FAIRCHILD FDMF6823C

FDMF6823C — Extra-Small, High-Performance,
High-Frequency DrMOS Module
Benefits
Description

Ultra-Compact 6x6mm PQFN, 72% Space-Saving
Compared to Conventional Discrete Solutions



Fully Optimized System Efficiency
The XS™ DrMOS family is Fairchild’s next-generation,
fully optimized, ultra-compact, integrated MOSFET plus
driver power stage solution for high-current, highfrequency, synchronous buck DC-DC applications. The
FDMF6823C integrates a driver IC, two power
MOSFETs, and a bootstrap Schottky diode into a
thermally enhanced, ultra-compact 6x6mm package.
Clean Switching Waveforms with Minimal Ringing
High-Current Handling
Features
With an integrated approach, the complete switching
power stage is optimized with regard to driver and
MOSFET dynamic performance, system inductance,
and power MOSFET RDS(ON). XS™ DrMOS uses
®
Fairchild's high-performance PowerTrench MOSFET
technology, which dramatically reduces switch ringing,
eliminating the need for snubber circuit in most buck
converter applications.






Over 93% Peak-Efficiency


Driver Output Disable Function (DISB# Pin)
Internal Pull-Up and Pull-Down for SMOD# and
DISB# Inputs, Respectively

A driver IC with reduced dead times and propagation
delays further enhances the performance. A thermal
warning function warns of a potential over-temperature
situation. The FDMF6823C also incorporates a Skip
Mode (SMOD#) for improved light-load efficiency. The
FDMF6823C also provides a 3-state 5V PWM input for
compatibility with a wide range of PWM controllers.
Fairchild PowerTrench® Technology MOSFETs for
Clean Voltage Waveforms and Reduced Ringing
Applications

Fairchild SyncFET™ (Integrated Schottky Diode)
Technology in Low-Side MOSFET
High-Performance Gaming Motherboards


Integrated Bootstrap Schottky Diode


Adaptive Gate Drive Timing for Shoot-Through
Protection

Desktop Computers, V-Core and Non-V-Core
DC-DC Converters





Under-Voltage Lockout (UVLO)



Workstations

Small Form-Factor Voltage Regulator Modules
High-Current Handling: 50A
High-Performance PQFN Copper-Clip Package
3-State 5V PWM Input Driver
Skip-Mode SMOD# (Low-Side Gate Turn Off) Input
Thermal Warning Flag for Over-Temperature
Condition
Optimized for Switching Frequencies up to 1MHz
Low-Profile SMD Package
Fairchild Green Packaging and RoHS Compliance
Based on the Intel® 4.0 DrMOS Standard
Compact Blade Servers, V-Core and Non-V-Core
DC-DC Converters
High-Current DC-DC Point-of-Load Converters
Networking and Telecom Microprocessor Voltage
Regulators
Ordering Information
Part Number
Current Rating
Package
Top Mark
FDMF6823C
50A
40-Lead, Clipbond PQFN DrMOS, 6.0mm x 6.0mm Package
FDMF6823C
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
www.fairchildsemi.com
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
April 2012
VIN
3V ~ 16V
V5V
CVIN
CVDRV
VCIN
VDRV
DISB#
VIN
RBOOT
DISB#
BOOT
PWM
OFF
CBOOT
FDMF6823C
PHASE
SMOD#
ON
VOUT
VSWH
LOUT
Open-Drain
Output
THWN#
COUT
PGND
CGND
Figure 1.
Typical Application Circuit
DrMOS Block Diagram
VDRV
VIN
BOOT
UVLO
VCIN
Q1
HS Power
MOSFET
DBoot
DISB#
GH
Logic
GH
Level-Shift
10µA
30kΩ
PHASE
VCIN
Dead-Time
RUP_PWM
Input
3-State
Logic
PWM
Control
VSWH
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Typical Application Circuit
VDRV
RDN_PWM
GL
Logic
THWN#
VCIN
GL
30kΩ
Temp.
Sense
Q2
LS Power
MOSFET
10µA
CGND
Figure 2.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
PGND
SMOD#
DrMOS Block Diagram
www.fairchildsemi.com
Figure 3.
Bottom View
Figure 4.
Top View
Pin Definitions
Pin #
1
2
Name
Description
When SMOD#=HIGH, the low-side driver is the inverse of the PWM input. When
SMOD# SMOD#=LOW, the low-side driver is disabled. This pin has a 10µA internal pull-up current
source. Do not add a noise filter capacitor.
VCIN
IC bias supply. Minimum 1µF ceramic capacitor is recommended from this pin to CGND.
3
VDRV
Power for the gate driver. Minimum 1µF ceramic capacitor is recommended to be connected as
close as possible from this pin to CGND.
4
BOOT
Bootstrap supply input. Provides voltage supply to the high-side MOSFET driver. Connect a
bootstrap capacitor from this pin to PHASE.
5, 37, 41
CGND
IC ground. Ground return for driver IC.
6
GH
7
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Pin Configuration
For manufacturing test only. This pin must float; it must not be connected to any pin.
PHASE Switch node pin for bootstrap capacitor routing. Electrically shorted to VSWH pin.
8
NC
No connect. The pin is not electrically connected internally, but can be connected to VIN for
convenience.
9 - 14, 42
VIN
Power input. Output stage supply voltage.
15, 29 35, 43
Switch node input. Provides return for high-side bootstrapped driver and acts as a sense point
VSWH
for the adaptive shoot-through protection.
16 – 28
PGND
36
GL
38
THWN#
39
DISB#
Output disable. When LOW, this pin disables the power MOSFET switching (GH and GL are
held LOW). This pin has a 10µA internal pull-down current source. Do not add a noise filter
capacitor.
40
PWM
PWM signal input. This pin accepts a three-state 5V PWM signal from the controller.
Power ground. Output stage ground. Source pin of the low-side MOSFET.
For manufacturing test only. This pin must float; it must not be connected to any pin.
Thermal warning flag, open collector output. When temperature exceeds the trip limit, the
output is pulled LOW. THWN# does not disable the module.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
www.fairchildsemi.com
Stresses exceeding the Absolute Maximum Ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.
The absolute maximum ratings are stress ratings only.
Symbol
VCIN
Parameter
Supply Voltage
Min.
Max.
Unit
Referenced to CGND
-0.3
6.0
V
VDRV
Drive Voltage
Referenced to CGND
-0.3
6.0
V
VDISB#
Output Disable
Referenced to CGND
-0.3
6.0
V
VPWM
PWM Signal Input
Referenced to CGND
-0.3
6.0
V
VSMOD#
VGL
VTHWN#
VIN
VBOOT
Skip Mode Input
Referenced to CGND
-0.3
6.0
V
Low Gate Manufacturing Test Pin
Referenced to CGND
-0.3
6.0
V
Thermal Warning Flag
Referenced to CGND
-0.3
6.0
V
Power Input
Referenced to PGND, CGND
-0.3
25.0
V
Referenced to VSWH, PHASE
-0.3
6.0
V
Referenced to CGND
-0.3
25.0
V
Referenced to VSWH, PHASE
-0.3
6.0
V
Bootstrap Supply
VGH
High Gate Manufacturing Test Pin
VPHS
PHASE
VSWH
Switch Node Input
VBOOT
Bootstrap Supply
ITHWN#
THWN# Sink Current
Referenced to CGND
-0.3
25.0
V
Referenced to CGND
-0.3
25.0
V
Referenced to PGND, CGND (DC Only)
-0.3
25.0
V
Referenced to PGND, <20ns
-8.0
28.0
V
Referenced to VDRV
22.0
V
Referenced to VDRV, <20ns
25.0
V
7.0
mA
-0.1
fSW=300kHz, VIN=12V, VO=1.0V
50
fSW=1MHz, VIN=12V, VO=1.0V
45
IO(AV)
Output Current(1)
θJPCB
Junction-to-PCB Thermal Resistance
TA
Ambient Temperature Range
TJ
Maximum Junction Temperature
TSTG
Storage Temperature Range
ESD
Electrostatic Discharge Protection
A
2.7
°C/W
-40
+125
°C
+150
°C
-55
+150
°C
Human Body Model, JESD22-A114
2000
Charged Device Model, JESD22-C101
2500
V
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Absolute Maximum Ratings
Note:
1. IO(AV) is rated using Fairchild’s DrMOS evaluation board, at TA = 25°C, with natural convection cooling. This rating
is limited by the peak DrMOS temperature, TJ = 150°C, and varies depending on operating conditions and PCB
layout. This rating can be changed with different application settings.
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to Absolute Maximum Ratings.
Symbol
Parameter
Min.
Typ.
Max.
Unit
VCIN
Control Circuit Supply Voltage
4.5
5.0
5.5
V
VDRV
Gate Drive Circuit Supply Voltage
4.5
5.0
5.5
V
(2)
VIN
Output Stage Supply Voltage
3.0
12.0
16.0
V
Note:
2. Operating at high VIN can create excessive AC overshoots on the VSWH-to-GND and BOOT-to-GND nodes
during MOSFET switching transients. For reliable DrMOS operation, VSWH-to-GND and BOOT-to-GND must
remain at or below the Absolute Maximum Ratings shown in the table above. Refer to the “Application
Information” and “PCB Layout Guidelines” sections of this datasheet for additional information.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
www.fairchildsemi.com
Typical values are VIN = 12V, VCIN = 5V, VDRV = 5V, and TA = TJ = +25°C unless otherwise noted.
Symbol
Parameter
Condition
Min. Typ. Max. Unit
Basic Operation
IQ
Quiescent Current
IQ=IVCIN+IVDRV, PWM=LOW or HIGH or Float
VUVLO
UVLO Threshold
VCIN Rising
VUVLO_Hys
UVLO Hysteresis
2.9
3.1
2
mA
3.3
V
0.4
V
10
kΩ
PWM Input (VCIN = VDRV = 5V ±10%)
RUP_PWM
Pull-Up Impedance
VPWM=5V
RDN_PWM
Pull-Down Impedance
VPWM=0V
VIH_PWM
PWM High Level Voltage
3.04
3.55
4.05
V
VTRI_HI
3-State Upper Threshold
2.95
3.45
3.94
V
VTRI_LO
3-State Lower Threshold
0.98
1.25
1.52
V
VIL_PWM
PWM Low Level Voltage
0.84
1.15
1.42
V
160
200
ns
2.50
2.80
V
10
tD_HOLD-OFF 3-State Shut-Off Time
VHiZ_PWM
3-State Open Voltage
2.20
tPWM-OFF_MIN PWM Minimum Off Time
kΩ
120
ns
PWM Input (VCIN = VDRV = 5V ±5%)
RUP_PWM
Pull-Up Impedance
VPWM=5V
10
kΩ
RDN_PWM
Pull-Down Impedance
VPWM=0V
10
kΩ
VIH_PWM
PWM High Level Voltage
3.22
3.55
3.87
V
VTRI_HI
3-State Upper Threshold
3.13
3.45
3.77
V
VTRI_LO
3-State Lower Threshold
1.04
1.25
1.46
V
VIL_PWM
PWM Low Level Voltage
0.90
1.15
1.36
V
160
200
ns
2.30
2.50
2.70
V
tD_HOLD-OFF 3-State Shut-Off Time
VHiZ_PWM
3-State Open Voltage
tPWM-OFF_MIN PWM Minimum Off Time
120
ns
2
V
DISB# Input
VIH_DISB
VIL_DISB
High-Level Input Voltage
Low-Level Input Voltage
IPLD
Pull-Down Current
tPD_DISBL
Propagation Delay
tPD_DISBH
Propagation Delay
0.8
V
10
µA
PWM=GND, Delay Between DISB# from
HIGH to LOW to GL from HIGH to LOW
25
ns
PWM=GND, Delay Between DISB# from
LOW to HIGH to GL from LOW to HIGH
25
ns
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Electrical Characteristics
SMOD# Input
VIH_SMOD
High-Level Input Voltage
VIL_SMOD
Low-Level Input Voltage
IPLU
2
V
0.8
Pull-Up Current
V
10
µA
tPD_SLGLL
Propagation Delay
PWM=GND, Delay Between SMOD# from
HIGH to LOW to GL from HIGH to LOW
10
ns
tPD_SHGLH
Propagation Delay
PWM=GND, Delay Between SMOD# from
LOW to HIGH to GL from LOW to HIGH
10
ns
Continued on the following page…
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
www.fairchildsemi.com
Typical values are VIN = 12V, VCIN = 5V, VDRV = 5V, and TA = TJ = +25°C unless otherwise noted.
Symbol
Parameter
Condition
Min. Typ. Max. Unit
Thermal Warning Flag
TACT
Activation Temperature
150
°C
TRST
Reset Temperature
135
°C
IPLD=5mA
30
Ω
SW=0V, Delay Between GH from HIGH to
LOW and GL from LOW to HIGH
250
ns
1
Ω
RTHWN
Pull-Down Resistance
250ns Timeout Circuit
tD_TIMEOUT
Timeout Delay
High-Side Driver (fSW = 1000kHz, IOUT = 30A, TA = +25°C)
RSOURCE_GH Output Impedance, Sourcing Source Current=100mA
RSINK_GH
Output Impedance, Sinking
Sink Current=100mA
0.8
Ω
tR_GH
Rise Time
GH=10% to 90%
10
ns
tF_GH
Fall Time
GH=90% to 10%
10
ns
tD_DEADON
LS to HS Deadband Time
GL Going LOW to GH Going HIGH,
1.0V GL to 10% GH
15
ns
tPD_PLGHL
PWM LOW Propagation
Delay
PWM Going LOW to GH Going LOW,
VIL_PWM to 90% GH
20
tPD_PHGHH
PWM HIGH Propagation
Delay (SMOD# =0)
PWM Going HIGH to GH Going HIGH,
VIH_PWM to 10% GH (SMOD# =0, ID_LS>0)
30
ns
tPD_TSGHH
Exiting 3-State Propagation
Delay
PWM (From 3-State) Going HIGH to GH
Going HIGH, VIH_PWM to 10% GH
30
ns
30
ns
Low-Side Driver (fSW = 1000kHz, IOUT = 30A, TA = +25°C)
RSOURCE_GL Output Impedance, Sourcing Source Current=100mA
1
Ω
Output Impedance, Sinking
Sink Current=100mA
0.5
Ω
tR_GL
Rise Time
GL=10% to 90%
20
ns
tF_GL
Fall Time
GL=90% to 10%
10
ns
SW Going LOW to GL Going HIGH,
2.2V SW to 10% GL
15
ns
RSINK_GL
tD_DEADOFF HS to LS Deadband Time
tPD_PHGLL
PWM-HIGH Propagation
Delay
PWM Going HIGH to GL Going LOW,
VIH_PWM to 90% GL
10
tPD_TSGLH
Exiting 3-State Propagation
Delay
PWM (From 3-State) Going LOW to GL
Going HIGH, VIL_PWM to 10% GL
20
ns
VF
Forward-Voltage Drop
IF=20mA
0.3
V
VR
Breakdown Voltage
IR=1mA
25
ns
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Electrical Characteristics
Boot Diode
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
22
V
www.fairchildsemi.com
V IL_PWM
PWM
90%
GL
1.0V
10%
90%
GH
to
VSWH
1.2V
10%
t D_TIMEOUT
(250ns Timeout)
2.2V
VSWH
t PD
t PD_PLGHL
PHGLL
t D_DEADOFF
t D_DEADON
Figure 5.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
PWM Timing Diagram
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
V IH_PWM
www.fairchildsemi.com
50
11
45
10
40
Module Power Loss, PLMOD (W)
Module Output Current, IOUT (A)
Test Conditions: VIN=12V, VOUT=1V, VCIN=5V, VDRV=5V, LOUT=250nH, TA=25°C, and natural convection cooling,
unless otherwise specified.
FSW = 300kHz
35
30
25
FSW = 1000kHz
20
15
10
VIN = 12V, VDRV & VCIN = 5V, VOUT = 1V
5
300kHz
500kHz
9
800kHz
8
1000kHz
7
6
5
4
3
2
1
0
0
0
25
50
75
100
PCB Temperature, T PCB (°C)
Figure 6.
125
0
150
Safe Operating Area
5
15
20
25
30
35
Module Output Current, IOUT (A)
40
45
Power Loss vs. Output Current
1.08
VIN = 12V, VDRV & VCIN = 5V, VOUT = 1V, IOUT = 30A
VDRV & VCIN = 5V, VOUT = 1V, FSW = 300kHz, IOUT = 30A
Normalized Module Power Loss
1.4
Normalized Module Power Loss
10
Figure 7.
1.5
1.3
1.2
1.1
1.0
0.9
100
200
Figure 8.
300 400 500 600 700 800 900
Module Switching Frequency, FSW (kHz)
1.06
1.04
1.02
1.00
0.98
1000 1100
4
Power Loss vs. Switching Frequency
6
Figure 9.
1.15
8
10
12
14
Module Input Voltage, VIN (V)
16
18
Power Loss vs. Input Voltage
1.8
VIN = 12V, VOUT = 1V, FSW = 300kHz, IOUT = 30A
1.7
1.10
Normalized Module Power Loss
Normalized Module Power Loss
VIN = 12V, VDRV & VCIN = 5V, VOUT = 1V
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Typical Performance Characteristics
1.05
1.00
0.95
1.6
1.5
1.4
1.3
1.2
1.1
1.0
VIN = 12V, VDRV & VCIN = 5V, FSW = 300kHz, IOUT = 30A
0.90
4.0
4.5
5.0
5.5
Driver Supply Voltage, VDRV & VCIN (V)
6.0
Figure 10. Power Loss vs. Driver Supply Voltage
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
0.9
0.5
1.0
1.5
2.0
2.5
3.0
Module Output Voltage, VOUT (V)
3.5
4.0
Figure 11. Power Loss vs. Output Voltage
www.fairchildsemi.com
Test Conditions: VIN=12V, VOUT=1V, VCIN=5V, VDRV=5V, LOUT=250nH, TA=25°C, and natural convection cooling,
unless otherwise specified.
1.01
45
VIN = 12V, VDRV & VCIN = 5V, FSW = 300kHz, VOUT = 1V, IOUT = 30A
VIN = 12V, VDRV & VCIN = 5V, VOUT = 1V, IOUT = 0A
Driver Supply Current, IDRV & ICIN (mA)
Normalized Module Power Loss
40
1.00
0.99
0.98
0.97
0.96
200
250
Figure 12.
300
350
400
Output Inductor, LOUT (nH)
450
35
30
25
20
15
10
5
100
500
Power Loss vs. Output Inductor
200
Figure 13.
VIN = 12V, VOUT = 1V, FSW = 300kHz, IOUT = 0A
Driver Supply Current vs. Switching
Frequency
VIN = 12V, VDRV & VCIN = 5V, VOUT = 1V
16
Normalized Driver Supply Current
1.03
15
14
13
12
11
1.02
FSW = 300kHz
1.01
1.00
FSW = 1000kHz
0.99
0.98
10
4.0
4.5
5.0
5.5
Driver Supply Voltage, VDRV & VCIN (V)
Figure 14.
0
6.0
5
Driver Supply Current vs. Driver Supply Figure 15.
Voltage
3.2
10
15
20
25
30
35
Module Output Current, IOUT (A)
40
45
Driver Supply Current vs. Output Current
4.5
TA = 25°C
UVLOUP
3.0
2.9
2.8
2.7
UVLODN
2.6
VIH_PWM
4.0
PWM Threshold Voltage, VPWM (V)
3.1
Driver IC Supply Voltage, VCIN (V)
1000 1100
1.04
17
Driver Supply Current, IDRV & ICIN (mA)
300 400 500 600 700 800 900
Module Switching Frequency, FSW (kHz)
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Typical Performance Characteristics
3.5
VTRI_HI
3.0
VHIZ_PWM
2.5
2.0
VTRI_LO
1.5
VIL_PWM
1.0
0.5
-55
Figure 16.
0
25
55
100
125
Driver IC Junction Temperature, T J (oC)
150
UVLO Threshold vs. Temperature
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
4.50
Figure 17.
4.75
5.00
5.25
Driver IC Supply Voltage, VCIN (V)
5.50
PWM Threshold vs. Driver Supply Voltage
www.fairchildsemi.com
Test Conditions: VCIN=5V, VDRV=5V, TA=25°C, and natural convection cooling, unless otherwise specified.
2.2
4.5
TA = 25°C
PWM Threshold Voltage, VPWM (V)
4.0
SMOD# Threshold Voltage, VSMOD (V)
VCIN = 5V
VIH_PWM
3.5
VTRI_HI
3.0
VHIZ_PWM
2.5
2.0
1.5
VTRI_LO
1.0
VIL_PWM
0.5
-55
0
25
55
100
125
Driver IC Junction Temperature, T J (oC)
Figure 18.
1.8
1.6
VIL_SMOD#
1.4
1.2
150
PWM Threshold vs. Temperature
VIH_SMOD#
2.0
4.50
Figure 19.
2.2
SMOD# Threshold vs. Driver Supply
Voltage
VCIN = 5V
SMOD# Pull-Up Current, IPLU (uA)
SMOD# Threshold Voltage, VSMOD (V)
5.50
-9.0
VCIN = 5V
2
VIH_SMOD#
1.8
1.6
VIL_SMOD#
1.4
1.2
-9.5
-10.0
-10.5
-11.0
-11.5
-12.0
-55
Figure 20.
0
25
55
100
125
Driver IC Junction Temperature, T J (oC)
150
SMOD# Threshold vs. Temperature
-55
Figure 21.
2.2
0
25
55
100
125
Driver IC Junction Temperature, T J (oC)
150
SMOD# Pull-Up Current vs. Temperature
2.2
VCIN = 5V
TA = 25°C
VIH_DISB#
2.0
DISB# Threshold Voltage, VDISB (V)
DISB# Threshold Voltage, VDISB (V)
4.75
5.00
5.25
Driver IC Supply Voltage, VCIN (V)
1.8
1.6
VIL_DISB#
1.4
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Typical Performance Characteristics
2.0
VIH_DISB#
1.8
1.6
VIL_DISB#
1.4
1.2
1.2
4.50
Figure 22.
4.75
5.00
5.25
Driver IC Supply Voltage, VCIN (V)
5.50
DISB# Threshold vs. Driver Supply
Voltage
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
-55
Figure 23.
0
25
55
100
125
Driver IC Junction Temperature, T J (oC)
150
DISB# Threshold vs. Temperature
www.fairchildsemi.com
Test Conditions: VCIN=5V, VDRV=5V, TA=25°C, and natural convection cooling, unless otherwise specified.
500
12.0
IF = 20mA
450
11.5
Boot Diode Forward Voltage, VF (mV)
DISB# Pull-Down Current, IPLD (uA)
VCIN = 5V
11.0
10.5
10.0
9.5
9.0
-55
Figure 24.
0
25
55
100
125
Driver IC Junction Temperature, T J (oC)
DISB# Pull-Down Current vs.
Temperature
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
150
400
350
300
250
200
150
100
-55
0
25
55
100
125
150
Driver IC Junction Temperature, T J (oC)
Figure 25.
Boot Diode Forward Voltage vs.
Temperature
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Typical Performance Characteristics
www.fairchildsemi.com
The FDMF6823C is a driver-plus-FET module optimized
for the synchronous buck converter topology. A single
PWM input signal is all that is required to properly drive
the high-side and the low-side MOSFETs. Each part is
capable of driving speeds up to 1MHz.
VCIN and Disable (DISB#)
The VCIN pin is monitored by an Under-Voltage Lockout
(UVLO) circuit. When VCIN rises above ~3.1V, the driver
is enabled. When VCIN falls below ~2.7V, the driver is
disabled (GH, GL=0). The driver can also be disabled by
pulling the DISB# pin LOW (DISB# < VIL_DISB), which
holds both GL and GH LOW regardless of the PWM
input state. The driver can be enabled by raising the
DISB# pin voltage HIGH (DISB# > VIH_DISB).
Table 1.
UVLO and Disable Logic
UVLO
DISB#
Driver State
0
X
Disabled (GH, GL=0)
1
0
Disabled (GH, GL=0)
1
1
Enabled (see Table 2)
1
Open
Disabled (GH, GL=0)
Note:
3. DISB# internal pull-down current source is 10µA.
Thermal Warning Flag (THWN#)
The FDMF6823C provides a thermal warning flag
(THWN#) to warn of over-temperature conditions. The
thermal warning flag uses an open-drain output that
pulls to CGND when the activation temperature (150°C)
is reached. The THWN# output returns to a highimpedance state once the temperature falls to the reset
temperature (135°C). For use, the THWN# output
requires a pull-up resistor, which can be connected to
VCIN. THWN# does NOT disable the DrMOS module.
HIGH
THWN#
Logic
State
135°C Reset 150°C
Temperature Activation
Temperature
Normal
Operation
Thermal
Warning
LOW
Three-State PWM Input
The FDMF6823C incorporates a three-state 5V PWM
input gate drive design. The three-state gate drive has
both logic HIGH level and LOW level, along with a
three-state shutdown window. When the PWM input
signal enters and remains within the three-state window
for a defined hold-off time (tD_HOLD-OFF), both GL and GH
are pulled LOW. This enables the gate drive to shut
down both high-side and low-side MOSFETs to support
features such as phase shedding, which is common on
multi-phase voltage regulators.
Exiting Three-State Condition
When exiting a valid three-state condition, the
FDMF6823C follows the PWM input command. If the
PWM input goes from three-state to LOW, the low-side
MOSFET is turned on. If the PWM input goes from
three-state to HIGH, the high-side MOSFET is turned
on. This is illustrated in Figure 27. The FDMF6823C
design allows for short propagation delays when exiting
the three-state window (see Electrical Characteristics).
Low-Side Driver
The low-side driver (GL) is designed to drive a groundreferenced, low-RDS(ON), N-channel MOSFET. The bias
for GL is internally connected between the VDRV and
CGND pins. When the driver is enabled, the driver's
output is 180° out of phase with the PWM input. When
the driver is disabled (DISB#=0V), GL is held LOW.
High-Side Driver
The high-side driver (GH) is designed to drive a floating
N-channel MOSFET. The bias voltage for the high-side
driver is developed by a bootstrap supply circuit
consisting of the internal Schottky diode and external
bootstrap capacitor (CBOOT). During startup, VSWH is held
at PGND, allowing CBOOT to charge to VDRV through the
internal diode. When the PWM input goes HIGH, GH
begins to charge the gate of the high-side MOSFET (Q1).
During this transition, the charge is removed from CBOOT
and delivered to the gate of Q1. As Q1 turns on, VSWH
rises to VIN, forcing the BOOT pin to VIN + VBOOT, which
provides sufficient VGS enhancement for Q1. To complete
the switching cycle, Q1 is turned off by pulling GH to
VSWH. CBOOT is then recharged to VDRV when VSWH falls to
PGND. GH output is in-phase with the PWM input. The
high-side gate is held LOW when the driver is disabled or
the PWM signal is held within the three-state window for
longer than the three-state hold-off time, tD_HOLD-OFF.
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Functional Description
TJ_driver IC
Figure 26.
THWN Operation
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
www.fairchildsemi.com
The driver IC advanced design ensures minimum
MOSFET dead-time, while eliminating potential shootthrough (cross-conduction) currents. It senses the state
of the MOSFETs and adjusts the gate drive adaptively
to ensure they do not conduct simultaneously. Figure 27
provides the relevant timing waveforms. To prevent
overlap during the LOW-to-HIGH switching transition
(Q2 off to Q1 on), the adaptive circuitry monitors the
voltage at the GL pin. When the PWM signal goes
V IH_PWM
HIGH, Q2 begins to turn off after a propagation delay
(tPD_PHGLL). Once the GL pin is discharged below 1.0V,
Q1 begins to turn on after adaptive delay tD_DEADON.
To preclude overlap during the HIGH-to-LOW transition
(Q1 off to Q2 on), the adaptive circuitry monitors the
voltage at the GH-to-PHASE pin pair. When the PWM
signal goes LOW, Q1 begins to turn off after a
propagation delay (tPD_PLGHL). Once the voltage across
GH-to-PHASE falls below 2.2V, Q2 begins to turn on
after adaptive delay tD_DEADOFF.
V IH_PWM
V IH_PWM
V IH_PWM
V TRI_HI
V TRI_HI
tD_HOLD-OFF
V TRI_LO
V IL_PWM
V IL_PWM
tR_GH
PWM
tF_GH
90%
GH
to
VSWH
10%
V IN
DCM
DCM
CCM
V OUT
2.2V
VSWH
tR_GL
GL
tF_GL
90%
90%
1.0V
tPD_PHGLL
tD_DEADON
10%
10%
tPD_PLGHL
tPD_TSGHH
tD_HOLD-OFF
t PD_TSGHH
tD_HOLD-OFF tPD_TSGLH
tD_DEADOFF
Exit
3-state
Enter
3-state
Enter
3-state
Exit
3-state
Enter
3-state
Exit
3-state
Notes:
tPD_xxx = propagation delay from external signal (PWM, SMOD#, etc.) to IC generated signal.
Example (tPD_PHGLL – PWM going HIGH to LS VGS (GL) going LOW)
tD_xxx = delay from IC generated signal to IC generated signal. Example (tD_DEADON – LS VGS (GL) LOW to HS VGS (GH) HIGH)
PWM
tPD_PHGLL = PWM rise to LS VGS fall, VIH_PWM to 90% LS VGS
tPD_PLGHL = PWM fall to HS VGS fall, VIL_PWM to 90% HS VGS
tPD_PHGHH = PWM rise to HS VGS rise, VIH_PWM to 10% HS VGS (SMOD# held LOW)
Exiting 3-state
tPD_TSGHH = PWM 3-state to HIGH to HS VGS rise, VIH_PWM to 10% HS VGS
tPD_TSGLH = PWM 3-state to LOW to LS VGS rise, VIL_PWM to 10% LS VGS
SMOD#
tPD_SLGLL = SMOD# fall to LS VGS fall, VIL_SMOD to 90% LS VGS
tPD_SHGLH = SMOD# rise to LS VGS rise, VIH_SMOD to 10% LS VGS
Dead Times
tD_DEADON = LS VGS fall to HS VGS rise, LS-comp trip value (~1.0V GL) to 10% HS VGS
tD_DEADOFF = VSWH fall to LS VGS rise, SW-comp trip value (~2.2V VSWH) to 10% LS VGS
Figure 27.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Adaptive Gate Drive Circuit
PWM and 3-StateTiming Diagram
www.fairchildsemi.com
The Skip Mode function allows for higher converter
efficiency when operated in light-load conditions. When
SMOD# is pulled LOW, the low-side MOSFET gate
signal is disabled (held LOW), preventing discharge of
the output capacitors as the filter inductor current
attempts reverse current flow – known as “Diode
Emulation” Mode.
Table 2.
SMOD# Logic
DISB#
PWM
SMOD#
GH
GL
0
X
X
0
0
1
3-State
X
0
0
1
0
0
0
0
1
1
0
1
0
1
0
1
0
1
1
1
1
1
0
Note:
4.
The SMOD# feature is intended to have a short propagation delay between the SMOD# signal and the low-side FET VGS
response time to control diode emulation on a cycle-by-cycle basis.
SMOD#
V IH_SMOD
V IL_SMOD
V IH_PWM
V IH_PWM
V IL_PWM
PWM
90%
GH
to
VSWH
10%
10%
DCM
V OUT
CCM
CCM
2.2V
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
When the SMOD# pin is pulled HIGH, the synchronous
buck converter works in Synchronous Mode. This mode
allows for gating on the Low Side MOSFET. When the
SMOD# pin is pulled LOW, the low-side MOSFET is
gated off. If the SMOD# pin is connected to the PWM
controller, the controller can actively enable or disable
SMOD# when the controller detects light-load condition
from output current sensing. Normally this pin is active
LOW. See Figure 28 for timing delays.
Skip Mode (SMOD#)
VSWH
GL
90%
1.0V
tPD_PHGLL
tD_DEADON
10%
10%
tPD_PLGHL
tPD_PHGHH
tPD_SLGLL
tD_DEADOFF
Delay from SMOD# going
LOW to LS VGS LOW
tPD_SHGLH
Delay from SMOD# going
HIGH to LS V GS HIGH
HS turn -on with SMOD# LOW
Figure 28.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
SMOD# Timing Diagram
www.fairchildsemi.com
VCIN Filter
Supply Capacitor Selection
The VDRV pin provides power to the gate drive of the
high-side and low-side power MOSFET. In most cases,
it can be connected directly to VCIN, the pin that
provides power to the logic section of the driver. For
additional noise immunity, an RC filter can be inserted
between the VDRV and VCIN pins. Recommended
values would be 10Ω and 1µF.
For the supply inputs (VCIN), a local ceramic bypass
capacitor is recommended to reduce noise and to
supply the peak current. Use at least a 1µF X7R or X5R
capacitor. Keep this capacitor close to the VCIN pin and
connect it to the GND plane with vias.
Bootstrap Circuit
The bootstrap circuit uses a charge storage capacitor
(CBOOT), as shown in Figure 30. A bootstrap capacitance
of 100nF X7R or X5R capacitor is usually adequate. A
series bootstrap resistor may be needed for specific
applications to improve switching noise immunity. The
boot resistor may be required when operating above
15VIN and is effective at controlling the high-side
MOSFET turn-on slew rate and VSHW overshoot. RBOOT
values from 0.5 to 3.0Ω are typically effective in
reducing VSWH overshoot.
V5V
A
I5V
RVCIN
CVDRV
Power Loss and Efficiency
Measurement and Calculation
Refer to Figure 30 for power loss testing method.
Power loss calculations are:
CVCIN
PIN=(VIN x IIN) + (V5V x I5V) (W)
(1)
PSW=VSW x IOUT (W)
(2)
POUT=VOUT x IOUT (W)
(3)
PLOSS_MODULE=PIN - PSW (W)
(4)
PLOSS_BOARD=PIN - POUT (W)
(5)
EFFMODULE=100 x PSW/PIN (%)
(6)
EFFBOARD=100 x POUT/PIN (%)
(7)
CVIN
A
IIN
VIN
VCIN
VDRV
VIN
DISB#
DISB#
PWM
Input
RBOOT
BOOT
PWM
OFF
FDMF6823C
FDM 67 5
CBOOT
IOUT
VSWH
SMOD#
ON
Open Drain
Output
A
LOUT
PHASE
VOUT
THWN#
Figure 29.
V5V
A
I5V
PWM
Input
COUT
Block Diagram With VCIN Filter
CVIN
CVDRV
VDRV
DISB#
V VSW
PGND
CGND
VCIN
A
IIN
VIN
VIN
DISB#
RBOOT
BOOT
PWM
OFF
FDMF6823C
FDM
5
CBOOT
IOUT
VSWH
ON
OpenDrain
Output
SMOD#
A
LOUT
PHASE
THWN#
CGND
Figure 30.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Application Information
PGND
V VSW
COUT
Power Loss Measurement
www.fairchildsemi.com
Figure 31 and Figure 32 provide an example of a proper
layout for the FDMF6823C and critical components. All
of the high-current paths, such as VIN, VSWH, VOUT,
and GND copper, should be short and wide for low
inductance and resistance. This aids in achieving a
more stable and evenly distributed current flow, along
with enhanced heat radiation and system performance.
Recommendations for PCB Designers
1. Input ceramic bypass capacitors must be placed
close to the VIN and PGND pins. This helps reduce
the high-current power loop inductance and the input
current ripple induced by the power MOSFET
switching operation.
2. The VSWH copper trace serves two purposes. In
addition to being the high-frequency current path
from the DrMOS package to the output inductor, it
serves as a heat sink for the low-side MOSFET in
the DrMOS package. The trace should be short and
wide enough to present a low-impedance path for
the high-frequency, high-current flow between the
DrMOS and inductor. The short and wide trace
minimizes electrical losses as well as the DrMOS
temperature rise. Note that the VSWH node is a highvoltage and high-frequency switching node with high
noise potential. Care should be taken to minimize
coupling to adjacent traces. Since this copper trace
acts as a heat sink for the lower MOSFET, balance
using the largest area possible to improve DrMOS
cooling while maintaining acceptable noise emission.
3. An output inductor should be located close to the
FDMF6823C to minimize the power loss due to the
VSWH copper trace. Care should also be taken so the
inductor dissipation does not heat the DrMOS.
®
4. PowerTrench MOSFETs are used in the output
stage and are effective at minimizing ringing due to
fast switching. In most cases, no VSWH snubber is
required. If a snubber is used, it should be placed
close to the VSWH and PGND pins. The selected
resistor and capacitor need to be the proper size for
power dissipation.
5. VCIN, VDRV, and BOOT capacitors should be
placed as close as possible to the VCIN-to-CGND,
VDRV-to-CGND, and BOOT-to-PHASE pin pairs to
ensure clean and stable power. Routing width and
length should be considered as well.
6. Include a trace from the PHASE pin to the VSWH pin
to improve noise margin. Keep this trace as short as
possible.
noise issues due to ground bounce or high positive
and negative VSWH ringing. Inserting a boot
resistance lowers the DrMOS efficiency. Efficiency
versus noise trade-offs must be considered. RBOOT
values from 0.5Ω to 3.0Ω are typically effective in
reducing VSWH overshoot.
8. The VIN and PGND pins handle large current
transients with frequency components greater than
100MHz. If possible, these pins should be connected
directly to the VIN and board GND planes. The use
of thermal relief traces in series with these pins is
discouraged since this adds inductance to the power
path. This added inductance in series with either the
VIN or PGND pin degrades system noise immunity
by increasing positive and negative VSWH ringing.
9. GND pad and PGND pins should be connected to
the GND copper plane with multiple vias for stable
grounding. Poor grounding can create a noise
transient offset voltage level between CGND and
PGND. This could lead to faulty operation of the gate
driver and MOSFETs.
10. Ringing at the BOOT pin is most effectively
controlled by close placement of the boot capacitor.
Do not add an additional BOOT to the PGND
capacitor. This may lead to excess current flow
through the BOOT diode.
11. The SMOD# and DISB# pins have weak internal
pull-up and pull-down current sources, respectively.
These pins should not have any noise filter
capacitors. Do not to float these pins unless
absolutely necessary.
12. Use multiple vias on the VIN and VOUT copper
areas to interconnect top, inner, and bottom layers
to distribute current flow and heat conduction. Do
not put many vias on the VSWH copper to avoid
extra parasitic inductance and noise on the
switching waveform. As long as efficiency and
thermal performance are acceptable, place only
one VSWH copper on the top layer and use no vias
on the VSWH copper to minimize switch node
parasitic noise. Vias should be relatively large and
of reasonably low inductance. Critical highfrequency components, such as RBOOT, CBOOT, RC
snubber, and bypass capacitors; should be located
as close to the respective DrMOS module pins as
possible on the top layer of the PCB. If this is not
feasible, they can be connected from the backside
through a network of low-inductance vias.
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
PCB Layout Guidelines
7. The layout should include the option to insert a
small-value series boot resistor between the boot
capacitor and BOOT pin. The boot-loop size,
including RBOOT and CBOOT, should be as small as
possible. The boot resistor may be required when
operating above 15VIN and is effective at controlling
the high-side MOSFET turn-on slew rate and VSHW
overshoot. RBOOT can improve noise operating
margin in synchronous buck designs that may have
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
www.fairchildsemi.com
Figure 32.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
PCB Layout Example (Top View)
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Figure 31.
PCB Layout Example (Bottom View)
www.fairchildsemi.com
B
0.10 C
PIN#1
INDICATOR
6.00
2X
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
Physical Dimensions
5.80
A
4.50
30
21
31
6.00
20
0.40
2.50
0.65
0.25
1.60
0.10 C
11
40
2X
1
SEE 0.60
DETAIL 'A' 0.50 TYP
TOP VIEW
10
0.35
0.15
2.10
0.40 21
FRONT VIEW
4.40±0.10
(2.20)
0.10
C A B
C
0.05
0.30
30 0.20 (40X)
31
2.10
LAND PATTERN
RECOMMENDATION
20
0.50
2.40±0.10
(0.70)
0.20
PIN #1 INDICATOR
1.50±0.10
11
10
0.40
2.00±0.10
(0.20)
40
1
2.00±0.10
0.50
NOTES: UNLESS OTHERWISE SPECIFIED
(0.20)
BOTTOM VIEW
1.10
0.90
0.10 C
0.08 C
0.30
0.20
0.50 (40X)
0.30
0.05
0.00
DETAIL 'A'
C
A) DOES NOT FULLY CONFORM TO JEDEC
REGISTRATION MO-220, DATED
MAY/2005.
B) ALL DIMENSIONS ARE IN MILLIMETERS.
C) DIMENSIONS DO NOT INCLUDE BURRS
OR MOLD FLASH. MOLD FLASH OR
BURRS DOES NOT EXCEED 0.10MM.
D) DIMENSIONING AND TOLERANCING PER
ASME Y14.5M-1994.
E) DRAWING FILE NAME: PQFN40AREV2
SEATING
PLANE
SCALE: 2:1
Figure 33.
40-Lead, Clipbond PQFN DrMOS, 6.0x6.0mm Package
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or
obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the
warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
www.fairchildsemi.com
FDMF6823C — Extra-Small, High-Performance, High-Frequency DrMOS Module
© 2011 Fairchild Semiconductor Corporation
FDMF6823C • Rev. 1.0.2
www.fairchildsemi.com