SC628A Datasheet

SC628A
LED Flash Driver
Charge Pump with 1000mA Flash Mode,
275mA Spotlight Mode, and I2C Interface
POWER MANAGEMENT
Features
Description
„
The SC628A is a high efficiency charge pump LED driver
using Semtech’s proprietary charge pump technology.
Performance is optimized for use in single-cell Li-ion
battery applications. The load and supply conditions
determine whether the charge pump operates in 1x, 1.5x,
or 2x mode.
„
„
„
„
„
„
„
„
„
„
Input supply voltage range — 3.0V to 5.5V
Charge pump modes — 1x, 1.5x and 2x
Flash LED — 1000mA max in flash mode, 275mA max
continuous for spotlight
Charge pump frequency — 250kHz
I2C compatible interface — up to 400kHz
External flash control pin to sync with camera
One second flash time out with disable feature
Automatic sleep mode (flash off ) — IQ = 100μA
Low shutdown current — 0.1μA (typical)
Ultra-thin package — 3mm x 3mm x 0.6mm
Fully WEEE and RoHS compliant
The charge pump provides continuous spotlight mode
current or pulsed flash mode current to an LED using a
dedicated current sink. In flash mode, a flash-timeout
feature turns off the flash if active for longer than 1 second.
In spotlight mode, the timeout feature is disabled to allow
continuous operation of the LED.
Applications
The SC628A uses an I2C compatible serial interface to set
the flash mode or the spotlight mode current. The flash/
spotlight output is triggered via either the I2C interface or
a dedicated flash enable pin (FLEN).
„
Cellular phone flash
„ PDA flash
In sleep mode, the device reduces quiescent current to
100μA while continuing to monitor the serial interface.
Total current reduces to 0.1μA in shutdown.
Typical Application Circuit
FLASH
VBAT = 3.0V to 5.5V
CIN
4.7μF
IN
OUT
I2C Data
SDA
2
SCL
I C Clock
Flash Control
Enable Control
SC628A
COUT
4.7μF
FLEN
EN
FL
AGND
PGND
C1+
C1-
C1
2.2μF
C2+ C2-
C2
2.2μF
US Patents: 6,504,422; 6,794,926
July 14, 2009
1
SC628A
C2-
1
PGND
2
FL
IN
C1+
C2+
OUT
Ordering Information
C1-
Pin Configuration
20
19
18
17
16
15
NC
14
NC
3
13
NC
NC
4
12
EN
NC
5
11
SDA
TOP VIEW
6
7
8
9
10
NC
NC
AGND
SCL
FLEN
T
Device
Package
SC628AULTRT(1)(2)
MLPQ-UT-20 3×3
SC628AEVB
Evaluation Board
Notes:
(1) Available in tape and reel only. A reel contains 3,000 devices.
(2) Lead-free package only. Device is WEEE and RoHS compliant.
MLPQ-UT-20; 3x3, 20 LEAD
θJA = 40°C/W
Marking Information
628A
yyww
xxxx
yyww = Date Code
xxxx = Semtech Lot No.
2
SC628A
Absolute Maximum Ratings
Recommended Operating Conditions
IN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0
Ambient Temperature Range (°C) . . . . . . . . -40 < TA < +85
OUT (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0
IN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 < VIN < 5.5
C1+, C2+ (V) . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VOUT + 0.3)
OUT (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 < VOUT < 5.25
Pin Voltage - All Other Pins (V) . . . . . . . . . . . -0.3 to (VIN + 0.3)
OUT Short Circuit Duration . . . . . . . . . . . . . . . . . Continuous
ESD Protection Level(1) (kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Thermal Information
Thermal Resistance, Junction to Ambient(2) (°C/W) . . . . 40
Maximum Junction Temperature (°C) . . . . . . . . . . . . . . +150
Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150
Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not recommended.
NOTES:
(1) Tested according to JEDEC standard JESD22-A114-B.
(2) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
Electrical Characteristics
Unless otherwise noted, TA = +25°C for Typ, -40ºC to +85°C for Min and Max, TJ(MAX) = 125ºC, VIN = 3.0V to 4.2V, CIN = COUT = 4.7μF (ESR = 0.03Ω),
C1 = C2 = 2.2μF (ESR = 0.03Ω), size code 0603 (1608 metric) for all capacitors
Parameter
Symbol
Conditions
IQ(OFF)
Min
Typ
Max
Units
Shutdown, VIN = 4.2V
0.1
2
μA
Sleep, EN = VIN
100
160
μA
Charge pump in 1x mode
3.8
4.65
Charge pump in 1.5x mode
4.6
5.85
Charge pump in 2x mode
4.6
5.85
OUT pin shorted to GND
450
mA
160
°C
Supply Specifications
Shutdown Current
Total Quiescent Current
IQ
mA
Fault Protection
Output Short Circuit
Current Limit
Over-Temperature
Flash Mode Safety Timer(1)
Charge Pump
Over-Voltage Protection
IOUT(SC)
TOTP
tFL(MAX)
Flash sink active
0.75
1.00
1.25
s
VOVP
OUT pin open circuit, VOUT = VOVP
rising threshold
5.3
5.7
6.0
V
3
SC628A
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
VUVLO
Increasing VIN
2.7
V
VUVLO-HYS
Hysteresis
800
mV
Fault Protection (continued)
Undervoltage Lockout
Charge Pump Electrical Specifications
Maximum Total Output
Current
IOUT(MAX)
VIN > 3.5V, VOUT(MAX) = 4.0V
tFL_SET
maximum time for current to settle
IFL
Nominal setting for FL
25
IFL_ACC
VIN = 3.7V, IFL = 450mA, TA = 25°C
-13
1x Mode to 1.5x Mode
Falling Transition Voltage
V TRANS1x
IOUT = 150mA, VOUT = 3.3V
3.37
V
1.5x Mode to 2x Mode
Falling Transition Voltage
V TRANS1.5x
IOUT = 150mA, VOUT = 4.5V(2)
3.3
V
IBLn
VIN = VFL = 4.2V
0.1
fPUMP
VIN = 3.2V
250
Flash Current Settling Time
Flash Current Setting
Flash Current Accuracy
Current Sink Off-State
Leakage Current
Pump Frequency
1000
mA
1
±5
ms
1000
mA
13
%
1
μA
kHz
Digital I/O Electrical Specifications (FLEN, EN)
Input High Threshold
VIH
VIN = 5.5V
Input Low Threshold
VIL
VIN = 3.0V
Input High Current
IIH
VIN = 5.5V
Input Low Current
IIL
VIN = 5.5V
1.4
V
0.4
V
-1
+1
μA
-1
+1
μA
0.4
V
I2C Interface
Interface complies with slave mode I2C interface as described by Philips I2C specification version 2.1 dated January, 2000.
VB-IL
Digital Input Voltage
VB-IH
SDA Output Low Level
1.4
V
IDIN (SDA) ≤ 3mA
-0.2
0.4
V
0.2
μA
Digital Input Current
IB-IN
Hysteresis of
Schmitt Trigger Inputs
VHYS
0.1
V
Maximum Glitch Pulse
Rejection
tSP
50
ns
I/O Pin Capacitance
CIN
10
pF
4
SC628A
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
400
440
kHz
I2C Timing
Clock Frequency
fSCL
SCL Low Period(3)
tLOW
1.3
μs
SCL High Period(3)
tHIGH
0.6
μs
Data Hold Time(3)
tHD_DAT
0
μs
Data Setup Time(3)
tSU_DAT
250
ns
Setup Time for Repeated
START Condition(3)
tSU_STA
0.6
μs
Hold Time for Repeated
START Condition(3)
tHD_STA
0.6
μs
Setup Time for STOP
Condition(3)
tSU_STO
0.6
μs
Bus-Free Time Between
STOP and START(3)
tBUF
1.3
μs
Interface Start-up Time(3)
tEN
Bus Start-up Time After EN Pin is Pulled High
1
ms
Notes:
(1) Once tripped, flash output will remain disabled until FLEN pin is cycled or reset via serial interface.
(2) Test voltage is VOUT = 4.5V — a relatively extreme LED voltage — to force a transition during test. Typically VOUT = 3.3V for the white LED at
100mA.
(3) Guaranteed by design
5
SC628A
Typical Characteristics
Spotlight Current — 25mA
VOUT = 2.97V, IOUT = 25mA, TA = 25°C
31
29
440
27
420
25
400
23
380
21
360
19
4.2
3.9
3.6
VIN (V)
VOUT = 3.41V, IOUT = 400mA, TA = 25°C
460
IFL (mA)
IFL (mA)
Flash Current — 400mA
3.3
3
340
2.7
4.2
3.9
Spotlight Current — 100mA
105
975
IFL (mA)
IFL (mA)
1075
100
775
90
675
3.9
3.6
VIN (V)
3.3
3
4.2
3.9
300
1100
IFL (mA)
IFL (mA)
1300
1200
275
900
225
800
200
VIN (V)
3.3
3
2.7
3
2.7
VOUT = 3.72V, IOUT = 1000mA, TA = 25°C
1000
250
3.6
3.3
Flash Current — 1000mA
325
3.9
3.6
VIN (V)
VOUT = 3.32V, IOUT = 275mA, TA = 25°C
4.2
2.7
575
2.7
Spotlight Current — 275mA
350
3
875
95
4.2
3.3
VOUT = 3.69V, IOUT = 875mA, TA = 25°C
1175
110
85
VIN (V)
Flash Current — 875mA
VOUT = 3.14V, IOUT = 100mA, TA = 25°C
115
3.6
700
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
6
SC628A
Typical Characteristics (continued)
Spotlight Efficiency — 275mA
Spotlight Efficiency — 25mA
VOUT = 2.97V, IOUT = 25mA, TA = 25°C
100
90
90
80
80
% Efficiency
% Efficiency
100
70
VOUT = 3.32V, IOUT = 275mA, TA = 25°C
70
60
60
50
4.2
3.9
3.6
VIN (V)
3.3
3
50
2.7
4.2
VOUT = 3.14V, IOUT = 100mA, TA = 25°C
100
% Efficiency
% Efficiency
VIN (V)
3.3
3
2.7
VOUT = 3.41V, IOUT = 400mA, TA = 25°C
90
90
80
70
80
70
60
60
50
4.2
3.6
Flash Efficiency — 400mA
Spotlight Efficiency — 100mA
100
3.9
3.9
3.6
VIN (V)
3.3
3
2.7
50
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
7
SC628A
Typical Characteristics (continued)
Spotlight Mode Ripple — 1x Mode
Spotlight Mode Ripple — 1.5x Mode
IOUT = 275mA, TA = 25°C, Spotlight Mode
IOUT = 275mA, TA = 25°C, Spotlight Mode
VIN (100mVAC/div)
VIN (100mVAC/div)
VOUT (100mVAC/div)
VOUT (100mVAC/div)
IOUT (200mADC/div)
IOUT (200mADC/div)
0mA—
0mA—
Time (4.0μs/div)
Time (4.0μs/div)
Flash Mode Ripple — 1x Mode
Flash Mode Ripple — 1.5x Mode
IOUT = 1000mA, TA = 25°C, Flash Mode
IOUT = 1000mA, TA = 25°C, Flash Mode
VIN (200mVAC/div)
VIN (200mVAC/div)
VOUT (200mVAC/div)
VOUT (200mVAC/div)
IOUT (500mADC/div)
0mA—
IOUT (500mADC/div)
Time (4.0μs/div)
0mA—
Flash Mode Ripple — 2x Mode
Flash Current Pulse
IOUT = 1000mA, TA = 25°C, Flash Mode
VIN (200mVAC/div)
Time (4.0μs/div)
VIN = 3.7V, IOUT = 1000mA, TA = 25°C, tON = 100ms
VFLEN (2VDC/div)
0V—
VOUT (2VDC/div)
VOUT (200mVAC/div)
0V—
IOUT (500mADC/div)
IOUT (500mADC/div)
0mA—
0mA—
Time (4.0μs/div)
Time (40ms/div)
8
SC628A
Typical Characteristics (continued)
Flash Mode Safety Timer
VIN = 4.2V, IOUT = 1000mA, TA = 25°C
VFLEN (2VDC/div)
0V—
VOUT (2VDC/div)
0V—
IOUT (500mADC/div)
0mA—
Time (200ms/div)
Output Open Circuit Protection
VIN = 3.7V, TA = 25°C
VFLEN (2VDC/div)
0V—
VOUT (2VDC/div)
0V—
IOUT (500mADC/div)
0mA—
Time (200ms/div)
Output Short Circuit Current Limit
VIN = 3.7V, VOUT = 0V, TA = 25°C
VFLEN (2VDC/div)
0V—
VOUT (2VAC/div)
0V—
IOUT (500mADC/div)
0mA—
Time (200ms/div)
9
SC628A
Pin Descriptions
Pin #
Pin Name
Pin Function
1
C2-
2
PGND
3
FL
Current sink output for flash LED(s)
4
NC
Unused pin — do not terminate
5
NC
Unused pin — do not terminate
6
NC
Unused pin — do not terminate
7
NC
Unused pin — do not terminate
8
AGND
9
SCL
I2C clock input pin
10
FLEN
Control pin for flash LED(s) — high = ON, low = OFF
11
SDA
I2C bi-directional data pin — used for read and write operations for all internal registers (refer to
Register Map and I2C Interface sections)
12
EN
Chip enable — active high — low state resets all registers (see register map table)
13
NC
Unused pin — do not terminate
14
NC
Unused pin — do not terminate
15
NC
Unused pin — do not terminate
16
OUT
Charge pump output — all LED anode pins should be connected to this pin — requires a 4.7μF
capacitor to PGND
17
C2+
Positive connection to bucket capacitor 2 — requires a 2.2μF capacitor connected to C2-
18
C1+
Positive connection to bucket capacitor 1 — requires a 2.2μF capacitor connected to C1-
19
IN
Battery voltage input — connect with a 4.7μF capacitor to PGND
20
C1-
Negative connection to bucket capacitor 1 — requires a 2.2μF capacitor connected to C1+
T
THERMAL PAD
Negative connection to bucket capacitor 2 — requires a 2.2μF capacitor connected to C2+
Ground pin for high current charge pump and Flash LED driver
Analog ground pin — connect to ground and separate from PGND current
Thermal pad for heatsinking purposes — connect to ground plane using multiple
vias — not connected internally
10
SC628A
Block Diagram
IN
12
SDA
11
FLEN
10
SCL
9
NC
C1-
C2+
C2-
18
20
17
1
mAhXLifeTM Fractional
Charge Pump
(1x, 1.5x, 2x)
19
EN
C1+
16
OUT
2
PGND
4
NC
5
NC
6
NC
7
NC
3
FL
15
NC
14
NC
Oscillator
I2 C
Compatible
Interface
and Logic
Control
Current
Setting
DAC
Flash Output
Current Sink
13
Bandgap
Reference
AGND
8
11
SC628A
Applications Information
General Description
This design is optimized for handheld applications
supplied from a single Li-Ion cell and includes the
following key features:
•
•
•
A high efficiency fractional charge pump that
supplies power to the flash LED
An LED flash output that provides up to 1000mA
of momentary current or up to 275mA of
continuous spotlight current
An I2C compatible interface that provides control
of all device functions
High Current Fractional Charge Pump
The flash output is supported by a high efficiency, high
current fractional charge pump output at the OUT pin.
The charge pump multiplies the input voltage by 1, 1.5, or
2 times. The charge pump switches at a fixed frequency of
250kHz in 1.5x and 2x modes and is disabled in 1x mode
to save power and improve efficiency.
The mode selection circuit automatically selects the
1x, 1.5x or 2x mode based on circuit conditions. Circuit
conditions such as low input voltage, high output current,
or high LED voltage place a higher demand on the
charge pump output. A higher numerical mode may be
needed momentarily to maintain regulation at the OUT
pin during intervals of high demand, such as the high
current of an LED flash or the droop at the IN pin during
a supply voltage transient. The charge pump responds
to these momentary high demands, setting the charge
pump to the optimum mode (1x, 1.5x or 2x), as needed
to deliver the output voltage and load current while
optimizing efficiency. Hysteresis is provided to prevent
mode toggling.
The charge pump requires two bucket capacitors for
low ripple operation. One capacitor must be connected
between the C1+ and C1- pins and the other must be
connected between the C2+ and C2- pins as shown in
the typical application circuit diagram. These capacitors
should be equal in value, with a minimum capacitance of
2.2μF to support the charge pump current requirements.
The device also requires a 4.7μF capacitor on the IN pin
and a 4.7μF capacitor on the OUT pin to minimize noise
and support the output drive requirements. Capacitor
case size is an important factor in the performance of
the SC628A. Due to the poor DC coefficient of the 0402
size (1005 metric), 0603 size (1608 metric) capacitors are
strongly recommended to achieve the rated electrical
specifications and performance shown in the typical
characteristics section.
Capacitors with X7R or X5R ceramic dielectric are
strongly recommended for their low ESR and superior
temperature and voltage characteristics. Y5V capacitors
should not be used as their temperature coefficients
make them unsuitable for this application.
LED Flash and Spotlight Current Sink
A single output current sink is provided to drive both
flash and spotlight functions. In flash mode, this current
sink provides up to 1000mA for a flash LED or array of
parallel LEDs. Flash current settings are available in 21
values from 300mA to 1000mA. Flash steps increments
are no larger than 75mA nominally. Some additional
settings that have smaller increments of 50mA, 25mA
and 12.5mA. Table 1 on page 12 contains detailed current
setting information for flash mode. The FLEN pin directly
triggers the FLASH function when pulled high, or it can
be wired to IN to enable software control via the serial
interface.
In spotlight mode, the output can be set for up to 275mA
of continuous current. Settings are available in 25mA
increments from 25mA to 275mA, with some additional
settings that have smaller increments of 12.5mA. Table 2
on page 13 contains detailed current setting information
for spotlight mode. Continuous operation above 275mA
is not recommended due to high power dissipation.
Flash and Spotlight Safety Timer
A safety timer disables the flash and spotlight output
current sink if the sink remains active for an extended
period. The timer protects the SC628A and the LED from
high power dissipation that can cause overheating. The
12
SC628A
Applications Information (continued)
timer’s default state is on, but the timer may be disabled
via the serial interface to allow continuous output current
in spotlight mode. The safety timer affects only the FL pin
and will turn off the sink after a period of 1 second. The
timer may be reset by either forcing the FLEN pin low
or by resetting the Flash/Spotlight control bits via the
interface.
Over-Temperature Protection
The Over-Temperature (OT) protection circuit helps
prevent the device from overheating and experiencing
a catastrophic failure. When the junction temperature
exceeds 160°C, the device goes into thermal shutdown
with all outputs disabled until the junction temperature
is reduced. All register information is retained during
thermal shutdown.
Shutdown State
The device is disabled when the EN pin is low. All registers
are reset to default condition when EN is low.
Sleep Mode
When the LED is off, sleep mode is activated. This is a
reduced current mode that helps minimize overall current
consumption by turning off the clock and the charge
pump while continuing to monitor the serial interface for
commands.
2
I C Compatible Interface Functions
All device functions can be controlled via the I2C
compatible interface. The interface is described in detail
in the Serial Interface section of the datasheet.
Protection Features
The SC628A provides several protection features to
safeguard the device from catastrophic failures. These
features include:
•
•
•
•
Charge Pump Output Current Limit
The device also limits the charge pump current at the
OUT pin. When OUT is shorted to ground, the typical
output current is 400mA. The current limiting is triggered
by an output under-voltage lockout below 2V. The output
returns to normal when the short is removed and OUT is
above 2.5V. Above 2.5V, a minimum current limit of
1000mA applies.
LED Float Detection
Float detect is a fault detection feature of the LED current
sink output. If the output is programmed to be enabled
and an open circuit fault occurs on the current sink, the
resulting open loop will cause the output voltage to
change to the default condition VOUT = 3.0V. The output
will remain 3.0V until the loop is once again completed by
an LED or the output is re-programmed to the off state.
Output Open Circuit Protection
Over-Temperature Protection
Charge Pump Output Current Limit
LED Float Detection
Output Open Circuit Protection
Over-Voltage Protection (OVP) is provided at the OUT
pin to prevent the charge pump from producing an
excessively high output voltage. In the event of an open
circuit at OUT, the charge pump runs in open loop and
the voltage rises up to the OVP limit. OVP operation is
hysteretic, meaning the charge pump will momentarily
turn off until VOUT is sufficiently reduced. The maximum
OVP threshold is 6.0V, allowing the use of a ceramic
output capacitor rated at 6.3V with no fear of over-voltage
damage.
13
SC628A
Applications Information (continued)
•
PCB Layout Considerations
The layout diagram in Figure 1 illustrates a proper
two-layer PCB layout for the SC628A and supporting
components. Following fundamental layout rules is
critical for achieving the performance specified in the
Electrical Characteristics table. The following guidelines
are recommended when developing a PCB layout:
•
OUT
IN
GND
GND
Figure 2 — Layer 1
C1+
COUT
C2
C2+
C1-
C1
OUT
CIN
C2-
NC
PGND
NC
SC628A
FL
NC
FLEN
SDA
SCL
EN
NC
NC
NC
AGND
•
IN
•
Place all bypass and decoupling capacitors —
C1, C2, CIN, and COUT as close to the device as
possible.
All charge pump current passes through IN,
OUT, and the bucket capacitor connection pins.
Ensure that all connections to these pins make
use of wide traces so that the resistive drop on
each connection is minimized.
The thermal pad should be connected to the
ground plane using multiple vias to ensure
proper thermal connection for optimal heat
transfer.
NC
•
•
Make all ground connections to a solid
ground plane as shown in the example layout
(Figure 3).
If a ground layer is not feasible, the following
groupings should be connected:
ƒ PGND — CIN, COUT
ƒ AGND — Ground Pad
If no ground plane is available, PGND and AGND
should be routed back to the negative battery
terminal as separate signals using thick traces.
Figure 3 — Layer 2
Figure 1 — Recommended PCB Layout
14
SC628A
Register Map
Address
0x02
D7
D6
D5
D4
0(1)
FLTO
Flash/Spotlight Bits
D3
D2
D1
Flash/Spotlight Bits
D0
Reset
Value
Description
0x10
Flash/Spotlight
Control
Notes:
(1) Always write a 0 to this bit
Register and Bit Definitions
Flash/Spotlight Control Register (0x02)
This register is used to select the flash or spotlight current
and to configure the flash time-out feature.
Bits D7, D6, D3, D2, D1, D0
The value of bits D7, D6, D3, D2, D1, and D0 are used to
set the current for the flash and spotlight modes. Flash
current values are set in accordance with Table 1 on page
12, and spotlight current values are set in accordance
with Table 2 on page 13.
FLTO
This bit is used to enable the flash safety time-out feature.
The default state is enabled with FLTO = 1. If this bit is set,
the device will turn off the flash after a nominal period of
1s. Two ways to re-enable the flash function after a safety
time-out are:
Pull the FLEN pin low to reset the flash
function
Clear and re-write bits D7, D6 D3, D2, D1, and
D0.
•
•
15
SC628A
Register and Bit Definitions (continued)
Table 1 — Flash Current Codes(1)
Data Bits for Register 02h
Flash Current
8 Bit Word
D7
D6
D5
D4
D3
D2
D1
D0
IFL (mA)
Hex
x(2)
x(2)
0(3)
1(4)
0
0
0
0
OFF
00h
(3)
1
(4)
1
0
1
1
300
5Bh
1
(4)
1
1
0
1
325
5Dh
1
(4)
0
1
0
1
337.5
D5h
1
(4)
1
1
1
0
350
1Eh
1
(4)
1
0
1
0
375
9Ah
1
(4)
0
0
1
1
400
13h
1
(4)
1
0
0
1
412.5
D9h
1
(4)
0
1
0
1
450
15h
1
(4)
1
1
0
1
487.5
DDh
1
(4)
0
1
1
1
500
17h
1
(4)
1
1
1
1
525
DFh
1
(4)
1
0
0
1
550
19h
1
(4)
1
0
1
1
600
1Bh
1
(4)
1
1
0
1
650
1Dh
1
(4)
0
1
0
1
675
95h
1
(4)
1
1
1
1
700
1Fh
(4)
0
0
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
1
0
0
0
1
0
1
0
1
0
0
0
0
0
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
1
0
0
1
0
1
1
1
750
97h
1
0
0(3)
1(4)
1
0
0
1
825
99h
1
0
0(3)
1(4)
1
0
1
1
875
9Bh
1
0
0(3)
1(4)
1
1
0
1
950
9Dh
1
0
0(3)
1(4)
1
1
1
1
1000
9Fh
Notes:
(1) Use only the data values shown in Table 1 for flash function.
(2) Either 1 or 0.
(3) Always write a 0 to this bit.
(4) Write a 1 to set the FLTO bit for flash mode.
16
SC628A
Register and Bit Definitions (continued)
Table 2 — Spotlight Current Codes(1)
Data Bits for Register 02h
Spotlight Current
8 Bit Word
D7
D6
D5
D4
D3
D2
D1
D0
IFL (mA)
Hex
x(2)
x(2)
0(3)
0(4)
0
0
0
0
OFF
00h
(3)
(4)
0
0
1
0
25
42h
(4)
0
0
1
0
37.5
C2h
(4)
0
0
1
0
50
02h
(4)
0
1
1
0
75
46h
(4)
0
1
0
0
100
04h
(4)
0
1
1
0
112.5
C6h
(4)
1
0
1
0
125
4Ah
(4)
0
1
1
0
150
06h
(4)
1
1
1
0
175
4Eh
(4)
1
0
1
0
187.5
CAh
(4)
1
0
0
0
200
08h
(4)
0
1
0
1
225
45h
(4)
0
1
1
1
250
47h
(4)
1
1
1
0
262.5
CEh
(4)
1
0
0
1
275
49h
0
1
0
0
0
1
0
0
0
1
0
0
0
1
0
1
1
0
1
0
1
1
0
1
1
0
1
1
1
1
0
(3)
0
0
(3)
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
(3)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Notes:
(1) Use only the data values shown in Table 2 for spotlight function.
(2) Either 1 or 0.
(3) Always write a 0 to this bit.
(4) Write a 0 to reset the FLTO bit for spotlight mode.
17
SC628A
Serial Interface
The I2C General Specification
2
The SC628A is a read-write slave-mode I C device and
complies with the Philips I2C standard Version 2.1, dated
January 2000. The SC628A has four user-accessible
internal 8-bit registers. The I2C interface has been
designed for program flexibility, supporting direct format
for write operation. Read operations are supported on
both combined format and stop separated format. While
there is no auto increment/decrement capability in the
SC628A I2C logic, a tight software loop can be designed
to randomly access the next register independent of
which register you begin accessing. The start and stop
commands frame the data-packet and the repeat start
condition is allowed if necessary.
SC628A Limitations to the I2C Specifications
The SC628A only recognizes seven bit addressing. This
means that ten bit addressing and CBUS communication
are not compatible. The device can operate in either
standard mode (100kbit/s) or fast mode (400kbit/s).
Slave Address Assignment
The seven bit slave address is 0110 111x. The eighth bit is
the data direction bit. 0x6E is used for a write operation,
and 0x6F is used for a read operation.
Supported Formats
The supported formats are described in the following
subsections.
Direct Format — Write
The simplest format for an I2C write is direct format. After
the start condition [S], the slave address is sent, followed
by an eighth bit indicating a write. The SC628A I2C then
acknowledges that it is being addressed, and the master
responds with an 8 bit data byte consisting of the register
address. The slave acknowledges and the master sends
the appropriate 8 bit data byte. Once again the slave
acknowledges and the master terminates the transfer
with the stop condition [P].
Combined Format — Read
After the start condition [S], the slave address is sent,
followed by an eighth bit indicating a write. The SC628A
I2C then acknowledges that it is being addressed, and the
master responds with an 8 bit data byte consisting of the
register address. The slave acknowledges and the master
sends the repeated start condition [Sr]. Once again, the
slave address is sent, followed by an eighth bit indicating
a read. The slave responds with an acknowledge and the
previously addressed 8 bit data byte; the master then
sends a non-acknowledge (NACK). Finally, the master
terminates the transfer with the stop condition [P].
Stop Separated Reads
Stop-separated reads can also be used. This format
allows a master to set up the register address pointer for
a read and return to that slave at a later time to read the
data. In this format the slave address followed by a write
command are sent after a start [S] condition. The SC628A
then acknowledges it is being addressed, and the master
responds with the 8-bit register address. The master
sends a stop or restart condition and may then address
another slave. After performing other tasks, the master
can send a start or restart condition to the SC628A with
a read command. The device acknowledges this request
and returns the data from the register location that had
previously been set up.
18
SC628A
Serial Interface (continued)
I2C Direct Format Write
S
Slave Address
W
A
Register Address
S – Start Condition
W – Write = ‘0’
A – Acknowledge (sent by slave)
P – Stop condition
A
Data
A
P
Slave Address – 7-bit
Register address – 8-bit
Data – 8-bit
I2C Stop Separated Format Read
Master Addresses
other Slaves
Register Address Setup Access
S Slave Address W A Register Address A P S
S – Start Condition
W – Write = ‘0’
R – Read = ‘1’
A – Acknowledge (sent by slave)
NAK – Non-Acknowledge (sent by master)
Sr – Repeated Start condition
P – Stop condition
Slave Address B
Register Read Access
S/Sr
Slave Address
R A
Data
NACK P
Data
NACK P
Slave Address – 7-bit
Register address – 8-bit
Data – 8-bit
I2C Combined Format Read
S
Slave Address
W A
Register Address
S – Start Condition
W – Write = ‘0’
R – Read = ‘1’
A – Acknowledge (sent by slave)
NAK – Non-Acknowledge (sent by master)
Sr – Repeated Start condition
P – Stop condition
A Sr
Slave Address
R
A
Slave Address – 7-bit
Register address – 8-bit
Data – 8-bit
19
SC628A
Outline Drawing — MLPQ-UT-20 3x3
A
D
PIN 1
INDICATOR
(LASER MARK)
DIMENSIONS
INCHES
MILLIMETERS
DIM
MIN NOM MAX MIN NOM MAX
B
E
A2
A
SEATING
PLANE
aaa C
A
A1
A2
b
D
D1
E
E1
e
L
N
aaa
bbb
.020
.000
-
.024
.002
(.006)
.006 .008 .010
.114 .118 .122
.061 .067 .071
.114 .118 .122
.061 .067 .071
.016 BSC
.012 .016 .020
20
.003
.004
0.50
0.00
-
0.60
0.05
(0.1524)
0.15 0.20 0.25
2.90 3.00 3.10
1.55 1.70 1.80
2.90 3.00 3.10
1.55 1.70 1.80
0.40 BSC
0.30 0.40 0.50
20
0.08
0.10
C
A1
D1
e
LxN
E/2
E1
2
1
N
D/2
bxN
bbb
C A B
NOTES:
1.
CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS .
3. DAP is 1.90 x 190mm.
20
SC628A
Land Pattern — MLPQ-UT-20 3x3
H
R
(C)
DIMENSIONS
K
G
Y
X
P
Z
DIM
INCHES
MILLIMETERS
C
G
H
K
P
R
X
Y
Z
(.114)
(2.90)
.083
.067
.067
.016
.004
.008
.031
.146
2.10
1.70
1.70
0.40
0.10
0.20
0.80
3.70
NOTES:
1.
CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2.
THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
3.
THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD
SHALL BE CONNECTED TO A SYSTEM GROUND PLANE.
FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR
FUNCTIONAL PERFORMANCE OF THE DEVICE.
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805) 498-2111 Fax: (805) 498-3804
www.semtech.com
21