current
requirements of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering
processes.
8
9
10
11
12
13
14
15
AVIN_FILT
RTN1
VOUT1
VSELA
VOUT3
AGND
Marking Information
RT5800GQWTF-21-01
0W= : Product Code
YMDNN : Date Code
WQFN-30L 4.5x5 (FC)
0W=YM
DNN
RT5800GQWF-22-01
0E= : Product Code
YMDNN : Date Code
0E=YM
DNN
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS5800-00
WDOG_RST
RTN3
November 2019
RT5800
Functional Pin Description
Pin No.
1
2, 6, 17, 21
3
4, 19
5
7
8
9
10
11
12
13
14
15
Pin Name
PVIN4
NC
LX4
PGND
LX1
PVIN1
VSELA
AVIN_FILT
RTN1
VOUT1
RTN3
VOUT3
AGND
WDOG_RST
Pin Function
Power input for power stage 4. It is recommended to use a 10F, X7R
capacitor.
No internal connection.
Switching node for power stage 4.
Power ground for power stage.
Switching node for power stage 1.
Power input for power stage 1. It is recommended to use a 10F, X7R
capacitor.
VSEL input pin for all channels. Using corresponding register to define
action. "Do Not" leave this pin floating.
Filtered analog supply voltage. It is recommended to use a 1F, X7R
capacitor.
Remote ground sense for Buck1.
Output voltage sense for Buck1.
Remote ground sense for Buck3.
Output voltage sense for Buck3.
Analog GND.
Digital input. Reset all Bucks to default output voltage and some relative
registers to default settings when this pin is pulled low. Connect this pin to
VIO pin if this pin is not used. "Do Not" leave this pin floating.
Power input for power stage 3. It is recommended to use a 10F, X7R
capacitor.
Switching node for power stage 3.
Switching node for power stage 2.
Power input for power stage 2. It is recommended to use a 10F, X7R
capacitor.
I
2
C clock. "Do Not" leave this pin floating.
I
2
C data. "Do Not" leave this pin floating.
Interrupt indicator. When INT function is used, set 0x33[6] = 1, 0x34[6] = 1
and 0x35[6] = 1.
I/O supply voltage for digital communications. Connect this pin to 1.8V. "Do
Not" leave this pin floating.
Master chip enable. A logic-high enables the converter; a logic-low forces
the device into shutdown mode. "Do Not" leave this pin floating.
Output voltage sense for Buck2.
Remote ground sense for Buck2.
Analog input voltage.
Exposed pad. The exposed pad is connected to PGND and must be
soldered to a large PCB copper area for maximum power dissipation.
16
18
20
22
23
24
25
26
27
28
29
30
PVIN3
LX3
LX2
PVIN2
SCL
SDA
INT
VIO
EN
VOUT2
RTN2
AVIN
31(Exposed PAD) PGND
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5800-00
November 2019
www.richtek.com
3
RT5800
Functional Block Diagram
VIO
AVIN_FILT
AVIN
RTNx
VOUTx
PVINx
Buck 1
UVLO Protection
Regulators
Voltage/Current
Protection
Current Sensing
EN
VSELA
Watchdog
Logic
Enable & VSELA
Logic
Voltage/Current
Reference
Buck 2
Voltage/Current
Protection
Oscillator
Core
Control
Current Sensing
Buck 3
Voltage/Current
Protection
Current Sensing
SDA
SCL
Buck 4
Thermal Protection
Voltage/Current
Protection
Current Sensing
LX1
LX2
WDOG_RST
LX3
INT
Interrupts
Digital Logic
DAC
Interface
I2C Buffer
LX4
AGND
PGND
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS5800-00
November 2019
RT5800
Operation
The RT5800 is a power management IC that integrates
four high efficiency Buck converters, and is factory
configured as a 2/1/1 phase converter. Each of the four
converters provides up to 5A output current over an
input supply voltage range of 3.3V to 6V.
The RT5800 utilizes the proprietary Advanced Constant
On-Time (ACOT
TM
) control architecture. The ultrafast
ACOT
TM
control enables the use of small ceramic
capacitors (MLCC) to save the PCB size.
During normal operation, the internal high-side power
switch (HSFET) is turned on for a fixed interval
determined by a one-shot timer at the beginning of each
clock cycle. When the HSFET is turned off, the internal
low-side power switch (LSFET) is turned on. The output
voltage is sensed remotely at VOUTx and RTNx for high
accuracy and is compared to an internal reference
voltage. Hence, the error signal is obtained and
internally compensated. The compensated error signal
is then compared to an internal ramp signal. When the
minimum off-time one-shot (100ns, max.) has timed out
and the inductor current is below the current limit
threshold, the one-shot is triggered again if the internal
ramp signal falls below the compensated error signal.
The ACOT
TM
control architecture features ultrafast
transient response. When a load is suddenly increased,
the output voltage drops quickly. and triggers a new
on-time to rise inductor current again.
Dynamic Voltage Scaling (DVS)
The RT5800 provides wide output voltage range with
8-bits resolution and each Buck converter has two
independently programmable voltage setting. They are
called DVS0 and DVS1. Take Buck1 as two-phase
configuration for an example, register 0x48[8:0] can set
voltage of DVS0 while 0x4A[8:0] is used to set voltage
of DVS1. There are two methods to select the DVS. For
the first method, it can be changed by software from
register 0x52[1:0]. Control DVS0 by setting
0x52[1:0]=00 and DVS1 by setting 0x52[1:0]=01. For
the second method, selecting the DVS can be from
external hardware pin when setting 0x52[1:0]=10.
VSELA pin can be this role and its polarity is defined by
0x52[2]. When setting 0x52[2]=0, pull VSELA high to
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
let DVS0 be used and pull VSELA low to let DVS1 be
used. Conversely, when setting 0x52[2]=1, pull VSELA
high to let DVS1 be used and pull VSELA low to let
DVS0 be used.
The RT5800 also supports DVS speed configuration,
whether the slew rate of voltage changing in the same
DVSx or between DVS0 and DVS1. Take Buck1 as
two-phase configuration for an example, when output
voltage is set from low to high or high to low, register
0x54[6:4] defines slew rate of DVS up while 0x54[2:0]
is used to define slew rate of DVS down. In order to
have better performance during voltage changing
operation, the master/slave enters PWM operation and
keeps 200s after the voltage achieves target even
when IC is set to Auto mode. Figure 1 and Figure 2
show the DVS up and down operation.
95%
VOUT
Intial Voltage
Target Voltage
5%
Master
Switch
Slave
Switch
Command
DVS Up Slew Rate
Register Setting
200μs
Figure 1. DVS Up Operation
Intial Voltage
VOUT
5%
95%
Target Voltage
Master
Switch
Slave
Switch
Command
DVS Down Slew Rate
Register Setting
200μs
Figure 2. DVS Down Operatio
n
is a registered trademark of Richtek Technology Corporation.
DS5800-00
November 2019
www.richtek.com
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