®
RT9078
2μ
μA IQ, 300mA Low-Dropout Linear Regulator
General Description
Features
The RT9078 is a low-dropout (LDO) voltage regulator with
enable function that operates from a 1.2V to 5.5V supply.
It provides up to 300mA of output current in miniaturized
packaging.
The feature of 2μA low quiescent current and 0.5μA
shutdown current are ideal for the battery application with
long service life. The other features include current limit
function, over temperature protection and output discharge
function.
Pin Configuration
(TOP VIEW)
VOUT
SNS/NC
5
4
2
PSRR = 75dB at 1kHz
Adjustable Output Voltage Range :
0.8V to 5V (TSOT-23-5 Package with SNS Pin Only)
±2% Output Accuracy
Low (0.1μ
μA) Shutdown Current
Dropout Voltage : 0.15V at 300mA when VOUT ≥ 3V
Support Fixed Output Voltage 0.8V, 1.0V, 1.05V, 1.1V,
1.2V, 1.25V, 1.3V, 1.5V, 1.8V, 1.85V, 2V, 2.5V, 2.8V,
2.85V, 3V, 3.1V, 3.3V, 3.45V
Current Limit Protection
Over Temperature Protection
Output Active Discharge Function
TSOT-23-5 and ZQFN-4L 1x1 (ZDFN-4L 1x1) Packages
Available
3
VIN GND EN
Applications
TSOT-23-5
VOUT
Input Voltage Range : 1.2V to 5.5V
2μ
μA Ground Current (IQ) at no Load
1
4
VIN
3
EN
Portable, Battery Powered Equipment
Ultra Low Power Microcontrollers
Notebook Computers
SGND
GND
2
5
ZQFN-4L 1x1 (ZDFN-4L 1x1)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9078-16
June 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
RT9078
Ordering Information
RT9078/NPin 1 Orientation***
(2) : Quadrant 2, Follow EIA-481-D
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Package Type
J5 : TSOT-23-5
QZ : ZQFN-4L 1x1 (Z-Type)
(ZDFN-4L 1x1)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Output Voltage
08 : 0.8V
:
20 : 2.0V
:
33 : 3.3V
1B : 1.25V
1H : 1.85V
2H : 2.85V
1K : 1.05V
3D : 3.45V (ZQFN-4L 1x1 only)
Special Request : Any voltage between
0.8V and 3.3V under specific business
agreement
Pin Function
RT9078 : Without SNS Pin
RT9078N : With SNS Pin**
Note :
***Empty means Pin1 orientation is Quadrant 1
**Available for output target adjustment (Ex : RT9078N-08GJ5
with 0.8V reference level for output target adjustment)
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.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
RT9078
Functional Pin Description
Pin No.
TSOT-23-5 ZQFN-4L 1x1 (ZDFN-4L 1x1)
Pin Name
Pin Function
1
4
VIN
Regulator input pin. Input capacitor should be placed
directly at this pin.
2
2
GND
Ground.
3
3
EN
Chip enable pin. Pulling this pin below 0.4V turns the
regulator off, reducing the quiescent current to a fraction
of its operating value.
4
--
SNS
Output voltage sense. (RT9078N only)
NC
No internal connection.
5
1
VOUT
Regulator output pin. Output capacitor should be placed
directly at this pin.
--
5 (Exposed Pad)
SGND
Substrate of chip. Tie to GND plane for maximum
thermal dissipation.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9078-16
June 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3
RT9078
Functional Block Diagram
VIN
(without sense
function)
Current/Thermal
Sense
GND
SNS
(with sense
function)
+
-
EN
Bandgap
Reference
VOUT
R1
EN
R2
Operation
Basic Operation
Current-Limit Protection
The RT9078 is a low quiescent current linear regulator
designed especially for low external components system.
The input voltage range is from 1.2V to 5.5V.
The RT9078 contains an independent current limiter, which
monitors and controls the pass transistor's gate voltage,
limiting the output current to 0.6A (typ.). The current
limiting level is reduced to around 0.3A named fold-back
current limit when the output voltage is further decreased.
The output can be shorted to ground indefinitely without
damaging the part.
The minimum required output capacitance for stable
operation is 1μF capacitance after consideration of the
temperature and voltage coefficient of the capacitor.
Pass Transistor
The RT9078 builds in a P-MOSFET pass transistor which
provides a low switch-on resistance for low dropout voltage
applications.
Error Amplifier
The Error Amplifier compares the internal reference voltage
with the output feedback voltage from the internal divider,
and controls the gate voltage of P-MOSFET.
Chip Enable and Shutdown
The RT9078 provides an EN pin, as an external chip enable
control, to enable or disable the device. The VEN below
0.4V turns the regulator off and enters the shutdown mode,
while VEN above 0.9V turns the regulator on. When the
regulator is shutdown, the ground current is reduced to a
maximum of 0.5μA.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
www.richtek.com
4
Over-Temperature Protection
The over-temperature protection function will turn off the
P-MOSFET when the junction temperature exceeds 150°C
(typ.), and the output current exceeds 80mA. Once the
junction temperature cools down by approximately 20°C,
the regulator will automatically resume operation.
Output Active Discharge
When the RT9078 is operating at shutdown mode, the
device has an internal active pull down circuit that connects
the output to GND through a resistor for output discharging
purpose.
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
RT9078
Absolute Maximum Ratings
(Note 1)
VIN, VOUT, SNS, EN to GND ------------------------------------------------------------------------------------------VOUT to VIN ---------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
TSOT-23-5 ------------------------------------------------------------------------------------------------------------------ZQFN-4L 1x1 (ZDFN-4L 1x1) -------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
TSOT-23-5, θJA ------------------------------------------------------------------------------------------------------------TSOT-23-5, θJC ------------------------------------------------------------------------------------------------------------ZQFN-4L 1x1 (ZDFN-4L 1x1), θJA -------------------------------------------------------------------------------------ZQFN-4L 1x1 (ZDFN-4L 1x1), θJC ------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3)
HBM (Human Body Model) ----------------------------------------------------------------------------------------------
Recommended Operating Conditions
−0.3V to 6.5V
−6.5V to 0.3V
0.43W
0.44W
230.6°C/W
21.8°C/W
226°C/W
43°C/W
260°C
150°C
−65°C to 150°C
2kV
(Note 4)
Input Voltage, VIN --------------------------------------------------------------------------------------------------------- 1.2V to 5.5V
Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C
Electrical Characteristics
(VOUT + 1 < VIN < 5.5V, TA = 25°C, unless otherwise specified)
Parameter
Fixed Output Voltage Range
Symbol
Min
Typ
Max
Unit
0.8
--
3.45
V
ILOAD = 1mA
2
--
2
%
ILOAD = 1mA
0.784
0.8
0.816
V
0.8V VOUT 1.05V
--
0.7
0.97
1.05V VOUT 1.2V
--
0.5
0.92
1.2V VOUT 1.5V
--
0.4
0.57
1.5V VOUT 1.8V
--
0.3
0.47
1.8V VOUT 2.1V
--
0.24
0.33
2.1V VOUT 2.5V
--
0.21
0.3
2.5V VOUT 2.8V
--
0.18
0.25
2.8V VOUT 3V
--
0.16
0.23
3V VOUT
--
0.15
0.2
VDROP
1.8V VOUT 2.1V
--
0.16
0.2
V
IQ
ILOAD = 0mA, VOUT 5.5V
VIN VOUT + VDROP
--
2
4
A
VOUT
DC Output Accuracy
SNS Reference Voltage (for
RT9078N-08GJ5 only)
Dropout Voltage
(ILOAD = 300mA)
Dropout Voltage
(ILOAD = 200mA)
(Note 5)
(Note 6)
VCC Consumption Current
Test Conditions
VREF
VDROP
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9078-16
June 2019
V
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
5
RT9078
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Shutdown GND Current
(Note 7)
VEN = 0V
--
0.1
0.5
A
Shutdown Leakage Current
(Note 7)
VEN = 0V, VOUT = 0V
--
0.1
0.5
A
VEN = 5.5V
--
--
0.1
A
1.2V VIN 1.5V
--
0.3
0.6
1.5V VIN 1.8V
--
0.15
0.3
1.8V VIN 5.5V
--
0.13
0.35
EN Input Current
IEN
LINE
Line Regulation
ILOAD = 1mA
%
Load Regulation
LOAD
1mA < ILOAD < 300mA
--
0.5
1
%
Power Supply Rejection Ratio
PSRR
VIN = 3V, ILOAD = 50mA,
COUT = 1F, VOUT = 2.5V, f = 1kHz
--
75
--
dB
VOUT = 0.8V
--
38
--
VOUT = 1.2V
--
46
--
VOUT = 1.8V
--
48
--
VOUT = 3.3V
--
51
--
COUT = 1F,
ILOAD = 150mA,
BW = 10Hz to
100kHz,
VIN = VOUT + 1V
Output Voltage Noise
Output Current Limit
VRMS
ILIM
VOUT = 90% of VOUT(NOM)
350
600
--
H-Level
VENH
VIN = 5V
0.5
0.7
0.9
L-Level
VENL
VIN = 5V
0.4
0.65
0.85
Thermal Shutdown
Temperature
TSD
ILOAD = 30mA, VIN 1.5V
--
150
--
C
Thermal Shutdown Hysteresis
TSD
--
20
--
C
--
80
--
Enable Threshold
Voltage
Discharge Resistance
EN = 0V, VOUT = 0.1V
mA
V
Note 1. Stresses beyond those listed under “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 in the natural convection at TA = 25°C on a two-layer Richtek Evaluation Board for ZQFN-4L 1x1 (ZDFN4L1x1) Package.
θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7 for TSOT-235 Package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Note 5. The dropout voltage is defined as VIN − VOUT, when VOUT is 98% of the normal value of VOUT.
Note 6. For the application under following condition :
1.8V ≤ VOUT < 2.1V, ILOAD = 200mA, TA = 85°C, the maximum dropout voltage is guaranteed by design that not over 0.28V.
Note 7. The specification is tested at wafer stage and guaranteed by design after assembly.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
www.richtek.com
6
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
RT9078
Typical Application Circuit
RT9078N
VIN
CIN
1µF
EN
VIN
VOUT
VOUT
COUT
(Capacitance 1µF)
SNS
EN
GND
Figure 1. Application with Sense Function
RT9078
VIN
CIN
1µF
EN
VIN
VOUT
VOUT
COUT
(Capacitance 1µF)
EN
GND
Figure 2. Application without Sense Function
RT9078N
VIN
CIN
1µF
VIN
VOUT
VOUT
R1
SNS
EN
EN
COUT
(Capacitance
1µF)
R2
GND
Figure 3. Adjustable Output Voltage Application Circuit
Table 1. Recommended External Components
Component
CIN
* COUT
Description
Vendor P/N
1F, 10V, X5R, 0402
GRM155R61A105KE15 (Murata)
1F, 6.3V, X5R, 0402
GRM153R60J105ME95(Murata)
CGB2A3X5R0J105M033BB(TDK)
2.2F, 6.3V, X5R, 0402
GRM153R60J225ME95 (Murata)
C1005X5R0J225M050BC (TDK)
4.7F, 6.3V, X5R, 0402
GRM153R60J475ME15 (Murata)
C1005X5R0J475K050BE(TDK)
*: Considering the effective capacitance derated with biased voltage level, the COUT component needs satisfy the
effective capacitance at least 0.7F or above at targeted output level for stable and normal operation.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9078-16
June 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
7
RT9078
Typical Operating Characteristics
Output Voltage vs. Temperature
3.40
0.88
3.38
0.86
3.36
Output Voltage (V)
Output Voltage (V)
Output Voltage vs. Temperature
0.90
0.84
0.82
0.80
VIN = 1.2V
VIN = 2.1V
VIN = 5.5V
0.78
0.76
0.74
3.34
3.32
VIN = 3.8V
VIN = 4.5V
VIN = 5.5V
3.30
3.28
3.26
3.24
0.72
3.22
VOUT = 0.8V, ILOAD = 1mA
0.70
VOUT = 3.3V, ILOAD = 1mA
3.20
-50
-25
0
25
50
75
100
125
-50
-25
Temperature (°C)
50
75
100
125
Output Voltage vs. Load Current
0.88
1.00
0.86
0.95
0.90
0.84
Output Voltage (V)
Output Voltage (V)
25
Temperature (°C)
Output Voltage vs. Input Voltage
0.82
0.80
0.78
0.76
0.85
0.80
VIN = 3V
VIN = 5V
0.75
0.70
0.65
0.60
0.74
0.55
VOUT = 0.8V, ILOAD = 1mA
0.72
ILOAD = 0mA to 300mA
0.50
1.2
1.7
2.2
2.7
3.2
3.7
4.2
4.7
5.2
5.7
0
50
0.35
100
150
200
Ground Current vs. Load Current
0.35
0.25
0.20
0.15
TA = 85°C
TA = 25°C
TA = −40°C
0.10
0.05
Ground Current vs. Load Current
0.25
0.20
TA = −40°C
TA = 25°C
TA = 125°C
0.15
0.10
0.05
VOUT = 3V
VOUT = 0.8V
0.01
0.1
1
10
100
Load Current (mA)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
www.richtek.com
8
300
0.30
GND Current (mA)
0.30
0.00
0.001
250
Load Current (mA)
Input Voltage (V)
GND Current (mA)
0
1000
0.00
0.001
0.01
0.1
1
10
100
1000
Load Current (mA)
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
RT9078
Shutdown Leakage Current vs. Temperature
Shutdown Current vs. Input Voltage
0.10
VOUT = 0.8V, EN = 0V
Shutdown Leakage Current (μA)1
Shutdown Current (μA)1
0.1
0.08
0.06
0.04
0.02
0
VOUT = 0.8V, EN = 0V
0.08
0.06
0.04
VIN = 1.8V
VIN = 5.5V
0.02
0.00
1
2
3
4
5
6
-50
-25
0
Input Voltage (V)
EN Threshold vs. Input Voltage
Enable High
EN Threshold (V)
EN Threshold (V)
125
Enable High
Enable Low
0.5
0.4
0.3
0.2
0.66
0.65
0.64
0.62
0
0.61
2
3
4
5
Enable Low
0.63
0.1
1
VIN = 5.5V
-50
6
-25
0
Input Voltage (V)
ILOAD = 300mA
Current Limit (mA)
0.16
ILOAD = 200mA
0.12
0.10
0.08
ILOAD = 100mA
0.06
0.04
100
125
VOUT = 0.8V
VOUT = 3.3V
500
400
300
200
100
ILOAD = 10mA
0.02
75
600
0.18
0.14
50
Current Limit vs. Temperature
700
VOUT = 2.85V
25
Temperature (°C)
Dropout Voltage vs. Temperature
Dropout Voltage (V)
100
0.67
0.6
VIN = 5V
0.00
0
-50
-25
0
25
50
75
100
Temperature (°C)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9078-16
75
EN Threshold vs. Temperature
0.7
0.20
50
0.68
0.8
0.22
25
Temperature (°C)
June 2019
125
-50
-25
0
25
50
75
100
125
Temperature (°C )
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
9
RT9078
Fold-Back Current Limit vs. Temperature
SNS Input Current vs. Temperature
350
0.9
0.8
SNS Input Current (μA)
Fold-Back Current Limit (mA)
VOUT = 0.8V
300
250
VOUT = 3.3V
200
150
100
50
VIN = 5V
0
0.7
0.6
0.5
0.4
0.3
0.2
0.1
VIN = 5V, VOUT = 0.8V, EN = H
0.0
-50
-25
0
25
50
75
100
125
-50
25
50
75
Temperature (°C)
Power On from EN
Power Off from EN
EN
(2V/Div)
VOUT
(2V/Div)
VOUT
(2V/Div)
VIN = 3.8V, VOUT = 2.8V, ILOAD = 300mA
I LOAD
(200mA/Div)
100
125
VIN = 3.8V, VOUT = 2.8V, ILOAD = 300mA
Time (250μs/Div)
Time (500μs/Div)
Line Transient
Load Transient
VIN = 3.8V, VOUT = 1.8V, ILOAD = 1mA to 300mA
VIN = 2.8V to 3.8V, VOUT = 1.8V, ILOAD = 1mA
I LOAD
(0.1A/Div)
VIN
(1V/Div)
VOUT
(10mV/Div)
VOUT
(2mV/Div)
Time (250μs/Div)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
www.richtek.com
10
0
Temperature (°C )
EN
(2V/Div)
I LOAD
(200mA/Div)
-25
Time (100μs/Div)
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
RT9078
PSRR vs. Frequency
Output Current Limit Protection
0
VOUT
(1V/Div)
PSRR (dB)
-20
IOUT
(200mA/Div)
ILOAD = 50mA
ILOAD = 30mA
ILOAD = 15mA
ILOAD = 10mA
-40
-60
-80
VIN = 5V, VOUT = 3.3V
VIN = 3.3V, VOUT = 2.8V, COUT = 1μF
-100
Time (500μs/Div)
10
100
1000
10000
100000
1000000
PSRR vs. Frequency
0
PSRR (dB)
-20
-40
ILOAD = 150mA
ILOAD = 50mA
ILOAD = 15mA
-60
-80
VIN = 2.8V, VOUT = 0.8V, COUT = 1μF
-100
10
100
1000
10000
100000
Frequency (Hz)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9078-16
June 2019
1000000
Output Spectral Noise Density (μV / Hz)
Frequency (Hz)
Output Noise vs. Frequency
100
VIN = 3.6V, VOUT = 3.3V, COUT = 1μF,
RMS Noise (10Hz to 100kHz)
49μVRMS (IOUT = 150mA)
53μVRMS (IOUT = 10mA)
10
1
IOUT = 10mA
IOUT = 150mA
0.1
0.01
0.001
10
100
1K
10K
100K
Frequency (Hz)
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
11
RT9078
Application Information
Like any low dropout linear regulator, the RT9078’s
external input and output capacitors must be properly
selected for stability and performance. Use a 1μF or larger
input capacitor and place it close to the IC's VIN and GND
pins. Any output capacitor meeting the minimum 1mΩ
ESR (Equivalent Series Resistance) and capacitance larger
than 1μF requirement may be used. Place the output
capacitor close to the IC's VOUT and GND pins. Increasing
capacitance and decreasing ESR can improve the circuit's
PSRR and line transient response.
Dropout Voltage
The dropout voltage refers to the voltage difference between
the VIN and VOUT pins while operating at specific output
current. The dropout voltage VDROP also can be expressed
as the voltage drop on the pass-FET at specific output
current (IRATED) while the pass-FET is fully operating at
ohmic region and the pass-FET can be characterized as
an resistance RDS(ON). Thus the dropout voltage can be
defined as (VDROP = VIN − VOUT = RDS(ON) x IRATED). For
normal operation, the suggested LDO operating range is
(VIN > VOUT + VDROP) for good transient response and
PSRR ability. Vice versa, while operating at the ohmic
region will degrade the performance severely.
Adjustable Output Voltage Setting
Because of the small input current at the SNS pin, the
RT9078N with SNS pin also can work as an adjustable
output voltage LDO. Figure 3 gives the connections for
the adjustable output voltage application. The resistor
divider from VOUT to SNS sets the output voltage when
in regulation.
The voltage on the SNS pin sets the output voltage and is
determined by the values of R1 and R2. The adjustable
output voltage can be calculated using the formula given
in equation 1 :
VOUT R1 + R2 VSNS
(1)
R2
The maximum adjustable output voltage can be as high
as input voltage deducted by the dropout voltage. The
Resistive divider total value of R1 and R2 are suggested
not over 50kΩ.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
PD(MAX) = (TJ(MAX) − TA) / θJA
where TJ(MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJA is the junction to ambient
thermal resistance.
For recommended operating condition specifications the
maximum junction temperature is 125°C and TA is the
ambient temperature. The junction to ambient thermal
resistance, θJA, is layout dependent. For TSOT-23-5
package, the thermal resistance, θJA, is 230.6°C/W on a
standard JEDEC 51-7 four-layer thermal test board. For
ZQFN-4L 1x1 (ZDFN-4L 1x1) package, the thermal
resistance, θJA, is 226°C/W on a two-layer Richtek
evaluation board. The maximum power dissipation at TA =
25°C can be calculated by the following formula :
PD(MAX) = (125°C − 25°C) / (230.6°C/W) = 0.43W for
TSOT-23-5 package
PD(MAX) = (125°C − 25°C) / (226°C/W) = 0.44W for
ZQFN-4L 1x1 (ZDFN-4L 1x1) package
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. The derating curve in Figure 4 allows the
designer to see the effect of rising ambient temperature
on the maximum power dissipation.
where VSNS is determined by the output voltage selections
in the ordering information of the RT9078N (Ex : For the
RT9078N-08GJ5, VSNS is 0.8V ).
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
www.richtek.com
12
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
RT9078
Maximum Power Dissipation (W)1
0.6
Four-Layer PCB for TSOT-23-5 package
Two-Layer Richtek EVB for ZQFN (ZDFN)-4L 1x1
package
0.5
0.4
0.3
ZQFN-4L 1x1 (ZDFN-4L 1x1)
0.2
TSOT-23-5
0.1
0.0
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 4. Derating Curve of Maximum Power Dissipation
Layout Considerations
For best performance of the RT9078, the PCB layout
suggestions below are highly recommend :
Input capacitor must be placed as close as possible to
IC to minimize the power loop area.
Minimize the power trace length and avoid using vias for
the input and output capacitors connection.
Figure 5 and Figure 6 shows the examples for the layout
reference which helps the inductive parasitic components
minimization, load transient reduction and good circuit
stability.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9078-16
June 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
13
RT9078
Ground Power Plane
VOUT
1
4
VIN
3
EN
SGND
GND
5
2
Place input/output capacitors as close
as possible to the connecting pins for
minimizing power loop area and low
impedance connection to GND plate.
Connected with
enable source by via
Figure 5. PCB Layout Guide for ZQFN-4L 1x1 package
Place input/output capacitors as close
as possible to the connecting pins for
minimizing power loop area and low
impedance connection to GND plate.
Resistive divider is for
output voltage adjustment
(RT9078N package only).
R1
R2
VOUT
SNS/NC
5
4
Ground Power Plane
2
3
VIN GND EN
Thermal vias help to
reduce power trace
and Improve thermal
dissipation.
Enable source
Figure 6. PCB Layout Guide for TSOT-23-5 package
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
www.richtek.com
14
is a registered trademark of Richtek Technology Corporation.
DS9078-16
June 2019
RT9078
Outline Dimension
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
0.700
1.000
0.028
0.039
A1
0.000
0.100
0.000
0.004
B
1.397
1.803
0.055
0.071
b
0.300
0.559
0.012
0.022
C
2.591
3.000
0.102
0.118
D
2.692
3.099
0.106
0.122
e
0.838
1.041
0.033
0.041
H
0.080
0.254
0.003
0.010
L
0.300
0.610
0.012
0.024
TSOT-23-5 Surface Mount Package
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
DS9078-16
June 2019
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
15
RT9078
1
1
2
2
DETAIL A
Pin #1 ID and Tie Bar Mark Options
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
0.300
0.400
0.012
0.016
A1
0.000
0.050
0.000
0.002
A3
0.117
0.162
0.005
0.006
b
0.175
0.275
0.007
0.011
D
0.900
1.100
0.035
0.043
D2
0.450
0.550
0.018
0.022
E
0.900
1.100
0.035
0.043
E2
0.450
0.550
0.018
0.022
e
L
0.625
0.200
0.025
0.300
0.008
0.012
H
0.039
0.002
H1
0.064
0.003
Z-Type 4L QFN 1x1 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. 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.
www.richtek.com
16
DS9078-16
June 2019
工商网监
湘ICP备2023018690号
