RT5796A [RICHTEK]
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| 型号： | RT5796A |
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RICHTEK TECHNOLOGY CORPORATION |
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RT5796A
1.5A, 1MHz, 6V CMCOT Synchronous Step-Down Converter
Features
Efficiency Up to 95%
General Description
The RT5796A is a high efficiency synchronous
RDSON 160m HS / 110m LS
step-down DC/DC converter. Its input voltage range is
VIN Range 2.5V to 6V
from 2.5V to 6V and provides an adjustable regulated
VREF 0.6V with 2% Accuracy
output voltage from 0.6V to 3.4V while delivering up to
CMCOT™ Control Loop Design for Best
1.5A of output current.
Transient Response, Robust Loop Stability with
The internal synchronous low on-resistance power
switches increase efficiency and eliminate the need for
an external Schottky diode. The Current Mode
Constant-On-time (CMCOT) operation with internal
compensation allows the transient response to be
optimized over a wide range of loads and output
capacitors. The RT5796A is available in the
T/SOT-23-5 and T/SOT-23-6 packages.
Low-ESR (MLCC) COUT
Fixed Soft-Start 1.2ms; PGOOD Function in
T/SOT-23-6
Cycle-by-Cycle Over Current Protection
Input Under Voltage Lockout
Output Under Voltage Protection (UVP Hiccup)
Thermal Shutdown Protection
Power Saving at Light Load
Ordering Information
Applications
STB, Cable Modem, & xDSL Platforms
LCD TV Power Supply & Metering Platforms
General Purpose Point of Load (POL)
RT5796A
Package Type
B : SOT-23-5
E : SOT-23-6
J5 : TSOT-23-5
J6 : TSOT-23-6
Pin Configurations
(TOP VIEW)
Lead Plating System
G : Green (Halogen Free and Pb Free)
FB
VIN
FB PG VIN
UVP Trim Option
H: Hiccup
5
4
6
5
4
PWM/PSM Mode
A : PSM/PWM
2
3
2
3
EN
LX
EN
LX
GND
GND
Note :
Richtek products are :
T/SOT-23-5
T/SOT-23-6
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
L
RT5796A
V
IN
LX
V
OUT
VIN
C
IN
C
R1
R2
OUT
EN
FB
PG*
GND
*For T/SOT-23-6 Package Only
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5796A-04 December 2019
www.richtek.com
1
RT5796A
Marking Information
RT5796AHGB
RT5796AHGE
21=DNN
58= : Product Code
21= : Product Code
DNN : Date Code
DNN : Date Code
58=DNN
RT5796AHGJ5
09=DNN
RT5796AHGJ6
0V=DNN
09= : Product Code
DNN : Date Code
0V= : Product Code
DNN : Date Code
Functional Pin Description
Pin No.
Pin Name
Pin Function
T/SOT-23-5 T/SOT-23-6
1
2
3
1
2
3
EN
Enable Control Input.
GND
LX
Power Ground and Quiet Ground for Controller Circuits.
Switch Node.
Supply Voltage Input. The RT5796A operates from a 2.5V to 6V
unregulated input. C1 is needed to prevent large voltage spikes from
appearing at the input.
4
4
VIN
Quiet ground for controller circuits.
Feedback Voltage Input. An external resistor divider from the output to
GND, tapped to the FB pin, sets the output voltage.
5
6
5
FB
Power Good Indicator. The output of this pin is an open-drain with
external pull-up resistor to IN. PG is pulled up to IN when the FB voltage
is within 90%, otherwise it is LOW.
--
PG
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS5796A-04 December 2019
RT5796A
Function Block Diagram
For T/SOT-23-5 Package
EN
VIN
UVLO
Shut Down
Control
LX
Ton
OTP
VIN
Error
Amplifier
Comparator
Logic
Control
FB
-
+
+
-
Driver
LX
V
REF
R
C
Current
Limit
C
COMP
GND
Detector
LX
Current
Sense
For T/SOT-23-6 Package
EN
VIN
UVLO
OTP
Shut Down
Control
LX
Ton
VIN
Error
Amplifier
Comparator
FB
-
+
Logic
Control
+
-
Driver
LX
V
REF
R
C
C
COMP
Current
Limit
GND
Detector
+
-
LX
Current
Sense
PG
Operation
The RT5796A is a synchronous low voltage step-down
converter that can support the input voltage range from
2.5V to 6V and the output current can be up to 1.5A.
The RT5796A uses a constant on-time, current mode
architecture. In normal operation, the high side
P-MOSFET is turned on when the switch controller is
set by the comparator and is turned off when the Ton
comparator resets the switch controller.
Low side MOSFET peak current is measured by
internal RSENSE. The error amplifier EA adjusts COMP
voltage by comparing the feedback signal (VFB) from
the output voltage with the internal 0.6V reference.
When the load current increases, it causes a drop in the
feedback voltage relative to the reference, then the
COMP voltage rises to allow higher inductor current to
match the load current.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5796A-04 December 2019
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3
RT5796A
UV Comparator
If the feedback voltage (VFB) is lower than threshold
voltage 0.2V, the UV comparator's output will go high
and the switch controller will turn off the high side
MOSFET. The output under voltage protection is
designed to operate in Hiccup mode.
PGOOD Comparator
When the feedback voltage (VFB) is higher than
threshold voltage 0.54V, the PGOOD open drain output
will be high impedance. The internal PG MOSFET is
typical 100. The PGOOD signal delay time from EN is
about 2ms.
Enable Comparator
A logic-high enables the converter; a logic-low forces
the IC into shutdown mode.
Soft-Start (SS)
An internal current source charges an internal capacitor
to build the soft-start ramp voltage. The VFB voltage will
track the internal ramp voltage during soft-start interval.
The typical soft-start time is 1.2ms.
Over Current Protection (OCP)
The RT5796A provides over current protection by
detecting low side MOSFET valley inductor current. If
the sensed valley inductor current is over the current
limit threshold (1.8A typ.), the OCP will be triggered.
When OCP is tripped, the RT5796A will keep the over
current threshold level until the over current condition is
removed.
Thermal Shutdown (OTP)
The device implements an internal thermal shutdown
function when the junction temperature exceeds 150°C.
The thermal shutdown forces the device to stop
switching when the junction temperature exceeds the
thermal shutdown threshold. Once the die temperature
decreases below the hysteresis of 20°C, the device
reinstates the power up sequence.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS5796A-04 December 2019
RT5796A
Absolute Maximum Ratings (Note 1)
Supply Input Voltage ----------------------------------------------------------------------------------------- 0.3V to 6.5V
LX Pin Switch Voltage---------------------------------------------------------------------------------------- 0.3V to (VIN + 0.3V)
<20ns------------------------------------------------------------------------------------------------------------- 4.5V to 7.5V
Power Dissipation, PD @ TA = 25C
T/SOT-23-5 ----------------------------------------------------------------------------------------------------- 0.43W
T/SOT-23-6 ----------------------------------------------------------------------------------------------------- 0.5W
Package Thermal Resistance
(Note 2)
T/SOT-23-5, JA ----------------------------------------------------------------------------------------------- 230.6C/W
T/SOT-23-6, JA ----------------------------------------------------------------------------------------------- 197.4C/W
T/SOT-23-5, JC ----------------------------------------------------------------------------------------------- 21.8C/W
T/SOT-23-6, JC ----------------------------------------------------------------------------------------------- 18.9C/W
Lead Temperature (Soldering, 10 sec.)------------------------------------------------------------------ 260C
Junction Temperature---------------------------------------------------------------------------------------- 40C to 150C
Storage Temperature Range------------------------------------------------------------------------------- 65C to 150C
ESD Susceptibility
(Note 3)
HBM (Human Body Model) --------------------------------------------------------------------------------- 2kV
Recommended Operating Conditions
(Note 4)
Supply Input Voltage -----------------------------------------------------------------------------------------2.5V to 6V
Ambient Temperature Range-------------------------------------------------------------------------------40C to 85C
Junction Temperature Range ------------------------------------------------------------------------------40C to 125C
Electrical Characteristics
(VIN = 3.6V, TA = 25C, unless otherwise specified)
Parameter
Input Voltage
Symbol
VIN
VREF
IFB
Test Conditions
Min
2.5
Typ
--
Max
6
Unit
V
Feedback Reference Voltage
Feedback Leakage Current
0.588
--
0.6
--
0.612
0.1
V
VFB = 0.6V
A
Active , VFB = 0.63V,
Not Switching
--
22
--
DC Bias Current
A
Shutdown
--
--
--
--
1
1
Switching Leakage Current
Switching Frequency
A
MHz
m
m
A
--
1
--
Switch On Resistance, High
Switch On Resistance, Low
Valley Current Limit
RPMOS
RNMOS
ILIM
ISW = 0.3A
ISW = 0.3A
--
160
110
1.8
2.25
2
--
--
--
1.53
--
2.4
2.5
--
VDD Rising
VDD Falling
V
Under-Voltage Lockout Threshold VUVLO
--
V
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5796A-04 December 2019
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5
RT5796A
Parameter
Over-Temperature Threshold
Logic-High VIH
Logic-Low VIL
Symbol
Test Conditions
Min
--
Typ
150
--
Max
--
Unit
°C
1.5
--
--
Enable Input Voltage
V
--
0.4
--
FB Rising
FB Falling
--
90
85
PG Pin Threshold (relative to
VOUT
%
)
--
--
PG Open-Drain Impedance
(PG = low)
--
--
100
Soft-Start Time
TSS
--
--
1.2
--
--
ms
ns
Minimum Off Time
120
Output Discharge Switch On
Resistance
--
1.8
--
k
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. JA is measured at TA = 25C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. The first
layer of copper area is filled. JC is measured at the top of the package.
Note 3. Devices are ESD sensitive. Handling precaution recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
6
DS5796A-04 December 2019
RT5796A
Typical Application Circuit
L
RT5796A
V
IN
LX
V
OUT
VIN
C
IN
10μF
C *
FF
C
R1
R2
OUT
EN
FB
PG*
GND
*For T/SOT-23-6 Package Only
*CFF : Optional for performance fine-tune
Table 1. Suggested Component Values
VOUT (V)
3.3
R1 (k)
90
R2 (k)
20
L (H)
1.5
COUT (F)
10
10
10
10
10
10
1.8
100
50
1.5
1.5
100
66.6
100
133
148
1.5
1.2
100
1.5
1.05
1
100
1.5
100
1.5
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5796A-04 December 2019
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7
RT5796A
Typical Operating Characteristics
Efficiency vs. Output Current
Efficiency vs. Output Current
100
100
90
80
70
60
50
40
30
20
10
0
90
80
V
V
= 5V, V
= 3.3V
OUT
V
V
= 5V, V
= 3.3V
OUT
IN
IN
IN
IN
70
60
50
40
30
20
10
0
= 3.3V, V
= 1.2V
= 3.3V, V
= 1.2V
OUT
OUT
0
0.25
0.5
0.75
1
1.25
1.5
1.5
5.5
0.001
0.01
0.1
1
10
1.5
5.5
Output Current (A)
Output Current (A)
Output Voltage vs. Output Current
Output Voltage vs. Output Current
1.28
1.26
1.24
1.22
1.20
1.18
1.16
1.14
1.12
3.40
3.38
3.36
3.34
3.32
3.30
3.28
3.26
V
= 5V, V
1
= 3.3V
OUT
IN
V
= 3.3V, V
= 1.2V
OUT
IN
0
0.25
0.5
0.75
1.25
0
0.25
0.5
0.75
1 1.25
Output Current (A)
Output Current (A)
Output Voltage vs. Input Voltage
Output Voltage vs. Input Voltage
1.26
1.24
1.22
1.20
1.18
1.16
1.14
1.12
3.40
3.38
3.36
3.34
3.32
3.30
3.28
3.26
3.24
3.22
V
=4.3V to 5.5V, V
= 3.3V, I
= 1A
IN
OUT
OUT
V
= 2.5V to 5.5V, V
= 1.2V, I
= 1A
IN
OUT
OUT
4.3
4.5
4.7
4.9
5.1
5.3
2.5
3
3.5
4
4.5
5
Input Voltage (V)
Input Voltage (V)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
8
DS5796A-04 December 2019
RT5796A
Reference Voltage vs Input Voltage
Reference Voltage vs. Temperature
0.65
0.63
0.61
0.59
0.57
0.55
0.65
0.64
0.63
0.62
0.61
0.60
0.59
0.58
0.57
0.56
0.55
V
= 3.6V, I = 0.5A
OUT
IN
V
= 2.5V to 5.5V, I
= 1A
IN
OUT
-50
2.5
2.5
-25
0
25
50
75
100
125
2.5
3
3.5
4
4.5
5
5.5
Temperature (°C)
Input Voltage(V)
Switching Frequency vs. Input Voltage
Shutdown Current vs. Input Voltage
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
V
= 1.2V, I
4.5
= 0.5A
OUT
OUT
EN = 0
2.5
3
3.5
4
5
5.5
3
3.5
4
4.5
5
5.5
Input Voltage (V)
Input Voltage (V)
Shutdown Currrent vs. Temperature
Quiescent Current vs. Input Voltage
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0.050
0.045
0.040
0.035
0.030
0.025
0.020
0.015
0.010
0.005
0.000
V = 0.63V, LX No Switch
FB
V
= 0
-25
EN
-50
0
25
50
75
100
125
3
3.5
4
4.5
5
5.5
Temperature (°C)
Input Voltage(V)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5796A-04 December 2019
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9
RT5796A
Inductor Current Limit vs. Input Voltage
Quiescent Current vs. Temperature
3.0
2.5
2.0
1.5
1.0
0.5
0.0
40
35
30
25
20
15
10
5
V
= 5V
IN
V
= 3.3V
IN
V
= 1.2V, Valley Current
OUT
0
2.5
3
3.5
4
4.5
5
5.5
-50
-25
0
25
50
75
100
125
Input Voltage (V)
Temperature (°C)
Inductor Current Limit vs. Temperature
Input UVLO vs. Temperature
3.0
2.5
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
2.5
2.0
1.5
1.0
0.5
0.0
Turn On
Turn Off
V
= 1.2V, Valley Current
OUT
V
= 3.3V
EN
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
Temperature (°C)
Temperature (°C)
Enable Threshold vs. Temperature
Load Transient Response
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
V
OUT
Enable On
Enable Off
(50mV/Div)
I
OUT
V
= 3.3V
(1A/Div)
IN
V
= 3.3V, V
= 1.2V, I
= 0A to 1.5A
IN
OUT
OUT
-50
-25
0
25
50
75
100
125
Time (100s/Div)
Temperature (°C)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
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10
DS5796A-04 December 2019
RT5796A
Load Transient Response
Voltage Ripple
V
V
OUT
OUT
(50mV/Div)
(10mV/Div)
V
I
LX
OUT
(2V/Div)
(1A/Div)
V
= 3.3V, V
= 1.2V, I
= 0.5A to 1.5A
OUT
V
= 3.3V, V
= 1.2V, I
= 1A
OUT
IN
OUT
IN
OUT
Time (500ns/Div)
Time (100s/Div)
Voltage Ripple
Power On from EN
V
EN
V
OUT
(5V/Div)
(10mV/Div)
V
PGOOD
(2V/Div)
V
OUT
(1V/Div)
V
LX
I
OUT
(2V/Div)
(1A/Div)
V
= 3.3V, V
= 1.2V, I
= 1A
OUT
V
= 5V, V
= 3.3V, I
= 1A
OUT
IN
OUT
IN
OUT
Time (500ns/Div)
Time (500s/Div)
Power Off from EN
Power On from EN
V
V
EN
EN
(5V/Div)
(5V/Div)
V
PGOOD
(2V/Div)
V
PGOOD
(2V/Div)
V
OUT
(1V/Div)
V
OUT
(2V/Div)
I
I
OUT
OUT
(1A/Div)
(1A/Div)
V
= 3.3V, V
= 1.2V, I
= 1A
OUT
V
= 5V, V
= 3.3V, I
= 1A
IN
OUT
IN
OUT
OUT
Time (10s/Div)
Time (500s/Div)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
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RT5796A
Power Off from EN
V
EN
(5V/Div)
V
PGOOD
(2V/Div)
V
OUT
(2V/Div)
I
OUT
(1A/Div)
V
= 5V, V
= 3.3V, I
= 1A
OUT
IN
OUT
Time (10s/Div)
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
12
DS5796A-04 December 2019
RT5796A
Application Information
The RT5796A is a single-phase step-down converter. It
provides single feedback loop, constant on-time current
mode control with fast transient response. An internal
0.6V reference allows the output voltage to be precisely
regulated for low output voltage applications. A fixed
switching frequency (1MHz) oscillator and internal
compensation are integrated to minimize external
component count. Protection features include over
current protection, under voltage protection and over
temperature protection.
voltage across the capacitor. This voltage clamps the
voltage at the FB pin, causing PWM pulse width to
increase slowly and in turn reduce the input surge
current. The internal 0.6V reference takes over the loop
control once the internal ramping-up voltage becomes
higher than 0.6V.
UVLO Protection
The RT5796A has input Under Voltage Lockout
protection (UVLO). If the input voltage exceeds the
UVLO rising threshold voltage (2.25V typ.), the
converter resets and prepares the PWM for operation.
If the input voltage falls below the UVLO falling
threshold voltage during normal operation, the device
will stop switching. The UVLO rising and falling
Output Voltage Setting
Connect a resistive voltage divider at the FB between
VOUT and GND to adjust the output voltage. The output
voltage is set according to the following equation :
threshold voltage has
noise-caused reset.
a
hysteresis to prevent
R1
R2
VOUT = VREF 1
Inductor Selection
where VREF is the feedback reference voltage 0.6V
(typ.).
The switching frequency (on-time) and operating point
(% ripple or LIR) determine the inductor value as
shown below:
V
OUT
R1
V
V V
IN OUT
OUT
L =
FB
f
LIR I
V
SW
LOAD(MAX) IN
R2
where LIR is the ratio of the peak-to-peak ripple current
to the average inductor current.
GND
Find a low loss inductor having the lowest possible DC
resistance that fits in the allotted dimensions. The core
must be large enough not to saturate at the peak
inductor current (IPEAK) :
Figure 1. Setting VOUT with a Voltage Divider
Chip Enable and Disable
The EN pin allows for power sequencing between the
controller bias voltage and another voltage rail. The
RT5796A remains in shutdown if the EN pin is lower
than 400mV. When the EN pin rises above the VEN trip
point, the RT5796A begins a new initialization and
soft-start cycle.
LIR
2
IPEAK = ILOAD(MAX)
+
ILOAD(MAX)
The calculation above serves as a general reference.
To further improve transient response, the output
inductor can be further reduced. This relation should be
considered along with the selection of the output
capacitor.
Internal Soft-Start
The RT5796A provides an internal soft-start function to
prevent large inrush current and output voltage
overshoot when the converter starts up. The soft-start
(SS) automatically begins once the chip is enabled.
During soft-start, the internal soft-start capacitor
becomes charged and generates a linear ramping up
Inductor saturation current should be chosen over IC’s
current limit.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
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13
RT5796A
VSAG = ILOAD ESR
Input Capacitor Selection
High quality ceramic input decoupling capacitor, such
as X5R or X7R, with values greater than 10F are
recommended for the input capacitor. The X5R and
X7R ceramic capacitors are usually selected for power
regulator capacitors because the dielectric material has
less capacitance variation and more temperature
stability.
For a given output voltage sag specification, the ESR
value can be determined.
Another parameter that has influence on the output
voltage sag is the equivalent series inductance (ESL).
The rapid change in load current results in di/dt during
transient. Therefore, the ESL contributes to part of the
voltage sag. Using a capacitor with low ESL can obtain
better transient performance. Generally, using several
capacitors connected in parallel can have better
transient performance than using a single capacitor for
the same total ESR.
Voltage rating and current rating are the key
parameters when selecting an input capacitor.
Generally, selecting an input capacitor with voltage
rating 1.5 times greater than the maximum input
voltage is a conservatively safe design.
Thermal Considerations
The input capacitor is used to supply the input RMS
current, which can be approximately calculated using
the following equation :
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 :
V
V
V
OUT
V
IN
OUT
I
= I
1
IN_RMS
LOAD
IN
The next step is selecting a proper capacitor for RMS
current rating. One good design uses more than one
capacitor with low equivalent series resistance (ESR) in
parallel to form a capacitor bank.
PD(MAX) = (TJ(MAX) TA) / JA
where TJ(MAX) is the maximum junction temperature,
TA is the ambient temperature, and JA is the junction to
ambient thermal resistance.
The input capacitance value determines the input ripple
voltage of the regulator. The input voltage ripple can be
approximately calculated using the following equation :
For recommended operating condition specifications,
the maximum junction temperature is 125C. The
junction to ambient thermal resistance, JA, is layout
dependent. For T/SOT-23-5 package, the thermal
resistance, JA, is 230.6C/W on a standard four-layer
thermal test board. For T/SOT-23-6 package, the
thermal resistance, JA, is 197.4C/W on a standard
four-layer thermal test board. The maximum power
dissipation at TA = 25C can be calculated by the
following formula :
IOUT(MAX)
VOUT
V
IN
VOUT
V
IN
V
=
1
IN
CIN fSW
Output Capacitor Selection
The output capacitor and the inductor form a low pass
filter in the Buck topology. In steady state condition, the
ripple current flowing into/out of the capacitor results in
ripple voltage. The output voltage ripple (VP-P) can be
calculated by the following equation :
PD(MAX) = (125C 25C) / (230.6C/W) = 0.43W for
T/SOT-23-5 package
1
VP_P = LIRILOAD(MAX) ESR +
8COUT fSW
PD(MAX) = (125C 25C) / (197.4C/W) = 0.5W for
T/SOT-23-6 package
When load transient occurs, the output capacitor
supplies the load current before the controller can
respond. Therefore, the ESR will dominate the output
voltage sag during load transient. The output voltage
undershoot (VSAG) can be calculated by the following
equation :
The maximum power dissipation depends on the
operating ambient temperature for fixed TJ(MAX) and
thermal resistance, JA. The derating curve in Figure 2
allows the designer to see the effect of rising ambient
temperature on the maximum power dissipation.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
14
DS5796A-04 December 2019
RT5796A
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Four-Layer PCB
T/SOT-23-6
T/SOT-23-5
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 2. Derating Curve of Maximum Power
Dissipation
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5796A-04 December 2019
www.richtek.com
15
RT5796A
Outline Dimension
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
A1
B
0.889
0.000
1.397
0.356
2.591
2.692
0.838
0.080
0.300
1.295
0.152
1.803
0.559
2.997
3.099
1.041
0.254
0.610
0.035
0.000
0.055
0.014
0.102
0.106
0.033
0.003
0.012
0.051
0.006
0.071
0.022
0.118
0.122
0.041
0.010
0.024
b
C
D
e
H
L
SOT-23-5 Surface Mount Package
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
16
DS5796A-04 December 2019
RT5796A
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
A1
B
0.889
0.000
1.397
0.250
2.591
2.692
0.838
0.080
0.300
1.295
0.152
1.803
0.560
2.997
3.099
1.041
0.254
0.610
0.031
0.000
0.055
0.010
0.102
0.106
0.033
0.003
0.012
0.051
0.006
0.071
0.022
0.118
0.122
0.041
0.010
0.024
b
C
D
e
H
L
SOT-23-6 Surface Mount Package
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5796A-04 December 2019
www.richtek.com
17
RT5796A
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
A1
B
0.700
0.000
1.397
0.300
2.591
2.692
0.838
0.080
0.300
1.000
0.100
1.803
0.559
3.000
3.099
1.041
0.254
0.610
0.028
0.000
0.055
0.012
0.102
0.106
0.033
0.003
0.012
0.039
0.004
0.071
0.022
0.118
0.122
0.041
0.010
0.024
b
C
D
e
H
L
TSOT-23-5 Surface Mount Package
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
18
DS5796A-04 December 2019
RT5796A
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
A1
B
0.700
0.000
1.397
0.300
2.591
2.692
0.838
0.080
0.300
1.000
0.100
1.803
0.559
3.000
3.099
1.041
0.254
0.610
0.028
0.000
0.055
0.012
0.102
0.106
0.033
0.003
0.012
0.039
0.004
0.071
0.022
0.118
0.122
0.041
0.010
0.024
b
C
D
e
H
L
TSOT-23-6 Surface Mount 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.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5796A-04 December 2019
www.richtek.com
19
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