LM3644YFFR [TI]
双 1.5A 电流源摄像头 LED 闪光灯驱动器 | YFF | 12 | -40 to 85;
| 型号： | LM3644YFFR |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 双 1.5A 电流源摄像头 LED 闪光灯驱动器 | YFF | 12 | -40 to 85 驱动 闪光灯 接口集成电路 驱动器 |
| 文件： | 总41页 (文件大小：1749K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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LM3644, LM3644TT
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
LM3644 双路 1.5A 电流源摄像头闪光灯 LED 驱动器
1 特性
3 说明
1
•
•
•
•
•
两个可独立编程的 1.5A LED 电流源
LM3644 是一款双 LED 闪存驱动器，能够以较小的解
决方案尺寸提供高度可调节性。LM3644 采用 2MHz
或 4MHz 固定频率同步升压转换器为 1.5A 恒流 LED
源供电。 两个 128 级电流源可灵活调整 LED1 与
LED2 之间的电流比，。自适应调节方法可确保电流源
保持可调节状态，并且最大限度地提升效率。
准确的可编程 LED 电流范围为 1.4mA 到 1.5A
手电筒电流最高可达 360mA (LM3644TT)
闪光灯超时值最长可达 1.6 秒 (LM3644TT)
优化了低电池电量条件下的闪存 LED 电流（输入
电压闪存监控器 (IVFM)）
•
手电筒模式（100mA 时）和闪存模式（1A 至 1.5A
时）的效率超过 85%
LM3643 LM3644 的功能由兼容 I2C 的接口控制。这些
功能 包括：硬件闪光灯和硬件手电筒引脚（STROBE
和 TORCH/TEMP）、TX 中断和负温度系数 (NTC) 热
敏电阻监视器。器件在每个输出引脚均提供了可独立编
程的电流，以便在闪存模式或录像（手电筒）模式条件
下驱动 LED。
•
•
•
•
•
•
•
支持阴极接地 LED 操作，改进了热管理
小型解决方案尺寸：< 16mm2
硬件选通使能 (STROBE)
射频功率放大器脉冲事件的同步输入 (TX)
硬件火炬使能 (TORCH/TEMP)
远程 NTC 监控 (TORCH/TEMP)
400kHz I2C 兼容接口
该器件的开关频率选项为 2MHz 或 4MHz，具备过压
保护 (OVP) 和可调节限流功能，因此可采用微型超薄
电感和 10μF 陶瓷电容。该器件的工作环境温度范围为
-40°C 至 +85°C。
–
LM3644（I2C 地址 = 0x63）
2 应用
器件信息(1)
可拍照手机白色 LED 闪光灯
器件型号
LM3644
封装
封装尺寸（最大值）
芯片级球状引脚
栅格阵列
1.69mm x 1.31mm
(DSBGA) (12)
(1) 要了解所有可用封装，请见数据表末尾的可订购产品附录。
简化电路原理图
1 mH
SW
OUT
IN
2.5V to 5.5V
10 mF
10 mF
LM3644
LED1
TORCH/TEMP
STROBE
HWEN
TX
SDA
SCL
Flash
LED
LED2
GND
Flash
LED
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
English Data Sheet: SNVSA52
LM3644, LM3644TT
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
www.ti.com.cn
目录
8.3 Feature Description ................................................ 13
8.4 Device Functioning Modes...................................... 15
8.5 Programming........................................................... 19
8.6 Register Descriptions.............................................. 21
Applications and Implementation ...................... 25
9.1 Application Information............................................ 25
9.2 Typical Application ................................................. 25
1
2
3
4
5
6
7
特性.......................................................................... 1
应用.......................................................................... 1
说明.......................................................................... 1
修订历史记录 ........................................................... 2
Device Comparison Table..................................... 2
Pin Configuration and Functions......................... 3
Specifications......................................................... 4
7.1 Absolute Maximum Ratings ...................................... 4
7.2 ESD Ratings ............................................................ 4
7.3 Recommended Operating Conditions....................... 4
7.4 Thermal Information.................................................. 4
7.5 Electrical Characteristics........................................... 5
7.6 Timing Requirements ............................................... 6
7.7 Switching Characteristics.......................................... 6
7.8 Typical Characteristics.............................................. 6
Detailed Description ............................................ 12
8.1 Overview ................................................................. 12
8.2 Functional Block Diagram ...................................... 13
9
10 Power Supply Recommendations ..................... 31
11 Layout................................................................... 31
11.1 Layout Guidelines ................................................. 31
11.2 Layout Example ................................................... 32
12 器件和文档支持 ..................................................... 33
12.1 器件支持................................................................ 33
12.2 相关文档................................................................ 33
12.3 商标....................................................................... 33
12.4 静电放电警告......................................................... 33
12.5 术语表 ................................................................... 33
13 机械、封装和可订购信息....................................... 33
8
4 修订历史记录
Changes from Revision C (April 2015) to Revision D
Page
•
•
Changed 0x00 to 0x02 - typo ............................................................................................................................................... 21
Changed 0x40 to 0x04 - typo ............................................................................................................................................... 21
Changes from Revision B (November 2014) to Revision C
Page
•
•
•
已添加 有关 LM3644TT 选项的信息 ....................................................................................................................................... 1
Changed Handling Ratings to ESD Ratings; moved storage temp to Ab Max ..................................................................... 4
Added full Thermal Information information .......................................................................................................................... 4
Changes from Revision A (October 2013) to Revision B
Page
•
Changed '011' to '000' - typo ................................................................................................................................................ 24
Changes from Original (August 2014) to Revision A
Page
•
•
已更改 标题“具有高侧电流源的 1.5A 同步升压白色 LED 驱动器”至“双路 1.5A 电流源摄像头闪光灯 LED 驱动器” ............... 1
Added Note to beginning of Applications and Implementations section .............................................................................. 25
5 Device Comparison Table
ORDERING PART NUMBER
MAXIMUM TORCH CURRENT
PER CHANNEL
FLASH TIME-OUT RANGE
LM3644YFFR
179 mA
360 mA
10 ms to 400 ms
40 ms to 1600 ms
LM3644TTYFFR
2
Copyright © 2014–2015, Texas Instruments Incorporated
LM3644, LM3644TT
www.ti.com.cn
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
6 Pin Configuration and Functions
YFF Package
12-Pin DSBGA
Top View
Top View
A1
B1
A2
B2
A3
B3
Pin A1
C2
D2
C1
D1
C3
D3
Pin Functions
PIN
NUMBER
TYPE
DESCRIPTION
NAME
A1
GND
Ground
Power
Ground
Input voltage connection. Connect IN to the input supply and bypass to GND with a 10-µF or
larger ceramic capacitor.
A2
IN
A3
B1
SDA
SW
I/O
Serial data input/output in the I2C Mode on LM3644.
Power
Drain Connection for Internal NMOS and Synchronous PMOS Switches.
Active high hardware flash enable. Drive STROBE high to turn on Flash pulse. Internal pulldown
resistor of 300 kΩ between STROBE and GND.
B2
STROBE
I/O
B3
C1
SCL
OUT
I/O
Serial clock input for LM3644.
Power
Step-up DC-DC converter output. Connect a 10-µF ceramic capacitor between this pin and GND.
Active high enable pin. High = Standby, Low = Shutdown/Reset. Internal pulldown resistor of 300
kΩ between HWEN and GND.
C2
HWEN
I/O
TORCH/T
EMP
C3
D1
D2
D3
I/O
Power
I/O
Torch terminal input or threshold detector for NTC temperature sensing and current scale back.
High-side current source output for flash LED.
LED2
Configurable dual polarity power amplifier synchronization input. Internal pulldown resistor of 300
kΩ between TX and GND.
TX
LED1
Power
High-side current source output for flash LED.
Copyright © 2014–2015, Texas Instruments Incorporated
3
LM3644, LM3644TT
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
www.ti.com.cn
7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN
MAX
UNIT
IN, SW, OUT, LED1, LED2
−0.3
6
V
SDA, SCL, TX, TORCH/TEMP, HWEN, STROBE
−0.3 to the lesser of
(VIN+0.3) w/ 6 V max
V
Continuous power dissipation(3)
Internally limited
150
Junction temperature (TJ-MAX
)
°C
°C
Maximum lead temperature (soldering)
Storage temperature, Tstg
See(4)
−65
150
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltages are with respect to the potential at the GND terminal.
(3) Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ = 150°C (typical) and
disengages at TJ = 135°C (typical). Thermal shutdown is ensured by design.
(4) For detailed soldering specifications and information, please refer to TI Application Note DSBGA Wafer Level Chip Scale Package
(SNVA009).
7.2 ESD Ratings
VALUE
±2500
±1500
UNIT
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)
Charged-device model (CDM), per JEDEC specification JESD22-C101(2)
Electrostatic
discharge
V(ESD)
V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
7.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN
MAX
5.5
UNIT
VIN
2.5
−40
−40
V
Junction temperature (TJ)
Ambient temperature (TA)(3)
125
85
°C
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltages are with respect to the potential at the GND terminal.
(3) In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may
have to be derated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP
=
125°C), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to-ambient thermal resistance of the
part/package in the application (RθJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (RθJA × PD-MAX).
7.4 Thermal Information
LM3644
THERMAL METRIC(1)
DSBGA
12 PINS
90.2
UNIT
RθJA
RθJC(top)
RθJB
ψJT
Junction-to-ambient thermal resistance
Junction-to-case (top) thermal resistance
Junction-to-board thermal resistance
0.5
40.0
°C/W
Junction-to-top characterization parameter
Junction-to-board characterization parameter
3.0
ψJB
39.2
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
4
Copyright © 2014–2015, Texas Instruments Incorporated
LM3644, LM3644TT
www.ti.com.cn
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
7.5 Electrical Characteristics
Typical limits tested at TA = 25°C. Minimum and maximum limits apply over the full operating ambient temperature range
(−40°C ≤ TA ≤ 85°C). Unless otherwise specified, VIN = 3.6 V, HWEN = VIN.(1)(2)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
CURRENT SOURCE SPECIFICATIONS
VOUT = 4 V, flash code = 0x7F = 1.5 A
flash
–7%
–10%
-10%
1.5
89.3
180
7%
10%
A
ILED1/2
Current source accuracy
VOUT = 4 V, torch code = 0x3F = 89.3 mA
torch or
mA
mA
Current source accuracy
(LM3644TT)
VOUT = 4 V, torch code = 0x3F = 180 mA
torch
ILED1/2
VHR
-10%
ILED1/2 = 729 mA
ILED1/2 = 179 mA
Flash
Torch
290
158
LED1 and LED2 current source
regulation voltage
mV
mV
V
LED1 and LED2 current source
regulation voltage (LM3644TT)
Torch and
Flash
VHR
ILED1/2 = 360 mA
270
ON threshold
OFF threshold
4.86
4.75
5
5.1
VOVP
4.88
4.99
STEP-UP DC/DC CONVERTER SPECIFICATIONS
RPMOS
RNMOS
PMOS switch on-resistance
NMOS switch on-resistance
86
65
mΩ
mΩ
Reg 0x07, bit[0] = 0
Reg 0x07, bit[0] = 1
Falling VIN
–12%
–12%
–2%
1.9
2.8
2.5
0.6
50
12%
12%
2%
ICL
Switch current limit
A
UVLO
VTRIP
INTC
Undervoltage lockout threshold
NTC comparator trip threshold
NTC current
V
V
Reg 0x09, bits[3:1] = '100'
–5%
5%
–6%
6%
µA
Input voltage flash monitor trip
threshold
VIVFM
IQ
Reg 0x02, bits[5:3] = '000'
–3%
2.9
0.3
0.1
3%
0.75
4
V
Quiescent supply current
Device not switching pass mode
mA
µA
Device disabled, HWEN = 0 V
2.5 V ≤ VIN ≤ 5.5 V
ISD
Shutdown supply current
Device disabled, HWEN = 1.8 V
2.5 V ≤ VIN ≤ 5.5 V
ISB
Standby supply current
2.5
10
µA
HWEN, TORCH/TEMP, STROBE, TX VOLTAGE SPECIFICATIONS
VIL
Input logic low
0
0.4
VIN
V
V
2.5 V ≤ VIN ≤ 5.5 V
VIH
Input logic high
1.2
I2C-COMPATIBLE INTERFACE SPECIFICATIONS (SCL, SDA)
VIL
Input logic low
Input logic high
Output logic low
0
0.4
VIN
V
V
2.5 V ≤ VIN ≤ 4.2 V
VIH
VOL
1.2
ILOAD = 3 mA
400
mV
(1) Minimum (Min) and Maximum (Max) limits are specified by design, test, or statistical analysis. Typical (typ.) numbers are not verified, but
do represent the most likely norm. Unless otherwise specified, conditions for typical specifications are: VIN = 3.6 V and TA = 25°C.
(2) All voltages are with respect to the potential at the GND pin.
Copyright © 2014–2015, Texas Instruments Incorporated
5
LM3644, LM3644TT
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
www.ti.com.cn
7.6 Timing Requirements
MIN
2.4
100
0
NOM
MAX
UNIT
µs
t1
t2
t3
t4
t5
SCL clock period
Data in set-up time to SCL high
Data out stable After SCL low
SDA low set-up time to SCL Low (start)
SDA high hold time after SCL high (stop)
ns
ns
100
100
ns
ns
7.7 Switching Characteristics
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
–6%
TYP
MAX
6%
UNIT
ƒSW
Switching frequency
2.5 V ≤ VIN ≤ 5.5 V
4
MHz
t
1
SCL
SDA_IN
t
t
5
4
t
2
SDA_OUT
t
3
Figure 1. I2C-Compatible Interface Specifications
7.8 Typical Characteristics
Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = COUT = 2 × 10 µF and L = 1 µH, unless otherwise
noted .
1.6
1.4
1.2
1
1.6
1.4
1.2
1
TA = -40°C
TA = +25°C
TA = +85°C
TA = -40°C
TA = +25°C
TA = +85°C
0.8
0.6
0.4
0.2
0
0.8
0.6
0.4
0.2
0
0
16
32
48
64
80
96
112
128
0
16
32
48
64
80
96
112
128
LED1 Code (dec#)
LED2 Code (dec#)
D001
D002
Figure 2. LED1 Flash Current vs Brightness Code
Figure 3. LED2 Flash Current vs Brightness Code
6
Copyright © 2014–2015, Texas Instruments Incorporated
LM3644, LM3644TT
www.ti.com.cn
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
Typical Characteristics (continued)
Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = COUT = 2 × 10 µF and L = 1 µH, unless otherwise
noted .
0.2
0.18
0.16
0.14
0.12
0.1
0.2
0.18
0.16
0.14
0.12
0.1
TA = -40°C
TA = +25°C
TA = +85°C
TA = -40°C
TA = +25°C
TA = +85°C
0.08
0.06
0.04
0.02
0
0.08
0.06
0.04
0.02
0
0
16
32
48
64
80
96
112
128
0
16
32
48
64
80
96
112
128
LED1 Code (dec#)
LED2 Code (dec#)
D015
D016
Figure 4. LED1 Torch Current vs Brightness Code
Figure 5. LED2 Torch Current vs Brightness Code
0.4
0.36
0.32
0.28
0.24
0.2
0.4
0.36
0.32
0.28
0.24
0.2
TA = -40°C
TA = +25°C
TA = +85°C
TA = -40°C
TA = +25°C
TA = +85°C
0.16
0.12
0.08
0.04
0
0.16
0.12
0.08
0.04
0
0
16
32
48
64
80
96
112
128
0
16
32
48
64
80
96
112
128
LED1 Code (dec#)
LED2 Code (dec#)
D040
D0401
LM3644TT
LM3644TT
Figure 6. LED1 Torch Current vs Brightness Code
Figure 7. LED2 Torch Current vs Brightness Code
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.6
1.5
1.4
1.3
1.2
1.1
1
BRC = 0
BRC = 7
BRC = 71
BRC = 79
BRC = 87
BRC = 95
BRC = 103
BRC = 111
BRC = 119
BRC = 127
BRC = 15
BRC = 23
BRC = 31
BRC = 39
BRC = 47
BRC = 55
BRC = 63
0.9
0.8
0.7
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D003
D004
Figure 8. LED1 Current vs Input Voltage
Figure 9. LED1 Current vs Input Voltage
Copyright © 2014–2015, Texas Instruments Incorporated
7
LM3644, LM3644TT
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
www.ti.com.cn
Typical Characteristics (continued)
Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = COUT = 2 × 10 µF and L = 1 µH, unless otherwise
noted .
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.6
1.5
1.4
1.3
1.2
1.1
1
BRC = 0
BRC = 7
BRC = 71
BRC = 79
BRC = 87
BRC = 95
BRC = 103
BRC = 111
BRC = 119
BRC = 127
BRC = 15
BRC = 23
BRC = 31
BRC = 39
BRC = 47
BRC = 55
BRC = 63
0.9
0.8
0.7
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D005
D006
Figure 10. LED2 Current vs Input Voltage
Figure 11. LED2 Current vs Input Voltage
1.62
1.6
1.6
1.58
1.56
1.54
1.52
1.5
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
1.58
1.56
1.54
1.52
1.5
1.48
1.46
1.44
1.42
1.4
1.48
1.46
1.44
1.42
1.4
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D021
D022
ILED = 1.5 A
ƒSW = 2 MHz
Flash
ILED = 1.5 A
ƒSW = 4 MHz
Flash
Figure 12. LED1/2 Current vs Input Voltage
Figure 13. LED1/2 Current vs Input Voltage
1.07
1.06
1.05
1.04
1.03
1.02
1.01
1
0.78
0.77
0.76
0.75
0.74
0.73
0.72
0.71
0.7
TA = -40èC
TA = +25èC
TA = +85èC
LED1, TA = -40èC
LED2, TA = -40èC
LED1, TA = +25èC
LED2, TA = +25èC
LED1, TA = +85èC
LED2, TA = +85èC
0.99
0.98
0.97
0.96
0.95
0.94
0.93
0.69
0.68
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D023
D024
ILED = 1 A
ƒSW = 2 MHz
Flash
ILED = 730 mA
ƒSW = 2 MHz
Flash
Figure 14. LED1/2 Current vs Input Voltage
Figure 15. LED1 and LED2 Current vs Input Voltage
8
Copyright © 2014–2015, Texas Instruments Incorporated
LM3644, LM3644TT
www.ti.com.cn
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
Typical Characteristics (continued)
Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = COUT = 2 × 10 µF and L = 1 µH, unless otherwise
noted .
1.05
1.025
1
1.05
1.025
1
0.975
0.95
0.925
0.9
0.975
0.95
0.925
0.9
0.875
0.85
0.825
0.8
0.775
0.75
0.725
0.7
0.875
0.85
0.825
0.8
0.775
0.75
0.725
0.7
ILED1, +25èC
ILED2, +25èC
ILED1, +85èC
ILED2, +85èC
ILED1, -40èC
ILED2, -40èC
ILED1, +25èC
ILED2, +25èC
ILED1, +85èC
ILED2, +85èC
ILED1, -40èC
ILED2, -40èC
0.675
0.65
0.675
0.65
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D037
D038
ILED = 1 A
ƒSW = 2 MHz
Flash
ILED = 1 A
ƒSW = 4 MHz
Flash
Figure 16. LED1 and LED2 Current vs Input Voltage
Figure 17. LED1 and LED2 Current vs Input Voltage
0.2
0.19
0.18
0.17
0.16
0.2
0.19
0.18
0.17
0.16
TA = -40èC
TA = -+25èC
TA = +85èC
TA = -40èC
TA = -+25èC
TA = +85èC
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D025
D026
ILED = 179 mA
ƒSW = 2 MHz
Torch
ILED = 179 mA
ƒSW = 4 MHz
Torch
Figure 18. LED Current vs Input Voltage
Figure 19. LED Current vs Input Voltage
0.2
0.19
0.18
0.17
0.16
0.45
0.44
0.43
0.42
0.41
0.4
LED1, TA = -40èC
LED2, TA = -40èC
LED1, TA = +25èC
LED2, TA = +25èC
LED1, TA = +85èC
LED2, TA = +85èC
LED1, TA = -40èC
LED2, TA = -40èC
LED1, TA = +25èC
LED2, TA = +25èC
LED1, TA = +85èC
LED2, TA = +85èC
0.39
0.38
0.37
0.36
0.35
0.34
0.33
0.32
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D027
D042
ILED = 179 mA
ƒSW = 2 MHz
Torch
LM3644TT
ILED = 360 mA
ƒSW = 2 MHz
Torch
Figure 20. LED1 and LED2 Current vs Input Voltage
Figure 21. LED1 and LED2 Current vs Input Voltage
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Typical Characteristics (continued)
Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = COUT = 2 × 10 µF and L = 1 µH, unless otherwise
noted .
1.2
3
2.5
2
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
1
0.8
0.6
0.4
0.2
0
1.5
1
0.5
0
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D007
D009
HWEN = 0 V
I2C = 0 V
HWEN = VIN
I2C = VIN
Figure 22. Shutdown Current vs Input Voltage
Figure 23. Standby Current vs Input Voltage
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D008
D010
HWEN = 1.8 V
I2C = 0 V
HWEN = 1.8 V
I2C = 1.8 V
Figure 24. Standby Current vs Input Voltage
Figure 25. Standby Current vs Input Voltage
2.2
2.16
2.12
2.08
2.04
2
2.2
2.16
2.12
2.08
2.04
2
1.96
1.92
1.88
1.84
1.8
1.96
1.92
1.88
1.84
1.8
1.76
1.72
1.68
1.64
1.6
1.76
1.72
1.68
1.64
1.6
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
VIN (V)
VIN (V)
D011
D012
ILED = 1.5 A
ICL = 1.9 A
ƒSW = 2 MHz
VLED = 4.5 V
ILED = 1.5 A
ICL = 1.9 A
ƒSW = 4 MHz
VLED = 4.5 V
Figure 26. Inductor Current Limit vs Input Voltage
Figure 27. Inductor Current Limit vs Input Voltage
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Typical Characteristics (continued)
Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = COUT = 2 × 10 µF and L = 1 µH, unless otherwise
noted .
3
2.8
2.6
2.4
2.2
2
3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.8
1.6
1.4
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
2.5 2.75
3
3.25 3.5 3.75
VIN (V)
4
4.25 4.5 4.75
5
2.5 2.75
3
3.25 3.5 3.75
VIN (V)
4
4.25 4.5 4.75
5
D013
D014
ILED = 1.5 A
ICL = 2.8 A
ƒSW = 2 MHz
VLED = 4.5 V
ILED = 1.5 A
ICL = 2.8 A
ƒSW = 4 MHz
VLED = 4.5 V
Figure 28. Inductor Current Limit vs Input Voltage
Figure 29. Inductor Current Limit vs Input Voltage
2.125
2.1
4.25
4.2
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
2.075
2.05
2.025
2
4.15
4.1
4.05
4
1.975
1.95
1.925
1.9
3.95
3.9
3.85
3.8
1.875
3.75
2.5 2.75
3
3.25 3.5 3.75
VIN (V)
4
4.25 4.5 4.75
5
2.5 2.75
3
3.25 3.5 3.75
VIN (V)
4
4.25 4.5 4.75
5
D017
D0178
Figure 30. 2-MHz Switching Frequency vs Input Voltage
Figure 31. 4-MHz Switching Frequency vs Input Voltage
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8 Detailed Description
8.1 Overview
The LM3644 is a high-power white LED flash driver capable of delivering up to 1.5 A in either of the two parallel
LEDs. The device incorporates a 2-MHz or 4-MHz constant frequency-synchronous current-mode PWM boost
converter and dual high-side current sources to regulate the LED current over the 2.5-V to 5.5-V input voltage
range.
The LM3644 PWM DC-DC boost converter switches and boosts the output to maintain at least VHR across each
of the current sources (LED1/2). This minimum headroom voltage ensures that both current sources remain in
regulation. If the input voltage is above the LED voltage + current source headroom voltage the device does not
switch, but turns the PFET on continuously (Pass mode). In Pass mode the difference between (VIN − ILED
×
RPMOS) and the voltage across the LED is dropped across the current source.
The LM3644 has three logic inputs including a hardware Flash Enable (STROBE), a hardware Torch Enable
(TORCH/TEMP, TORCH = default), and a Flash Interrupt input (TX) designed to interrupt the flash pulse during
high battery-current conditions. These logic inputs have internal 300-kΩ (typical) pulldown resistors to GND.
Additional features of the LM3644 include an internal comparator for LED thermal sensing via an external NTC
thermistor and an input voltage monitor that can reduce the Flash current during low VIN conditions. It also has a
Hardware Enable (HWEN) pin that can be used to reset the state of the device and the registers by pulling the
HWEN pin to ground.
Control is done via an I2C-compatible interface. This includes adjustment of the Flash and Torch current levels,
changing the Flash Timeout Duration, and changing the switch current limit. Additionally, there are flag and
status bits that indicate flash current time-out, LED overtemperature condition, LED failure (open/short), device
thermal shutdown, TX interrupt, and VIN undervoltage conditions.
12
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8.2 Functional Block Diagram
SW
Over Voltage
Comparator
IN
2/4 MHz
Oscillator
-
+
V
REF
V
OVP
86 mW
Input Voltage
Flash Monitor
OUT
UVLO
I
I
LED2
LED1
PWM
Control
65 mW
TORCH/
TEMP
I
NTC
Thermal
Shutdown
+150oC
LED1
LED2
Error
Amplifier
FB
SELECT
+
-
OUT-VHR
Current Sense/
Current Limit
NTC V
TRIP
Slope
Compensation
Soft-Start
SDA
Control
Logic/
Registers
2
I C
Interface
SCL
HWEN
GND
TX
STROBE
8.3 Feature Description
8.3.1 Flash Mode
In Flash Mode, the LED current sources (LED1/2) provide 128 target current levels from 10.9 mA to 1500 mA.
Once the Flash sequence is activated the current source (LED) ramps up to the programmed Flash current by
stepping through all current steps until the programmed current is reached. The headroom in the two current
sources can be regulated to provide 10.9 mA to 1.5 A on each of the two output legs. There is an option in the
register settings to keep the two currents in the output leg the same.
When the device is enabled in Flash Mode through the Enable Register, all mode bits in the Enable Register are
cleared after a flash time-out event.
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Feature Description (continued)
8.3.2 Torch Mode
In Torch mode, the LED current sources (LED1/2) provide 128 target current levels from 0.977 mA to 179 mA or
1.954 mA to 360 mA on LM3644TT. The Torch currents are adjusted via the LED1 and LED2 LED Torch
Brightness Registers. Torch mode is activated by the Enable Register (setting M1, M0 to '10'), or by pulling the
TORCH/TEMP pin HIGH when the pin is enabled (Enable Register) and set to Torch Mode. Once the TORCH
sequence is activated the active current sources (LED1/2) ramps up to the programmed Torch current by
stepping through all current steps until the programmed current is reached. The rate at which the current ramps
is determined by the value chosen in the Timing Register.
Torch Mode is not affected by Flash Timeout or by a TX Interrupt event.
8.3.3 IR Mode
In IR Mode, the target LED current is equal to the value stored in the LED1/2 Flash Brightness Registers. When
IR mode is enabled (setting M1, M0 to '01'), the boost converter turns on and set the output equal to the input
(pass-mode). At this point, toggling the STROBE pin enables and disables the LED1/2 current sources (if
enabled). The strobe pin can only be set to be Level sensitive, meaning all timing of the IR pulse is externally
controlled. In IR Mode, the current sources do not ramp the LED outputs to the target. The current transitions
immediately from off to on and then on to off.
.hh{Ç
t!{{
hCC
ëhÜÇ
{Çwh.9
L[951
L[952
Figure 32. IR Mode with Boost
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Feature Description (continued)
ëhÜÇ
{Çwh.9
L[951
L[952
Figure 33. IR Mode Pass Only
ëhÜÇ
{Çwh.9
L[951
L[952
Çime-hut
ëꢀlue
Figure 34. IR Mode Timeout
8.4 Device Functioning Modes
8.4.1 Start-Up (Enabling The Device)
Turn on of the LM3644 Torch and Flash modes can be done through the Enable Register. On start-up, when
VOUT is less than VIN the internal synchronous PFET turns on as a current source and delivers 200 mA (typical)
to the output capacitor. During this time the current source (LED) is off. When the voltage across the output
capacitor reaches 2.2 V (typical) the current source turns on. At turnon the current source steps through each
FLASH or TORCH level until the target LED current is reached. This gives the device a controlled turnon and
limits inrush current from the VIN supply.
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Device Functioning Modes (continued)
8.4.2 Pass Mode
The LM3644 starts up in Pass Mode and stays there until Boost Mode is needed to maintain regulation. If the
voltage difference between VOUT and VLED falls below VHR, the device switches to Boost Mode. In Pass Mode the
boost converter does not switch, and the synchronous PFET turns fully on bringing VOUT up to VIN − ILED
×
RPMOS. In Pass Mode the inductor current is not limited by the peak current limit.
8.4.3 Power Amplifier Synchronization (TX)
The TX pin is a Power Amplifier Synchronization input. This is designed to reduce the flash LED current and thus
limit the battery current during high battery current conditions such as PA transmit events. When the LM3644 is
engaged in a Flash event, and the TX pin is pulled high, the LED current is forced into Torch Mode at the
programmed Torch current setting. If the TX pin is then pulled low before the Flash pulse terminates, the LED
current returns to the previous Flash current level. At the end of the Flash time-out, whether the TX pin is high or
low, the LED current turns off.
8.4.4 Input Voltage Flash Monitor (IVFM)
The LM3644 has the ability to adjust the flash current based upon the voltage level present at the IN pin utilizing
the Input Voltage Flash Monitor (IVFM). The adjustable threshold IVFM-D ranges from 2.9 V to 3.6 V in 100-mV
steps, with three different usage modes (Stop and Hold, Adjust Down Only, Adjust Up and Down). The Flags2
Register has the IVFM flag bit set when the input voltage crosses the IVFM-D value. Additionally, the IVFM-D
threshold sets the input voltage boundary that forces the LM3644 to either stop ramping the flash current during
start-up (Stop and Hold Mode) or to start decreasing the LED current during the flash (Down Adjust Only and Up
and Down Adjust). In Adjust Up and Down mode, the IVFM-D value plus the hysteresis voltage threshold set the
input voltage boundary that forces the LM3644 to start ramping the flash current back up towards the target.
16
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Device Functioning Modes (continued)
LëCa 9b!.[9
[9ë9[ {Çwh.9
ëLb twhCL[9 for {ꢀop ꢁnd Iold aode
LëCa-5
5oꢀꢀed line sꢂoꢃs huꢀpuꢀ
/urrenꢀ trofile ꢃiꢀꢂ LëCa
5isꢁꢄled
{eꢀ Çꢁrgeꢀ Clꢁsꢂ /urrenꢀ
huꢀpuꢀ /urrenꢀ
trofile in {ꢀop
ꢁnd Iold aode
{9Ç w!at Cwha
ÇI9 w!at
w9DL{Ç9w Ü{95
ëLb twhCL[9 for 5oꢃn aode
Iysꢀeresis = 0 ë or ꢆ0 më
Iysꢀeresis
LëCa-5
huꢀpuꢀ /urrenꢀ
trofile in 5oꢃn
aode
ëLb twhCL[9 for Üpꢅ 5oꢃn aode
Iysꢀeresis
LëCa-5
huꢀpuꢀ /urrenꢀ
trofile in Üp ꢁnd
5oꢃn aode
Figure 35. IVFM Modes
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Device Functioning Modes (continued)
8.4.5 Fault/Protections
8.4.5.1 Fault Operation
If the LM3644 enters a fault condition, the device sets the appropriate flag in the Flags1 and Flags2 Registers
(0x0A and 0x0B), and place the device into standby by clearing the Mode Bits ([1],[0]) in the Enable Register.
The LM3644 remains in standby until an I2C read of the Flags1 and Flags2 Registers are completed. Upon
clearing the flags/faults, the device can be restarted (Flash, Torch, IR, etc.). If the fault is still present, the
LM3644 re-enters the fault state and enters standby again.
8.4.5.2 Flash Time-Out
The Flash Time-Out period sets the amount of time that the Flash Current is being sourced from the current
sources (LED1/2). The LM3644 has 16 timeout levels ranging from 10 ms to 400 ms or 40 ms to 1.6 s on
LM3644TT (see Timing Configuration Register (0x08) for more detail).
8.4.5.3 Overvoltage Protection (OVP)
The output voltage is limited to typically 5 V (see VOVP spec in the Electrical Characteristics). In situations such
as an open LED, the LM3644 raises the output voltage in order to try and keep the LED current at its target
value. When VOUT reaches 5 V (typical) the overvoltage comparator trips and turns off the internal NFET. When
VOUT falls below the “VOVP Off Threshold”, the LM3644 begins switching again. The mode bits are cleared, and
the OVP flag is set, when an OVP condition is present for three rising OVP edges. This prevents momentary
OVP events from forcing the device to shut down.
8.4.5.4 Current Limit
The LM3644 features two selectable inductor current limits that are programmable through the I2C-compatible
interface. When the inductor current limit is reached, the LM3644 terminates the charging phase of the switching
cycle. Switching resumes at the start of the next switching period. If the overcurrent condition persists, the device
operates continuously in current limit.
Since the current limit is sensed in the NMOS switch, there is no mechanism to limit the current when the device
operates in Pass Mode (current does not flow through the NMOS in pass mode). In Boost mode or Pass mode if
VOUT falls below 2.3 V, the device stops switching, and the PFET operates as a current source limiting the
current to 200 mA. This prevents damage to the LM3644 and excessive current draw from the battery during
output short-circuit conditions. The mode bits are not cleared upon a Current Limit event, but a flag is set.
8.4.5.5 NTC Thermistor Input (Torch/Temp)
The TORCH/TEMP pin, when set to TEMP mode, serves as a threshold detector and bias source for negative
temperature coefficient (NTC) thermistors. When the voltage at TEMP goes below the programmed threshold,
the LM3644 is placed into standby mode. The NTC threshold voltage is adjustable from 200 mV to 900 mV in
100-mV steps. The NTC bias current is set to 50 µA. The NTC detection circuitry can be enabled or disabled via
the Enable Register. If enabled, the NTC block turns on and off during the start and stop of a Flash/Torch event.
Additionally, the NTC input looks for an open NTC connection and a shorted NTC connection. If the NTC input
falls below 100 mV, the NTC short flag is set, and the device is disabled. If the NTC input rises above 2.3 V, the
NTC Open flag is set, and the device is disabled. These fault detections can be individually disabled/enabled via
the NTC Open Fault Enable bit and the NTC Short Fault Enable bit.
V
IN
NTC Control Block
I
NTC
TEMP
-
+
Control
Logic
V
TRIP
NTC
Figure 36. Temp Detection Diagram
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Device Functioning Modes (continued)
8.4.5.6 Undervoltage Lockout (UVLO)
The LM3644 has an internal comparator that monitors the voltage at IN and forces the LM3644 into standby if
the input voltage drops to 2.5 V. If the UVLO monitor threshold is tripped, the UVLO flag bit is set in the Flags1
Register (0x0A). If the input voltage rises above 2.5 V, the LM3644 is not available for operation until there is an
I2C read of the Flags1 Register (0x0A). Upon a read, the Flags1 register is cleared, and normal operation can
resume if the input voltage is greater than 2.5 V.
8.4.5.7 Thermal Shutdown (TSD)
When the LM3644 die temperature reaches 150°C, the thermal shutdown detection circuit trips, forcing the
LM3644 into standby and writing a '1' to the corresponding bit of the Flags1 Register (0x0A) (Thermal Shutdown
bit). The LM3644 is only allowed to restart after the Flags1 Register (0x0A) is read, clearing the fault flag. Upon
restart, if the die temperature is still above 150°C, the LM3644 resets the Fault flag and re-enters standby.
8.4.5.8 LED and/or VOUT Short Fault
The LED Fault flags read back a '1' if the device is active in Flash or Torch mode and either active LED output
experiences a short condition. The Output Short Fault flag reads back a '1' if the device is active in Flash or
Torch mode and the boost output experiences a short condition. An LED short condition is determined if the
voltage at LED1 or LED2 goes below 500 mV (typ.) while the device is in Torch or Flash mode. There is a
deglitch time of 256 μs before the LED Short flag is valid and a deglitch time of 2.048 ms before the VOUT Short
flag is valid. The LED Short Faults can be reset to '0' by removing power to the LM3644, setting HWEN to '0',
setting the SW RESET bit to a '1', or by reading back the Flags1 Register (0x0A on LM3644). The mode bits are
cleared upon an LED and/or VOUT short fault.
8.5 Programming
8.5.1 Control Truth Table
MODE1
MODE0
STROBE EN
TORCH EN
STROBE PIN
TORCH PIN
ACTION
Standby
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
1
1
X
X
0
1
1
0
1
0
1
1
1
X
X
X
X
X
X
X
X
pos edge
Ext Torch
pos edge
X
Ext Flash
0
pos edge
Standalone Torch
Standalone Flash
Standalone Flash
Int Torch
pos edge
0
pos edge
pos edge
X
X
X
X
X
X
X
Int Flash
X
0
IRLED Standby
IRLED Standby
IRLED enabled
pos edge
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8.5.2 I2C-Compatible Interface
8.5.2.1 Data Validity
The data on SDA must be stable during the HIGH period of the clock signal (SCL). In other words, the state of
the data line can only be changed when SCL is LOW.
SCL
SDA
data
change
allowed
data
change
allowed
data
valid
data
change
allowed
data
valid
Figure 37. Data Validity Data
A pullup resistor between the controller's VIO line and SDA must be greater than [(VIO - VOL) / 3 mA] to meet the
VOL requirement on SDA. Using a larger pullup resistor results in lower switching current with slower edges, while
using a smaller pullup results in higher switching currents with faster edges.
8.5.2.2 Start and Stop Conditions
START and STOP conditions classify the beginning and the end of the I2C session. A START condition is
defined as the SDA signal transitioning from HIGH to LOW while SCL line is HIGH. A STOP condition is defined
as the SDA transitioning from LOW to HIGH while SCL is HIGH. The I2C master always generates START and
STOP conditions. The I2C bus is considered busy after a START condition and free after a STOP condition.
During data transmission, the I2C master can generate repeated START conditions. First START and repeated
START conditions are equivalent, function-wise.
SDA
SCL
S
P
Start Condition
Stop Condition
Figure 38. Start and Stop Conditions
8.5.2.3 Transferring Data
Every byte put on the SDA line must be eight bits long, with the most significant bit (MSB) transferred first. Each
byte of data has to be followed by an acknowledge bit. The acknowledge related clock pulse is generated by the
master. The master releases the SDA line (HIGH) during the acknowledge clock pulse. The LM3644 pulls down
the SDA line during the 9th clock pulse, signifying an acknowledge. The LM3644 generates an acknowledge
after each byte is received. There is no acknowledge created after data is read from the device.
After the START condition, the I2C master sends a chip address. This address is seven bits long followed by an
eighth bit which is a data direction bit (R/W). The LM3644 7-bit address is 0x63. For the eighth bit, a '0' indicates
a WRITE and a '1' indicates a READ. The second byte selects the register to which the data is written. The third
byte contains data to write to the selected register.
20
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ack from slave
ack from slave
msb DATA lsb ack stop
ack from slave
start msb Chip Address lsb
w
ack
msb Register Add lsb
ack
SCL
SDA
start
Id = 63h
w
ack
addr = 0Ah
ack
Data = 03h
ack stop
Figure 39. Write Cycle W = Write (SDA = "0") R = Read (SDA = "1") Ack = Acknowledge
(SDA Pulled Down by Either Master or Slave) ID = Chip Address, 63h for LM3644
8.5.2.4 I2C-Compatible Chip Address
The device address for the LM3644 is 1100011 (0x63). After the START condition, the I2C-compatible master
sends the 7-bit address followed by an eighth read or write bit (R/W). R/W = 0 indicates a WRITE and R/W = 1
indicates a READ. The second byte following the device address selects the register address to which the data is
written. The third byte contains the data for the selected register.
MSB
LSB
1
Bit 7
1
Bit 6
0
Bit 5
0
Bit 4
0
Bit 3
1
Bit 2
1
Bit 1
R/W
Bit 0
2
I C Slave Address (chip address)
Figure 40. I2C-Compatible Chip Address
8.6 Register Descriptions
POWER ON/RESET VALUE
REGISTER NAME
INTERNAL HEX ADDRESS
LM3644
Enable Register
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
0x0A
0x0B
0x0C
0x0D
0x80
IVFM Register
0x01
LED1 Flash Brightness Register
LED2 Flash Brightness Register
LED1 Torch Brightness Register
LED2 Torch Brightness Register
Boost Configuration Register
Timing Configuration Register
TEMP Register
0xBF
0x3F
0xBF
0x3F
0x09
0x1A
0x08
Flags1 Register
0x00
Flags2 Register
0x00
0x02 or 0x04 for LM3644TT
0x00
Device ID Register
Last Flash Register
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8.6.1 Enable Register (0x01)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
TX Pin Enable Strobe Type
Strobe Enable TORCH/TEMP
Mode Bits: M1, M0
00 = Standby (Default)
01 = IR Drive
10 = Torch
11 = Flash
LED2 Enable
0 = OFF
(Default )
1 = ON
LED1 Enable
0 = OFF
(Default)
0 = Disabled
1 = Enabled
(Default )
0 = Level
Triggered
(Default)
1 = Edge
Triggered
0 = Disabled
(Default )
1 = Enabled
Pin Enable
0 = Disabled
(Default )
1 = ON
1 = Enabled
NOTE
Edge Strobe Mode is not valid in IR MODE. Switching between Level and Edge Strobe
Types while the device is enabled is not recommended.
In Edge or Level Strobe Mode, it is recommended that the trigger pulse width be set
greater than 1 ms to ensure proper turn-on of the device.
8.6.2 IVFM Register (0x02)
Bit 7
Bit 6
UVLO
Circuitry
(Default)
0 = Disabled
(Default)
Bit 5
Bit 4
Bit 3
Bit 2
IVFM
Hysteresis
0 = 0 mV
(Default)
Bit 1
Bit 0
IVFM Levels
000 = 2.9 V (Default)
001 = 3 V
010 = 3.1 V
011 = 3.2 V
100 = 3.3 V
101 = 3.4 V
110 = 3.5 V
111 = 3.6 V
IVFM Selection
00 = Disabled
01 = Stop and Hold Mode (Default)
10 = Down Mode
11 = Up and Down Mode
RFU
1 = 50 mV
1 = Enabled
NOTE
IVFM Mode Bits are static once the LM3644 is enabled in Torch, Flash or IR modes. If the
IVFM mode needs to be updated, disable the device and then change the mode bits to the
desired state.
8.6.3 LED1 Flash Brightness Register (0x03)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
LED2 Flash
Current
Override
0 = LED2
LED1 Flash Brightness Level
Flash Current IFLASH1/2 (mA) ≈ (Brightness Code × 11.725 mA) + 10.9 mA
is not set to
LED1 Flash
Current
0000000 = 10.9 mA
.......................
0111111 = 729 mA (Default)
.......................
1 = LED2
Flash Current 1111111 = 1.5 A
is set to LED1
Flash Current
(Default)
8.6.4 LED2 Flash Brightness Register (0x04)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
LED2 Flash Brightness Levels
IFLASH1/2 (mA) ≈ (Brightness Code × 11.725 mA) + 10.9 mA
0000000 = 10.9 mA
RFU
.......................
0111111 = 729 mA (Default)
.......................
1111111 = 1.5 A
22
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8.6.5 LED1 Torch Brightness Register (0x05)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
LED2 Torch
Current
Override
0 = LED2
Torch Current
is not set to
LED1 Torch
Current
LED1 Torch Brightness Levels
ITORCH1/2 (mA) ≈ (Brightness Code × 1.4 mA) + 0.977 mA or ITORCH1/2 (mA) ≈ (Brightness Code × 2.8 mA) + 1.954 mA
(LM3644TT)
0000000 = 0.977 mA or 1.954 mA for LM3644TT
.......................
0111111 = 89.3 mA (Default) or 178.6 mA for LM3644TT
.......................
1111111 = 179 mA or 360mA for LM3644TT
1 = LED2
Torch Current
is set to LED1
Torch Current
(Default)
8.6.6 LED2 Torch Brightness Register (0x06)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
LED2 Torch Brightness Levels
ITORCH1/2 (mA) ≈ (Brightness Code × 1.4 mA) + 0.977 mA or ITORCH1/2 (mA) ≈ (Brightness Code × 2.8 mA) + 1.954 mA
(LM3644T)T
0000000 = 0.977 mA or 1.954 mA (LM3644TT)
.......................
RFU
0111111 = 89.3 mA (Default) or 178.6 mA (LM3644TT)
.......................
1111111 = 179 mA or 360mA (LM3644TT)
8.6.7 Boost Configuration Register (0x07)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Boost
Frequency
Select
Bit 0
LED Pin Short
Fault Detect
0 = Disabled
1 = Enabled
(Default)
Boost Mode
0 = Normal
(Default)
Boost Current
Limit Setting
0 = 1.9 A
1 = 2.8 A
(Default)
Software
Reset Bit
0 = Not Reset
(Default)
RFU
RFU
RFU
1 = Pass Mode 0 = 2 MHz
Only
(Default)
1 = 4 MHz
1 = Reset
8.6.8 Timing Configuration Register (0x08)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Torch Current Ramp Time
000 = No Ramp
001 = 1 ms (Default)
010 = 32 ms
011 = 64 ms
100 = 128 ms
101 = 256 ms
110 = 512 ms
111 = 1024 ms
Flash Time-Out Duration
0000 = 10 ms or 40 ms (LM3644TT)
0001 = 20 ms or 80 ms (LM3644TT)
0010 = 30 ms or 120 ms (LM3644TT)
0011 = 40 ms or 160 ms (LM3644TT)
0100 = 50 ms or 200 ms (LM3644TT)
0101 = 60 ms or 240 ms (LM3644TT)
0110 = 70 ms or 280 ms (LM3644TT)
0111 = 80 ms or 320 ms (LM3644TT)
1000 = 90 ms or 360 ms (LM3644TT)
1001 = 100 ms or 400 ms (LM3644TT)
1010 = 150 ms (Default) or 600 ms (LM3644TT)
1011 = 200 ms or 800 ms(LM3644TT)
1100 = 250 ms or 1000 ms (LM3644TT)
1101 = 300 ms or 1200 ms (LM3644TT)
1110 = 350 ms or 1400 ms (LM3644TT)
1111 = 400 ms or 1600 ms (LM3644TT)
RFU
NOTE
On the LM3644TT, special care must be take with regards to thermal management when
using time-outs values greater than 400 ms. Depending on the PCB layout, input voltage
and output current, it is possible to have the internal thermal shutdown circuit trip prior to
reaching the desired flash time-out value.
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8.6.9 TEMP Register (0x09)
Bit 7
RFU
Bit 6
TORCH
Polarity
0 = Active
High (Default) (Default)
(Pulldown
Resistor
Enabled)
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
NTC Open
Fault Enable
0 = Disabled
NTC Short
Fault Enable
0 = Disabled
(Default)
TEMP Detect Voltage Threshold
000 = 0.2 V
001 = 0.3 V
010 = 0.4 V
011 = 0.5 V
TORCH/TEMP
Function
Select
0 = TORCH
(Default)
1 =Enable
1 =Enable
100 = 0.6 V (Default)
101 = 0.7 V
1 = TEMP
1 = Active Low
(Pulldown
Resistor
110 = 0.8 V
111 = 0.9 V
Disabled)
NOTE
The Torch Polarity bit is static once the LM3644 is enabled in Torch, Flash or IR modes. If
the Torch Polarity bit needs to be updated, disable the device and then change the Torch
Polarity bit to the desired state.
8.6.10 Flags1 Register (0x0A)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Thermal
Shutdown
(TSD) Fault
VOUT Short
Fault
VLED1 Short VLED2 Short
Current Limit
Flag
Flash Time-Out
Flag
TX Flag
UVLO Fault
Fault
Fault
8.6.11 Flags2 Register (0x0B)
Bit 7
RFU
Bit 6
RFU
Bit 5
RFU
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
NTC Short
Fault
IVFM Trip
Flag
TEMP Trip
Fault
NTC Open Fault
OVP Fault
8.6.12 Device ID Register (0x0C)
Bit 7
RFU
Bit 6
RFU
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Device ID
Silicon Revision Bits
'010' or '100' for LM3644TT
'000'
8.6.13 Last Flash Register (0x0D)
Bit 7
RFU
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
The value stored is always the last current value the IVFM detection block set. ILED = IFLASH – TARGET × ((Code + 1) / 128)
24
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9 Applications and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The LM3644 can drive two flash LEDs at currents up to 1.5 A per LED. The 2-MHz/4-MHz DC-DC boost
regulator allows for the use of small value discrete external components.
9.2 Typical Application
[1
1 mH
LM3644
IN
SW
ëLb
2.ꢁë t ꢁ.ꢁë
/1
10 mF
HWEN
SDA
OUT
/2
10 mF
SCL
LED1
LED2
mtꢀm/
STROBE
51
52
TORCH/
TEMP
TX
GND
Figure 41. LM3644 Typical Application
9.2.1 Design Requirements
Example requirements based on default register values:
DESIGN PARAMETER
Input voltage range
Brightness control
EXAMPLE VALUE
2.5 V to 5.5 V
I2C Register
LED configuration
2 parallel flash LEDs
2 MHz (4 MHz selectable)
750 mA per LED
Boost switching frequency
Flash brightness
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9.2.2 Detailed Design Procedure
9.2.2.1 Output Capacitor Selection
The LM3644 is designed to operate with a 10-µF ceramic output capacitor. When the boost converter is running,
the output capacitor supplies the load current during the boost converter on-time. When the NMOS switch turns
off, the inductor energy is discharged through the internal PMOS switch, supplying power to the load and
restoring charge to the output capacitor. This causes a sag in the output voltage during the on-time and a rise in
the output voltage during the off-time. The output capacitor is therefore chosen to limit the output ripple to an
acceptable level depending on load current and input/output voltage differentials and also to ensure the converter
remains stable.
Larger capacitors such as a 22-µF or capacitors in parallel can be used if lower output voltage ripple is desired.
To estimate the output voltage ripple considering the ripple due to capacitor discharge (ΔVQ) and the ripple due
to the capacitors ESR (ΔVESR) use the following equations:
For continuous conduction mode, the output voltage ripple due to the capacitor discharge is:
(
)
ILED x VOUT - V
IN
DVQ =
fSW x VOUT x COUT
(1)
The output voltage ripple due to the output capacitors ESR is found by:
ILED x VOUT
≈
«
’
◊
+DIL
DVESR = RESR
x
VIN
where
(
)
x VOUT - V
IN
V
IN
DIL =
2x fSW x L x VOUT
(2)
In ceramic capacitors the ESR is very low so the assumption is that 80% of the output voltage ripple is due to
capacitor discharge and 20% from ESR. Table 1 lists different manufacturers for various output capacitors and
their case sizes suitable for use with the LM3644.
9.2.2.2 Input Capacitor Selection
Choosing the correct size and type of input capacitor helps minimize the voltage ripple caused by the switching
of the LM3644 boost converter and reduce noise on the boost converter's input pin that can feed through and
disrupt internal analog signals. In the typical application circuit a 10-µF ceramic input capacitor works well. It is
important to place the input capacitor as close as possible to the LM3644 input (IN) pin. This reduces the series
resistance and inductance that can inject noise into the device due to the input switching currents. Table 1 lists
various input capacitors recommended for use with the LM3644.
Table 1. Recommended Input/Output Capacitors (X5R/X7R Dielectric)
MANUFACTURER
TDK Corporation
TDK Corporation
Murata
PART NUMBER
C1608JB0J106M
VALUE
10 µF
10 µF
10 µF
10 µF
CASE SIZE
VOLTAGE RATING
0603 (1.6 mm × 0.8 mm × 0.8 mm)
0805 (2.0 mm × 1.25 mm × 1.25 mm)
0603 (1.6 mm x 0.8 mm x 0.8 mm)
0805 (2.0 mm × 1.25 mm × 1.25 mm)
6.3 V
10 V
6.3 V
10 V
C2012JB1A106M
GRM188R60J106M
GRM21BR61A106KE19
Murata
9.2.2.3 Inductor Selection
The LM3644 is designed to use a 0.47-µH or 1-µH inductor. Table 2 lists various inductors and their
manufacturers that work well with the LM3644. When the device is boosting (VOUT > VIN) the inductor is typically
the largest area of efficiency loss in the circuit. Therefore, choosing an inductor with the lowest possible series
resistance is important. Additionally, the saturation rating of the inductor should be greater than the maximum
operating peak current of the LM3644. This prevents excess efficiency loss that can occur with inductors that
operate in saturation. For proper inductor operation and circuit performance, ensure that the inductor saturation
and the peak current limit setting of the LM3644 are greater than IPEAK in the following calculation:
26
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ILOAD VOUT
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
( )
IN x VOUT - V
IN
V
IPEAK
=
x
+DIL
where
DIL =
h
V
2 x fSW x L x VOUT
IN
where
•
ƒSW = 2 or 4 MHz
(3)
Efficiency details can be found in the Application Curves .
Table 2. Recommended Inductors
MANUFACTURER
TOKO
L
PART NUMBER
DFE201610P-R470M
DFE201610P-1R0M
DIMENSIONS (L×W×H)
2.0 mm x 1.6 mm x 1.0 mm
2.0 mm x 1.6 mm x 1.0 mm
ISAT
4.1 A
3.7 A
RDC
0.47 µH
1 µH
32 mΩ
58 mΩ
TOKO
9.2.3 Application Curves
Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = 2 × 10 µF, COUT = 2 × 10 µF and L = 1 µH, unless
otherwise noted.
100
95
90
85
80
75
70
65
60
55
50
100
95
90
85
80
75
70
65
60
55
50
VLED = 3.0V
VLED = 3.2V
VLED = 3.5V
VLED = 3.8V
VLED = 4.1V
VLED = 4.4V
VLED = 3.0V
VLED = 3.2V
VLED = 3.5V
VLED = 3.8V
VLED = 4.1V
VLED = 4.4V
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D019
D020
ILED = 1.5 A
ƒSW = 2 MHz
Flash
ILED = 1.5 A
ƒSW = 2 MHz
Flash
Figure 42. 2-MHz LED Efficiency vs Input Voltage
Figure 43. 4-MHz LED Efficiency vs Input Voltage
100
96
92
88
84
80
76
72
68
64
60
100
96
92
88
84
80
76
72
68
64
60
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D028
D029
ILED = 1.5 A
ƒSW = 2 MHz
Flash
ILED = 1.5 A
ƒSW = 4 MHz
Flash
VLED = 3.55 V
VLED = 3.55 V
Figure 44. LED Efficiency vs Input Voltage
Figure 45. LED Efficiency vs Input Voltage
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Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = 2 × 10 µF, COUT = 2 × 10 µF and L = 1 µH, unless
otherwise noted.
100
96
92
88
84
80
76
72
68
64
60
100
96
92
88
84
80
76
72
68
64
60
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D030
D031
ILED = 1 A
VLED = 3.32 V
ƒSW = 2 MHz
Flash
ILED = 729 mA
VLED = 3.18 V
ƒSW = 2 MHz
Flash
Figure 46. LED Efficiency vs Input Voltage
Figure 47. LED Efficiency vs Input Voltage
100
96
92
88
84
80
76
72
68
64
60
100
95
90
85
80
75
70
65
60
55
50
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D032
D033
ILED1 and LED2 = 729 mA
VLED = 3.18 V
Flash
ƒSW = 2 MHz
ILED = 179 mA
VLED = 2.83 V
Torch
ƒSW = 2 MHz
Figure 48. LED Efficiency vs Input Voltage
Figure 49. LED Efficiency vs Input Voltage
100
95
90
85
80
75
70
65
60
55
50
100
95
90
85
80
75
70
65
60
55
50
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
VIN (V)
D034
D035
ILED = 179 mA
VLED = 2.83 V
ƒSW = 4 MHz
Torch
ILED1 and LED2 = 179 mA
VLED = 2.83 V
ƒSW = 2 MHz
Torch
Figure 50. LED Efficiency vs Input Voltage
Figure 51. LED Efficiency vs Input Voltage
28
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Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = 2 × 10 µF, COUT = 2 × 10 µF and L = 1 µH, unless
otherwise noted.
100
95
90
85
80
75
70
65
60
55
50
100
95
90
85
80
75
70
65
60
55
50
TA = -40èC
TA = +25èC
TA = +85èC
TA = -40èC
TA = +25èC
TA = +85èC
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
D044
VIN (V)
D036
ILED1 and LED2 = 179 mA
VLED = 2.83 V
ƒSW = 2 MHz
Torch
LM3644TT
ILED1 and LED2 = 179 mA
VLED = 2.83 V
ƒSW = 4 MHz
Torch
Figure 53. LED Efficiency vs Input Voltage
Figure 52. LED Efficiency vs Input Voltage
100
95
90
85
80
75
70
65
60
55
50
TA = -40èC
TA = +25èC
TA = +85èC
VOUT (2 V/DIV)
ILED1 (500 mA/DIV)
ILED2 (500 mA/DIV)
IIN (1 A/DIV)
Time (400 ms / DIV)
2.5
3
3.5
4
4.5
5
5.5
VIN (V)
D045
ILED1 and LED2 = 179 mA
VLED = 2.83 V
ƒSW = 4 MHz
Torch
LM3644TT
ILED1 = ILED2 = 730 mA
VLED = 3.18 V
ƒSW = 2 MHz
Figure 54. LED Efficiency vs Input Voltage
Figure 55. Start-Up
Tx Signal
VOUT (2 V/DIV)
VOUT (2 V/DIV)
ILED1 (500 mA/DIV)
ILED1 (500 mA/DIV)
ILED2 (500 mA/DIV)
IIN (1 A/DIV)
ILED2 (500 mA/DIV)
IIN (1 A/DIV)
Time (400 ms / DIV)
Time (2 ms / DIV)
ILED1 = ILED2 = 730 mA
VLED = 3.18 V
ƒSW = 2 MHz
ILED1 = ILED2 = 730 mA
VLED = 3.18 V
ƒSW = 2 MHz
Figure 56. Ramp Down
Figure 57. TX Interrupt
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Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = 2 × 10 µF, COUT = 2 × 10 µF and L = 1 µH, unless
otherwise noted.
VOUT (50 mV/DIV)
ILED1 (20 mA/DIV)
VOUT (50 mV/DIV)
ILED1 (20 mA/DIV)
ILED2 (20 mA/DIV)
IL (100 mA/DIV)
ILED2 (20 mA/DIV)
IL (100 mA/DIV)
Time (400 ns / DIV)
Time (400 ns / DIV)
ILED1 = ILED2 = 730 mA
VLED = 3.18 V
ƒSW = 2 MHz
ILED1 = ILED2 = 730 mA
VLED = 3.18 V
ƒSW = 4 MHz
Figure 58. Ripple @ 2 MHz
Figure 59. Ripple @ 4 MHz
VIN (50 mV/DIV) w/ Offset = 3.2V
VIN (50 mV/DIV) w/ Offset = 3.2V
ILED1 (200 mA/DIV)
ILED2 (200 mA/DIV)
IIN (500 mA/DIV)
ILED1 (200 mA/DIV)
ILED2 (200 mA/DIV)
IIN (500 mA/DIV)
Time (400 ms / DIV)
Time (400 ms / DIV)
ILED1 = ILED2 = 730 mA
VLED = 3.18 V
ƒSW = 2 MHz
VIVFM = 3.2 V
ILED1 = ILED2 = 730 mA
VLED = 3.18 V
ƒSW = 2 MHz
VIVFM = 3.2 V
Figure 60. IVFM - Ramp and Hold
Figure 61. IVFM - Down Adjust Only
VIN (50 mV/DIV) w/ Offset = 3.2V
ILED1 (200 mA/DIV)
ILED2 (200 mA/DIV)
IIN (500 mA/DIV)
Time (400 ms / DIV)
ILED1 = ILED2 = 730 mA
VLED = 3.18 V
ƒSW = 2 MHz
VIVFM = 3.2 V
Figure 62. IVFM - Up and Down Adjust
30
Copyright © 2014–2015, Texas Instruments Incorporated
LM3644, LM3644TT
www.ti.com.cn
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
10 Power Supply Recommendations
The LM3644 is designed to operate from an input voltage supply range between 2.5 V and 5.5 V. This input
supply must be well regulated and capable to supply the required input current. If the input supply is located far
from the LM3644 additional bulk capacitance may be required in addition to the ceramic bypass capacitors.
11 Layout
11.1 Layout Guidelines
The high switching frequency and large switching currents of the LM3644 make the choice of layout important.
The following steps should be used as a reference to ensure the device is stable and maintains proper LED
current regulation across its intended operating voltage and current range.
1. Place CIN on the top layer (same layer as the LM3644) and as close to the device as possible. The input
capacitor conducts the driver currents during the low-side MOSFET turn-on and turn-off and can detect
current spikes over 1 A in amplitude. Connecting the input capacitor through short, wide traces to both the IN
and GND pins reduces the inductive voltage spikes that occur during switching which can corrupt the VIN
line.
2. Place COUT on the top layer (same layer as theLM3644) and as close as possible to the OUT and GND pin.
The returns for both CIN and COUT should come together at one point, as close to the GND pin as possible.
Connecting COUT through short, wide traces reduce the series inductance on the OUT and GND pins that can
corrupt the VOUT and GND lines and cause excessive noise in the device and surrounding circuitry.
3. Connect the inductor on the top layer close to the SW pin. There should be a low-impedance connection
from the inductor to SW due to the large DC inductor current, and at the same time the area occupied by the
SW node should be small so as to reduce the capacitive coupling of the high dV/dT present at SW that can
couple into nearby traces.
4. Avoid routing logic traces near the SW node so as to avoid any capacitively coupled voltages from SW onto
any high-impedance logic lines such as TORCH/TEMP, STROBE, HWEN, SDA, and SCL. A good approach
is to insert an inner layer GND plane underneath the SW node and between any nearby routed traces. This
creates a shield from the electric field generated at SW.
5. Terminate the Flash LED cathodes directly to the GND pin of the LM3644. If possible, route the LED returns
with a dedicated path so as to keep the high amplitude LED currents out of the GND plane. For Flash LEDs
that are routed relatively far away from the LM3644, a good approach is to sandwich the forward and return
current paths over the top of each other on two layers. This helps reduce the inductance of the LED current
paths.
版权 © 2014–2015, Texas Instruments Incorporated
31
LM3644, LM3644TT
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
www.ti.com.cn
11.2 Layout Example
IN
10 mF
VIAs to GND
tlane
GND
IN
SDA
SCL
SDA
SCL
1 mH
10 mF
SW
STROBE
SW
TORCH/
TEMP
TORCH/
TEMP
HWEN
OUT
OUT
LED1
LED2
TX
LED2
TX
LED1
Figure 63. Layout Example
32
版权 © 2014–2015, Texas Instruments Incorporated
LM3644, LM3644TT
www.ti.com.cn
ZHCSCQ8D –AUGUST 2014–REVISED SEPTEMBER 2015
12 器件和文档支持
12.1 器件支持
12.1.1 Third-Party Products Disclaimer
TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT
CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES
OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER
ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.
12.2 相关文档
12.2.1 相关链接
列出了快速访问链接。范围包括技术文档、支持与社区资源、工具和软件，以及样片或购买的快速访问。
表 3. 相关链接
器件
产品文件夹
请单击此处
请单击此处
样片与购买
请单击此处
请单击此处
技术文档
请单击此处
请单击此处
工具与软件
请单击此处
请单击此处
支持与社区
请单击此处
请单击此处
LM3644
LM3644TT
12.3 商标
12.4 静电放电警告
ESD 可能会损坏该集成电路。德州仪器 (TI) 建议通过适当的预防措施处理所有集成电路。如果不遵守正确的处理措施和安装程序 , 可
能会损坏集成电路。
ESD 的损坏小至导致微小的性能降级 , 大至整个器件故障。 精密的集成电路可能更容易受到损坏 , 这是因为非常细微的参数更改都可
能会导致器件与其发布的规格不相符。
12.5 术语表
SLYZ022 — TI 术语表。
这份术语表列出并解释术语、缩写和定义。
13 机械、封装和可订购信息
以下页中包括机械、封装和可订购信息。这些信息是针对指定器件可提供的最新数据。这些数据会在无通知且不对
本文档进行修订的情况下发生改变。欲获得该数据表的浏览器版本，请查阅左侧的导航栏。
版权 © 2014–2015, Texas Instruments Incorporated
33
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status Package Type Package Pins Package
Eco Plan
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
Samples
Drawing
Qty
(1)
(2)
(3)
(4/5)
(6)
LM3644TTYFFR
LM3644YFFR
ACTIVE
ACTIVE
DSBGA
DSBGA
YFF
YFF
12
12
3000 RoHS & Green
3000 RoHS & Green
SNAGCU
Level-1-260C-UNLIM
Level-1-260C-UNLIM
-40 to 85
-40 to 85
3644TT
3644
SNAGCU
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two
lines if the finish value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
8-Mar-2021
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
B0
K0
P1
W
Pin1
Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant
(mm) W1 (mm)
LM3644TTYFFR
LM3644YFFR
DSBGA
DSBGA
YFF
YFF
12
12
3000
3000
180.0
180.0
8.4
8.4
1.36
1.36
1.76
1.76
0.77
0.77
4.0
4.0
8.0
8.0
Q1
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
8-Mar-2021
*All dimensions are nominal
Device
Package Type Package Drawing Pins
SPQ
Length (mm) Width (mm) Height (mm)
LM3644TTYFFR
LM3644YFFR
DSBGA
DSBGA
YFF
YFF
12
12
3000
3000
182.0
182.0
182.0
182.0
20.0
20.0
Pack Materials-Page 2
PACKAGE OUTLINE
YFF0012
DSBGA - 0.625 mm max height
SCALE 8.000
DIE SIZE BALL GRID ARRAY
A
B
E
BALL A1
CORNER
D
0.625 MAX
C
SEATING PLANE
0.05 C
BALL TYP
0.30
0.12
0.8 TYP
0.4 TYP
D
C
B
SYMM
1.2
TYP
D: Max = 1.69 mm, Min = 1.63 mm
E: Max = 1.31 mm, Min = 1.25 mm
A
0.4 TYP
1
2
3
0.3
12X
0.015
0.2
SYMM
C A
B
4222191/A 07/2015
NOTES:
1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
www.ti.com
EXAMPLE BOARD LAYOUT
YFF0012
DSBGA - 0.625 mm max height
DIE SIZE BALL GRID ARRAY
(0.4) TYP
3
12X ( 0.23)
(0.4) TYP
1
2
A
B
C
SYMM
D
SYMM
LAND PATTERN EXAMPLE
SCALE:30X
0.05 MAX
0.05 MIN
METAL UNDER
SOLDER MASK
(
0.23)
METAL
(
0.23)
SOLDER MASK
OPENING
SOLDER MASK
OPENING
NON-SOLDER MASK
SOLDER MASK
DEFINED
DEFINED
(PREFERRED)
SOLDER MASK DETAILS
NOT TO SCALE
4222191/A 07/2015
NOTES: (continued)
3. Final dimensions may vary due to manufacturing tolerance considerations and also routing constraints. For more information,
see Texas Instruments literature number SNVA009 (www.ti.com/lit/snva009).
www.ti.com
EXAMPLE STENCIL DESIGN
YFF0012
DSBGA - 0.625 mm max height
DIE SIZE BALL GRID ARRAY
(0.4) TYP
(R0.05) TYP
12X ( 0.25)
1
2
3
A
(0.4) TYP
B
SYMM
METAL
TYP
C
D
SYMM
SOLDER PASTE EXAMPLE
BASED ON 0.1 mm THICK STENCIL
SCALE:30X
4222191/A 07/2015
NOTES: (continued)
4. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release.
www.ti.com
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相关型号：
LM3646
1.5A Synchronous Boost Converter with Dual High-Side Current Sources and I2CCompatible Interface
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