ISSI IS31LT3352

IS31LT3352
40V LED DRIVER WITH TEMPERATURE COMPENSATION
OCTOBER 2011
GENERAL DESCRIPTION
The IS31LT3352 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 required LED voltage. The chip
operates from an input supply between 6V and 40V and
provides an externally adjustable output current of up to
750mA. Depending upon supply voltage and external
components, this can provide up to 30 watts of output
power.
The IS31LT3352 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 IS31LT3352 integrates temperature compensation
function in order to maintain LEDs’ stable and reliable
operation. The IS31LT3352 measures the thermistance
mounted close to LEDs. When ambient temperature near
LEDs goes too high and the Negative Temperature
Coefficient thermistors reach the value of threshold
resistance connected at RTH pin, output current starts to
reduce automatically. After the ambient temperature falls
down to a safe temperature，the current will return to the
set value.
The IS31LT3352 can be connected as LED drivers’ chain
with the same temperature compensation percentage. In
this chain, every IS31LT3352’s ADJO output pin drives
next stage’s IS31LT3352 ADJI input pin with temperature
compensation information. So, only one thermistor is
needed in the whole IS31LT3352 system.
FEATURES
 Simple low parts count
 Internal 40V power switch
 Wide input voltage range: 6V to 40V
 Up to 750mA output current
 High efficiency (up to 95% )
 1200：1 dimming ratio
 Typical 5% output current accuracy
 Single pin on/off and brightness control using DC
voltage or PWM
 Up to 1MHz switching frequency
 Inherent open-circuit LED protection
 Thermal shutdown to protect IC itself
 Temperature compensation to protect LEDs
APPLICATIONS
 Low voltage halogen replacement LEDs
 Automotive lighting
 Low voltage industrial lighting
 LED back-up lighting
 Illuminated signs
APPLICATION CIRCUIT
IS31LT3352
Copyright © 2011 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. A, 09/01/2011
1
IS31LT3352
SYSTEM APPLICATION
IS31LT3352
IS31LT3352
IS31LT3352
Note:
Each IS31LT3352 can driver up to three slave chips in the next stages, and it is recommend no more than three stages are used for the current
coherence, therefore, up to thirteen IS31LT3352s are allowed in one system
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
2
IS31LT3352
PIN CONFIGURATIONS
Package
Pin Configurations
SOP8
PIN DESCRIPTION
Pin
NO.
Name
VIN
1
ISENSE
2
RTH
3
RNTC
4
ADJO
5
ADJI
6
GND
LX
7
8
Description
Input voltage (6V to 40V). Decouple to ground with 1μF or higher X7R ceramic capacitor
close to device
Connect resistor RS from this pin to VIN to define nominal average output current IOUTnom
=0.1/RS
The pin set the starting temperature of temperature compensation by connecting an
external resistor.
The output currents reduction slope set pin by connecting an external thermistor in
temperature compensation mode.
LED drivers chain application pin.
* When R3(NTC)>R2,VADJO=VADJI
* When R3(NTC)<R2, ADJO pin outputs ADJI voltage with temperature compensation
information
VADJIO=VADJI*R3/R2
Multi-function On/Off and brightness control pin:
* Leave floating for normal operation.(VADJI = 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<VADJI <1.2V) to adjust output current from 25% to 100% of
IOUTnom
* Drive with PWM signal to adjust output current.
*When driving the ADJI pin above 1.2V, the current will be clamped to 100% brightness
automatically.
Ground (0V)
Drain of power switch
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Rev. A, 09/01/2011
3
IS31LT3352
ORDERING INFORMATION
Industrial Range: -40°C to +85°C
Order Number
Quantity per reel
IS31LT3352-V1GRLS2-TR
2,500
IS31LT3352-V2GRLS2-TR
2,500
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
Package
SOP-8, Lead-free
SOP-8, Lead-free
VSENSE
91mV to 101mV
99mV to 110mV
4
IS31LT3352
ABSOLUTE MAXIMUM RATINGS (NOTE 1)
Symbol
Parameter
Rating
VIN
Input voltage
-0.3V to +50V
VISENSE
ISENSE voltage
VLX
LX output voltage
VADJ ,VADJO,
Rth, RNTC
VIN+0.3V to VIN-5V ,VIN>5V
VIN+0.3V to -0.3V,VIN<5V
-0.3V to +50V
Pin input voltage
-0.3V to +6V
ILX
Switch output current
800mA
Ptot
Power dissipation
1.2W
TOP
Operating temperature
-40 to 85°C
TST
Storage temperature
-55 to 150°C
Tj MAX
Junction temperature
150°C
RθJA
Junction to ambient
80°C/W
ESD Susceptibility(human body
mode)
2kV
ELECTRICAL CHARACTERISTICS
(VIN=12V, Tamb=25°C unless otherwise stated) (NOTE 2)
Symbol
VIN
IINQoff
IINQon
VISENSE
VSENSEHYS
Parameter
Conditions
Input voltage
Quiescent supply current with
output off
Quiescent supply current with
output switching
Mean current sense threshold
voltage
ADJI pin grounded
40
ADJI pin floating
Measured on ISENSE
pin with respect to
VIN ADJI pin
floating
60
80
μA
450
600
μA
IS31LT3352-V2
99
105
110
±15
Internal reference voltage
Measured on ADJI pin with pin floating
VOS
V
101
VREF
DC voltage on ADJI pin to
switch chip from quiescent
(off) state to active (on) state
RTH and RNTC pin offset
voltage
40
95
VSENSE =0.1V
VADJIon
Unit
91
ISENSE pin input current
VADJIoff
Max.
IS31LT3352-V1
Sense threshold hysteresis
External control voltage range
on ADJI pin for dc brightness
control
DC voltage on ADJI pin to
switch chip from active (on)
state to quiescent (off) state
Typ.
6
ISENSE
VADJI
Min.
8
%
10
1.2
0.3
mV
μA
V
1.2
V
VADJI falling
0.15
0.2
0.25
V
VADJI rising
0.2
0.25
0.3
V
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
10
mV
5
IS31LT3352
ELECTRICAL CHARACTERISTICS
(VIN=12V, Tamb=25°C unless otherwise stated) (NOTE 2) (continued)
Symbol
ILX(leak)
VADJO
Parameter
Conditions
Min.
Typ.
LX switch leakage current
No temperature compensation
ADJI pin floating
ADJO terminal voltage
Max.
Unit
1
μA
V
1.20
IADJO=30μA
RLX
LX Switch ‘On’ resistance
0.9
ILXmean
Continuous LX switch current
0.65
A
RADJI
Resistance between ADJI pin and
VREF
500
KΩ
DPWM(LF)
DPWM(HF)
fLX
VADJO to
VADJI offset
Brightness control range at low
frequency PWM signal
PWM frequency =100Hz PWM
amplitude=5V,Vin=15V, L=27uH,
Driving 1 LED
1200:1
Brightness control range at high
frequency PWM signal
PWM frequency =10kHz PWM
amplitude=5V,Vin=15V, L=27uH,
Driving 1 LED
13:1
Operating frequency
ADJI pin floating
L=100μH (0.82Ω) IOUT=350mA @
VLED=3.4V Driving 1 LED
154
ADJI pin to ADJO pin drift voltage
-38
1.5
Ω
KHz
38
mV
TONmin
Minimum switch ‘ON’ time
LX switch ‘ON’
200
ns
TOFFmin
Minimum switch ‘OFF’ time
LX switch ‘OFF’
200
ns
fLXmax
Recommended
operating frequency
maximum
1
MHz
DLX
Recommended duty cycle range of
output switch at fLXmax
TPD
Internal comparator propagation
delay
50
ns
TSD
Thermal shutdown temperature
140
°C
Thermal shutdown hysteresis
20
°C
TSD-HYS
0.3
0.7
0.9
NOTES:
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 under recommended operating conditions is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
2. All parts are production tested at TA=25°C. Other temperature limits are guaranteed by design.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
6
IS31LT3352
TYPICAL OPERATING CONDITIONS
For typical application circuit ,at Tamb=25°C unless otherwise stated.
1
6
1LED
4LED
5LED
0.8
6LED
7LED
0.7
8LED
9LED
0.6
10LED
D e v il a t io n fr o m n o m in a l
c u rr e n t( % )
Efficiency (%)
3LED
1LED
5
2LED
0.9
2LED
4
3LED
3
4LED
5LED
2
6LED
1
7LED
8LED
0
9LED
-1
0.5
5
10
15
20
25
30
35
10LED
-2
40
5
10
15
1LED
2LED
0.9
3LED
Effiency (%)
4LED
0.8
5LED
6LED
7LED
0.7
8LED
9LED
0.6
10LED
0.5
15
20
25
30
35
40
Vin(V)
Efficiency vs. No. of LEDs
L=47uH, Rs=0.33Ohm
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
Devilation from nominal current(%)
1
10
25
30
35
40
Output current variation with Supply Voltage
L=100uH,Rs=0.33Ohm
Efficiency vs. No. of LEDs
L=100uH, Rs=0.33Ohm
5
20
V in ( V)
Vin(V)
7
6
1LED
5
2LED
4
3LED
4LED
3
5LED
2
6LED
1
7LED
0
8LED
-1
9LED
-2
10LED
-3
5
10
15
20
25
30
35
40
Vin(V)
Output current variation with Supply Voltage
L=47uH, Rs=0.33Ohm
7
IS31LT3352
Typical operating conditions (continued)
1.4
1.201
1.2
1.2005
Vref(V)
Vref(V)
1
1.2
1.1995
0.8
0.6
0.4
1.199
0.2
0
1.1985
5
10
15
20
25
30
35
0
40
2
4
Vin(V)
Vref vs. Vin over nominal supply voltage range
8
10
Vref vs. Vin at low supply voltage
600
120
500
100
400
80
Iin(uA)
Iin(uA)
6
Vin(V)
300
200
100
60
40
20
0
0
0
5
10
15
20
25
30
35
40
Vin(V)
0
5
10
15
20
25
30
35
40
Vin(V)
Supply Current vs. Vin (Operating)
Shutdown Current vs. Vin (Quiescent)
1.4
1.2
Vadjo(V)
1
0.8
0.6
0.4
0.2
0
0
300
600
900
1200
Rntc(ohm)
Vadjo vs. Rntc
Rntc falling, Rth=1kohm
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Rev. A, 09/01/2011
8
IS31LT3352
APPLICATION INFORMATION
Setting nominal average output current with external
resistor RS
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 and is
given by:
Output current adjustment by PWM control
Directly driving ADJI input
A Pulse Width Modulated (PWM) signal with duty cycle
DPWM can be applied to the ADJI pin, as shown below, to
adjust the output current to a value below the nominal
average value set by resistor RS, the signal range from
0V~5V. The PWM signal must have the driving ability to
drive an internal 500KΩ pull-up resistor.
IOUT nom = 0.1/RS [for RS>0.13Ω]
The table below gives values of nominal average output
current for several preferred values of current setting
resistor (RS) in the typical application circuit shown on
page 1:
RS (Ω)
Nominal average
output current (mA)
0.13
769
0.15
667
0.27
0.3
370
333
Vsense is divided into two ranges to improve current
accuracy, please refer to bin information on page 4.
The above values assume that the ADJI pin is floating
and at a nominal voltage of VREF =1.2V.
Note that RS=0.13Ω 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 ADJI pin is
driven from an external voltage.
Output current adjustment by external DC control
voltage
The ADJI pin can be driven by an external dc voltage
(VADJI), as shown, to adjust the output current to a value
below the nominal average value defined by RS.
DC
ADJI
IS31LT3352
GND
GND
The nominal average output current in this case is given
by:
IOUTdc = 0.083*VADJI/RS [for 0.3V< VADJI <1.2V]
Note that 100% brightness setting corresponds to VADJI =
VREF. When driving the ADJI pin above 1.2V, the current
will be clamped to 100% brightness automatically.
The input impedance of the ADJI pin is 500k ±25%.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
Driving the ADJI input from a microcontroller
Another possibility is to drive the chip from the open drain
output of a microcontroller. The diagram below shows
one method of doing this:
K10
MCU
ADJI
IS31LT3352
GND
GND
The diode and resistor suppress possible high amplitude
negative spikes on the ADJI 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 ADJI pin to a voltage below 0.2V will turn off
the output and supply current will fall to a low standby
level of 60μA nominally.
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 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.
9
IS31LT3352
If the source is a DC supply, the capacitor is decided by
ripple of the source, the value is given by:
I *T
C min  F on
U MAX
IF is the value of output current， U MAX is the ripple of
power supply. Ton is the “ON” time of MOSFET. The
value is normally 2 times of the minimum value.
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 200μF, the AC
input
waveform is distorted, sometimes the lowest value will be
lower than the forward voltage of LED strings. This will
lower the average current of the LEDs. So it is
recommended to set the value of the capacitor bigger
than 200uF.
For maximum stability over temperature and voltage,
capacitors with X7R, X5R, or better dielectric are
recommended. Capacitors with Y5V dielectric are not
suitable for decoupling in this application and should not
be used.
Inductor selection
Recommended inductor values for the IS31LT3352 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. (See graphs). 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 1.2A for 700mA 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 'Off' time
TOFF 
V LED
L I
 V D  I AVG ( rL  R S )
Note: TOFFmin>200ns
Where:
L is the coil inductance (H)
rL is the coil resistance (Ω)
Iavg is the required LED current (A)
∆I is the coil peak-peak ripple current (A) {Internally set to
0.3 × Iavg}
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=0.64Ω, VLED=3.4V, Iavg =333mA
and VD =0.36V
TON = (47e-6 × 0.105)/(12 - 3.4 - 0.612) = 0.62μs
TOFF = (47e-6 × 0.105)/(3.4 + 0.36 + 0.322)= 1.21μs
This gives an operating frequency of 546kHz and a duty
cycle of 0.34.
Optimum performance will be achieved by setting the
duty cycle close to 0.5 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
above 85°C. Excess leakage will increase the power
dissipation in the device.
The higher forward voltage and overshoot due to 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.
LX Switch 'On' time
TON 
V IN  V LED
L I
 I AVG ( R S  rL  R LX )
Note: TONmin>200ns
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Rev. A, 09/01/2011
Reducing output ripple
Peak to peak ripple current in the LED can be reduced, if
required, by shunting a capacitor Cled across the LED(s)
as shown below:
10
IS31LT3352
Rs
Vin
LED
L1
D1
VIN
CLED
ISENSE
LX
IS31LT3352
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.
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).
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.
Thermal considerations
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. Note that the chip power dissipation will most often
be a maximum at minimum supply voltage. 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.
minimize the change in output current when no
compensation is employed. If output current
compensation is required, it is possible to use an external
temperature sensing network - normally using Negative
Temperature Coefficient (NTC) thermistors and/or
diodes, mounted very close to the LED(s). The output of
the sensing network can reduce output current with
increasing temperature through internal circuit.
As shown in the figure below, the temperature
compensation curve is decided by R1, NTC thermistor
R2 and resistor R3. When LED(s) temperature increases,
thermistance of R2 starts to reduce. As R2 reduces to the
point that R2’s thermistance plus R3 resistance equaling
to R1 resistance, temperature compensation function
starts to work and Iout starts to reduce.
The Iout current with temperature compensation’s
equation is:
In the case that 0.3< VADJI <1.2V:
IOUTdc = 0.083*VADJI (R2+R3)/R1*RS
In the case that VADJI >1.2V:
IOUTdc = 0.1*(R2+R3)/R1*RS
R2 and R3 decide the temperature compensation slope,
if R3 is just 0ohm, slope is only decided by thermistor
R2’s parameter B-constant. And larger R3’s resistance
results in slope more even.
If the temperature compensation threshold is selected,
larger R2 and R3 selected need larger R1 to match and
vice versa. Too large R1 make Rth pin more sensitive to
noise, too small R1 will make IC current consumption
larger. From 1K to 100K of R1 is recommended.
RNTC
R3
RTH
R2(NTC)
ADJO
IS31LT3352
GND
R1
An IS31LT3352 calculator is available from the ISSI to
assist with temperature compensation design and here
are some detail examples as below:
Temperature compensation of output current
High luminance LEDs often need to be supplied with a
temperature compensated current in order to maintain
stable and reliable operation at all drive levels. The LEDs
are usually mounted remotely from the chip. For this
reason, the temperature coefficients of the internal
circuits for the IS31LT3352 have been optimized to
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Rev. A, 09/01/2011
11
IS31LT3352
400
400
350
350
Current (mA)
300
Current (mA)
300
250
200
150
250
200
150
100
100
50
50
0
0
0
0
20
40
60
80
100
120
140
160
20
40
60
80
100
120
140
160
L E D A m b i e n t T e m p ( ℃)
L E D A m b i e n t T e m p ( ℃)
B=4485, R1=58.6k, R2=100k, R3=10k
B=4485, R1=48.6k, R2=100k, R3=0R
400
350
Current (mA)
300
250
200
150
100
50
0
0
20
40
60
80
100
120
140
160
140
160
L E D A m b i e n t T e m p ( ℃)
B=4485, R1=20.6k, R2=100k, R3=0R
400
350
Current (mA)
300
250
200
150
100
50
0
0
20
40
60
80
100
120
L E D A m b i e n t T e m p ( ℃)
B=4485, R1=22.1k, R2=220k, R3=0R
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Rev. A, 09/01/2011
12
IS31LT3352
LAYOUT CONSIDERATIONS
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.
Coil and decoupling capacitors
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.
High voltage traces
Avoid running any high voltage traces close to the ADJI
pin, to reduce the risk of leakage due to board
contamination. Any such leakage may raise the ADJI pin
voltage and cause excessive output current. A ground
ring placed around the ADJI pin will minimize changes in
output current under these conditions
RTH, RNTC pin
The PCB trace from R1 to RTH pin should be as short as
possible to reduce noise pickup. Because NTC thermistor
R2 is mounted close to the LEDs and remote from
IS31LT3352, the PCB trace from R2 to RNTC pin will be
longer and pick up noise more easily. A 0.1uF capacitor
from RNTC pin to ground and close to the RNTC pin is
recommended to filter the frequency noise and provide
protection against high voltage transients.
ADJO pin
Because ADJO pin drives next stages, ADJI pins and the
PCB trace may be longer which picks up noise easily. In
this case 200pF (max) capacitor is needed to connect
from ADJO trace to ground to filter out the noise. Best
practice is to connect one capacitor respectively close to
ADJO output pin and the next stage ADJI input pins, but
the total capacitance besides the parasitic capacitance
from ADJO pin to ground must be less than 200pF.
Please refer to the connection as below.
ADJI pin
The ADJI 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. The ADJI 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. ADJI 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
ADJI=1.2V.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
13
IS31LT3352
PACKAGE INFORMATION
SOP-8
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
14