PWM Controller. RT8845A Datasheet


RT8845A Controller. Datasheet pdf. Equivalent


Part Number

RT8845A

Description

Multi-Phase PWM Controller

Manufacture

Richtek

Total Page 24 Pages
Datasheet
Download RT8845A Datasheet


RT8845A
®
RT8845A
Multi-Phase PWM Controller with PWM-VID Reference
General Description
The RT8845A is a 4/3/2/1 phase synchronous Buck PWM
controller which is optimized for high performance graphic
microprocessor and computer applications. The RT8845A
adopts G-NAVPTM (Green Native AVP) which is Richtek's
proprietary topology derived from finite DC gain of EA
amplifier with current mode control. By utilizing the G-
NAVPTM topology, the operating frequency of the RT8845A
varies with VID, load and input voltage to further enhance
the efficiency even in CCM. Moreover, the G-NAVPTM with
CCRCOT (Constant Current Ripple COT) technology
provides superior output voltage ripple over the entire input/
output range. The RT8845A provides complete fault
protection functions including Over-Voltage (OV), Negative
Voltage (NV), Over-Current (OC) and Under-Voltage
Lockout (UVLO). The RT8845A is available in the WQFN-
40L 5x5 package.
The RT8845A features external reference input and PWM-
VID dynamic output voltage control, in which the feedback
voltage is regulated and tracks external input reference
voltage. Other features include adjustable switching
frequency, dynamic phase number control, internal/external
soft- start, power good indicator, and enable functions.
Features
Multi-Phase PWM Controller
Power State Indicator
1P-CCM/4P-CCM/1P-DEM
Support 1.8V PWM-VID Interface
External Reference Input Control
PWM-VID Dynamic Voltage Control
Dynamic Phase Number Control
Internal/External Soft-Start
Adjustable Current Limit Threshold
Adjustable Switching Frequency
UVP/OVP Protection
Support an Ultra-Low Output Voltage as Standby
Voltage
Thermal Shutdown
Power Good Indicator
Applications
GPU Core Supply for nVidia OVR4 + Spec.
Pin Configuration
(TOP VIEW)
Ordering Information
RT8845A
Package Type
QW : WQFN-40L 5x5 (W-Type)
Lead Plating System
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.
40 39 38 37 36 35 34 33 32 31
REFIN 1
VREF 2
30
29
NC 3
28
SS 4
PER_PH_OC 5
SUM_OC_ALERT 6
GND
27
26
25
NC 7
24
PWM4 8
PWM3 9
41 23
22
PWM2 10
21
11 12 13 14 15 16 17 18 19 20
COMP
FB
NC
TON
0LL
NC
SUM_OC
CSOUT
CSPSUM
CSNSUM
WQFN-40L 5x5
Copyright ©2020 Richtek Technology Corporation. All rights reserved.
DS8845A-01 January 2020
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1

RT8845A
RT8845A
Marking Information
RT8845A
GQW
YMDNN
RT8845AGQW : Product Number
YMDNN : Date Code
Functional Pin Description
Pin No.
1
Pin Name
REFIN
2 VREF
3, 7,13, 14, 15,
16, 25, 28, 34, 35
NC
4 SS
5 PER_PH_OC
Pin Function
External reference input.
Reference voltage output. This is a high precision voltage reference (2V)
from the VREF pin to RGND pin.
No internal connection.
Soft-start time setting. Connect an external capacitor to adjust soft-start
time. When the external capacitor is removed, the internal soft-start
function will be chose.
Per phase current limit setting. Connect a resistor from PER_PH_OC to
GND to set the per phase current limit threshold.
6 SUM_OC_ALERT Sum OC alert. Active high open drain output.
8
9
10
11
12
20,19,18,17
PWM4
PWM3
PWM2
PWM1
DRON
ISEN[1:4]
PWM output for 4th phase.
PWM output for 3rd phase.
PWM output for 2nd phase.
PWM output for 1st phase.
Bidirectional gate driver enable for external drivers.
Current sense inputs of phase1, 2, 3 and 4.
21 CSNSUM
Sum current sense negative pin.
22 CSPSUM
23 CSOUT
Sum current sense positive pin. Connect NTC network between this pin
and CSOUT pin for thermal compensation. The CSPSUM to CSOUT pin
differential voltage must be less than 450mV.
Sum current sense output pin. Connect NTC network between this pin
and CSPSUM pin for thermal compensation. The CSPSUM to CSOUT
pin differential voltage must be less than 450mV.
Copyright ©2020 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8845A-01 January 2020


Features ® RT8845A Multi-Phase PWM Controller w ith PWM-VID Reference General Descript ion The RT8845A is a 4/3/2/1 phase sync hronous Buck PWM controller which is op timized for high performance graphic mi croprocessor and computer applications. The RT8845A adopts G-NAVPTM (Green Nat ive AVP) which is Richtek's proprietary topology derived from finite DC gain o f EA amplifier with current mode contro l. By utilizing the GNAVPTM topology, t he operating frequency of the RT8845A v aries with VID, load and input voltage to further enhance the efficiency even in CCM. Moreover, the G-NAVPTM with CCR COT (Constant Current Ripple COT) techn ology provides superior output voltage ripple over the entire input/ output ra nge. The RT8845A provides complete faul t protection functions including Over-V oltage (OV), Negative Voltage (NV), Ove r-Current (OC) and Under-Voltage Lockou t (UVLO). The RT8845A is available in t he WQFN40L 5x5 package. The RT8845A fea tures external reference input and PWMVID dynamic output voltage.
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