Data Sheet

SSL3252
Photo flash LED driver
Rev. 1 — 7 July 2011
Product data sheet
1. General description
The SSL3252 is a photo flash LED driver designed for battery operated mobile devices
such as mobile phones and PDAs. The boost converter delivers high performance and
drives a single or dual high brightness LED at up to 500 mA with over 85 % efficiency. The
driver can be programmed to operate in Flash mode, Torch mode, Assist light mode, or
Indicator mode.
The small silicon size and the high internal switching frequency of 2 MHz minimize the
size of the application and make the SSL3252 very suitable for mobile phones where
space is limited, and only requiring three external components. System protection has
been a very important part of the SSL3252 design, so a time-out function can be
programmed to prevent overstressing the LED, and the driver itself is protected from
overheating.
2. Features and benefits

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
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

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High power single or dual LED output driving up to 500 mA flash current
Separate indicator LED output of 2.5 mA to 10 mA
High side current source for main and indicator LEDs
Output voltage of up to 8.85 V
Wide input voltage ranging from 2.5 V to 5.5 V
High efficiency of over 85 % at optimum output current
Switching frequency of 2 MHz
Flash mode, Assist light mode, Torch mode and Indicator mode are supported
Internally timed flash operation up to 850 ms
I2C-bus, programmable up to 400 kHz
Strobe signal to avoid I2C latency for the flash
Direct enable signals for stand-alone operation
Forward voltage sensing to allow single/dual LED detection
Soft start/soft stop
Integrated protection circuits for enhanced system reliability:
 Internal time-out
 OverTemperature Protection (OTP)
 UnderVoltage LockOut (UVLO)
 OverVoltage Protection (OVP)
 Short-circuit protection
 Inductor peak current limit and broken coil detection
 Low device shut-down current of less than 1 A
 Small WLCSP12 package with 500 m bump pitch
SSL3252
NXP Semiconductors
Photo flash LED driver
3. Applications
 Photo flash LED driver for mobile phones and digital cameras
 White LED driver for battery powered portable devices
4. Ordering information
Table 1.
Ordering information
Type number
Package
SSL3252UK/C2
Name
Description
Version
WLCSP12
wafer level chip-size package; 12 bumps; 1.58  2.06  0.6 mm
SSL3252UK
5. Block diagram
VBAT
4.7 µF
2.2 µH
PGND
VIN
LX
VO
4.7 µF
LINEAR
CURRENT
SOURCE
IF_SEL
SDA/EN2
I2C-BUS
INTERFACE
AND CONTROL
SCL/EN1
STRB/2LED
PGND
Isource
LED one or two LEDs
400 kHz
TORCH
R1
CURRENT
FEEDBACK
SYNCHRONOUS
SWITCHER
UP CONVERTER
R2
(1)
R3
(2)
R4
(2)
I_IND
GND
GND
PGND
PGND
014aaa297
(1) Pull-down resistor R2 is connected to STRB/2LED pin only in I2C mode.
(2) Pull-down resistors R3 and R4 are connected to the EN1 and EN2 functions of the SCL/EN1 and SDA/EN2 pins only in Direct
enable mode.
Fig 1.
Block diagram
SSL3252
Product data sheet
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Photo flash LED driver
6. Pinning information
6.1 Pinning
SSL3252UK/C2
Bump A1
Index area
1
2
3
A
B
C
D
Transparent top view
002aag318
Fig 2.
Pin configuration
6.2 Pin description
Table 2.
SSL3252
Product data sheet
Pin description
Symbol
Pin
Type
Description
PGND
A1
ground
power ground
GND
A2
ground
signal ground
VIN
A3
input
input voltage
LX
B1
analog input
inductor connection
TORCH
B2
input
Torch mode activate
I_IND
B3
analog output
indicator LED current source
VO
C1
analog output
output voltage
STRB/2LED
C2
input/output (I/O)
strobe signal input to trigger flash in I2C mode;
2LED signal output in Direct enable mode (open-drain)
IF_SEL
C3
input
interface select; choose between Direct enable mode
or I2C mode
LED
D1
analog output
main LED current source
SDA/EN2
D2
input/output (I/O)
serial data line in I2C mode / enable 2 in Direct enable
mode
SCL/EN1
D3
input
serial clock line in I2C mode / enable 1 in Direct enable
mode.
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SSL3252
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Photo flash LED driver
7. Functional description
7.1 Introduction
The SSL3252 is a boost converter intended to drive either a single high power flash LED
or two high power flash LEDs in series. The LED current is controlled by the output
voltage of the boost converter and the integrated linear current source. The SSL3252 has
two interface modes and six operational modes. The interface mode is selected by the
interface select pin IF_SEL. Depending on the Interface mode selected, the device can
either be controlled by an I2C-bus interface, or external enable lines.
The interface modes are:
• I2C mode
• Direct enable mode
The operational modes are:
•
•
•
•
•
•
Standby mode
Shut-down mode
Flash mode
Torch mode
Assist light mode
Indicator mode
In all LED modes, to ensure a constant switching frequency, the regulated converter
employs Pulse Width Modulation (PWM).
In applications where the required LED voltage is lower than the applied input voltage, the
converter switches to linear mode. The excess voltage difference between the required
LED voltage and input voltage is now compensated by increasing the voltage over the
linear current source and therefore on the LED pin.
Apart from the main LED(s), a separate indicator LED can be driven from the SSL3252.
This is driven by a linear current source circuit that operates independent of the switch
mode converter for the main LED(s).
7.2 Interface modes
The device is equipped with two interfaces: I2C and Direct enable. Which interface mode
is used is defined by the level of the IF_SEL pin. Table 3 describes the interface
possibilities.
Table 3.
SSL3252
Product data sheet
Interface modes
IF_SEL
Interface mode
Relevant controls
1
I2C
SDA, SCL, STRB/2LED, TORCH
0
Direct enable mode
mode
EN1, EN2, TORCH
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Photo flash LED driver
7.2.1 Using the direct enable control
When the Direct enable mode is used, the device can be switched to the various
operational modes using the TORCH, EN1 and EN2 control signals. The definitions of
these control signals are given in Table 4. The EN1 and EN2 functions of the SCL/EN1
and SDA/EN2 pins have a higher priority than the pin TORCH. Figure 3 shows all the
possible transitions between the various interface modes.
The device is in Shut-down mode when all control pins (IF_SEL, EN1, EN2, TORCH) are
LOW.
Shut-down
mode
Indicator
mode
Torch
mode
Flash
mode
Assist light
mode
014aaa303
Fig 3.
Direct enable mode transitions
Table 4.
Direct enable logic definition
IF_SEL SCL/ SDA/ TORCH Mode
pin
EN1 EN2 pin
pin
pin
Output states
0
0
0
0
Shut-down
Outputs disabled; shut-down current less than
1 A
0
0
0
1
Torch
Fixed value; 40 mA dual LEDs; 80 mA single LED
0
0
1
X[1]
Assist light
Fixed value; 40 mA dual LEDs; 80 mA single LED
0
X[1]
Indicator
Fixed value 2.5 mA
1
X[1]
Flash
Fixed value; 320 mA dual LEDs;
500 mA single LED
0
SSL3252
Product data sheet
1
0
1
[1]
X = Don’t care.
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Photo flash LED driver
7.2.2 Using the I2C control
Using the I2C interface mode enables additional features and settings as described in the
I2C register set Table 6. The definition of the control pins is given in Table 5. Figure 4
shows the typical transitions between the various modes.
The device cannot enter Shut-down mode when in I2C mode. The lowest power
consumption can be achieved in Standby mode. When using I2C, the device can still be
put in Shut-down mode by first making all control pins LOW (SDA = SCL = TORCH = 0)
and then going to Direct enable Shut-down mode by making IF_SEL LOW.
Flash
without
strobe
Flash with
edge sensitive
strobe
Shut-down
mode
Standby
mode
Output
ON
Torch
mode
Flash with
level sensitive
strobe
Indicator
mode
Assist light
mode
014aaa304
Fig 4.
I2C mode typical transitions
I2C logic definition
Table 5.
IF_SEL Torch mode; Output ON; Output
pin
bit D4;
bit D3;
mode;
Reg 04h
Reg 04h
bit D1;
Reg 04h
Output
mode;
bit D0;
Reg 04h
TORCH Mode
pin
Output states
1
X
0
X
X
0
Standby
Outputs disabled; standby current
less than 10 A
1
1
X
0
0
1
Torch
Depends on the register value;
between 20 mA and 160 mA;
TORCH signal triggers this mode
only if the registers allow it
1
X
1
1
0
X
Assist light
Depends on the register value;
between 20 mA and 160 mA
1
X
1
0
1
X
Indicator
Depends on the register value;
between 2.5 mA and 10 mA
1
X
1
1
1
X
Flash
Depends on the register value;
between 200 mA and 500 mA for a
single LED and 200 mA to 400 mA
for dual LEDs
SSL3252
Product data sheet
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Photo flash LED driver
7.3 Operational modes
7.3.1 Shut-down mode
To enter the Shut-down mode, all control pins, IF_SEL, EN1 function of SCL/EN1, EN2
function of SDA/EN2, and TORCH, must be LOW. In this mode, the internal circuitry of the
device is turned off to guarantee a shut-down current of less than 1 A. The PMOS switch
of the converter is conducting, and the NMOS is set to high-impedance. To avoid current
leakage into the LED, the current source circuitry for both the main LED and the indicator
LED are switched to high-impedance.
7.3.2 Standby mode
The device only enters Standby mode in I2C mode when pin IF_SEL is HIGH and the
outputs are not active. In Standby mode, part of the internal circuitry of the device remains
on, but the converter is not switching. To avoid current leakage into the LED, the current
source circuitry for both the main LED and the indicator LED are switched to
high-impedance. In this mode, I2C communication with the device is possible.
7.3.3 Switching between Standby mode and Shut-down mode
When using the I2C interface, the lowest power mode is the Standby mode. To further
reduce the power, switching to Direct enable mode allows the device to enter Shut-down
mode. When switching to and from the Direct enable interface, the I2C lines have to be
switched LOW to avoid that they are interpreted as EN1 and EN2.
When IF_SEL is switched HIGH, the I2C lines may still be LOW. After the SDA lines and
the SCL lines have become HIGH, the bus free time has to be respected, as is specified in
the I2C-bus timing specifications. I2C communication cannot be started until at least
350 s after the IF_SEL line is switched HIGH.
When switching from Standby mode to Shut-down mode, the I2C lines need to be set
LOW before the IF_SEL line is set LOW, or at least within 5 s after that, to avoid the
I2C levels being interpreted as EN1 and EN2, which may cause the LEDs to be lit.
IF_SEL
Shut-down/
Torch mode
minimum
350 µs
I2C mode/Standby mode
Shut-down/
Torch mode
maximum
5 µs
SDA/EN2
SCL/EN1
START
condition
Fig 5.
SSL3252
Product data sheet
STOP
condition
014aaa305
Switching between Standby mode and Shut-down mode
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Photo flash LED driver
7.3.4 Torch mode
The Torch mode allows the main LED to be switched on at a lower LED current setting
without timing limitations. Torch mode can be selected by connecting pin TORCH to
HIGH. Pin TORCH is a debounced input. This allows the pin to be directly connected to a
mechanical switch. The debouncing circuit is active during both the LOW-to-HIGH and the
HIGH-to-LOW transitions. It uses a time constant of typically 9 ms.The main LEDs will
light to the set torch current level. The TORCH pin has an internal 350 k pull-down
resistor.
In I2C mode, the LED current is defined by bits D[2:0] in the current set register. The torch
current can be set between 20 mA and 160 mA. The same bits are also used for Assist
light mode. For details see Table 5 and Figure 4.
When using the Direct enable mode, the default torch current values are used. When only
one LED is used, the torch current will be set to a default level of 80 mA. For two LEDs
this value is 40 mA. The EN1 and EN2 signals have higher priority than the TORCH pin
signal. For details see Table 4 and Figure 3.
Figure 6 shows the current register setting for the torch.
ILED (mA)
160
140
120
(1)
100
(2)
80
60
(3)
40
20
0
1
2
3
4
5
6
7
register
value
014aaa306
(1) I2C level
(2) Direct enable level; one LED
(3) Direct enable level; two LEDs
Fig 6.
SSL3252
Product data sheet
Torch and Assist light LED current levels
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Photo flash LED driver
7.3.5 Assist light mode
The Assist light mode allows the main LED to be switched on at a lower LED current
setting, without any timing limitations. The Assist light mode can be selected in both I2C
and Direct enable modes.
In I2C mode, the LED current is defined by bits D[2:0] in the current set register. The
Assist light current value can be set between 20 mA and 160 mA. The same bits are also
used for Torch mode. Entering Assist light mode is possible if bits D[1:0] from the control
register are set to 10 and bit D3 from the same register is set to 1.
When using the Direct enable mode, the default Assist light current values are used.
When only one LED is used, the Assist light current will be set to a default level of 80 mA.
For two LEDs this value is 40 mA. The state of the EN1 function of the SCL/EN1 pin must
be LOW and the state of the EN2 function of the SDA/EN2 pin HIGH to enter Assist light
mode (see Table 4). Figure 6 shows the current register setting for the Assist light.
7.3.6 Flash mode
The Flash mode allows the main LEDs to be used at high current settings. The Flash
mode current can be set to up to 500 mA in both the I2C mode and Direct enable mode.
In I2C mode, the current is defined by bits D[7:4] in the current set register. When two
LEDs are used and the register is set for more than 400 mA, the maximum current is
clipped to 400 mA. Generating the Flash mode can be done in the following three ways:
• software controlled
• edge sensitive strobe
• level sensitive strobe
When using the I2C software controlled flash, the bits in the control register D[1:0] = 11,
D2 = 0 and D3 = 1 must be set and the timing of the flash is determined by the value of
the bits D[3:0] in the indicator/timer register. Figure 7 shows the software controlled flash
operation.
I2C
command
SDA/SCL
output on bit D3
register 04h
ILED
014aaa655
Fig 7.
I2C Flash mode
The strobe signal coming directly from the host, or camera processor, can be used to
avoid I2C latency for the flash. To select Strobe flash mode, bit D2 in the control register
must be set to 1. In I2C mode the STRB function of the STRB/2LED pin has an internal
SSL3252
Product data sheet
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Photo flash LED driver
pull-down resistor of 350 k, and can be either level sensitive or edge sensitive,
depending on the value of the bit D5 in the control register (0 = edge sensitive,
1 = level sensitive).
When using the level sensitive strobe, the flash operates as long as the strobe signal is
active, or until the time limit set by the ‘flash timer’ bits in the indicator/timer register is
reached. This will generate time-out fault. Figure 8 shows the level sensitive strobe flash
operation.
output on bit D3
register 04h
STRB
ILED
014aaa656
Fig 8.
Level sensitive strobe
When the edge sensitive strobe signal is used, the flash is activated at the positive edge
of the STRB function of the STRB/2LED pin, and the flash operation time will be defined
from the timer register value. Figure 9 shows the edge sensitive strobe flash operation.
output on bit D3
register 04h
STRB
ILED
014aaa654
Fig 9.
Edge sensitive strobe
After the flash pulse in all three flash modes, the output ON bit is automatically cleared.
In Direct enable mode, the flash current will be set to a default level. When only one LED
is used, the flash current will be set to a default level of 500 mA. For two LEDs, this value
is 320 mA. Entering Flash mode in Direct enable mode can be done by switching the level
to HIGH on both the EN1 and EN2 functions of the SCL/EN1 and SDA/EN2 pins (Table 4).
The LED will stay lit in Flash mode for as long as the enable pins are set to Flash mode,
but limited to a maximum of 850 ms by the time-out timer. Figure 10 shows the current
levels for the flash in both the I2C and the Direct enable use case. More details on flash
timing are given in Section 7.4.1.
SSL3252
Product data sheet
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Photo flash LED driver
ILED (mA)
(2)
500
480
440
(1)
(3)
400
360
(4)
320
280
240
200
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
register
value
014aaa308
(1) I2C level for one LED.
(2) Direct enable default level for one LED.
(3) I2C maximum level for two LEDs.
(4) Direct enable default level for two LEDs.
Fig 10. Flash mode LED current levels
7.3.7 Indicator
The indicator LED is connected between the dedicated indicator LED current output pin
(I_IND) and GND. Internally, a linear current source controls the indicator LED current to
the required current level.
In I2C interface mode, the indicator LED current can be set between 2.5 mA and 10 mA by
bits D[7:6] of the indicator/timer register.
When using the Direct enable mode, the indicator current is set to a default level of
2.5 mA.
Figure 11 shows the LED current levels for the indicator in both the I2C and the Direct
enable use case.
SSL3252
Product data sheet
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Photo flash LED driver
II_IND (mA)
10
7.5
5
Direct enable
2.5
0
1
2
3
register
value
014aaa309
Fig 11. Indicator LED current levels
7.4 Protection circuits
There are several integrated protection circuits that protect the device and the application
against defects. Some of the protection circuits trigger the corresponding bit in the
fault and info register. In I2C mode, the external logic can read out the status of the
protection circuits to determine what fault has occurred, and decide on the proper action
to take. In Direct enable mode, the status register cannot be read out, but the protection
circuits are still functional. In I2C mode the faults are cleared automatically by reading the
fault and info register. In Direct enable mode the faults are cleared when the EN1 function
of SCL/EN1, EN2 function of SCL/EN2 and TORCH pins are set to LOW.
7.4.1 Time-out protection
A time-out protection function is used to avoid main LED overloading during flash. The
timer is started when the Flash mode is activated by the software, or by hardware strobe
signals in I2C mode, or by the signals EN1 and EN2 in Direct enable mode.
The time-out protection is active in I2C level sensitive strobe Flash and Direct enable
modes. When using I2C level sensitive strobe Flash mode the time-out protection is
triggered when the STRB signal is active longer than the time set by the ‘flash timer’ bits in
indicator/timer register. In Direct enable mode, the default time limit is used as a trigger for
this protection. If the EN1/EN2 signals are active (HIGH) longer than the default limit of
850 ms, the time-out protection is triggered. In case of a time-out fault the IC will stop
switching and go into Fault mode. The fault and info register is set accordingly to flag a
fault condition.
SSL3252
Product data sheet
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Photo flash LED driver
7.4.2 Overtemperature protection
If the chip temperature exceeds its limit (Totp, see Table 9), the SSL3252 will stop
switching and enter Fault mode.
When an overtemperature situation is encountered, the fault and info register is set
accordingly to flag a fault condition. If the chip temperature drops below the Totp(hys) level
and the fault register is cleared, the SSL3252 can operate normally.
7.4.3 Overvoltage protection
If the output voltage (VO) exceeds its limit (VO(ovp), see Table 9), the SSL3252 will stop
switching and enter Fault mode. Overvoltage protection will be triggered when there is no
LED connected to LED pin (open), or no capacitor connected to VO pin (open).
If the overvoltage protection is triggered, the fault and info register is set accordingly to
flag a fault condition.
7.4.4 Short-circuit protection
The output is short-circuit protected to avoid device and battery overloading. If the LED is
shorted to GND (voltage on LED drops below 1.2 V) due to a main LED, or application
failure, the SSL3252 will stop switching and enter Fault mode.
If the short-circuit protection is triggered, the fault and info register is set accordingly to
flag a fault condition.
7.4.5 Broken coil detection
To avoid device and battery overloading from high peak currents, the device is equipped
with broken coil peak current protection. This protection will be triggered when the core of
the coil is broken and the inductance of the coil drops below 800 nH (25 %). The broken
coil detection is done at the beginning of the ramp-up of the LED current. In case of
broken coil detection, the SSL3252 will stop switching and go in Fault mode.
If the broken coil protection is triggered, the fault and info register is set accordingly to flag
a fault condition.
7.4.6 Indicator output protection
The I_IND output is short-circuit and open-circuit protected to detect the fault condition.
In case I_IND is shorted (VI_IND is less than 1.2 V) to GND or open (I_IND current is lower
than 1.25 mA), the SSL3252 will only stop the indicator LED current source. The rest of
the device will remain functional.
If the indicator output protection is triggered, the fault and info register is set accordingly to
flag a fault condition.
7.4.7 Undervoltage lockout
As a result of a low input voltage, the input voltage can drop too low to guarantee normal
operation. When the input voltage has dropped below the undervoltage lockout level, the
device switches to Fault mode stopping the switching completely. Start-up in I2C mode is
only possible by crossing the start-up level (VI(UVLO) + Vhys(UVLO)) and if the TORCH pin is
LOW, see Table 9. Start-up in Direct enable mode is only possible by crossing the start-up
level and if EN1 function of SCL/EN1, EN2 function of SDA/EN2 and TORCH pins are
SSL3252
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Photo flash LED driver
LOW. Recovering from this error results in the reset of all register settings. This protection
cannot be read out in the status register. Figure 12 shows the UVLO and trigger points
and hysteresis.
50 mV to 150 mV
VI
UVLO (hysteresis)
UVLO
2.3 V to 2.5 V
014aaa310
Fig 12. UVLO levels and hysteresis VI
7.5 Soft ramp-up/ramp-down of LED current
The device is equipped with a soft ramp-up/ramp-down circuit to avoid battery
overloading. When entering the Torch mode, Assist light mode or Flash mode, when
switching back to Standby mode or Shut-down mode, or just going from one current mode
to another (e.g., Torch mode to Flash mode), the soft start circuit will slowly increase or
decrease the output current until the required LED current has been reached. The
maximum total ramp-up time will be 1 ms including the 150 s wake-up time for going
from 0 mA to the maximum current of 500 mA and the maximum ramp-down time of
770 s for going from 500 mA to 0 mA. The ramp-up/ramp-down time depends on the
LED current setting.
770 µs
770 µs
500 mA
ILED
150 µs
0A
shut-down
wake-up
ramp-up
ramp-down
014aaa311
Fig 13. Maximum soft ramp-up and ramp-down time (for 500 mA LED current)
7.6 Peak current limit
The device is equipped with a peak current limit function to avoid saturation of the
inductor. This circuit limits the peak inductor currents to the value set in the control register
(04h bits D[7:6]). In Direct enable mode the default current limit value is 1.75 A. No
protection is activated.
SSL3252
Product data sheet
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7.7 Start-up sequence
When I2C mode is selected (IF_SEL is HIGH) and the voltage on the VIN pin is rising to a
level higher than the Power-On Reset (POR) value (POR level is typically 2.0 V) all
registers are set to their reset state. After the registers are set, the device enters Standby
mode and waits for I2C commands.
If the Direct enable mode is selected (IF_SEL is low), POR is detected, and pins EN1
function of SCL/EN1, EN2 function of SDA/EN2, and TORCH are set to LOW, the device
will stay in Shut-down mode. When activity is detected on one of the control pins (EN1
function of SCL/EN1, EN2 function of SDA/EN2 or TORCH), the SSL3252 will start to
operate using the default settings. When the activity ends (all control pins are LOW) the
device will go back to Shut-down mode.
7.8 LED detection
There is an internal circuit integrated into the SSL3252, which is capable of detecting the
number of LEDs connected in series to the LED output, and automatically selecting the
right default current settings. The number of LEDs is detected every time the LED is
ramping up. At an LED current of 80 mA the voltage at the LED output is compared to the
reference level of 4.35 V plus the offset set by bits D[5:4] in the indicator/timer register. If
the measured voltage is higher than the reference level, this is interpreted as two LEDs
connected in series at the LED pin and the device changes all current settings to the dual
LED default value. If the voltage is lower than the reference level, the single LED current
settings are selected.
In I2C mode, bit D3 in the fault and info register is set according to the detected amount of
LEDs. In Direct enable mode, the 2LED function of the STRB/2LED pin is used to indicate
the number of detected LEDs. The STRB/2LED pin is an open-drain output pin in Direct
enable mode with a maximum sink current of 1 mA. The 2LED function of the STRB/2LED
pin will only signal the number of LEDs in Flash mode. The signal on the 2LED function of
the STRB/2LED pin will be active during the flash period from the moment of the detection
(80 mA LED current) until the moment the LED current is back to 0 mA. In all other
operating modes, the 2LED function of the STRB/2LED pin will be high-impedance.
In I2C mode, LED detection can be disabled by setting bit D3 in the current set register to
0. In this case, the number of LEDs can only be set via the I2C-bus by writing the required
value to bit 3 from the fault and info register, which results in the corresponding default
currents being set.
When operating in Assist light mode or Torch mode and with the LED detection enabled,
the LED output will always first ramp-up to 80 mA and then ramp-up or ramp-down to the
value set by the current register.
7.9 I2C-bus protocol
The I2C interface is a 2-wire serial interface developed by NXP Semiconductors to
communicate between different ICs or modules. The two wires are a Serial DAta line
(SDA) and a Serial Clock Line (SCL). Both lines must be connected to a positive supply
via a pull-up resistor when connected to the output stages of a device. Data transfer may
only be initiated when the bus is not busy. The SSL3252 I2C-bus characteristic is the
400 kbit/s Fast-mode I2C-bus from the I2C-bus specification.
SSL3252
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Remark: For more details on the I2C-bus standard, refer to the document
UM10204, “I2C-bus specification and user manual”
(www.nxp.com/documents/user_manual/UM10204.pdf).
The following text describes the protocols used by the SSL3252 for the read and write
sequences. The read sequence may use a repeated START condition during the
sequence, to stop the bus being released during the communication. The sequences can
be used to read or write only one data byte, or to read or write a sequence of data bytes.
After a START condition, a valid hardware address must be sent to the SSL3252 followed
by a subaddress and n data bytes. See Figure 14 and Figure 15 below. For the format and
the timing of the START condition (S), the STOP condition (P) and the Acknowledge bit
(A), refer to the user manual UM10204.
S
slave address
W
A
subaddress n
A
nth register
A
P
S = START condition
P = STOP condition
A = Acknowledge
N = Not Acknowledged
from master to slave
from slave to master
014aaa316
Fig 14. I2C write data transfer format
S
slave address
W
A
subaddress n
A
S
slave address
R
A
nth register
N
P
S = START condition
P = STOP condition
A = Acknowledge
N = Not Acknowledged
from master to slave
from slave to master
014aaa317
Fig 15. I2C read data transfer format
7.9.1 Addressing
Each SSL3252 in an I2C-bus system is activated by sending a valid slave address to the
device. The slave address always has to be sent as the first byte after the START
condition in the I2C-bus protocol. See Figure 16.
MSB
0
LSB
1
1
0
0
0
0
R
W
014aaa318
Fig 16. I2C slave address
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There is one address byte required since 7-bit addresses are used. The last bit of the
address byte is the read/write bit and should always be set according to the required
operation. This 7-bit address is 0110 000b (30h). The combination with the LSB R/W bit
gives a write address of 60h and a read address of 61h.
The second byte sent to the SSL3252 is the subaddress of the specific register.
7.9.2 Data
After the subaddress the data bytes are sent. The definition of the data transfer is given in
Figure 14 and Figure 15. After each data byte an acknowledge is given and the
subaddress is automatically incremented to the next subaddress.
A description of the data that can be programmed in the registers is given in Table 6.
7.9.3 Register map
Table 6.
Description of registers
Legend: * default reset register value.
Address
Register
Bit
Symbol
Access Value
Description
00h
Design info
7 to 4
Man_ID
R
0100*
Manufacturer ID
3 to 0
Model_ID
R
0001*
Model ID
7 to 4
Reserved
R
0000*
Reserved for future use
3 to 0
Design version
R
0000
Design version 1
0001
Design version 2
:
:
1111
Design version 16
00*
Indicator LED current 2.5 mA (default)
01
Indicator LED current 5 mA
10
Indicator LED current 7.5 mA
11
Indicator LED current 10 mA
00*
No offset (default)
01
Offset = Vref + 0.3 V
10
Offset = Vref  0.3 V
11
Offset = Vref + 0.6 V
0000
Software flash timer value 100 ms
0001
Software flash timer value 150 ms
:
:
1111*
Software flash timer value 850 ms (default)
01h
02h
Version control
Indicator/timer
7 to 6
5 to 4
3 to 0
SSL3252
Product data sheet
Indicator
current
Vref offset
Flash timer
R/W
R/W
R/W
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Table 6.
Description of registers …continued
Legend: * default reset register value.
Address
03h
Current set
04h
Control
05h
[1]
Register
Fault and info
Bit
Symbol
Access Value
Description
7 to 4
Flash[1]
R/W
0000
Flash current 200 mA
0001
Flash current 220 mA
:
:
0110*
Flash current 320 mA (default dual LEDs)
:
:
1111
Flash current 500 mA (default single LED)
3
LED detection
enable
R/W
1*
Enabled number of LED detection
(default enabled)
2 to 0
Assist/Torch
current
R/W
000
Assist/Torch current 20 mA
001*
Assist/Torch current 40 mA
(default two LEDs)
:
:
011
Assist/Torch current 80 mA
(default one LED)
7 to 6
Coil peak
R/W
:
:
111
Assist/Torch current 160 mA
00
Coil peak current limit 1.25 A
01
Coil peak current limit 1.5 A
10*
Coil peak current limit 1.75 A (default)
11
Coil peak current limit 2.00 A
5
Strobe signal
R/W
1*
Strobe signal usage (0 = edge sensitive,
1 = level sensitive)
4
Torch mode
R/W
1*
Torch mode allowed in Standby mode
(1 = allowed)
3
Output ON
R/W
0*
Turn ON outputs Indicator mode,
Assist light mode or Flash mode (1 = ON)
2
Strobe
R/W
1*
Strobe signal mode (1 = enabled)
1 to 0
Output mode
R/W
00*
Torch mode (default)
01
Indicator mode
10
Assist light mode
11
Flash mode
7
OVP
R
0*
Overvoltage protection (1 = fault)
6
Short circuit
R
0*
Short-circuit LED (1 = fault)
5
Over temp
R
0*
Overtemperature (1 = fault)
4
Timeout
R
0*
Time-out (1 = fault)
3
Amount LEDs
R/W
-
Amount of LEDs on LED (0 = one LED,
1 = two LEDs)
2
Indicator LED
R
0*
Short or open circuit on I_IND (1 = fault)
1
Broken coil
R
0*
Broken coil (1 = fault)
0
Reserved
R
0*
Reserved for future use
For register settings above 400 mA and dual LED detected, the output LED current will be limited to 400 mA.
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8. Limiting values
Table 7.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Parameter
Conditions
Min
Max
Unit
VI
input voltage
on pin VIN
0.5
+5.5
V
VSDA_EN2
voltage on pin SDA/EN2
0.5
VI
V
VSCL_EN1
voltage on pin SCL/EN1
0.5
VI
V
VSTRB_2LED
voltage on pin STRB/2LED
0.5
VI
V
VIF_SEL
voltage on pin IF_SEL
0.5
VI
V
VTORCH
voltage on pin TORCH
0.5
VI
V
VI_IND
voltage on pin I_IND
0.5
VI
V
LED output voltage
pin LED
0.5
+10[1]
V
pin VO
0.5
+10[1]
V
0.5
+10[1]
V
-
0.8
W
VO(LED)
output voltage
VO
VLX
voltage on pin LX
Ptot
total power dissipation
Tj
junction temperature
40
+150
C
Tamb
ambient temperature
40
+85
C
Tstg
storage temperature
IC
55
+150
C
VESD
electrostatic discharge
voltage
human body model
according to
JESD22-A114-E
-
2000
V
charged-device
model according to
JESD22-C101-A
-
500
V
[1]
Tamb = 85 C
Tolerant to the specified maximum voltage while operating. Do not apply voltages externally; this may
cause permanent damage to the device.
9. Thermal characteristics
Table 8.
Symbol
Parameter
Conditions
Typ
Unit
Rth(j-a)
thermal resistance from junction
to ambient
mounted on dedicated
4 layer PCB in free air[1]
83
K/W
[1]
SSL3252
Product data sheet
Thermal characteristics
The junction to ambient thermal resistance is dependent on board layout, PCB material application and
environmental conditions.
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10. Characteristics
Table 9.
Characteristics
VI = 2.7 V to 5.5 V; Tamb = 40 C to +85 C, unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ[1]
Max
Unit
General voltage levels
VI
input voltage
VI(extnd)(VIN)
extended input voltage on
pin VIN
VI(UVLO)
undervoltage lockout
input voltage
Vhys(UVLO)
Vth
pin VIN
2.7
-
5.5
V
2.5
-
5.5
V
VI falling
2.3
2.4
2.5
V
undervoltage lockout
hysteresis voltage
VI rising
50
100
150
mV
threshold voltage
on pin LED for single and dual LED
detection; no offset;
register value 00
4.25
4.35
4.45
V
[2]
General current levels
Istb
standby current
Standby and Fault modes
-
-
10
A
Isd
shutdown current
Shut-down mode
-
-
1
A
Ilmtr(IM)(LX)
peak current limiter current
on pin LX
inductor peak current limiter
register value 00
1.125
1.25
1.375
A
register value 01
1.35
1.5
1.65
A
register value 10
1.575
1.75
1.925
A
register value 11
1.8
2.0
2.2
A
pin LED
2.8
-
8.5
V
short-circuit protection level on
pin LED
-
-
1.2
V
High power LED parameters
VO(LED)
LED output voltage
Vhr
headroom voltage
current source; headroom voltage;
Vhr = VO  VLED; in Boost mode,
VI = 3.6 V
-
300
-
mV
ILED
LED current
pin LED; I2C mode; single LED
20
-
500
mA
20
-
400
mA
from 20 mA to 180 mA
-
-
20
%
from 200 mA to 500 mA
-
-
10
%
9
9.5
10
V
2.5
-
10
mA
-
2.5
-
mA
open-circuit protection level at pin
I_IND
-
-
1.25
mA
1.2
-
VI  0.01 V
short-circuit protection level at pin
I_IND
-
-
1.2
V
-
-
20
%
pin LED;
ILED
LED current variation
VO(ovp)
overvoltage protection output pin VO
voltage
I2C
mode; dual LED
Indicator LED parameters
II_IND
IF_SEL = 1 (I2C mode)
current on pin I_IND
IF_SEL = 0 (Direct enable mode)
VI_IND
II_IND
voltage on pin I_IND
current variation on pin I_IND
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Table 9.
Characteristics …continued
VI = 2.7 V to 5.5 V; Tamb = 40 C to +85 C, unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ[1]
Max
Unit
NMOS
-
240
-
m
PMOS
-
400
-
m
1.85
2.0
2.15
MHz
-
850
-
ms
-
-
7.5
%
Power MOSFETs
RDSon
drain-source on-state
resistance
Timing
fsw
switching frequency
tto
time-out time
tto
time-out time variation
tstart(soft)
soft start time
from Standby mode or Shut-down
mode to maximum current on LED
(from 0 mA to 500 mA)
-
-
1000
s
tstop(soft)
soft stop time
from maximum current on LED (from
500 mA to 0 mA) to Standby mode
or Shut-down mode
-
-
825
s
VIL
LOW-level input voltage
SCL/SDA
0
-
0.54
V
VIH
HIGH-level input voltage
SCL/SDA
1.26
-
VI
V
VOL
LOW-level output voltage
LOW on SDA; Isink = 3 mA
0
-
0.4
V
fSCL
SCL clock frequency
0
-
400
kHz
Flash mode; the absolute value can
be set with I2C
I2C interface
2LED function of STRB/2LED
VOL
LOW-level output voltage
Isink = 1 mA; LOW state
0
-
0.4
V
IOH
HIGH-level output current
HIGH state
-
-
1
A
SCL/EN1, SDA/EN2, IF_SEL, STRB function of STRB/2LED, TORCH
VIL
LOW-level input voltage
LOW - digital input voltage
0
-
0.54
V
VIH
HIGH-level input voltage
HIGH - digital input voltage
1.26
-
VI
V
Rpd(int)
internal pull-down resistance pins TORCH, STRB function of
STRB/2LED (only in I2C mode),
SCL/EN1, SDA/EN2 (only in Direct
enable mode)
-
350
-
k
tdegl(TORCH)
deglitch time on pin TORCH
6.3
9
11.7
ms
Temperature
Totp
overtemperature protection
trip
temperature rising
-
150
-
C
Totp(hys)
overtemperature protection
trip hysteresis
temperature falling
-
20
-
C
[1]
All typical values are measured at Tamb = 25 C and VI = 3.6 V.
[2]
When operating in extended input voltage range, the device will be fully functional but has a reduced performance specification on
certain parameters. An extended input voltage range is entered when the input voltage is dropping below 2.7 V, assuming the device is
not in undervoltage lockout mode.
[3]
When operating in Direct enable mode, the device will apply a default current setting. See Section 7.3 for details. The pin IF_SEL should
then be connected to GND.
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11. Application information
11.1 Input capacitor
For good input voltage decoupling, a low ESR ceramic capacitor is highly recommended.
A 4.7 F (X5R/X7R) 6.3 V is the minimum recommended value. Since the input capacitor
is supplying the input ripple current, a larger capacitor will improve both the transient
behavior of the regulator and the EMI behavior of the power supply. Taking capacitor DC
bias and temperature de-rating specifications into account, a 10 F (X5R/X7R) is
preferred. Although increasing component count, a smaller capacitor of 100 nF
(X5R/X7R) placed in parallel to the input capacitor will also improve EMI behavior.
11.2 Output capacitor
The output capacitor supplies the current into the main LED, while the inductor is being
charged, and it also ensures loop stability. The minimum capacitance for stable loop
operation would be 4.7 F, but taking capacitor DC bias and temperature de-rating
specifications into account, a low ESR ceramic capacitor of 10 F (X5R/X7R) is highly
recommended. A higher value of capacitance will improve output current ripple, while
maintaining loop stability. Typically the SSL3252 overvoltage limit on pin VO is at 9.5 V,
and the rated voltage of the output capacitor should be at least 10 V.
11.3 Inductor
The device has been designed to operate well with inductance values between 1.5 H
and 3.3 H, in order to optimize for solution size. In a typical high current dual flash LED
application a 2.2 H inductance is recommended. The inductor’s saturation current should
be greater than or equal to the inductor peak current limiter current, which is a typical
1.75 A. During normal operation, it is recommended to keep the inductor peak current
below this value. The copper losses and magnetic hysteresis losses in the inductor also
contribute to the total system losses.
11.4 PCB layout
It is essential to have a good circuit layout in order to maximize efficiency and minimize
EMI disturbance. The circuit topology uses an inductor, which is often seen as a main
source of EMI disturbance, but any loop of wire carrying a current is essentially an
electromagnet, whose field strength is proportional to the current. Careful circuit layout is
therefore very important, keeping loop areas small and minimizing the magnetic flux. Due
to the way a boost converter operates, there are two power states. One state when the
internal NMOS switch is ON, and one when the NMOS switch is OFF. During each state
there will be a current loop made by the power components that are conducting. The input
and output capacitors must be arranged in such a way on the SSL3252 that during each
of the two states the current loop is conducting in the same direction. This prevents phase
reversal of the magnetic field, and reduces radiated EMI. The current loop area should be
kept small by placing the power components as close as possible to the SSL3252. Use
ground planes to keep the loop areas to a minimum.
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Priority should be given for the output capacitor to be positioned as close as possible to
the VO and PGND nodes of the SSL3252. Since large currents will flow from input
capacitor to the inductor and not to the VIN pin of the SSL3252, it is wise to locate the
input capacitor near the inductor. The VIN pin should be star-connected to the positive
pad of the input capacitor.
PGND and GND of the SSL3252 should be directly connected to each other. Place the
ground connection of the output capacitor as close as possible to the PGND pin of the
SSL3252.
The preferred minimum trace width for the high current width is 15 mm/A.
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12. Package outline
WLCSP12: wafer level chip-size package; 12 bumps; 1.58 x 2.06 x 0.6 mm
B
D
SSL3252UK
A
bump A1
index area
A2
E
A
A1
detail X
e1
e
∅v
∅w
b
C
C A B
C
M
M
y
D
e
C
e2
1/2 e
B
A
1
2
3
X
0
1
2 mm
scale
DIMENSIONS (mm are the controlling dimensions)
UNIT
A
max
A1
A2
b
D
E
e
e1
e2
v
w
y
mm
0.64
0.26
0.22
0.38
0.34
0.34
0.30
1.60
1.55
2.08
2.03
0.5
1
1.5
0.01
0.04
0.02
OUTLINE
VERSION
REFERENCES
IEC
JEDEC
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
07-11-19
07-11-23
SSL3252UK
Fig 17. Package outline SSL3252UK (WLCSP12)
SSL3252
Product data sheet
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13. Soldering of WLCSP packages
13.1 Introduction to soldering WLCSP packages
This text provides a very brief insight into a complex technology. A more in-depth account
of soldering WLCSP (Wafer Level Chip-Size Packages) can be found in application note
AN10439 “Wafer Level Chip Scale Package” and in application note AN10365 “Surface
mount reflow soldering description”.
Wave soldering is not suitable for this package.
All NXP WLCSP packages are lead-free.
13.2 Board mounting
Board mounting of a WLCSP requires several steps:
1. Solder paste printing on the PCB
2. Component placement with a pick and place machine
3. The reflow soldering itself
13.3 Reflow soldering
Key characteristics in reflow soldering are:
• Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see Figure 18) than a PbSn process, thus
reducing the process window
• Solder paste printing issues, such as smearing, release, and adjusting the process
window for a mix of large and small components on one board
• Reflow temperature profile; this profile includes preheat, reflow (in which the board is
heated to the peak temperature), and cooling down. It is imperative that the peak
temperature is high enough for the solder to make reliable solder joints (a solder paste
characteristic) while being low enough that the packages and/or boards are not
damaged. The peak temperature of the package depends on package thickness and
volume and is classified in accordance with Table 10.
Table 10.
Lead-free process (from J-STD-020C)
Package thickness (mm)
Package reflow temperature (C)
Volume (mm3)
< 350
350 to 2000
> 2000
< 1.6
260
260
260
1.6 to 2.5
260
250
245
> 2.5
250
245
245
Moisture sensitivity precautions, as indicated on the packing, must be respected at all
times.
Studies have shown that small packages reach higher temperatures during reflow
soldering, see Figure 18.
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maximum peak temperature
= MSL limit, damage level
temperature
minimum peak temperature
= minimum soldering temperature
peak
temperature
time
001aac844
MSL: Moisture Sensitivity Level
Fig 18. Temperature profiles for large and small components
For further information on temperature profiles, refer to application note AN10365
“Surface mount reflow soldering description”.
13.3.1 Stand off
The stand off between the substrate and the chip is determined by:
• The amount of printed solder on the substrate
• The size of the solder land on the substrate
• The bump height on the chip
The higher the stand off, the better the stresses are released due to TEC (Thermal
Expansion Coefficient) differences between substrate and chip.
13.3.2 Quality of solder joint
A flip-chip joint is considered to be a good joint when the entire solder land has been
wetted by the solder from the bump. The surface of the joint should be smooth and the
shape symmetrical. The soldered joints on a chip should be uniform. Voids in the bumps
after reflow can occur during the reflow process in bumps with high ratio of bump diameter
to bump height, i.e. low bumps with large diameter. No failures have been found to be
related to these voids. Solder joint inspection after reflow can be done with X-ray to
monitor defects such as bridging, open circuits and voids.
13.3.3 Rework
In general, rework is not recommended. By rework we mean the process of removing the
chip from the substrate and replacing it with a new chip. If a chip is removed from the
substrate, most solder balls of the chip will be damaged. In that case it is recommended
not to re-use the chip again.
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All information provided in this document is subject to legal disclaimers.
Rev. 1 — 7 July 2011
© NXP B.V. 2011. All rights reserved.
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Device removal can be done when the substrate is heated until it is certain that all solder
joints are molten. The chip can then be carefully removed from the substrate without
damaging the tracks and solder lands on the substrate. Removing the device must be
done using plastic tweezers, because metal tweezers can damage the silicon. The
surface of the substrate should be carefully cleaned and all solder and flux residues
and/or underfill removed. When a new chip is placed on the substrate, use the flux
process instead of solder on the solder lands. Apply flux on the bumps at the chip side as
well as on the solder pads on the substrate. Place and align the new chip while viewing
with a microscope. To reflow the solder, use the solder profile shown in application note
AN10365 “Surface mount reflow soldering description”.
13.3.4 Cleaning
Cleaning can be done after reflow soldering.
14. Abbreviations
Table 11.
Abbreviations
Abbreviation
Description
EMI
ElectroMagnetic Interference
ESR
Equivalent Series Resistance
IC
Integrated Circuit
I/O
Input/Output
LED
Light Emitting Diode
MOSFET
Metal-Oxide Semiconductor Field-Effect Transistor
NMOS
N-type Metal-Oxide Semiconductor
PCB
Printed-Circuit Board
PDA
Personal Digital Assistant
PMOS
P-type Metal-Oxide Semiconductor
POR
Power-On Reset
PWM
Pulse Width Modulation
RF
Radio Frequency
15. Revision history
Table 12.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
SSL3252 v.1
20110707
Product data sheet
-
-
SSL3252
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 7 July 2011
© NXP B.V. 2011. All rights reserved.
27 of 30
SSL3252
NXP Semiconductors
Photo flash LED driver
16. Legal information
16.1 Data sheet status
Document status[1][2]
Product status[3]
Definition
Objective [short] data sheet
Development
This document contains data from the objective specification for product development.
Preliminary [short] data sheet
Qualification
This document contains data from the preliminary specification.
Product [short] data sheet
Production
This document contains the product specification.
[1]
Please consult the most recently issued document before initiating or completing a design.
[2]
The term ‘short data sheet’ is explained in section “Definitions”.
[3]
The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status
information is available on the Internet at URL http://www.nxp.com.
16.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with the same product type number(s) and title. A short data sheet is intended
for quick reference only and should not be relied upon to contain detailed and
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
Product specification — The information and data provided in a Product
data sheet shall define the specification of the product as agreed between
NXP Semiconductors and its customer, unless NXP Semiconductors and
customer have explicitly agreed otherwise in writing. In no event however,
shall an agreement be valid in which the NXP Semiconductors product is
deemed to offer functions and qualities beyond those described in the
Product data sheet.
16.3 Disclaimers
Limited warranty and liability — Information in this document is believed to
be accurate and reliable. However, NXP Semiconductors does not give any
representations or warranties, expressed or implied, as to the accuracy or
completeness of such information and shall have no liability for the
consequences of use of such information.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removal or
replacement of any products or rework charges) whether or not such
damages are based on tort (including negligence), warranty, breach of
contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards
customer for the products described herein shall be limited in accordance
with the Terms and conditions of commercial sale of NXP Semiconductors.
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors accepts no liability for inclusion and/or use of
NXP Semiconductors products in such equipment or applications and
therefore such inclusion and/or use is at the customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP Semiconductors
accepts no liability for any assistance with applications or customer product
design. It is customer’s sole responsibility to determine whether the NXP
Semiconductors product is suitable and fit for the customer’s applications and
products planned, as well as for the planned application and use of
customer’s third party customer(s). Customers should provide appropriate
design and operating safeguards to minimize the risks associated with their
applications and products.
NXP Semiconductors does not accept any liability related to any default,
damage, costs or problem which is based on any weakness or default in the
customer’s applications or products, or the application or use by customer’s
third party customer(s). Customer is responsible for doing all necessary
testing for the customer’s applications and products using NXP
Semiconductors products in order to avoid a default of the applications and
the products or of the application or use by customer’s third party
customer(s). NXP does not accept any liability in this respect.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) will cause permanent
damage to the device. Limiting values are stress ratings only and (proper)
operation of the device at these or any other conditions above those given in
the Recommended operating conditions section (if present) or the
Characteristics sections of this document is not warranted. Constant or
repeated exposure to limiting values will permanently and irreversibly affect
the quality and reliability of the device.
Terms and conditions of commercial sale — NXP Semiconductors
products are sold subject to the general terms and conditions of commercial
sale, as published at http://www.nxp.com/profile/terms, unless otherwise
agreed in a valid written individual agreement. In case an individual
agreement is concluded only the terms and conditions of the respective
agreement shall apply. NXP Semiconductors hereby expressly objects to
applying the customer’s general terms and conditions with regard to the
purchase of NXP Semiconductors products by customer.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
No offer to sell or license — Nothing in this document may be interpreted or
construed as an offer to sell products that is open for acceptance or the grant,
conveyance or implication of any license under any copyrights, patents or
other industrial or intellectual property rights.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in life support, life-critical or
safety-critical systems or equipment, nor in applications where failure or
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from national authorities.
SSL3252
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 7 July 2011
© NXP B.V. 2011. All rights reserved.
28 of 30
SSL3252
NXP Semiconductors
Photo flash LED driver
Non-automotive qualified products — Unless this data sheet expressly
states that this specific NXP Semiconductors product is automotive qualified,
the product is not suitable for automotive use. It is neither qualified nor tested
in accordance with automotive testing or application requirements. NXP
Semiconductors accepts no liability for inclusion and/or use of
non-automotive qualified products in automotive equipment or applications.
In the event that customer uses the product for design-in and use in
automotive applications to automotive specifications and standards, customer
(a) shall use the product without NXP Semiconductors’ warranty of the
product for such automotive applications, use and specifications, and (b)
whenever customer uses the product for automotive applications beyond
NXP Semiconductors’ specifications such use shall be solely at customer’s
own risk, and (c) customer fully indemnifies NXP Semiconductors for any
liability, damages or failed product claims resulting from customer design and
use of the product for automotive applications beyond NXP Semiconductors’
standard warranty and NXP Semiconductors’ product specifications.
16.4 Trademarks
Notice: All referenced brands, product names, service names and trademarks
are the property of their respective owners.
I2C-bus — logo is a trademark of NXP B.V.
17. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
SSL3252
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 7 July 2011
© NXP B.V. 2011. All rights reserved.
29 of 30
SSL3252
NXP Semiconductors
Photo flash LED driver
18. Contents
1
2
3
4
5
6
6.1
6.2
7
7.1
7.2
7.2.1
7.2.2
7.3
7.3.1
7.3.2
7.3.3
7.3.4
7.3.5
7.3.6
7.3.7
7.4
7.4.1
7.4.2
7.4.3
7.4.4
7.4.5
7.4.6
7.4.7
7.5
7.6
7.7
7.8
7.9
7.9.1
7.9.2
7.9.3
8
9
10
11
11.1
11.2
11.3
11.4
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features and benefits . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Pinning information . . . . . . . . . . . . . . . . . . . . . . 3
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 3
Functional description . . . . . . . . . . . . . . . . . . . 4
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Interface modes . . . . . . . . . . . . . . . . . . . . . . . . 4
Using the direct enable control . . . . . . . . . . . . . 5
Using the I2C control. . . . . . . . . . . . . . . . . . . . . 6
Operational modes . . . . . . . . . . . . . . . . . . . . . . 7
Shut-down mode . . . . . . . . . . . . . . . . . . . . . . . 7
Standby mode. . . . . . . . . . . . . . . . . . . . . . . . . . 7
Switching between Standby mode
and Shut-down mode . . . . . . . . . . . . . . . . . . . . 7
Torch mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Assist light mode . . . . . . . . . . . . . . . . . . . . . . . 9
Flash mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Protection circuits . . . . . . . . . . . . . . . . . . . . . . 12
Time-out protection. . . . . . . . . . . . . . . . . . . . . 12
Overtemperature protection . . . . . . . . . . . . . . 13
Overvoltage protection . . . . . . . . . . . . . . . . . . 13
Short-circuit protection . . . . . . . . . . . . . . . . . . 13
Broken coil detection . . . . . . . . . . . . . . . . . . . 13
Indicator output protection . . . . . . . . . . . . . . . 13
Undervoltage lockout . . . . . . . . . . . . . . . . . . . 13
Soft ramp-up/ramp-down of LED current . . . . 14
Peak current limit . . . . . . . . . . . . . . . . . . . . . . 14
Start-up sequence. . . . . . . . . . . . . . . . . . . . . . 15
LED detection . . . . . . . . . . . . . . . . . . . . . . . . . 15
I2C-bus protocol . . . . . . . . . . . . . . . . . . . . . . . 15
Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Register map . . . . . . . . . . . . . . . . . . . . . . . . . 17
Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 19
Thermal characteristics . . . . . . . . . . . . . . . . . 19
Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 20
Application information. . . . . . . . . . . . . . . . . . 22
Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . 22
Output capacitor . . . . . . . . . . . . . . . . . . . . . . . 22
Inductor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
12
13
13.1
13.2
13.3
13.3.1
13.3.2
13.3.3
13.3.4
14
15
16
16.1
16.2
16.3
16.4
17
18
Package outline. . . . . . . . . . . . . . . . . . . . . . . .
Soldering of WLCSP packages . . . . . . . . . . .
Introduction to soldering WLCSP packages .
Board mounting . . . . . . . . . . . . . . . . . . . . . . .
Reflow soldering . . . . . . . . . . . . . . . . . . . . . .
Stand off . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality of solder joint . . . . . . . . . . . . . . . . . . .
Rework. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . .
Revision history . . . . . . . . . . . . . . . . . . . . . . .
Legal information . . . . . . . . . . . . . . . . . . . . . .
Data sheet status . . . . . . . . . . . . . . . . . . . . . .
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . .
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact information . . . . . . . . . . . . . . . . . . . .
Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24
25
25
25
25
26
26
26
27
27
27
28
28
28
28
29
29
30
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP B.V. 2011.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
Date of release: 7 July 2011
Document identifier: SSL3252
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