IS31LT3353

IS31LT3353
40V/1A BUCK LED DRIVER WITH INTERNAL SWITCH
May 2015
GENERAL DESCRIPTION
FEATURES
The IS31LT3353 is a continuous mode inductive
step-down converter, designed for driving a single
LED or multiple series connected LEDs efficiently
from a voltage source higher than the LED voltage.
The chip operates from an input supply between 6V
and 40V and provides an externally adjustable output
current of up to 1A.







The IS31LT3353 includes an integrated output
switch and a high-side output current sensing circuit,
which uses an external resistor to set the nominal
average output current.


The output current can be dynamically adjusted by
adding either a digital PWM or analog voltage level
signal to the ADJ pin. A PWM signal will provide a
gated output current while a voltage signal will
generate a continuously linear output current.
APPLICATIONS
Applying a voltage less than 0.2V to the ADJ pin
turns the output off and switches the chip into a low
current standby state.
The chip is assembled in SOT23-5 and SOT89-5
packages. It operates from 6V to 40V over the
temperature range of -40°C to +125°C.


Up to 1A output current
High efficiency (up to 97% )
Wide input voltage range: 6V to 40V
Internal 40V power switch
Simple low parts count
Typical 3% output current accuracy
Single pin on/off and brightness control using
DC voltage or PWM
Up to 1MHz switching frequency
Inherent LED open-circuit/short-circuit
protection
Thermal shutdown protection circuitry
Up to 1200: 1 dimming rate






LED MR16, MR11 spot light
LED street light
PAR light
Industrial lighting
Refrigeration lights
Other LED lighting
APPLICATION CIRCUIT
Figure 1
Typical Application Circuit
Note: The capacitor, C2, can’t be removed. And it should be placed as close as possible to the VIN and GND pins, otherwise the operation
might be abnormal.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
1
IS31LT3353
PIN CONFIGURATION
Package
Pin Configuration
SOT23-5
SOT89-5
LX
1
GND
2
ADJ
3
5
VIN
Thermal Pad
4
ISENSE
PIN DESCRIPTION
No.
Pin
Description
1
LX
Drain of power switch.
2
GND
SOT23-5 SOT89-5
3
4
5
-
Ground (0V).
Multi-function On/Off and brightness control pin:
* Leave floating for normal operation.(VADJ = VREF = 1.2V
giving nominal average output current IOUT_NOM =0.1/RS)
* Drive to voltage below 0.2V to turn off output current.
* Drive with DC voltage (0.3V<VADJ <1.2V) to adjust output
ADJ
current from 25% to 100% of IOUT_NOM.
* Drive with PWM signal to adjust output current.
* When driving the ADJ pin above 1.2V, the current will be
clamped to 100% brightness automatically.
Connect resistor RS from this pin to VIN to define nominal
ISENSE
average output current IOUT_NOM =0.1/RS.
VIN
Input voltage (6V ~ 40V). Decouple to ground with 0.1μF
X7R ceramic capacitor as close to device as possible.
Thermal
Connect to GND.
Pad
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
2
IS31LT3353
ORDERING INFORMATION
Industrial Range: -40°C to +125°C
Order Part No.
Package
QTY/Reel
IS31LT3353-STLS4-TR
IS31LT3353-SDLS4-TR
SOT23-5, Lead-free
SOT89-5, Lead-free
3000
2500
Copyright © 2015 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: a.) the risk of injury or damage has been minimized; b.) the user assume all such risks; and c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
3
IS31LT3353
ABSOLUTE MAXIMUM RATINGS (Note 1)
Input voltage, VIN
ISENSE voltage, VSENSE
LX output voltage, VLX
Adjust pin input voltage, VADJ
Switch output current, ILX
Power dissipation, PD(MAX) (SOT23-5)(Note 2)
Power dissipation, PD(MAX) (SOT89-5)
Operating temperature, TA
Storage temperature, TST
Junction temperature, TJMAX
Junction to ambient, θJA (SOT23-5)
Junction to ambient, θJA (SOT89-5)
ESD (HBM) at LX pin
ESD (HBM) at other pins
ESD (CDM)
-0.3V ~ +43V
VIN-5V ~ VIN+0.3V (VIN≥5V)
-0.3V ~ VIN+0.3V (VIN<5V)
-0.3V ~ +43V
-0.3V ~ +6V
1.2A
0.46W
0.94W
-40°C ~ +125°C
-55°C ~ +150°C
150°C
271°C/W
132.6°C/W
1kV
3kV
1kV
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 condition beyond those indicated in the operational sections of the specifications is not
implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Note 2:
Detail information please refer to package thermal de-rating curve on Page 12.
ELECTRICAL CHARACTERISTICS
Test conditions: VIN = 12V, TA =TJ = 25°C, unless otherwise stated. (Note 3)
Symbol
VIN
Parameter
Conditions
Input voltage
Quiescent supply current with output off
ADJ pin grounded
IINQ_ON
Quiescent supply current with output
switching
ADJ pin floating
VSENSE
Mean current sense threshold voltage
70
97
Sense threshold hysteresis
ISENSE
ISENSE pin input current
VSENSE =VIN -0.1V
VREF
Internal reference voltage
Measured on ADJ pin
with pin floating
VADJ
External control voltage range on ADJ
pin for dc brightness control
VADJ_OFF
DC voltage on ADJ pin to switch chip
from active (on) state to quiescent (off)
state
VADJ falling
0.15
VADJ_ON
DC voltage on ADJ pin to switch chip
from quiescent (off) state to active (on)
state
VADJ rising
0.2
RADJ
Resistance between ADJ pin and VREF
ILX_MEAN
Continuous LX switch current
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
Typ.
Max.
Unit
40
V
120
160
μA
450
600
μA
100
103
mV
6
IINQ_OFF
VSENSEHYS
Min.
±15
%
8
μA
1.2
V
0.3
(Note 4)
1.2
V
0.2
0.25
V
0.25
0.3
V
500
kΩ
1
A
4
IS31LT3353
ELECTRICAL CHARACTERISTICS (CONTINUED)
Test conditions: VIN = 12V, TA =TJ = 25°C, unless otherwise stated. (Note 3)
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
1
μA
1
Ω
ILX_LEAK
LX switch leakage current
RLX
LX switch ‘ON’ resistance
tON_MIN
Minimum switch ‘ON’ time
LX switch ‘ON’ (Note 4)
200
ns
tOFF_MIN
Minimum switch ‘OFF’ time
LX switch ‘OFF’ (Note 4)
200
ns
Typical contrast ratio
fPWM =100Hz, VIN =15V,
1LED, L=27µH (Note 4)
1200:1
1
Recommended maximum
operating frequency
(Note 4)
DLX
Recommended duty cycle range
of output switch at fLX_MAX
(Note 4)
tPD
Internal comparator propagation
delay
(Note 4)
50
ns
TSD
Thermal shutdown temperature
(Note 4)
150
°C
Thermal shutdown hysteresis
(Note 4)
20
°C
DDIM
fLX_MAX
TSD_HYS
0.5
30
70
1
MHz
90
%
Note 3: Production testing of the device is performed at 25°C. Functional operation of the device and parameters specified over -40°C to
+125°C temperature range, are guaranteed by design, characterization and process control.
Note 4: Guaranteed by design.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
5
IS31LT3353
TYPICAL PERFORMANCE CHARACTERISTICS
4
6
L = 47μH
RS = 0.1Ω
3
4
2
3
1
Error (%)
Error(%)
L = 47μH
RS = 0.2Ω
5
1LED
0
2LED
3LED
-1
4LED
6LED
7LED
10
15
2LED
20
3LED 4LED
25
5LED 6LED
-4
8LED
9LED 10LED
5
0 1LED
-1
-3
-3
-4
1
-2
5LED
-2
2
30
35
7LED 8LED
-6
40
5
10
15
Output Current Error vs. Power Supply
95
Figure 3
5LED
6LED 7LED
8LED 9LED
10LED
95
Efficiency (%)
Efficiency (%)
2LED
85
1LED
80
6
10
5LED
4LED
40
6LED
7LED 8LED 9LED
10LED
85 1LED
80
15
20
25
30
35
75
40
6
10
15
Efficiency vs. Power Supply
Figure 4
20
25
30
35
40
Power Supply(V)
Figure 5
Efficiency vs. Power Supply
140
700
Shutdown Mode
Operating Mode
120
Supply Current (µA)
600
Supply Current (µA)
35
2LED
90
Power Supply(V)
500
400
300
200
100
80
60
40
100
0
30
3LED
3LED
90
25
Output Current Error vs. Power Supply
L = 47μH
RS = 0.2Ω
4LED
75
20
100
100
L = 47μH
RS = 0.1Ω
10LED
Power Supply(V)
Power Supply(V)
Figure 2
9LED
-5
20
6
10
15
20
25
30
35
40
0
6
Supply Current vs. Power Supply (Operating Mode)
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
15
20
25
30
35
40
Power Supply(V)
Power Supply(V)
Figure 6
10
Figure 7
Supply Current vs. Power Supply (Shutdown Mode)
6
IS31LT3353
1.25
1.25
Low Supply Voltage
Normal Supply Voltage
1.23
VREF Voltage (V)
VREF Voltage (V)
1.23
1.21
1.19
1.17
1.15
1.21
1.19
1.17
6
6.5
7
7.5
8
8.5
9
9.5
1.15
10
6
10
14
18
Power Supply(V)
26
30
34
38 40
Power Supply(V)
VREF vs. Power Supply (Low Supply Voltage)
Figure 8
22
Figure 9
1200
VREF vs. Power Supply (Normal Supply Voltage)
700
VIN = 12V
VIN = 12V
600
1180
RDS_ON (mΩ)
VADJ (mV)
500
1160
1140
400
300
200
1120
100
1100
-40 -25
-10
5
20
35
50
65
80
95
110 125
0
-40
-25
-10
5
20
Temperature (°C)
Figure 10
35
50
65
80
95
110 125
Temperature (°C)
VADJ vs. Temperature
Figure 11
RDS_ON vs. Temperature
110
Time (10µs/Div)
VSENSE Voltage (mV)
VIN = 12V
106
VADJ
2.0V/Div
102
98
94
90
-40
-25
-10
5
20
35
50
65
80
95
Temperature (°C)
Figure 12
VSENSE vs. Temperature
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
110 125
VIN = 12V
L = 47µH
RS = 0.13Ω
IL
200mA/Div
Figure 13
ADJ Pin Voltage vs. IL
7
IS31LT3353
VIN = 12V
L = 47µH
RS = 0.13Ω
VIN = 12V
L = 47µH
RS = 0.13Ω
IL
500mA/Div
LED Open
VLED
5V/Div
LED Short
VLX
10V/Div
IL
500mA/Div
Time (100ms/Div)
Figure 14
LED Open-Circuit Protection
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
Time (100ms/Div)
Figure 15
LED Short-Circuit Protection
8
IS31LT3353
FUNCTIONAL BLOCK DIAGRAM
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
9
IS31LT3353
APPLICATION INFORMATION
SETTING NOMINAL AVERAGE OUTPUT
CURRENT WITH EXTERNAL RESISTOR R S
the current will be clamped to 100% brightness
automatically.
The nominal average output current in the LED(s) is
determined by the value of the external current sense
resistor (RS) connected between VIN and ISENSE
pins and in is given by Equation (1):
The input impedance of the ADJ pin is 500kΩ (Typ.).
I OUT _ NOM
OUTPUT CURRENT ADJUSTMENT BY PWM
CONTROL
Directly Driving ADJ Input
0.1

RS
(1)
Note that RS=0.1Ω is the minimum allowed value of
sense resistor under these conditions to maintain
switch current below the specified maximum value. It
is possible to use different values of RS if the ADJ pin
is driven from an external voltage.
The table below gives values of nominal average
output current for several preferred values of current
setting resistor (RS) in the typical application circuit
Figure 1:
A Pulse Width Modulated (PWM) signal with duty
cycle DPWM can be applied to the ADJ pin, as shown
in Figure 17, to adjust the output current to a value
below the nominal average value set by resistor RS,
the signal range is from 0V~5V.The logic “HIGH” is
higher than 1.2V, the logic “LOW” is lower than
0.2V.The PWM signal must have the driving ability to
drive internal 500kΩ pull-up resistor.
RS (Ω)
Nominal Average Output
Current (mA)
Figure 17 PWM Dimming Control Via ADJ Pin
0.1
1000
Driving The ADJ Input From A Microcontroller
0.15
667
0.3
333
Another possibility is to drive the chip from the open
drain output of a microcontroller. The Figure 18
below shows one method of doing this:
The above values assume that the ADJ pin is floating
and at a nominal voltage of VREF =1.2V.
Rs need to be chosen 1% accuracy resistor with
enough power tolerance and good temperature
characteristic to ensure stable output current.
OUTPUT CURRENT ADJUSTMENT BY
EXTERNAL DC CONTROL VOLTAGE
The ADJ pin can be driven by an external DC voltage
(VADJ), as shown in Figure 16, to adjust the output
current to a value above or below the nominal
average value defined by RS.
Figure 18 Dimming By MCU
The diode and resistor suppress possible high
amplitude negative spikes on the ADJ input resulting
from the drain-source capacitance of the FET.
Negative spikes at the input to the chip should be
avoided as they may cause errors in output current or
erratic device operation.
SHUTDOWN MODE
Taking the ADJ pin to a voltage below 0.2V will turn
off the output and supply current will fall to a low
standby level of 120μA nominal.
Figure 16 Dimming by External DC Voltage
The nominal average output current in this case is
given by Equation (2):
I OUT _ DC 
0.083  V ADJ
RS
(2)
For 0.3V< VADJ <1.2V.
Note that 100% brightness setting corresponds to
VADJ = VREF. When driving the ADJ pin above 1.2V,
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
INHERENT OPEN-CIRCUIT LED PROTECTION
If the connection to the LED(s) is open-circuited, the
coil is isolated from the LX pin of the chip, so the chip
will not be damaged, unlike in many boost converters,
where the back EMF may damage the internal switch
by forcing the drain above its breakdown voltage.
CAPACITOR SELECTION
A low ESR capacitor should be used for input
decoupling, as the ESR of this capacitor appears in
10
IS31LT3353
series with the supply source impedance and lowers
overall efficiency. This capacitor has to supply the
relatively high peak current to the coil and smooth the
current ripple on the input supply.
If the source is DC supply, the capacitor is decided
by ripple of the source, the value is given by Equation
(3):
C MIN
I t
 F ON
U MAX
(3)
t ON 
VIN  VLED
L  I
(4)
 I AVG ( RS  RL  RLX )
Note: tON_MIN > 200ns.
LX Switch 'OFF' time:
t OFF 
VLED
L  I
 VD  I AVG ( RL  RS )
(5)
Note: tOFF_MIN > 200ns.
IF is the value of output current, U MAX is the ripple
of power supply. tON is the “ON” time of MOSFET.
Where:
The value is higher than the minimum value. A
100µF capacitor is recommended.
RL is the coil resistance (Ω)
If the source is an AC supply, typical output voltages
ripple from a nominal 12V AC transformer can be
±10%.If the input capacitor value is lower than 220μF,
the AC input waveform is distorted, sometimes the
lowest value will be lower than the forward voltage of
LED strings. This lower the average current of the
LEDs. So it is recommended to set the value of the
capacitor bigger than 220µF.
∆I is the coil peak-peak ripple current (A) {Internally
set to 0.3 × IAVG}
To minimize the ground bounce, It must connect a
0.1µF capacitor as close to device as possible. This
capacitor can’t be removed, otherwise the operation
might be abnormal.
INDUCTOR SELECTION
Recommended inductor values for the IS31LT3353
are in the range 47μH to 220μH.
Higher values of inductance are recommended at
higher supply voltages and low output current in
order to minimize errors due to switching delays,
which result in increased ripple and lower efficiency.
Higher values of inductance also result in a smaller
change in output current over the supply voltage
range. The inductor should be mounted as close to
the chip as possible with low resistance connections
to the LX and VIN pins.
The chosen coil should have a saturation current
higher than the peak output current and a continuous
current rating above the required mean output
current. It is recommended to use inductor with
saturation current bigger than 1.5A for 1A output
current and inductor with saturation current bigger
than 500mA for 350mA output current.
The inductor value should be chosen to maintain
operating duty cycle and switch 'on/off' times within
the specified limits over the supply voltage and load
current range.
The following equations can be used as a guide.
LX Switch 'ON' time:
L is the coil inductance (H)
IAVG is the required LED current (A)
VIN is the supply voltage (V)
VLED is the total LED forward voltage (V)
RLX is the switch resistance (Ω)
VD is the diode forward voltage at the required load
current (V)
Example:
For VIN=12V, L=47μH, RL=0.26Ω, VLED=3.4V, IAVG
=333mA, VD =0.36V, RS = 0.3Ω, RLX=0.5Ω:
47  0.3  0.333
 0.569 s
12  3.4  0.333  (0.3  0.26  0.5)
47  0.3  0.333

 1.19 s
3.4  0.36  0.333  (0.26  0.3)
t ON 
t OFF
This gives an operating frequency of 569kHz and a
duty cycle of 32%.
Optimum performance will be achieved by setting the
duty cycle close to 50% at the nominal supply voltage.
This helps to equalize the undershoot and overshoot
and improves temperature stability of the output
current.
DIODE SELECTION
For maximum efficiency and performance, the
rectifier (D1) should be a fast low capacitance
Schottky diode with low reverse leakage at the
maximum operating voltage and temperature.
If alternative diodes are used, it is important to select
parts with a peak current rating above the peak coil
current and a continuous current rating higher than
the maximum output load current. It is very important
to consider the reverse leakage of the diode when
operating at high temperature. Excess leakage will
increase the power dissipation in the device.
The higher forward voltage and overshoot due to
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
11
IS31LT3353
REDUCING OUTPUT RIPPLE
A value of 1μF will reduce nominal ripple current by a
factor three (approx.). Proportionally lower ripple can
be achieved with higher capacitor values. Note that
the capacitor will not affect operating frequency or
efficiency, but it will increase start-up delay, by
reducing the rate of rise of LED voltage.
PD ( MAX ) 
When operating the chip at high ambient
temperatures, or when driving maximum load current,
care must be taken to avoid exceeding the package
power dissipation limits. The maximum power
dissipation can be calculated using the following
Equation (6):
TJ ( MAX )  TA
 JA
(6)
Where TJ(MAX) is the maximum operating junction
temperature, TA is the ambient temperature, and θJA
is the junction to ambient thermal resistance.
The recommended maximum junction temperature,
TJ(MAX), is 150°C and so maximum ambient
temperature is determined by the junction to ambient
thermal resistance, θJA.
Therefore the maximum power dissipation at TA =
25°C is:
PD ( MAX ) 
150C  25C
 0.46W
271C / W
0.3
0.2
0
-40 -25
(SOT23-5)
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
-10
5
20
35
50
65
80
95
110 125
80
95
110
Temperature (°C)
1
SOT89-5
0.8
0.6
0.4
0.2
0
-40
THERMAL CONSIDERATIONS
PD ( MAX ) 
SOT23-5
0.4
0.1
Power Dissipation (W)
Note that when driving loads of two or more LEDs,
the forward drop will normally be sufficient to prevent
the chip from switching below approximately 6V. This
will minimize the risk of damage to the chip.
(SOT89-5)
0.5
OPERATION AT LOW SUPPLY VOLTAGE
The internal regulator disables the drive to the switch
until the supply has risen above the startup threshold
set internally which makes power MOSFET
on-resistance small enough. Above this threshold,
the chip will start to operate. However, with the
supply voltage below the specified minimum value,
the switch duty cycle will be high and the chip power
dissipation will be at a maximum. Care should be
taken to avoid operating the chip under such
conditions in the application, in order to minimize the
risk of exceeding the maximum allowed die
temperature. (See next section on thermal
considerations).
150C  25C
 0.94W
132.6C / W
The graph below gives details for power derating.
Power Dissipation (W)
reverse recovery time in silicon diodes will increase
the peak voltage on the LX output. If a silicon diode is
used, care should be taken to ensure that the total
voltage appearing on the LX pin including supply
ripple, does not exceed the specified maximum
value.
-25
-10
5
20
35
50
65
125
Temperature (°C)
Figure 19
PD vs. TA
It will also increase if the efficiency of the circuit is low.
This may result from the use of unsuitable coils, or
excessive parasitic output capacitance on the switch
output.
LAYOUT CONSIDERATIONS
VIN Pin
The GND of power supply usually have some
distance to the chip GND pin, which cause parasitic
resistance and inductance. It causes ground voltage
bounce while the MOSFET is switching. Connect a
0.1µF capacitor C2 as close to device as possible to
minimize the ground bounce.
LX Pin
The LX pin of the chip is a fast switching node, so
PCB traces should be kept as short as possible. To
minimize ground 'bounce', the ground pin of the chip
should be soldered directly to the ground plane.
12
IS31LT3353
Coil And Decoupling Capacitor C 1
High Voltage Traces
It is particularly important to mount the coil and the
input decoupling capacitor close to the chip to
minimize parasitic resistance and inductance, which
will degrade efficiency. It is also important to take
account of any trace resistance in series with current
sense resistor RS.
Avoid running any high voltage traces close to the
ADJ pin, to reduce the risk of leakage due to board
contamination. Any such leakage may affect the ADJ
pin voltage and cause unexpectable output current.
The IS31LT3353 has external protection circuitry to
prevent excessive output current if ADJ voltage rises
above 1.2V. A ground ring placed around the ADJ
pin will minimize changes in output current under
these conditions.
ADJ Pin
The ADJ pin is a high impedance input, so when left
floating, PCB traces to this pin should be as short as
possible to reduce noise pickup. ADJ pin can also be
connected to a voltage between 1.2V~5V. In this
case, the internal circuit will clamp the output current
at the value which is set by VADJ=1.2V.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
13
IS31LT3353
CLASSIFICATION REFLOW PROFILES
Profile Feature
Pb-Free Assembly
Preheat & Soak
Temperature min (Tsmin)
Temperature max (Tsmax)
Time (Tsmin to Tsmax) (ts)
150°C
200°C
60-120 seconds
Average ramp-up rate (Tsmax to Tp)
3°C/second max.
Liquidous temperature (TL)
Time at liquidous (tL)
217°C
60-150 seconds
Peak package body temperature (Tp)*
Max 260°C
Time (tp)** within 5°C of the specified
classification temperature (Tc)
Max 30 seconds
Average ramp-down rate (Tp to Tsmax)
6°C/second max.
Time 25°C to peak temperature
Figure 20
8 minutes max.
Classification Profile
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
14
IS31LT3353
PACKAGE INFORMATION
SOT23-5
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
15
IS31LT3353
SOT89-5
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
16
IS31LT3353
RECOMMENDED LAND PATTERN
SOT23-5
Note:
1. Land pattern complies to IPC-7351.
2. All dimensions in MM.
3. This document (including dimensions, notes & specs) is a recommendation based on typical circuit board manufacturing parameters. Since
land pattern design depends on many factors unknown (eg. user’s board manufacturing specs), user must determine suitability for use.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
17
IS31LT3353
SOT89-5
Note:
1. Land pattern complies to IPC-7351.
2. All dimensions in MM.
3. This document (including dimensions, notes & specs) is a recommendation based on typical circuit board manufacturing parameters. Since
land pattern design depends on many factors unknown (eg. user’s board manufacturing specs), user must determine suitability for use.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
18
IS31LT3353
REVISION HISTORY
Revision
Detail Information
Date
A
Initial release
2012.07.05
B
1. Add SOT89-5 package information
2. Add land pattern
2015.05.20
Integrated Silicon Solution, Inc. – www.issi.com
Rev. B, 05/20/2015
19