IS32LT3120-GRLA3-TR

IS32LT3120
DUAL CHANNEL, LINEAR LED DRIVER WITH FADE IN/FADE OUT
Preliminary Information
July 2015
GENERAL DESCRIPTION
FEATURES
The IS32LT3120 is a linear programmable current
regulator consisting of 2 output channels capable of up
to 200mA each. Each channel features an ON/OFF
input pin to toggle the channel between the OFF
condition and the source condition.

A single external resistor programs the current level for
both of the channels, while a separate, single resistor
programs the fade in and fade out rate for both
channels.
The device integrates a 63 steps fade in and fade out
algorithm (Gamma correction) which causes the output
LED current to gradually ramp up to the full source
value after the channel’s control pin is pulsed. The
same controller causes the LED current to gradually
ramp down to zero if the channel’s input control pin is
pulsed while the output channel is on. The LED current
output can be controlled by a momentary contact
switch or logic level signal.
The IS32LT3120 is targeted at the automotive market
with end applications to include map and dome lighting
as well as exterior accent lighting. For 12V automotive
applications the low dropout driver can support 1 to 3
LEDs per channel. It is offered in a small thermally
enhanced SOP-8-EP package.







Dual output channels can source up to 200mA
each
Independent on/off control for each channel
-Inputs are debounced
Programmable current via a single external
resistor
Programmable fade in, fade out via external
resistor
- Pull down resistor value sets fade speed
- Gamma corrected fade in/out algorithm
Fault Protection:
- LED string shorted to GND
- Over temperature
SOP-8-EP package
Automotive Grade - AEC-Q100 (pending)
Operating temperature range from -40°C ~ +125°C
APPLICATIONS

Automotive Interior:
- Map light
- Dome lighting
- Puddle lamp in doors
- Glove box
- Vanity mirror
TYPICAL APPLICATION CIRCUIT
Figure 1
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
Typical Application Circuit
1
IS32LT3120
PIN CONFIGURATION
Package
Pin Configuration (Top view)
SOP-8-EP
PIN DESCRIPTION
No.
Pin
Description
1
TSET
Timing control for the fade in and fade out feature. Connect a
resistor between this pin and GND to set the fade in and fade
out time. Connect this pin directly to ground to disable the fade
function for instant on/off.
2
ISET
Output current setting for both channel 1 and channel 2.
Connect a resistor between this pin and GND to set the
maximum output current.
3
GND
Ground pin for the device.
4
OUT1
Output current source channel 1.
5
OUT2
Output current source channel 2.
6
VCC
Power supply input pin.
EN2
Internally debounced input pin for control of channel 2.
Momentary contact will toggle the state of the corresponding
OUT2 LED. Fade in or out function can be interrupted by EN2
pin state change after debounce period.
EN1
Internally debounced input pin for control of channel 1.
Momentary contact will toggle the state of the corresponding
OUT1 LED. Fade in or out function can be interrupted by EN1
pin state change after debounce period.
Thermal Pad
Connect to GND.
7
8
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
2
IS32LT3120
ORDERING INFORMATION
Automotive Range: -40°C to +125°C
Order Part No.
Package
QTY/Reel
IS32LT3120-GRLA3-TR
SOP-8-EP, Lead-free
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.0C, 07/08/2015
3
IS32LT3120
ABSOLUTE MAXIMUM RATINGS
VCC, OUT1, OUT2
EN1, EN2, ISET, TSET
Ambient operating temperature, TA
Maximum continuous junction temperature, TJ(MAX)
Storage temperature range, TSTG
Maximum power dissipation, PDMAX
ESD (HBM)
ESD (CDM)
-0.3V ~ +50V
-0.3V ~ +7.0V
-40°C ~ +125°C
150°C
-55°C ~ +150°C
1.81W
2kV
750V
Note:
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.
THERMAL CHARACTERISTICS
Characteristic
Package Thermal Resistance
(Junction to Ambient), RθJA
Package Thermal Resistance
(Junction to Pad), RθJP
Test Conditions
Value
On 4-layer PCB based on JEDEC standard
55.4°C/W
2.25°C/W
ELECTRICAL CHARACTERISTICS
TJ = -40°C ~ +125°C, VCC=12V, the detail refer to each condition description. Typical values are at TJ = 25°C.
Symbol
Parameter
VCC
Supply voltage range
VDO
Minimum dropout voltage
Condition
Max.
Unit
45
V
VCC – VOUTx, IOUTx= -200mA (Note1)
900
mV
VCC – VOUTx, IOUTx= -100mA (Note1)
700
mV
1
mA
ICC
Quiescent supply current
ISET=20kΩ, enable. OUTx connected to
VCC
tON
Startup time
VCC> 6V to IOUTx<-5mA (Note 4)
IOUT
EIOUT
EIOUTM
Output current (Note 2,3)
Absolute current accuracy
(Note 2,3)
Channel to channel current
matching (Note 2,3)
Typ.
6
OUT1 and OUT2 is shutdown
IOUT_LIM Output limit current
Min.
0.1
3.6
mA
400
μs
VCC – VOUTx =1V, OUTx sourcing current,
VISET = 0V
-310
-240
-205
mA
ISET = 20kΩ, VCC – VOUTx =1V
-105
-100
-95
mA
-50mA≤IOUTx<-20mA, VCC – VOUTx =1V,
-40°C<TJ<+125°C
-8
8
%
-200mA<IOUTx<-50mA, VCC – VOUTx =1V,
-40°C<TJ<+125°C
-6
6
%
IOUTx = -100mA, VCC – VOUTx =1V,
TJ = 25°C
2
%
IOUTx = -100mA, VCC – VOUTx =1V,
-40°C < TJ < +125°C
4
%
gLINE
Output current line regulation
IOUTx = -50mA, 6V<VCC<18V,
VOUT = VCC -2V (Note 4)
-0.2
0.2
mA/V
gLOAD
Output current load
regulation
2.5V < VOUTx < VCC-2.0V, IOUTx = -50mA
(Note 4)
-0.2
0.2
mA/V
Current slew time
Current rise/fall between 0%~100%
VTSET = 0V
100
μs
tSL
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
45
70
4
IS32LT3120
ELECTRICAL CHARACTERISTICS (CONTINUE)
TJ = -40°C ~ +125°C, VCC=12V, the detail refer to each condition description. Typical values are at TJ = 25°C.
Symbol
Parameter
Condition
Min.
Typ.
Max.
Unit
Logic Input TSET
VTSET Voltage reference
TACC
Fade timing accuracy
1
*Neglecting the RTSET Tolerance*
RTSET=100kΩ, TJ = 25°C
-5
V
5
%
0.8
V
Logic Input ENx
VIL
Input low voltage
VIH
Input high voltage
VIN_HY Input hysteresis
RPU
Pull-up resistor
IPU
Pull-up current
tSW
ENx input debounce time
2
(Note 4)
150
(Note 4)
ENx pin must not change state within
this time to be interpreted as a switch
press or release
25
Measured at OUTx
1.2
V
350
mV
50
kΩ
75
μA
37
50
ms
1.8
V
Protection
VSCD
Short detect voltage
VSC_HY Short detect voltage hysteresis VSCR - VSCD (Note 4)
220
mV
tFD
Fault detect persistence time
(Note 4)
5
ms
TRO
Thermal roll off threshold
(Note 4)
130
°C
TSD
Thermal shutdown threshold
Temperature increasing (Note 4)
155
°C
THY
Over temperature hysteresis
Recovery = TSHT - TJ_HY (Note 4)
20
°C
Note 1: IOUTX output current in case of VCC-VOUTX=VDO called IOUT_VDO. IOUTX output current in case of VCC-VOUTX=1V called IOUT_VDO1V, VDO accuracy
is computed as |IOUT_VDO-IOUT_VDO1V|/IOUT_VDO1V<5%.
Note 2: Output current accuracy is computed as 100×[1 - 2×IOUTx/(IOUT1+IOUT2)]. Output current channel to channel match is computed as 100 ×
[Max ( |IOUTx– IOUT(AV)| ) / IOUT(AV)] , where IOUT(AV) is the average current of all active outputs.
Note 3: Output current accuracy is not intended to be guaranteed at output voltages less than 1.8V.
Note 4: Guaranteed by design.
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
5
IS32LT3120
TYPICAL PERFORMANCE CHARACTERISTICS
250
5
RTSET = 100kΩ
RISET = 20kΩ
No Load
4
RTSET = 100kΩ
VDO = 1V
Output Current (mA)
Supply Current (mA)
4.5
3.5
3
Operating Mode
2.5
2
1.5
200
RISET = 10kΩ
150
RISET = 20kΩ
100
RISET = 40kΩ
Shutdown Mode
1
50
RISET = 200kΩ
0.5
0
5
10
15
20
25
30
35
40
0
5
45
10
15
20
Supply Current vs. Supply Voltage
45
200
RTSET = 100kΩ
TJ = 25°C
Output Current (mA)
Output Current (mA)
40
250
VCC = 12V
RTSET = 100kΩ
VDO = 1V
TJ = 25°C
150
100
0
10
200
RISET = 10kΩ
150
RISET = 20kΩ
100
RISET = 40kΩ
50
50
30
50
70
90
110
130
150
170
0
190 200
RISET = 200kΩ
0
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
RISET (kΩ)
Figure 4
2500
Headroom Voltage (mV)
Output Current vs. RISET
Figure 5
Output Current vs. Headroom Voltage
3000
RISET = 20kΩ
VCC = 12V
RISET = 20kΩ
2500
1500
Fade Time (ms)
RTSET = 1MΩ
2000
Fade Time (ms)
35
Output Current vs. Supply Voltage
Figure 3
250
RTSET = 510kΩ
1000
2000
RTSET = 1MΩ
RTSET = 510kΩ
1500
1000
RTSET = 100kΩ
500
0
30
Supply Voltage (V)
Supply Voltage (V)
Figure 2
25
RTSET = 100kΩ
500
5
10
15
20
25
30
35
40
45
0
-40 -25
-10
Supply Voltage (V)
Figure 6
Fade Time vs. Supply Voltage
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
5
20
35
50
65
80
95
110 125
Temperature (°C)
Figure 7
Fade Time vs. Temperature
6
IS32LT3120
250
5
4
225
Output Current (mA)
Supply Current (mA)
4.5
VCC = 12V
RTSET = 100kΩ
RISET = 20kΩ
No Load
3.5
3
Operating Mode
2.5
2
1.5
Shutdown Mode
1
200
VCC = 12V
RTSET = 0Ω
VDO = 1V
175
RISET = 10kΩ
150
RISET = 20kΩ
125
100
RISET = 40kΩ
75
50
RISET = 200kΩ
25
0.5
0
-40 -25
-10
5
20
35
50
65
80
95
110 125
0
-40 -25 -10
5
20
50
65
80
95 110 125 140 155
Temperature (°C)
Temperature (°C)
Supply Current vs. Temperature
Figure 8
35
Output Current vs. Temperature
Figure 9
RTSET = 0Ω
RTSET = 0Ω
IOUT
20mA/Div
IOUT
20mA/Div
Time (20µs/Div)
Time (20µs/Div)
Figure 10
Instant on
Figure 11
Fade In
RTSET = 100kΩ
Instant Off
Fade Out
RTSET = 100kΩ
IOUT
20mA/Div
IOUT
20mA/Div
VEN
2V/Div
VEN
2V/Div
Time (100ms/Div)
Time (100ms/Div)
Figure 12
VEN vs. IOUT
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
Figure 13
VEN vs. IOUT
7
IS32LT3120
Fade In
RTSET = 510kΩ
Fade Out
RTSET = 510kΩ
IOUT
20mA/Div
IOUT
20mA/Div
VEN
2V/Div
VEN
2V/Div
Time (400ms/Div)
Time (400ms/Div)
Figure 14
VEN vs. IOUT
Figure 15
Fade In
RTSET = 510kΩ
Enable Twice
Fade Out
RTSET = 510kΩ
Enable Twice
IOUT
20mA/Div
IOUT
20mA/Div
VEN
2V/Div
VEN
2V/Div
Time (400ms/Div)
Time (400ms/Div)
Figure 16
VEN vs. IOUT
VEN vs. IOUT
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
Figure 17
VEN vs. IOUT
8
IS32LT3120
FUNCTIONAL BLOCK DIAGRAM
VCC
EN1
EN2
Switch Debounce &
Detection Logic
Fade In/ Fade Out
Control
Output Driver
- Constant Current
Control
- Open Circuit Detect
Thermal Current
Rollback
Output Current
Reference
- DC Current Setting
OUTx
TSET
GND
ISET
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
9
IS32LT3120
APPLICATION INFORMATION
The IS32LT3120 is a 2-channel linear current driver
optimized to drive an automotive interior map light, or
other interior lamp which is frequently toggled between
the on and off condition. The device integrates a
separate input control for each channel allowing for
independent on/off operation of either channel. In
addition, a programmable fade in and fade out feature
is integrated into each channel’s control block to allow
the end customer maximum flexibility in setting up their
light timing requirements.
The device LED current outputs can be connected in
parallel or left unused as required. The regulated LED
current (up to 200mA) from each channel output is set
by a single reference resistor (RISET). Current is
matched in each string eliminating the need for ballast
resistors. (Note: When connecting the outputs in
parallel, both ENx inputs should also be connected
together so that both OUTx channels are controlled by
the same signal.)
OUTPUT CURRENT SETTING
A single programming resistor (RISET) controls the
maximum output current for both output channels
simultaneously. The programming resistor may be
computed using the following Equation (1):
RISET 
2000
I SET
(1)
(10kΩ≤RISET≤100kΩ)
The device is protected from an output overcurrent
condition caused by an accidental short circuit of the
ISET pin, by internally limiting the maximum current in
the event of an ISET short circuit to 260mA.
EN PIN OPERATION
The EN inputs to the device include internal pull-up
sources so that no external components are required
to provide the input high level to the pin.
Both output channels power up in the ‘OFF’ condition.
Toggling the EN pin from high to low on a given
channel for a period of time that exceeds the debounce
time will cause that channel’s output to toggle from the
OFF condition to the source condition. When this
happens, the output current of the channel gradually
ramps up from zero to the programmed value (set by
RISET) over the time set by the resistor (RTSET) attached
to the ISET pin. Conversely, if a channel is already in
the source condition, and that channel’s EN pin is
toggled low, then the output current shall begin to ramp
down towards zero in the time period as programmed
by the resistor (RTSET) attached to the TSET pin.
Note, the EN inputs are available during the period of
either fade in or fade out condition.
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
ENx
Debounce
Time
Debounce
Time
OUTx (On Condition)
OUTx (Off Condition)
t
Figure 18
ENx Debounced
Debounce - Output control is provided by a
debounced switch input, providing an ON/OFF toggle
action for various switch or button characteristics. An
internal debounce circuit will condition the input signal
so a single press of the mechanical switch doesn't
appear like multiple presses. The ENx inputs are
debounced by typically 37ms.
Note: The debounce time applies to both falling and
rising edges of the ENx signal.
FADE IN AND FADE OUT
When an ENx channel is turned on (pulled low), the
output current of the channel shall gradually ramp up
from zero to the final value as programmed by the
resistor (RISET) connected to the ISET pin. The time
period over which the ramping happens is determined
by the resistor (RTSET) connected to the TSET pin. The
output current shall ramp up (or down) in 63 steps, with
integrated gamma correction for an extremely linear
ramping of the luminous output of the LED bulb.
SETTING THE FADE TIME
The fade time, either in or out, for both channels is the
same, and is set by a single external programming
resistor (RTSET). The fade time is programmable by
Equation (2):
t  RTSET  2.5s
(2)
For example, RTSET=100kΩ, fade time is about 0.25s.
Note: In order to get the optimized effect, the
recommended fading time is between 1.5s
(RTSET=600kΩ) and 0.25s (RTSET=100kΩ).
If the TSET pin is tied directly to GND, the fade in/out
function is canceled and the ramp time is about 73µs,
or ‘instant on’. However, the debounce feature of the
ENx pin is not disabled.
10
IS32LT3120
1000
2500
VCC = 12V
RISET = 20kΩ
TJ = 25°C
800
LED Current Duty
Fade Time (ms)
2000
900
1500
1000
500
700
600
500
400
300
200
100
0
0
100
200
300
400
500
600
700
800
900 1000
0
0
5
10
15
20
RTSET (kΩ)
30
35
40
45
50
55
60 62
Gamma Steps
Fade Time vs. RTSET
Figure 19
25
Figure 20
Gamma Correction (63 Steps)
GAMMA CORRECTION
FAULT DETECTION
In order to perform a better visual LED breathing effect
we recommend using a gamma corrected value to set
the LED intensity. This results in a reduced number of
steps for the LED intensity setting, but causes the
change in intensity to appear more linear to the human
eye.
An output shorted to GND fault is detected if the output
voltage on a channel drops below the low voltage
threshold VSCD and remains below the threshold for tFD.
The channel (OUTx) with the short condition will
reduce its output current to 20% of ISET.
Gamma correction, also known as gamma
compression or encoding, is used to encode linear
luminance to match the non-linear characteristics of
display. Gamma correction will vary the step size of the
current such that the fading of the light appears linear
to the human eye. Even though there may be 1000
linear steps for the fading algorithm, when gamma
corrected, the actual number of steps could be as low
as 63.
Table 1 63 Gamma Steps Correction
C(0)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
0
2
4
6
8
10
12
16
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
20
24
28
32
36
42
48
54
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
60
66
72
80
88
96
104
112
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
120
130
140
150
160
170
180
194
C(32)
C(33)
C(34)
C(35)
C(36)
C(37)
C(38)
C(39)
208
222
236
250
264
282
300
318
C(40)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(47)
336
354
372
394
416
438
460
482
C(48)
C(49)
C(50)
C(51)
C(52)
C(53)
C(54)
C(55)
504
534
564
594
624
654
684
722
C(56)
C(57)
C(58)
C(59)
C(60)
C(61)
C(62)
760
798
836
874
914
956
1000
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
When short condition is removed, output current will
recover to original value.
When output current is larger than limit value, about
260mA, the output current will be clamped. When the
open fault condition is recovered, there will be a large
current pulse about 10µs.
OVERTEMPERATURE PROTECTION
The device features an integrated thermal rollback
feature which will reduce the output current of both
channels in a linear fashion if the silicon temperature
exceeds 130°C (Typical). In the event that the die
temperature continues to increase, the device will
enter thermal shutdown if the temperature exceeds
155°C.
THERMAL ROLLOFF
The output current of both channels will be equal to the
set value so long as the die temperature of the IC
remains below 130°C (Typical). If the die temperature
exceeds this threshold, the output current of the device
will begin to reduce at a rate of 3%/°C.
The roll off slope is related to ISET value. When
ISET=20mA, the roll off slope is about 3.7%. When
ISET=200mA, the roll off slope is about 2.2%.
THERMAL SHUTDOWN
In the event that the die temperature exceeds 155°C,
both output channels will go to the ‘OFF’ state. At this
point, the IC presumably begins to cool off. Any
attempt to toggle one or both of the channels back to
the source condition before the IC cooled to < 135°C
will be blocked and the IC will not be allowed to restart.
11
IS32LT3120
The package thermal resistance, RθJA, determines the
amount of heat that can pass from the silicon die to the
surrounding ambient environment. The RθJA is a
measure of the temperature rise created by power
dissipation and is usually measured in degree Celsius
per watt (°C/W). The junction temperature, TJ, can be
calculated by the rise of the silicon temperature, ∆T,
the power dissipation, PD, and the package thermal
resistance, RθJA, as in Equation (3):
2
PD  VCC  I CC   (VCC  VOUTx )  I OUTx
x 1
(3)
and,
TJ  TA  T  TA  PD  RJA
(4)
Where VCC is the supply voltage, VOUTx is the voltage of
OUTx pin and TA is the ambient temperature.
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 (5):
PD ( MAX ) 
125C  25C
RJA
PD ( MAX ) 
So,
125C  25C
 1.81W
55.4C / W
Figure 21, shows the power derating of the
IS32LT3120 on a JEDEC boards (in accordance with
JESD 51-5 and JESD 51-7) standing in still air.
2.5
SOP-8-EP
Power Dissipation (W)
THERMAL CONSIDERATIONS
2
1.5
1
0.5
0
-40
-25
-10
5
20
35
50
65
80
95
110
125
Temperature (°C)
Figure 21
Dissipation Curve
(5)
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
12
IS32LT3120
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
8 minutes max.
Figure 22
Classification Profile
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
13
IS32LT3120
PACKAGE INFORMATION
SOP-8-EP
Integrated Silicon Solution, Inc. – www.issi.com
Rev.0C, 07/08/2015
14
IS32LT3120
RECOMMENDED LAND PATTERN
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.0C, 07/08/2015
15