®
RT7021A/B
0.3A/0.6A, High/Low-Side MOSFET Driver
General Description
Features
The RT7021A/B is a high-voltage gate driver IC with dual
outputs. The IC, together with an external bootstrap
network, drives dual n-channel MOSFETs or IGBTs with
input voltage rail up to 600V.
Floating Channels Designed for Bootstrap
Operation with Input Voltage up to 600V
The IC is equipped with a “common-mode dV/dt noise
canceling technique” to provide high dV/dt immunity which
enables stable operation under high dV/dt noise
circumstances. Two Under-Voltage Lockout (UVLO)
functions continuously monitor the bias voltages on VCC
and BOOT-to-LX for preventing malfunction when the bias
voltages are lower than the specified threshold voltages.
The logic level of the PWM signal input pins are compatible
with standard TTL logic level for ease of interfacing with
controlling devices.
300mA/600mA Sourcing/Sinking Current
High dV/dt Immunity : ±50V/nsec
VCC and VBOOT − LX Supply Range from 13V to 20V
Under-Voltage Lockout Functions for Both Channels
TTL Compatible Logic Input
Matched Propagation Delay below 20ns
Outputs in Phase with Input (RT7021A) or Out of
Phase with Input (RT7021B)
RoHS Compliant and Halogen Free
Ordering Information
RT7021A/B
Package Type
S : SOP-8
N : DIP-8
Applications
Lead Plating System
G : Green (Halogen Free and Pb Free)
PDP Scan Driver
Fluorescent Lamp Ballast
SMPS
Motor Driver
With Input
A : In Phase
B : Out of Phase
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.
Simplified Application Circuit
VCC
VCC
C1
BOOT
VCC
RT7021A
GND
600V
C1
RUGATE
BOOT
VCC
RT7021B
GND
UGATE
UGATE
600V
RUGATE
To Load
PWM
Signal
HIN
LX
LIN
LGATE
RLGATE
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
DS7021A/B-03
September 2016
To Load
PWM
Signal
HIN
LX
LIN
RLGATE
LGATE
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1
RT7021A/B
Pin Configuration
(TOP VIEW)
BOOT UGATE LX
VCC
HIN
2
LIN
GND
8
BOOT
7
UGATE
3
6
LX
4
5
LGATE
8
8
VCC
2
7
UGATE
LIN
3
6
LX
GND
4
5
LGATE
SOP-8
RT7021A
RT7021B
7
6
5
2
3
4
BOOT UGATE LX
8
LGATE
7
6
5
2
3
4
BOOT
HIN
SOP-8
LGATE
VCC
HIN
VCC
LIN GND
HIN
LIN GND
DIP-8
DIP-8
RT7021A
RT7021B
Marking Information
RT7021AGS
RT7021BGS
RT7021AGS : Product Number
RT7021A
GSYMDNN
RT7021BGS : Product Number
RT7021B
GSYMDNN
YMDNN : Date Code
RT7021AGN
YMDNN : Date Code
RT7021BGN
RT7021AGN : Product Number
RichTek
RT7021A
GNYMDNN
YMDNN : Date Code
RichTek
RT7021B
GNYMDNN
RT7021BGN : Product Number
YMDNN : Date Code
Functional Pin Description
Pin No.
SOP-8
DIP-8
1
1
2
2
3
3
4
Pin Name
Pin Function
VCC
Supply voltage input.
HIN (RT7021A)
Logic input for high-side gate driver.
HIN (RT7021B)
Logic input for high-side gate driver.
LIN (RT7021A)
Logic input for low-side gate driver.
LIN (RT7021B)
Logic input for low-side gate driver.
4
GND
Logic ground and low-side driver return.
5
5
LGATE
Low-side driver output.
6
6
LX
Return for high-side gate driver.
7
7
UGATE
High-side driver output.
8
8
BOOT
Bootstrap supply for high-side gate driver.
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is a registered trademark of Richtek Technology Corporation.
DS7021A/B-03
September 2016
RT7021A/B
Functional Block Diagram
For RT7021A
BOOT
BOOT-to-LX
Under-Voltage
Lockout
UVLO1
Driver
Pulse
Generator
Level
Shifter
R
Noise
Filter
S
UGATE
Q
LX
UGATE High/Low
VCC
VCC
VCC
UVLO2
Under-Voltage
Lockout
HIN
IIN+
Driver
LGATE High/Low
LIN
LGATE
Delay
GND
IIN+
For RT7021B
BOOT
BOOT-to-LX
Under-Voltage
Lockout
UVLO1
Driver
Pulse
Generator
VCC
Level
Shifter
Noise
Filter
R
S
Q
LX
UGATE High/Low
VCC
IIN+
VCC
VCC
UVLO2
Under-Voltage
Lockout
HIN
VCC
Driver
IIN+
LGATE High/Low
LIN
LGATE
Delay
GND
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DS7021A/B-03
UGATE
September 2016
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RT7021A/B
Operation
The RT7021A/B is a high-voltage gate driver for driving
high-side and low-side MOSFETs. The RT7021A/B uses
ultra high voltage device and floating well to allowed UGATE
to drive external MOSFET operating up to 600V. When
the HIN voltage is above the logic-high threshold, the
UGATE voltage goes high to turn on the external MOSFET.
When the HIN voltage is below the logic-low threshold,
the MOSFET is turned off. The operating behavior of the
LGATE, controlled by the LIN pin, is like the behavior of
the UGATE.
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Under-Voltage Lockout (UVLO) Function
When the VCC or BOOT-to-LX voltage is lower the UVLO
threshold, the UGATE and LGATE output will be disabled.
Pulse Generator
The pulse generator is used to transmit the HIN input signal
to the UGATE driver.
is a registered trademark of Richtek Technology Corporation.
DS7021A/B-03
September 2016
RT7021A/B
Absolute Maximum Ratings
(Note 1)
VCC Supply Voltage, VCC ----------------------------------------------------------------------------------LX to GND ------------------------------------------------------------------------------------------------------BOOT to LX, VBOOT − LX --------------------------------------------------------------------------------------UGATE to LX --------------------------------------------------------------------------------------------------LGATE to GND ------------------------------------------------------------------------------------------------HIN, LIN, HIN, LIN to GND ----------------------------------------------------------------------------------Allowable LX Voltage Slew Rate, dVLX/dt ---------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
−0.3V to 25V
−0.3V to 625V
−0.3V to 25V
−0.3V to VBOOT − LX + 0.3V
−0.3V to VCC + 0.3V
−0.3V to VCC + 0.3V
−50V/ns to 50V/ns
SOP-8 -----------------------------------------------------------------------------------------------------------DIP-8 ------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
SOP-8, θJA -----------------------------------------------------------------------------------------------------DIP-8, θJA -------------------------------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------Storage Temperature Range --------------------------------------------------------------------------------
0.53W
0.74W
Recommended Operating Conditions
188°C/W
134.9°C/W
150°C
260°C
−65°C to 150°C
(Note 3)
VCC Supply Voltage, VCC ----------------------------------------------------------------------------------LX to GND ------------------------------------------------------------------------------------------------------BOOT-to-LX, VBOOT − LX --------------------------------------------------------------------------------------UGATE to LX --------------------------------------------------------------------------------------------------LGATE to GND ------------------------------------------------------------------------------------------------HIN, LIN, HIN, LIN to GND ----------------------------------------------------------------------------------Ambient Temperature Range --------------------------------------------------------------------------------
13V to 20V
−5V to 600V
13V to 20V
−5V to VBOOT − LX
0 to VCC
0 to VCC
−40°C to 125°C
Electrical Characteristics
(VCC = VBOOT − LX = 15V, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
VCC Under-Voltage Lockout
Threshold (On)
VTHON_VCC
9
10.5
12
V
VBOOT LX Under-Voltage
Lockout Threshold (On)
VTHON_BOOT
9
10.5
12
V
VCC Under-Voltage Lockout
Threshold (Off)
VTHOFF_VCC
8
9.5
11
V
VBOOT LX Under-Voltage
Lockout Threshold (Off)
V THOFF_BOOT
8
9.5
11
V
VCC Under-Voltage Lockout
Hysteresis
VHYS_VCC
--
1
--
V
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September 2016
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RT7021A/B
Parameter
Symbol
VBOOT LX Under-Voltage
Lockout Hysteresis
VHSY_BOOT
LX Leakage Current
ILK
VCC Quiescent Current
IQ_VCC
Test Conditions
Min
Typ
Max
Unit
--
1
--
V
--
--
50
A
--
220
400
A
--
100
200
A
--
--
600
A
--
--
600
A
2.5
--
--
--
--
0.8
VBOOT = VLX = 600V
BOOT-to-LX Quiescent Current IQ_BOOT LX
VCC Operating Current
IP_VCC
BOOT-to-LX Operating Current IP_BOOT LX
f = 20kHz,
UGATE = LGATE = Open
Logic-High VIH
HIN, LIN, HIN ,
LIN Input Voltage Logic-Low VIL
UGATE, LGATE
Output Voltage
High-Level VOH
Sourcing Current = 2mA,
VBOOT VLGATE, VCC VLGATE
--
50
200
Low-Level
Sourcing Current = 2mA,
VUGATE LX, VLGATE
--
20
100
VOL
V
mV
HIN, LIN Input
Current
Logic-High IIN+
HIN = LIN = VCC (RT7021A)
--
2
10
Logic-Low
HIN = LIN = 0V (RT7021A)
1
--
--
HIN , LIN Input
Current
Logic-High IIN
HIN = LIN = VCC (RT7021B)
1
--
--
Logic-Low
IIN+
HIN = LIN = 0V (RT7021B)
--
2
10
UGATE and LGATE Sourcing
Current
IO+
UGATE = LX, LGATE = GND, Current
pulse width < 10s, Low duty
--
290
--
mA
UGATE and LGATE Sinking
Current
IO
UGATE = BOOT, LGATE = VCC,
Current pulse width < 10s, Low duty
--
600
--
mA
IIN
A
A
Dynamic Electrical Characteristics (Note 4)
(VCC = VBOOT − LX = 15V, LX = GND, CL = 1000pF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
--
150
220
ns
--
150
220
ns
Turn-on Delay
tON
Turn-off Delay
tOFF
Turn-on Rising Time
tR
--
70
170
ns
Turn-off Falling Time
tF
--
35
90
ns
Delay Matching Time, HS and
LS Turn-on/off
tM
--
--
20
ns
VLX = 0 or 600V
(Note 5)
Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2. θJA is measured under natural convection (still air) at TA = 25°C with the component mounted on a high effectivethermal-conductivity four-layer test board on a JEDEC 51-7 thermal measurement standard.
Note 3. The device is not guaranteed to function outside its operating conditions.
Note 4. Please refer to the Timing Diagram and Dynamic Waveforms in the Application Information.
Note 5. Turn-off Delay for VLX = 600V is guaranteed by design.
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is a registered trademark of Richtek Technology Corporation.
DS7021A/B-03
September 2016
RT7021A/B
Typical Application Circuit
VCC
DBOOT
1
C1
BOOT 8
VCC
RT7021A
4 GND
2
PWM
Signal
UGATE
7
CBOOT
RUGATE
3 LIN
LGATE
5
Q1
To Load
LX 6
HIN
600V
RLGATE
Q2
VCC
DBOOT
1
C1
BOOT 8
VCC
RT7021B
4 GND
PWM
Signal
2
HIN
UGATE
7
LGATE 5
DS7021A/B-03
September 2016
RUGATE
600V
Q1
To Load
LX 6
3 LIN
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CBOOT
RLGATE
Q2
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RT7021A/B
Typical Operating Characteristics
Turn-On Delay Time vs. Temperature
Turn-On Delay Time vs. VCC
200
Turn-On Delay Time (ns)1
Turn-On Delay Time (ns)1
200
150
UGATE
100
LGATE
50
150
UGATE
100
LGATE
50
TA = 25°C
0
0
-50
-25
0
25
50
75
100
10
125
12
14
Ambient Temperature (°C)
18
20
Turn-Off Delay Time vs. VCC
Turn-Off Delay Time vs. Temperature
200
Turn-Off Delay Time (ns)
200
Turn-Off Delay Time (ns) 1
16
VCC (V)
150
UGATE
100
LGATE
50
150
UGATE
100
LGATE
50
TA = 25°C
0
0
-50
-25
0
25
50
75
100
10
125
12
14
Turn-On Rising Time vs. Temperature
18
20
Turn-On Rising Time vs. VCC
160
160
Turn-On Rising Time (ns)1
Turn-On Rising Time (ns)1
16
VCC (V)
Ambient Temperature (°C)
120
UGATE
80
LGATE
40
120
UGATE
80
LGATE
40
TA = 25°C
0
0
-50
-25
0
25
50
75
100
Ambient Temperature (°C)
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8
125
10
12
14
16
18
20
VCC (V)
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DS7021A/B-03
September 2016
RT7021A/B
Turn-Off Falling Time vs. VCC
Turn-Off Falling Time vs. Temperature
50
Turn-Off Falling Time (ns)
Turn-Off Falling Time (ns)
50
40
LGATE
30
UGATE
20
10
40
LGATE
30
UGATE
20
10
TA = 25°C
0
0
-50
-25
0
25
50
75
100
10
125
12
14
Ambient Temperature (°C)
VCC Operating Current vs. Temperature
18
20
VCC Operating Current vs. VCC
600
600
VCC Operating Current (µA)
VCC Operating Current (µA)
16
VCC (V)
500
400
300
200
100
500
400
300
200
100
TA = 25°C
0
0
-50
-25
0
25
50
75
100
125
10
12
14
VBOOT - LX Operating Current vs. Temperature
18
20
VBOOT - LX Operating Current vs. VBOOT - LX
300
300
VBOOT - LX Operating Current (µA)
VBOOT - LX Operating Current (µA) 1
16
VCC (V)
Ambient Temperature (°C)
240
180
120
60
240
180
120
60
TA = 25°C
0
0
-50
-25
0
25
50
75
100
Temperature (°C)
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DS7021A/B-03
September 2016
125
10
12
14
16
18
20
VBOOT - LX (V)
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RT7021A/B
Logic-High Threshold Voltage vs. Temperature
LX Leakage Current vs. Temperature
Logic-High Threshold Voltage (V)
LX Leakage Current (µA)1
15
12
9
6
3
3.0
2.5
HIN
2.0
LIN
1.5
1.0
0
-50
-25
0
25
50
75
100
-50
125
-25
Ambient Temperature (°C)
50
75
100
125
Logic-Low Threshold Voltage vs. Temperature
3.0
2.5
HIN
2.0
LIN
1.5
TA = 25°C
Logic-Low Threshold Voltage (V)
Logic-High Threshold Voltage (V)1
25
Ambient Temperature (°C)
Logic-High Threshold Voltage vs. VCC
2.0
1.8
1.6
LIN
1.4
HIN
1.2
1.0
1.0
10
12
14
16
18
-50
20
-25
VCC (V)
0
25
50
75
100
125
Ambient Temperature (°C)
Logic-Low Threshold Voltage vs. VCC
High-Level Output Voltage vs. Temperature
2.0
100
1.8
1.6
1.4
LIN
HIN
1.2
TA = 25°C
1.0
High-Level Output Voltage (mV)1
Logic-Low Threshold Voltage (V)
0
80
VCC − VLGATE
60
VBOOT − VUGATE
40
20
0
10
12
14
16
18
VCC (V)
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10
20
-50
-25
0
25
50
75
100
125
Ambient Temperature (°C)
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DS7021A/B-03
September 2016
RT7021A/B
Low-Level Output Voltage vs. Temperature
High-Level Output Voltage vs. VCC or VBOOT - LX
25
Low-Level Output Voltage (mV)
High-Level Output Voltage (mV)1
100
80
VCC − VLGATE
60
VBOOT − VUGATE
40
20
TA = 25°C
20
VLGATE
15
VUGATE-LX
10
5
0
0
10
12
14
16
18
-50
20
-25
VCC or VBOOT - LX (V)
50
75
100
125
Output Sourcing Current vs. Temperature
600
Output Sourcing Current (mA)1
25
Low-Level Output Voltage (mV)1
25
Ambient Temperature (°C)
Low-Level Output Voltage vs. VCC or VBOOT - LX
20
VLGATE
15
10
VUGATE-LX
5
TA = 25°C
500
400
LGATE
300
UGATE
200
100
0
0
10
12
14
16
18
-50
20
-25
VCC or VBOOT - LX (V)
0
25
50
75
100
125
Junction Temperature (°C)
Output Sourcing Current vs. VCC or VBOOT - LX
Output Sinking Current vs. Temperature
600
1000
Output Sinking Current (mA)1
Output Sourcing Current (mA)1
0
500
400
LGATE
300
UGATE
200
100
800
UGATE
600
LGATE
400
200
TA = 25°C
0
0
10
12
14
16
18
VCC or VBOOT - LX (V)
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DS7021A/B-03
September 2016
20
-50
-25
0
25
50
75
100
125
Junction Temperature (°C)
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RT7021A/B
VTHON_VCC / VTHOFF_VCC vs. Temperature
Output Sinking Current vs. VCC or VBOOT - LX
15
800
VTHON_VCC / VTHOFF_VCC (V)
Output Sinking Current (mA)1
1000
UGATE
600
LGATE
400
200
12
V THON_VCC
9
VTHOFF_VCC
6
3
0
0
10
12
14
16
18
-50
20
-25
VCC or VBOOT - LX (V)
25
50
75
100
125
Ambient Temperature (°C)
VTHON_BOOT / VTHOFF_BOOT vs. Temperature
VHYS_VCC vs. Temperature
2.0
15
12
VTHON_BOOT
1.5
VHYS_VCC (V)
VTHON_BOOT / VTHOFF_BOOT (V)
0
9
VTHOFF_BOOT
6
1.0
0.5
3
0.0
0
-50
-25
0
25
50
75
100
125
Ambient Temperature (°C)
-50
-25
0
25
50
75
100
125
Ambient Temperature (°C)
VHYS_BOOT vs. Temperature
2.0
VHYS_BOOT (V)
1.5
1.0
0.5
0.0
-50
-25
0
25
50
75
100
125
Ambient Temperature (°C)
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is a registered trademark of Richtek Technology Corporation.
DS7021A/B-03
September 2016
RT7021A/B
Application Information
Timing Diagram and Dynamic Waveforms
Figure 1 is RT7021A/B input / output timing diagram, and
Figure 2, Figure 3 are the definition of dynamic
characteristics. You can know those definitions and the
relationship between input and output from these figures.
For example : tON, tOFF, tR, tF, tM...
VHIN
VLIN
Matched Propagation Delays between Both
Channels
Because the IC internal level shifter circuit causes the
propagation delay of the high-side output signal, shown
in Figure 4. The RT7021A/B adds a propagation delay
matching circuit in the low-side logic circuit, so that highside and low-side output signals approximately
synchronization.
BOOT
VHIN
VLIN
BOOT-to-LX
Under-Voltage
Lockout
UVLO1
Driver
Pulse
Generator
VUGATE
VLGATE
Level
Shifter
UGATE High/Low
Figure 1. Input/Output Timing Diagram
HIN
IIN+
Noise
Filter
R
S
LX
VCC
VCC
VCC
UVLO2
Under-Voltage
Lockout
Driver
VHIN, VLIN
VUGATE
VLGATE
VLIN
50%
tON tR
tF
10%
10%
The junction temperature should never exceed the
absolute maximum junction temperature TJ(MAX), listed
tM
90%
Figure 2. Dynamic Electrical Characteristics Definition
for RT7021A
VHIN, VLIN
50%
50%
tOFF
PD(MAX) = (TJ(MAX) − TA) / θJA
10%
10%
50%
tM
tM
90%
VUGATE
VLGATE
10%
Figure 3. Dynamic Electrical Characteristics Definition
for RT7021B
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
DS7021A/B-03
September 2016
under Absolute Maximum Ratings, to avoid permanent
damage to the device. The maximum allowable power
dissipation depends on the thermal resistance of the IC
package, the PCB layout, the rate of surrounding airflow,
and the difference between the junction and ambient
temperatures. The maximum power dissipation can be
calculated using the following formula :
tF
90%
50%
Figure 4. Propagation Delay Matching Circuit
Thermal Considerations
50%
50%
10%
VLIN
GND
IIN+
VUGATE
VLGATE
VUGATE
VLGATE
Delay
LIN
tOFF
90%
tON tR
LGATE
LGATE High/Low
50%
tM
UGATE
Q
where TJ(MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJA is the junction-to-ambient
thermal resistance.
For continuous operation, the maximum operating junction
temperature indicated under Recommended Operating
Conditions is 125°C. The junction-to-ambient thermal
resistance, θJA, is highly package dependent. For a SOP8 package, the thermal resistance, θJA, is 188°C/W on a
standard JEDEC 51-7 high effective-thermal-conductivity
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RT7021A/B
four-layer test board. For a DIP-8 package, the thermal
resistance, θJA, is 134.9°C/W on a standard JEDEC 51-7
high effective-thermal-conductivity four-layer test board.
The maximum power dissipation at TA = 25°C can be
calculated as below :
In order to reduce the noise coupling, it is recommended
that the ground layout should not be placed under or
near the high voltage floating side.
The layout between high-side and low-side power
switches should be thick and straight, avoiding the
formation of long loops. Too long distance will increase
the loop area, and electromagnetic interference
suppression capabilities would be affected. However,
too short distance may cause overheating situation. It
is necessary to consider the most appropriate way.
Refer to typical application circuit, the VCC capacitor
(C1), BOOT to LX capacitor (CBOOT), and bootstrap diode
(DBOOT) need to be placed as close to the IC as possible
to minimize parasitic inductance and resistance. The
CBOOT selected range is from 0.1μF to 0.47μF, and the
VCC capacitor (C1) is greater than ten times CBOOT. It is
recommended to use fast or ultra fast reverse recovery
time bootstrap diode DBOOT.
In Figure 6, the LX pin voltage drop can be improved by
adding RLX (RLX = 1 to 10Ω), because the dv/dt is affected
by (RLX + RUGATE).
PD(MAX) = (125°C − 25°C) / (188°C/W) = 0.53W for a
SOP-8 package.
PD(MAX) = (125°C − 25°C) / (134.9°C/W) = 0.74W for a
DIP-8 package.
The maximum power dissipation depends on the operating
ambient temperature for the fixed TJ(MAX) and the thermal
resistance, θJA. The derating curves in Figure 5 allows
the designer to see the effect of rising ambient temperature
on the maximum power dissipation.
Maximum Power Dissipation (W)1
1.0
Four-Layer PCB
0.9
DIP-8
0.8
0.7
0.6
SOP-8
0.5
0.4
0.3
0.2
VCC
+VDC
0.1
DBOOT
0.0
0
25
50
75
100
BOOT
125
CBOOT
Ambient Temperature (°C)
RUGATE
LX
Layout Consideration
A proper PCB layout for power supply can reduce
unnecessary waveform noise and electromagnetic
interference problems to ensure proper system operation,
please refer to the following PCB layout considerations :
For the high voltage and high current loop layout of
power supply should be as thick and short. Avoid
excessive layout generated parasitic inductance and
resistors to cause significant noise.
In order to shorten the length of IC layout, you need to
consider the relative placement for IC and the power
switches. It is recommended that the power switches
placed in a symmetrical manner, and the IC close to
high-side and low-side elements.
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
www.richtek.com
14
Q1
UGATE
Figure 5. Derating Curve of Maximum Power Dissipation
RLX
Figure 6. LX Pin Resister
If the gate current loop opens circuit for some factors,
at this time the current flows through the gate loop via
the power MOSFET drain-to-gate parasitic capacitor. The
current will charge the gate-to-source parasitic capacitor
to result in power MOSFET wrong action. The power
switches can be damaged or burned out, the resisters
(about least 10kΩ) are connected between the gate and
source pin can prevent malfunction of the power
switches.
is a registered trademark of Richtek Technology Corporation.
DS7021A/B-03
September 2016
RT7021A/B
The selection of larger parasitic capacitor power switch
or gate resister may result in too long turn-off time
making the high-side and low-side power switches shoot
through. In order to prevent the situation, reverse parallel
with diodes (DUGATE & DLGATE) in the RUGATE and RLGATE
(shown in Figure 7), providing a fast discharge path for
the power switches in a short time to complete the
closing operation.
VCC
+VDC
DBOOT
BOOT
CBOOT
DUGATE
RUGATE
Q1
UGATE
LX
To
Load
DLGATE
RLGATE
LGATE
Q2
Figure 7. Reverse Parallel with Diodes
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
DS7021A/B-03
September 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
15
RT7021A/B
Outline Dimension
H
A
M
J
B
F
C
I
D
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
4.801
5.004
0.189
0.197
B
3.810
3.988
0.150
0.157
C
1.346
1.753
0.053
0.069
D
0.330
0.508
0.013
0.020
F
1.194
1.346
0.047
0.053
H
0.170
0.254
0.007
0.010
I
0.050
0.254
0.002
0.010
J
5.791
6.200
0.228
0.244
M
0.400
1.270
0.016
0.050
8-Lead SOP Plastic Package
Copyright © 2016 Richtek Technology Corporation. All rights reserved.
www.richtek.com
16
is a registered trademark of Richtek Technology Corporation.
DS7021A/B-03
September 2016
RT7021A/B
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
3.700
4.320
0.146
0.170
A1
0.381
0.710
0.015
0.028
A2
3.200
3.600
0.126
0.142
b
0.360
0.560
0.014
0.022
b1
1.143
1.778
0.045
0.070
D
9.050
9.550
0.356
0.376
E
6.200
6.600
0.244
0.260
E1
7.620
8.255
0.300
0.325
e
L
2.540
3.000
0.100
3.600
0.118
0.142
8-Lead DIP Plastic Package
Richtek Technology Corporation
14F, No. 8, Tai Yuen 1st Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot
assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be
accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
DS7021A/B-03
September 2016
www.richtek.com
17
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