Data Sheet

SSL3250A
Photo flash dual LED driver
Rev. 05 — 16 December 2009
Product data sheet
1. General description
The SSL3250A 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, Torch or Indicator / Video-on mode.
The small silicon size and the high internal switching frequency of 1.2 MHz minimize the
SSL3250A footprint making it very suitable for mobile phones where space is limited, and
only requiring four external components. Driving a high power flash LED within its safe
operating limits was a concern when the SSL3250A was designed, so a time-out function
can be programmed via the I2C interface, which will prevent overstressing the LED. Due
to the specific requirements of a mobile phone, the flash current can be rapidly lowered
during RF transmit by using optional external setting resistors.
2. Features
„
„
„
„
„
„
„
„
„
„
„
„
„
„
„
High power single, or dual, LED output driving up to 500 mA flash current
Separate indicator LED output of 2.5 mA to 20 mA
Output voltage of up to 9.5 V
Wide input voltage range of 2.7 V to 5.5 V
High efficiency, over 85 % at optimum output current
Switching frequency of 1.2 MHz
Flash, Torch, and Indicator mode supported
Internally timed flash operation up to 820 ms
I2C-bus, programmable up to 400 kHz
Strobe signal to avoid I2C latency for flash
Discrete enable signals for stand-alone operation
Optional resistor configurable output currents
Fast response to accommodate external TxMasking functionality
Soft start in Torch and Flash modes to avoid battery overloading
Integrated protection circuits for enhanced system reliability
‹ Internal time-out function
‹ OverTemperature Protection (OTP)
‹ UnderVoltage LockOut (UVLO)
‹ OverVoltage Protection (OVP)
‹ Output current protection
‹ Interrupt signaling to system controller
„ Low device shut-down current, less than 1 μA
„ SOT758-3, thermally enhanced 16 terminal HVQFN package
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
3. Applications
„ White LED driver for battery powered portable devices
„ Photo flash LED driver for mobile phones and digital cameras
4. Ordering information
Table 1.
Ordering information
Type number
Package
Name
SSL3250AHN/C1 HVQFN16
Description
Version
plastic thermal enhanced very thin quad flat package; SOT758-3
no leads; 16 terminals; body 3 × 3 × 0.85 mm
4.1 Ordering options
Table 2.
Ordering options
Type number
Orderable part number
Pin 1 indicator location for tape and reel
SSL3250AHN/C1
SSL3250AHN/C1,528
Pin 1 in quadrant 2. See Figure 1.
5. Marking
pin 1 indicator
direction of unreeling
002aae613
Fig 1.
SSL3250AHN/C1,528 with package rotated 90° clockwise with pin 1 in quadrant 2
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
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SSL3250A
NXP Semiconductors
Photo flash dual LED driver
6. Block diagram
VBAT
4.7 μF
Ceramic
2.2 μH
PGND
VIN
I_IND
LX
SSL3250A
INTERNAL
SUPPLY
VO
4.7 μF
Ceramic
IF_SEL
LINEAR
CURRENT SINK
SDA/EN1
PGND
CURRENT
FEEDBACK
UP CONVERTER
SCL/EN2
STRB
I2C INTERFACE
AND CONTROL
INT
LED
One or two LEDs
Isink
ACT
PGND
R_IND
R_FL
R1
GND
R2
PGND
R_TR
R3
GND
014aaa286
Fig 2.
Block diagram
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
3 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
7. Pinning information
R_TR
1
R_FL
2
13 LX
14 VIN
15 ACT
terminal 1
index area
16 STRB
7.1 Pinning
12 PGND
11 INT
SSL3250A
7
8
VO
GND
9 LED
6
4
I_IND
SDA/EN1
10 IF_SEL
5
3
R_IND
SCL/EN2
014aaa363
Transparent top view
Fig 3.
Pin configuration (terminal 1 index area is die pad GND)
7.2 Pin description
Table 3.
Pin description
Symbol
Pin
Type
Description
R_TR
1
analog IO
setting resistor for torch current
R_FL
2
analog IO
setting resistor for flash current
SCL / EN2
3
I
Serial Clock Line (SCL) in I2C mode / Enable 2 in Direct enable
mode
SDA / EN1
4
I/O
Serial Data Line (SDL) in I2C mode / Enable 1 in Direct enable
mode
R_IND
5
analog IO
setting resistor for indicator current
I_IND
6
analog I
indicator LED current sink
VO
7
analog O
output voltage
GND
8
ground
ground
LED
9
analog I
feedback of the main LED current
IF_SEL
10
I
interface select; choose between direct enable control or I2C
INT
11
O
interrupt output (open collector)
PGND
12
ground
power ground
LX
13
analog I
inductor connection
VIN
14
input
input voltage
ACT
15
I
activate
STRB
16
I
strobe signal to enable flash in I2C mode
die pad
-
analog
exposed die pad; connect to GND
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
4 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
8. Functional description
8.1 Introduction
The SSL3250A is an asynchronous boost converter intended to drive either a single high
power flash LED or two high power flash LEDs in series. The main LED current is
controlled by the output voltage of the boost converter and the integrated linear current
sink. The SSL3250A has two interface modes and five operational modes. The control
interface is selected by the interface select pin IF_SEL. Depending on the interface mode
selected, the device can either be controlled by an I2C interface or by external enable
lines. Both interface modes control the five operational modes. These operational modes
are:
•
•
•
•
•
Shut-down mode
Standby mode
Indicator mode
Torch mode
Flash mode
The first mode is entered by putting a LOW level on the activate pin (ACT). This pin is
common for both interface modes. The operational modes Torch and Flash apply to the
same main LED current source, and the Indicator mode applies to a separate indicator
LED current source. Only when the I2C interface mode is enabled, the operational modes
Indicator, Flash and/or Torch can be used in parallel.
In normal operation, the regulated converter uses Pulse Width Modulation (PWM), so the
switching frequency is constant in all modes.
In applications where the required main 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 the input voltage is now compensated by increasing the
voltage over the current sink and therefore on the LED pin.
Apart from the main LED(s), a separate indicator LED can be driven from the SSL3250A.
This indicator LED is driven by a linear current sink circuit that operates independently
from the switch mode converter for the main LED(s).
8.2 Interface modes
The device is equipped I2C mode and Direct enable mode interfaces. Which interface
mode is used, is defined by the level of the IF_SEL pin at the start-up of the device
(VACT → LOW to HIGH). The state of the IF_SEL pin should be kept static after powering
up the device. Table 4 shows the interface possibilities.
Table 4.
Interface modes
IF_SEL
Interface mode
0
I2C
1
Direct enable mode
mode
Relevant controls
SDA, SCL, STRB, ACT, R_FL, INT.
EN1, EN2, ACT, INT, R_TR, R_FL, R_IND, INT.
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
5 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
8.2.1 Using the direct enable control
When the Direct enable mode is used, the device can be switched to the various
operational modes using the ACT, EN1 and EN2 control signals. The definition of these
control signals is given in Table 5. The current in the main LED, in Torch mode and Flash
mode and the LED current in the indicator LED can be independently controlled by the
external current setting resistors R_IND, R_TR and R_FL. When no external current
setting resistors are used, the pins should preferably be connected to VIN and the default
current levels for each LED.
Table 5.
Enable definition
ACT
EN2
EN1
Operational mode
LED active
0
X
X
Shut-down mode
-
1
0
0
Standby mode
-
1
0
1
Indicator mode
indicator LED
1
1
0
Torch mode
main LED
1
1
1
Flash mode
main LED
The relation between the ACT and EN1, EN2 signals is given in Figure 4. All modes can
be entered from the Standby mode. Entering Torch mode or Indicator mode before
entering Flash mode is not required.
tstart(soft)
Main LED
current
Indicator
LED current
EN1
EN2
ACT
Shut-down
Standby
Indicator
Torch
Flash
Torch
Indicator
014aaa294
Fig 4.
Functional description of the SSL3250A
8.2.2 Using the I2C control
Using the I2C mode enables additional features and settings as described in the I2C
register set (see Table 6). The I2C mode has the same operational modes as described in
Section 8.2.1, Figure 4. The Flash mode is entered in two steps:
1. Set the correct current and timing values in the current control and timing registers.
This arms the device for the required flash operation.
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
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SSL3250A
NXP Semiconductors
Photo flash dual LED driver
2. Trigger the Flash mode either by the hardware STRB pin or by the FLASH_STRB bit
in the Flash strobe register 02h. When the external strobe pin is not used it should be
connected to GND to prevent false strobing of the main LED.
The external current setting resistor R_FL can still be used in Flash mode but is not
required. When the external current setting resistor R_FL is not used, the pin should
preferably be connected to VIN, this way a default resistor value of approximately 50 kΩ is
assumed. The current setting resistors for the indicator LED, R_IND and for the
Torch mode, R_TR have no function in I2C mode and the pins should preferably be
connected to VIN.
8.3 Operational modes
8.3.1 Shut-down mode
The device is in Shut-down mode when the activate pin (ACT) is LOW. In Shut-down
mode the internal circuitry of the device is turned off to guarantee a low shut-down
current. The N-channel MOSFET (NMOS) is set to high-impedance. To limit the LED
current to a minimum leakage, the current sink circuitry for both the main LED and the
indicator LED are switched to high-impedance. After making the pin ACT HIGH, the
device will start up and is ready to receive commands through the selected interface.
8.3.2 Standby mode
In Standby mode the internal circuitry of the device remains on, but the converter is not
switching. The NMOS is set to high-impedance. To limit the LED current to a minimum
leakage, the current sink circuitry for both the main LED and the indicator LED are
switched to high-impedance. In this mode the device is able to respond to I2C
communication.
8.3.3 Torch mode
The Torch mode allows the main LED to be switched on, without timing limitations, at a
lower LED current setting. The Torch mode current in the main LED can be set between
50 mA and 200 mA in both the I2C and Direct enable control mode.
In I2C mode, the LED current is defined by entering a value between a minimum of 1 and
a maximum of 11 in the current control register. In I2C mode the external R_TR resistor is
ignored. If an external R_FL resistor is connected, this resistor will also scale down the set
torch current. See Section 8.3.6. The current in the main LED using I2C mode is defined
using Equation 1. When not using the resistor R_FL, assume a value of 50 kΩ in the
equation. Entering Torch mode is done by writing the required current setting in the
current control register. The LED will light to the set torch current. Switching off the Torch
mode can be done by writing 0h into the current control register, or by entering Flash
mode, see Section 8.3.4.
50 kΩ
I LED = --------------- × ( 35 mA + 15 mA × Register )
R R_FL
(1)
When using the Direct enable mode, the torch current is defined by an external resistor
connected to the R_TR pin. The LED current is defined using Equation 2. When not using
the current set resistor, the torch current will be set to a default level of 125 mA. The
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
7 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
default current is equal to connecting an external current set resistor of 50 kΩ. Entering
Torch mode in Direct enable mode can be done using the EN1 and EN2 pins. The LED
will stay on in Torch mode for as long as the enable pins are set to Torch mode.
50 kΩ
I LED = --------------- × 125 mA
R R_TR
(2)
When not using an external resistor, the R_TR pin can be left unconnected, but it is
preferably connected to VIN. Never connect the R_TR pin to GND since it will cause
unnecessary reference currents to flow to GND.
Figure 5 illustrates the Torch mode current setting equation for I2C, while Figure 6
illustrates the Torch mode current setting equation for the Direct enable mode.
200
ILED (mA)
150
100
50
0
0
1
3
5
7
9
11
Torch current using I2C mode
Register
value
014aaa364
Fig 5.
Torch mode LED current in I2C mode
250
200
ILED (mA)
150
125
100
50
0
125
50
Torch current using direct control mode
31.3
Register
value (kΩ)
014aaa365
Fig 6.
Torch mode LED current in Direct enable mode
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
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SSL3250A
NXP Semiconductors
Photo flash dual LED driver
8.3.4 Flash mode
The Flash mode allows the main LED to be used at high LED current setting. The Flash
mode current can be set up to 500 mA in both the I2C and Direct enable mode.
In I2C mode, the current is defined by entering a value between a minimum of 12 and a
maximum of 31 in the current control register. The external resistor R_FL can be used to
scale down the set current. This can be used in the application to enable TxMasking as
described in Section 8.3.6. The current in the main LED is defined using Equation 3.
When not using the R_FL resistor, assume a resistor value of 50 kΩ in the equation.
Entering Flash mode can be done either by using the STRB pin or the FLASH_STRB bit in
Flash Strobe register 02h. The duration of the flash can be determined by a timer, STRB
triggering or by a time-out. The flash timing is given by Equation 3 and in Section 8.4.2.
50 kΩ
I LED = --------------- × ( 35 mA + 15 mA × Register )
R R_FL
(3)
When using the Direct enable mode, the flash current can be defined by an external
resistor connected to the R_FL pin. The current in the main LED is defined using
Equation 4. When not using the current set resistor, the flash current will be set to a
default level of 500 mA. The default current is equal to connecting an external current set
resistor of 50 kΩ. Entering Flash mode in Direct enable mode can be done using the EN1
and EN2 pins. The LED will stay on in Flash mode for as long as the enable pins are set to
Flash mode, but is limited to 820 ms maximum by the time-out timer.
50 kΩ
I LED = --------------- × 500 mA
R R_FL
(4)
When no external current set resistor is used, the R_FL pin can be left unconnected but is
preferably connected to VIN. Never connect the R_FL pin to GND as this will cause
unnecessary reference currents to flow to GND.
Figure 7 illustrates the Flash mode current setting equation for I2C, while Figure 8
illustrates the Flash mode current setting equation for the Direct enable mode.
600
ILED (mA)
500
No
Resistor
375
66.7
250
215
161
125
110
55
0
100
200
0
12
16
20
24
Flash current using I2C mode
28
32
Register
Value (kΩ)
014aaa366
Fig 7.
Flash mode LED current in I2C mode
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
9 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
600
ILED (mA)
500
400
300
200
100
70
0
357
125
Flash current using direct control mode
50
Resistor
Value (kΩ)
014aaa367
Fig 8.
Flash mode LED current in Direct enable mode
8.3.5 Timed Flash mode
The timed operation of the Flash mode can only be used in the I2C interface mode. When
the flash is used in Timed mode (bit 4, TO_DEF = 1 in Timer control register 01h), the
internal timer will switch off the main LED after the preprogrammed maximum time in the
timer control register has expired.
The timer starts when the Flash mode is activated either by the software strobe
(FLASH_STRB bit in register 02h) or by a LOW to HIGH transition of the hardware strobe
(STRB pin) signal.
In timed mode strobing of the flash is edge sensitive, therefore the flash time is
independent of the level of the software or hardware strobe signal. The flash time is set
according to Equation 5:
t flash = 820 ms – Register × 54.6 ms
(5)
Once the Flash time has expired no interrupt will be generated nor will it be flagged in the
status register. A new flash period can be started immediately after the previous timed
flash period has expired.
8.3.6 Flash mode during RF transmit
Although the driver is not equipped with a separate TXMASK pin, the device can operate
like that to lower the current in the main LED in Flash mode during an RF transmission in
a mobile phone application. An external switch can be connected to the resistor
controlling the nominal current value for the Flash mode. By lowering the current in the
main LED, the inductor current and therefore the current drawn from the battery will be
lowered. Reducing the inductor current has to be fast because the inductor current is
reduced within 50 μs after changing the nominal current level to a lower setting. At the end
of the transmission period, the main LED current can be increased again to the nominal
current level. A soft start circuit will increase the inductor current with a limited slope as
defined by the soft start settings. See Section 8.5.
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
10 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
Average
inductor
t < 50 μs
current
T×Mask
Flash
014aaa296
Fig 9.
The inductor current during TxMask
8.3.7 Indicator LED
The indicator LED is connected between the VBAT and the dedicated indicator LED current
input pin. Internally a linear current sink controls the indicator LED current to reach the
required current level.
In I2C mode, the indicator LED current can be set between 2.5 mA and 17.5 mA. The
internal 3-bit register sets the actual indicator LED according to the formula in Equation 6.
The external resistor R_IND is ignored.
I I_IND = Register × 2.5 mA
(6)
When using the Direct enable mode, the indicator current can be determined by an
external resistor R_IND. The indicator current is defined using Equation 7. It can be set
between 2.5 mA and 20 mA. When not using the resistor, the indicator current will be set
to a default level of 10 mA. This current is similar to connecting an external resistor of
50 kΩ. Entering Flash mode in Direct enable mode can be done using the EN1 and EN2
pins. The LED will stay on in Flash mode for as long as the enable pins are set.
50 kΩ
I I_IND = ------------------ × 10 mA
R R_IND
(7)
If there is no resistor connected to the R_IND pin, it can either be left unconnected or
connected to VIN. Never connect the R_IND pin to GND since it will cause unnecessary
reference currents to flow to GND.
Figure 10 illustrates the Indicator mode current setting equation for I2C, while Figure 11
illustrates the Indicator mode current setting equation for the Direct enable mode.
SSL3250A_5
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 05 — 16 December 2009
11 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
II_IND (mA)
17.5
12.5
7.5
2.5
0
0
1
3
5
7
Indicator current using I2C mode
Register
value
014aaa368
Fig 10. Indicator LED currents in I2C mode
22.5
20.0
17.5
II_IND (mA)
12.5
10.0
7.5
3.0
2.5
0
165
50
Indicator current using direct control mode
25
Register
value (kΩ)
014aaa369
Fig 11. Indicator LED currents in Direct enable mode
8.4 Protection circuits
There are several protection circuits integrated in the device. These protection circuits
protect the device and the application against defects. The SSL3250A has four protection
circuits that will inhibit switching of the converter, programming the status register 03h and
pulling LOW the interrupt line. The interrupt line, which can be connected to external logic,
signaling an error condition. The external logic can read the status register to determine
which fault caused the interrupt and decide on the proper action to take. When not using
the I2C mode, the status register cannot be read out but the interrupt line still is functional
to signal a fault condition.
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
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SSL3250A
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Photo flash dual LED driver
The four protection circuits and their bits in the status register are as follows:
•
•
•
•
Overvoltage protection
Time-out protection
Overtemperature protection
Output short protection
When a protection is triggered, switching of the IC is inhibited without a soft ramp-down of
the current in the main LED and also the indicator LED will be switched off.
To recover from this fault condition in I2C mode, write 00h to the current control register
(00h) to clear the status register release the INT line. After clearing the status register, the
current control register can be reloaded and the flash can be retriggered. Reloading the
other registers is not necessary as they will not lose their value when an interrupt is
generated. In Direct enable mode the status register is cleared and the INT line is
released, by making both the EN1 and EN2 pins lO.
8.4.1 Overvoltage protection
If the output voltage (VO) exceeds its limit (Vovp, see Table 9), switching of the converter is
inhibited. The output voltage will exceed Vovp limit when no LEDs are connected between
pins VO and LED. In some cases an overvoltage protection may occur when the LED pin
is shorted to GND during the period a Flash is generated.
The converter is trying to compensate for the loss of feedback current by increasing VO.
When an overvoltage is encountered, the OVPtrig flag (bit 0) is set in the status register.
8.4.2 Untimed Flash mode
To avoid overloading of the main LED during a flash in Direct enable mode or I2C control
mode in untimed Flash mode (bit 4, TO_DEF = 0 in Timer control register 01h). A time-out
timer limits the maximum ON time of the flash. In both control modes the flash time-out
time is set to a fixed level of 820 ms.
When the flash strobe signal is set to LOW in I2C control mode, bit 0 in register 02h is
set to 0. When the EN1 signal is set to LOW before the time-out timer has expired in
Direct enable mode, the time-out timer is reset.
When a time-out situation is encountered, the TOtrig flag (bit 1) is set in the status
register. See also Section 8.3.5.
8.4.3 Overtemperature protection
If the chip temperature exceeds its limit (Totp, see Table 9), switching of the converter is
inhibited until the temperature drops below its limit minus a small hysteresis.
When an overtemperature situation is encountered, the OTtrig flag (bit 2) is set in the
status register.
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
13 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
8.4.4 Short circuit protection
To prevent device and battery overloading, the converter is short circuit protected. In case
the LED pin is shorted to GND due to an application failure, the switching of the converter
is inhibited. Typical response times between detection of the LED pin shorted to GND and
inhibit switching of the converter is less than 1 ms. The short circuit protection is functional
at any time during Torch mode and also during the soft start phase of the flash period.
The short circuit protection may also be triggered when either the inductor or the diode is
not connected. Also, a shorted diode may trigger the output short protection, if two LEDs
are connected in series between VO and LED pins. Therefore little or no current will flow
through the LEDs or into the LED pin and VLED will stay almost at GND level.
When an overvoltage is encountered, the OS_PROT flag (bit 3) is set in the status
register.
Remark: If VBAT is HIGH and only one White LED is connected between VO and LED
pins, the Schottky diode may be irreversibly damaged when the LED pin is shorted. This
is inherent to the asynchronous boost converter topology.
8.4.5 Interrupt line
The interrupt pin INT is an active LOW open-drain output allowing for multiple devices to
be connected as a wired OR, using the same interrupt line to the external control logic. On
the interrupt line, only one pull-up resistor is needed in the complete system.
8.4.6 Undervoltage lockout
As a result of a low battery 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 an undervoltage lockout state stopping all operations of the device.
Start-up is only possible by crossing the start-up level again. Recovering from this error
results in the loss of all register settings. This protection does not generate an interrupt on
the INT line nor is it flagged in the status register 03h.
8.5 Soft start
To avoid battery overloading when entering the Torch mode or the Flash mode, the device
is equipped with a soft start circuit. This circuit limits the rate of rise of the LED current to
4.5 mA/μs until the required LED current has been reached. When the device ends Flash
mode or Torch mode, the LED current decreases with a controlled slope of 9 mA/μs.
Whenever a protection is activated, the LED current decreases without the controlled
slope and drops immediately to zero.
8.6 Peak current limit
To avoid saturation of the inductor, the device is equipped with a peak current limit
function. This circuit limits the peak inductor currents to 2.2 A. No protection is activated.
8.7 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 an SDA wire and an
SCL wire. Both lines must be connected to a positive supply via a pull-up resistor when
SSL3250A_5
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SSL3250A
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Photo flash dual LED driver
connected to the output stages of a device. Data transfer may only be initiated when the
bus is not busy. The SSL3250A I2C bus characteristic is according to the 400 kbit/s
Fast-mode I2C from the I2C-bus specification.
Remark: For more details on the I2C standard, refer to the document UM10204, “I2C-bus
specification and user manual”, version 0.3, June 2007, which can be downloaded from
the NXP web site (www.nxp.com).
The following describes the protocols used by the SSL3250A for the read and write
sequences. The read sequence may use a repeated start condition during the sequence
to avoid that the bus is 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.
Figure 12 shows a write sequence for a single byte write. Figure 13 show the read
sequence for a single byte.
S
Slave address
W
A
Sub address n
A
nth Register
A
P
From master to slave
S = START condition
P = STOP condition
A = Acknowledge
N = Not Acknowledged
From slave to master
014aaa292
Fig 12. Single byte I2C write sequence
S
Slave address
W
A
Sub address n
A
Sr
Slave address
R
A
nth Register
N
From master to slave
From slave to master
P
S = START condition
P = STOP condition
A = Acknowledge
N = Not Acknowledged
Sr = Start repeat
014aaa290
Fig 13. Single byte I2C read sequence
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
15 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
8.7.1 Addressing
Each SSL3250A in an I2C-bus system is activated by sending a valid address to the
device. The address always has to be sent as the first byte after the start condition in the
I2C-bus protocol Figure 14.
MSB
0
LSB
1
1
0
0
0
0
R
W
014aaa288
Fig 14. I2C slave address
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 I2C address is 0110000b (30h). The 7-bit address plus the R/W bit
create an 8-bit write address of 60h and a read address of 61h.
The second byte sent to the SSL3250A is the subaddress of a specific register.
8.7.2 Data
After the subduers have been sent the data byte(s) are sent. The definition of the data
byte(s) is given in Figure 12. After each data byte an acknowledge is given and the
subduers is automatically incremented to the next subduers.
A description of the data that can be programmed in the registers is given in the register
map in Section 8.7.3.
8.7.3 Register map
Table 6.
Description of registers
Legend: * default register value
Address
Register
Bit
Symbol
Access
Value
Description
00h
Current control
7 to 3
MAIN_LEVEL
R/W
00000*
OFF (default)
2 to 0
IND_LEVEL
R/W
00001
Torch mode, see Section 8.3.3
00010
Torch mode, see Section 8.3.3
.....
.....
01010
Torch mode, see Section 8.3.3
01011
Torch mode, see Section 8.3.3
01100
Flash mode (armed), see Section 8.3.4
01101
Flash mode (armed), see Section 8.3.4
.....
.....
11110
Flash mode (armed), see Section 8.3.4
11111
Flash mode (armed), see Section 8.3.4
000*
OFF (default)
001
indicator ON, 2.5 mA
011
indicator ON, 5 mA
.....
.....
111
indicator ON, 17.5 mA
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
16 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
Table 6.
Description of registers …continued
Legend: * default register value
Address
Register
Bit
Symbol
Access
Value
Description
01h
Timer control
7 to 5
Reserved
-
-
-
4
TO_DEF
R/W
3 to 0
02h
03h
Flash strobe
Status
TO
R/W
7 to 1
Reserved
-
0
FLASH_STRB R/W
0*
select time-out limit (default)
1
select timed operation
0000*
820 ms (default)
0001
765 ms
.....
.....
1110
56 ms
1111
1 ms
-
-
0*
-
1
enable flash
7 to 4
Reserved
-
-
-
3
OStrig
R
0*
LED not shorted to GND
1
LED shorted to GND
2
OTPtrig
R
0*
temperature < maximum temperature
1
temperature > maximum temperature;
protection triggered
1
0
TOtrig
R
OVPtrig
R
0*
flash time < time-out
1
flash time > time-out, protection triggered
0*
VO < Vovp
1
VO > Vovp, protection triggered
9. Application design-in information
9.1 Input capacitor
For good input voltage decoupling a low ESR ceramic capacitor is highly recommended. A
4.7 μF (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 transient behavior of the
regulator and EMI behavior of the power supply. Taking the capacitor DC bias and the
temperature derating specifications into account, a 10 μF (X5R/X7R) is preferred.
Although it is increasing the component count, a smaller capacitor of 100 nF (X5R/X7R)
placed in parallel to the input capacitor will also improve EMI behavior.
When the circuit is used in other than battery powered applications and the input capacitor
is located relatively far from the DC buffer capacitors, it is recommended to add a 150 μF
tantalum or a 470 μF electrolytic capacitor in parallel near the input capacitor.
9.2 Output capacitor
The output capacitor supplies the current to the main LED, while the inductor is being
charged, and it also ensures loop stability. The minimum capacitance for stable loop
operation would be 2.2 μF, but taking the capacitor DC bias and the temperature derating
specifications into account, a low ESR ceramic capacitor of 4.7 μF (X5R/X7R) is highly
recommended. A higher value of capacitance will improve output current ripple, while
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
17 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
maintaining loop stability. The SSL3250A overvoltage limit on VO is 10.3 V (typ). The rated
voltage of the output capacitor should be at least 16 V. For solution size reasons lower
value ceramic capacitors could be placed in parallel.
9.3 Inductor
The device has been designed to operate well with inductance values between
1.5 μH and 3.3 μH, in order to optimize for solution size. In a typical high current dual flash
LED application a 2.2 μH inductance is recommended. The inductors saturation current
should be greater than or equal to the inductor peak current limiter current, which is typical
2.2 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.
9.4 Rectifier diode
Selecting a Schottky diode with low forward voltage drop improves efficiency. Although
the average current through the diode is equal to the load current and independent on
duty cycle for a boost converter topology, it is recommended to select a diode with an
average current rating that is significantly higher. The peak current rating of the diode
should be greater than the peak current through the inductor.
9.5 PCB layout
It is essential to have a good circuit layout to maximize efficiency and minimize EMI
disturbance. Because the circuit topology uses an inductor, it is often appointed as a main
source for EMI disturbance. But any loop of wire carrying a current is essentially an
electromagnet with a field strength that is proportional to the current. Therefore careful
circuit layout is important, keeping loop areas small and minimizing magnetic flux. Due to
the way an asynchronous boost converter operates, there are two power states. One state
is 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. Arrange the input capacitor, rectifier diode and output capacitor in such a way
around the SSL3250A 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 SSL3250A. Use ground planes to keep loop
areas to a minimum.
Priority should be given to positioning the output capacitor and the rectifier diode as close
as possible to the LX and PGND nodes of the SSL3250A. Since large currents will flow
from the input capacitor to the inductor and not into the VIN pin of the SSL3250A, 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. It is recommended to place an extra 100 nF
capacitor from VIN to GND directly next to the SSL3250A.
PGND and GND of the SSL3250A should be directly connected to each other preferably
by using the die pad area under the SSL3250A. Place the ground connection of the output
capacitor as close as possible to the PGND pin of the SSL3250A.
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
18 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
If the SSL3250A is used in Direct enable mode and external resistors are used, place the
external resistors near the SSL3250A, to minimize disturbance on the output current.
Connect the other end of the resistors to a ‘clean’ ground, that is ground that is not
carrying any large currents. It is preferable to connect all resistor grounds to one trace and
connect that trace to the GND pin of the SSL3250A.
The preferred minimum trace width for the high current width is 15 mil per Ampere.
10. Limiting values
Table 7.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).Voltages referenced to
GND.
Symbol
Parameter
VI
Conditions
Min
Max
Unit
input voltage
−0.5
+5.5
V
VACT
voltage on pin ACT
−0.5
VI
V
VSDA
voltage on pin SDA
−0.5
VI
V
VEN1
voltage on pin EN1
−0.5
VI
V
VSCL
voltage on pin SCL
−0.5
VI
V
VEN2
voltage on pin EN2
−0.5
VI
V
VSTRB
voltage on pin STRB
−0.5
VI
V
VIF_SEL
voltage on pin IF_SEL
−0.5
VI
V
VINT
voltage on pin INT
−0.5
VI
V
VI_IND
voltage on pin I_IND
−0.5
VI
V
VLED
voltage on pin LED
−0.5
VO[1]
V
VO
output voltage
−0.5
+20[1]
V
VLX
voltage on pin LX
−0.5
+20[1]
V
VR_IND
voltage on pin R_IND
−0.5
VI
V
VR_TR
voltage on pin R_TR
−0.5
VI
V
VR_FL
voltage on pin R_FL
−0.5
VI
V
VPGND
voltage on pin PGND
−0.5
+0.5
V
Ptot
total power dissipation
-
1.0
W
Tamb = 85 °C
Tj
junction temperature
−40
+150
°C
Tamb
ambient temperature
−40
+85
°C
Tstg
storage temperature
−40
+150
°C
VESD
electrostatic discharge
voltage
class 2
human body model;
all pins
[2]
-
2000
V
machine model;
all pins
[2]
-
150
V
charged-device
model; all pins
[3]
-
500
V
[1]
Tolerant to the specified maximum voltage while operating. Do not apply voltages externally; this may
cause permanent damage to the device.
[2]
Equivalent to discharging a 200 pF capacitor through a 0.75 μH coil and a 10 Ω resistor.
[3]
Equivalent to discharging the device (charged with > 10 MΩ resistor) through a 1 Ω measurement resistor.
SSL3250A_5
Product data sheet
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Rev. 05 — 16 December 2009
19 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
11. Thermal characteristics
Table 8.
Thermal characteristics
Symbol
Parameter
Conditions
Typ
Unit
Rth(j-a)
thermal resistance from junction to ambient
based on modeling on a four layer
board in free air and five thermal vias
under the IC[1]
63
K/W
[1]
The junction to ambient thermal resistance is dependent on the board layout, PCB material application, and environmental conditions.
12. Characteristics
Table 9.
Characteristics
VI = 3.0 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)
undervoltage lockout hysteresis
voltage
on pin VIN
3.0
-
5.5
V
2.75
-
5.5
V
VI falling
2.55
2.65
2.8
V
VI rising
50
100
150
mV
[2]
General current levels
Isd
shutdown current
Shut-down mode; ACT = 0
-
-
1
μA
Ileak(LX)
leakage current on pin LX
ACT = 0
-
-
0.5
μA
Ilmtr(IM)(LX)
peak current limiter current on
pin LX
inductor peak current limiter
-
2.2
2.4
A
Output voltages on external resistor pins
VR_IND
voltage on pin R_IND
independent of load
[3]
1.17
1.22
1.27
V
VR_TR
voltage on pin R_TR
independent of load
[3]
1.17
1.22
1.27
V
VR_FL
voltage on pin R_FL
independent of load
[3]
1.17
1.22
1.27
V
voltage on pin R_IND
[3]
1.4
-
VI
V
VR_TR
voltage on pin R_TR
[3]
1.4
-
VI
V
VR_FL
voltage on pin R_FL
[3]
1.4
-
VI
V
25
-
165
kΩ
25
-
200
kΩ
50
-
357
kΩ
Allowed input voltages on external resistor pins
VR_IND
External resistors
Rext(R_IND)
external resistance on pin R_IND
IF_SEL = 1; resistors used
[3][4]
[5]
Rext(R_TR)
external resistance on pin R_TR
IF_SEL = 1; resistors used
[3][4]
[5]
Rext(R_FL)
external resistance on pin R_FL
IF_SEL = 1 or 0; resistors used
[3][4]
[5]
SSL3250A_5
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 05 — 16 December 2009
20 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
Table 9.
Characteristics …continued
VI = 3.0 V to 5.5 V; Tamb = −40 °C to +85 °C, unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ[1]
Max
Unit
High power LED parameters
[6]
VO
output voltage
on pin VO
-
-
9.5
V
ILED
LED current
IF_SEL = 0;
current control register = 08h;
STRB = 0
40
50
60
mA
IF_SEL = 0;
current control register = 30h;
STRB = 0
106
125
144
mA
IF_SEL = 0;
current control register = C0h;
STRB = 1
356
395
435
mA
IF_SEL = 0;
current control register = F8h;
STRB = 1
450
500
550
mA
Ileak(LED)
VLED
Vovp
leakage current on pin LED
voltage on pin LED
default flash current;
IF_SEL = 1; EN1 = 1; EN2 = 1;
R_FL = HIGH
[3]
450
500
550
mA
default torch current;
IF_SEL = 1; EN1 = 0; EN2 = 1;
R_TR = HIGH
[3]
106
125
144
mA
-
-
0.5
μA
Boost mode; ILED = 0.5 A
[7]
-
300
-
mV
Follower mode
[7]
350
-
-
mV
9.8
10.5
11.0
V
ACT = 0; Shut-down mode
overvoltage protection voltage
Indicator LED parameters
II_IND
current on pin I_IND
ΔII_IND
current variation on pin I_IND
Ileak(I_IND)
leakage current on pin I_IND
IF_SEL = 0 (I2C)
2.5
-
17.5
mA
IF_SEL = 1 (direct enable)
2.5
-
20
mA
default indicator current;
IF_SEL = 1; EN1 = 1; EN2 = 0;
R_IND = HIGH
-
10
-
mA
-
-
15
%
ACT = 0; Shut-down mode
-
-
1
μA
NFET
-
200
425
mW
Power MOSFET
RDSon
drain-source on-state resistance
Timing
fsw
switching frequency
1.08
1.2
1.32
MHz
δmax
maximum duty cycle
-
-
82
%
tstart(soft)
soft start time
ACT = 0 to ACT = 1
response time
-
160
400
μs
tto(acc)
accuracy of time-out time
the absolute value can be
set with I2C
10
-
10
%
SSL3250A_5
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 05 — 16 December 2009
21 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
Table 9.
Characteristics …continued
VI = 3.0 V to 5.5 V; Tamb = −40 °C to +85 °C, unless otherwise specified.
Symbol
I2C
Parameter
Conditions
Min
Typ[1]
Max
Unit
interface
VIL
LOW-level input voltage
-
-
0.5
V
VIH
HIGH-level input voltage
1.2
-
VIN
V
VOL
LOW-level output voltage
0
-
0.4
V
fSCL
SCL clock frequency
0
-
400
kHz
Isink = 3 mA
Digital levels: EN1, EN2, STRB, ACT
VIL
LOW-level input voltage
digital
0
-
0.5
V
VIH
HIGH-level input voltage
digital
1.2
-
-
V
Digital levels: IF_SEL pin
VIL
LOW-level input voltage
IF_SEL pin
0
-
0.5VI
V
VIH
HIGH-level input voltage
IF_SEL pin
0.5VI
-
VI
V
Isink = 3 mA
0
-
0.4
V
Digital levels: INT
VOL
LOW-level output voltage
IIH
HIGH-level input current
0
-
0.5
μA
Tamb
ambient temperature
−40
+25
+85
°C
Totp
overtemperature protection trip
temperature rising
-
150
-
°C
Totp(hys)
overtemperature protection trip
hysteresis
temperature falling
-
20
-
°C
Temperature
[1]
All typical values are measured at Tamb = 25 °C and VI = 3.6 V.
[2]
When operating in an 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 3.0 V, assuming the device is
not in undervoltage lockout mode.
[3]
When no external resistor is connected, the device will apply a default current setting. See Section 8.3 for details. Corresponding pins
should then be connected to high (> 1.4 V)
[4]
Higher resistor values than the maximum are considered as no resistor is connected and therefore result in the default current setting.
[5]
Lower resistor values than the minimum will result in large currents being drawn from the device resulting in bad operation.
[6]
To accommodate two LEDs with a spread in VF between 2.7 V and 4.3 V each.
[7]
Only valid in Boost mode: typically in a dual LED configuration. When in linear mode, used in specific cases of single LED applications,
excess voltage will fall over the LED pin.
SSL3250A_5
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 05 — 16 December 2009
22 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
13. Package outline
HVQFN16: plastic thermal enhanced very thin quad flat package; no leads;
16 terminals; body 3 x 3 x 0.85 mm
SOT758-3
B
D
D1
A
terminal 1
index area
A4
E1
E
A
c
A1
detail X
e1
e
1/2 e
v
w
b
5
M
M
C
C A B
C
y
y1 C
8
L
4
9
e
e2
Eh
1/2 e
1
12
terminal 1
index area
16
13
X
Dh
0
2.5
5 mm
scale
DIMENSIONS (mm are the original dimensions)
UNIT
A
max
A1
A4
b
c
D
D1
Dh
E
E1
Eh
e
e1
e2
L
v
w
y
y1
mm
0.9
0.05
0.00
0.7
0.6
0.30
0.18
0.2
3.1
2.9
2.85
2.65
1.6
1.4
3.1
2.9
2.85
2.65
1.6
1.4
0.5
1.5
1.5
0.5
0.3
0.1
0.05
0.05
0.1
OUTLINE
VERSION
SOT758-3
REFERENCES
IEC
JEDEC
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
07-10-11
08-02-08
MO-220
Fig 15. Package outline SOT758-3 (HVQFN16)
SSL3250A_5
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 05 — 16 December 2009
23 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
14. Abbreviations
Table 10.
Abbreviations
Abbreviation
Description
EMI
ElectroMagnetic Interference
ESR
Equivalent Series Resistance
IC
Integrated Circuit
IO
Input/Output
LED
Light Emitting Diode
MOSFET
Metal-Oxide Semiconductor Field-Effect Transistor
NMOS
N-type Metal-Oxide Semiconductor
PDA
Personal Digital Assistants
PWM
Pulse Width Modulation
RF
Radio Frequency
15. Revision history
Table 11.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
SSL3250A_5
20091216
Product data sheet
-
SSL3250A_4
Modifications:
•
Equation 1 modified
SSL3250A_4
20091104
Product data sheet
-
SSL3250A_3
SSL3250A_3
20090630
Product data sheet
-
SSL3250A_2
SSL3250A_2
20090421
Product data sheet
-
SSL3250A_1
SSL3250A_1
20090205
Product data sheet
-
-
SSL3250A_5
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 05 — 16 December 2009
24 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
16. Legal information
16.1 Data sheet status
Document status[1][2]
Product status[3]
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.
Definition
[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.
16.3 Disclaimers
General — 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.
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.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in medical, military, aircraft,
space or life support equipment, nor in applications where failure or
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.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) may cause permanent
damage to the device. Limiting values are stress ratings only and operation of
the device at these or any other conditions above those given in the
Characteristics sections of this document is not implied. Exposure to limiting
values for extended periods may affect device reliability.
Terms and conditions of 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, including those pertaining to warranty,
intellectual property rights infringement and limitation of liability, unless
explicitly otherwise agreed to in writing by NXP Semiconductors. In case of
any inconsistency or conflict between information in this document and such
terms and conditions, the latter will prevail.
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.
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.
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]
SSL3250A_5
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 05 — 16 December 2009
25 of 26
SSL3250A
NXP Semiconductors
Photo flash dual LED driver
18. Contents
1
2
3
4
4.1
5
6
7
7.1
7.2
8
8.1
8.2
8.2.1
8.2.2
8.3
8.3.1
8.3.2
8.3.3
8.3.4
8.3.5
8.3.6
8.3.7
8.4
8.4.1
8.4.2
8.4.3
8.4.4
8.4.5
8.4.6
8.5
8.6
8.7
8.7.1
8.7.2
8.7.3
9
9.1
9.2
9.3
9.4
9.5
10
11
12
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Ordering options . . . . . . . . . . . . . . . . . . . . . . . . 2
Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pinning information . . . . . . . . . . . . . . . . . . . . . . 4
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4
Functional description . . . . . . . . . . . . . . . . . . . 5
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Interface modes . . . . . . . . . . . . . . . . . . . . . . . . 5
Using the direct enable control . . . . . . . . . . . . . 6
Using the I2C control. . . . . . . . . . . . . . . . . . . . . 6
Operational modes . . . . . . . . . . . . . . . . . . . . . . 7
Shut-down mode . . . . . . . . . . . . . . . . . . . . . . . 7
Standby mode. . . . . . . . . . . . . . . . . . . . . . . . . . 7
Torch mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Flash mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Timed Flash mode . . . . . . . . . . . . . . . . . . . . . 10
Flash mode during RF transmit . . . . . . . . . . . 10
Indicator LED . . . . . . . . . . . . . . . . . . . . . . . . . 11
Protection circuits . . . . . . . . . . . . . . . . . . . . . . 12
Overvoltage protection . . . . . . . . . . . . . . . . . . 13
Untimed Flash mode . . . . . . . . . . . . . . . . . . . 13
Overtemperature protection . . . . . . . . . . . . . . 13
Short circuit protection . . . . . . . . . . . . . . . . . . 14
Interrupt line . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Undervoltage lockout . . . . . . . . . . . . . . . . . . . 14
Soft start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Peak current limit . . . . . . . . . . . . . . . . . . . . . . 14
I2C-bus protocol . . . . . . . . . . . . . . . . . . . . . . . 14
Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Register map . . . . . . . . . . . . . . . . . . . . . . . . . 16
Application design-in information . . . . . . . . . 17
Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . 17
Output capacitor . . . . . . . . . . . . . . . . . . . . . . . 17
Inductor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Rectifier diode. . . . . . . . . . . . . . . . . . . . . . . . . 18
PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 19
Thermal characteristics . . . . . . . . . . . . . . . . . 20
Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 20
13
14
15
16
16.1
16.2
16.3
16.4
17
18
Package outline. . . . . . . . . . . . . . . . . . . . . . . .
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . .
Revision history . . . . . . . . . . . . . . . . . . . . . . .
Legal information . . . . . . . . . . . . . . . . . . . . . .
Data sheet status . . . . . . . . . . . . . . . . . . . . . .
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . .
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact information . . . . . . . . . . . . . . . . . . . .
Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
24
24
25
25
25
25
25
25
26
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. 2009.
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: 16 December 2009
Document identifier: SSL3250A_5
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