LM2758 [TI]
采用 DSBGA 封装的开关电容 LED 闪光灯驱动器;
| 型号： | LM2758 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 采用 DSBGA 封装的开关电容 LED 闪光灯驱动器 开关 驱动 闪光灯 驱动器 |
| 文件： | 总23页 (文件大小：700K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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LM2758
ZHCSF17E –APRIL 2008–REVISED MAY 2016
LM2758 采用 DSBGA 封装的开关电容闪光 LED 驱动器
1 特性
3 说明
1
•
•
•
•
输出电流高达 700mA
LM2758 器件是一款带有稳压电流阱的低噪声、高电流
开关电容集成 DC-DC 转换器。由单节锂离子电池供电
时，该器件最高可驱动 700mA 负载。该器件会根据
LED 正向电压和电流需求主动选择适当增益，从而在
整个输入电压范围内实现效率最大化。
90% 的峰值效率
指示灯、手电筒和闪光灯模式
超时电路可将闪光持续时间限制为 814 毫秒（典型
值）
•
•
•
•
自适应增益（1× 和 1.5×），可实现效率最大化
真正的关断
该器件通过外接一个低功耗电阻设置指示灯、手电筒和
闪光灯三种模式所需的电流。LM2758 内置一个超时电
路。该电路能够在器件因故障长时间处于闪光灯模式时
将其关断，从而保护器件和闪光灯 LED。内置的软启
动电路可在器件启动时限制浪涌电流。
内部软启动，可消除浪涌电流
超小型解决方案尺寸
–
–
无需电感，只需使用 4 个电容和 1 个电阻
2.022mm × 1.527mm × 0.6mm 薄型芯片尺寸
球栅阵列 (DSBGA) 封装
器件信息(1)
器件型号
LM2758
封装
封装尺寸（最大值）
2 应用
DSBGA (12)
2.022mm x 1.527mm
•
•
手机摄像头闪光灯
数码相机闪光灯
(1) 要了解所有可用封装，请参见数据表末尾的可订购产品附录。
典型应用电路
C1
C2
C1-
C2-
CPOUT
C2+
C1+
VIN
2.7 V to 5.5 V
CIN
COUT
+
-
LM2758
EN1
EN2
LED-
PGND SGND
ISET
RSET
Copyright © 2016, Texas Instruments Incorporated
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: SNVS551
LM2758
ZHCSF17E –APRIL 2008–REVISED MAY 2016
www.ti.com.cn
目录
1
2
3
4
5
6
特性.......................................................................... 1
应用.......................................................................... 1
说明.......................................................................... 1
修订历史记录 ........................................................... 2
Pin Configuration and Functions......................... 3
Specifications......................................................... 4
6.1 Absolute Maximum Ratings ..................................... 4
6.2 ESD Ratings.............................................................. 4
6.3 Recommended Operating Conditions....................... 4
6.4 Thermal Information.................................................. 4
6.5 Electrical Characteristics........................................... 5
6.6 Typical Characteristics.............................................. 6
Detailed Description .............................................. 7
7.1 Overview ................................................................... 7
7.2 Functional Block Diagram ......................................... 7
7.3 Feature Description................................................... 7
7.4 Device Functional Modes........................................ 10
8
9
Application and Implementation ........................ 11
8.1 Application Information............................................ 11
8.2 Typical Application ................................................. 11
Power Supply Recommendations...................... 14
9.1 Power Dissipation ................................................... 14
10 Layout................................................................... 15
10.1 Layout Guidelines ................................................. 15
10.2 Layout Example .................................................... 15
10.3 DSBGA Package Assembly and Use ................... 16
11 器件和文档支持 ..................................................... 17
11.1 器件支持................................................................ 17
11.2 文档支持................................................................ 17
11.3 社区资源................................................................ 17
11.4 商标....................................................................... 17
11.5 静电放电警告......................................................... 17
11.6 Glossary................................................................ 17
12 机械、封装和可订购信息....................................... 17
7
4 修订历史记录
注：之前版本的页码可能与当前版本有所不同。
Changes from Revision D (May 2013) to Revision E
Page
•
•
已添加 器件信息以及引脚配置和功能部分，ESD 额定值表，特性 描述，器件功能模式，应用和实施，电源相关建
议，布局，器件和文档支持以及机械、封装和可订购信息部分............................................................................................... 1
Added Thermal Information table with revised RθJA value (from 56°C/W to 93.6°C/W) and additional thermal values. ....... 4
Changes from Revision C (May 2013) to Revision D
Page
•
Changed layout of National Data Sheet to TI format .......................................................................................................... 16
2
Copyright © 2008–2016, Texas Instruments Incorporated
LM2758
www.ti.com.cn
ZHCSF17E –APRIL 2008–REVISED MAY 2016
5 Pin Configuration and Functions
YZR Package
12-Pin DSBGA
Top View
YZR Package
12-Pin DSBGA
Bottom View
PGND LED-
EN2
B3
LED-
EN2
D3
C3
B3
C3
I
SET
+
I
SET
A3
C2
C2
B2
CP
D3
PGND
A3
+
OUT
B2
C2
C2
-
SGND
A2
C1
D2
D2
-
A2
SGND
C1
-
EN1
A1
C2
D1
D1
-
A1
EN1
C2
C1
VIN
B1
+
C1
B1
C1
C1
VIN
+
Pin Functions
PIN
TYPE
DESCRIPTION
NO.
NAME
The EN2 pins is used to select the modes (torch, indicator, flash), as well as to put the part into
shutdown mode.
A1
EN1
Input
Analog and control ground for charge pump. Connect this pin directly to a low impedance
ground plane.
A2
SGND
Ground
LED current programming resistor pin. A resistor connected between this pin, and GND is used
to set torch, flash and indicator currents.
A3
B1
B2
ISET
C1+
Power
Power
Output
Flying capacitor pin — connect a 1-µF ceramic capacitor from C1+ to C1−
Charge pump regulated output. A 2.2-µF ceramic capacitor is required from CPOUT to GND.
Connect flash LED anode to this pin.
CPOUT
The EN1 pin is used to select the modes (torch, indicator, flash), as well as to put the part into
Shutdown mode.
B3
EN2
Input
C1
C2
C3
D1
D2
VIN
C2+
LED−
C2−
C1−
Input
Power
Output
Power
Power
Supply voltage connection
Flying capacitor pins — connect a 1-µF ceramic capacitor from C2+ to C2−.
Regulated current source output. Connect flash LED cathode to this pin.
Flying capacitor pin — connect a 1-µF ceramic capacitor from C2+ to C2−.
Flying capacitor pin — connect a 1-µF ceramic capacitor from C1+ to C1−
Power ground for the charge pump and the current source. Connected the pin directly to a low-
impedance ground plane.
D3
PGND
Ground
Copyright © 2008–2016, Texas Instruments Incorporated
3
LM2758
ZHCSF17E –APRIL 2008–REVISED MAY 2016
www.ti.com.cn
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)(2)(3)
MIN
MAX
UNIT
VIN, CPOUT pins: voltage to GND
EN1, EN2 pins: Voltage to GND
–0.3
6
V
(VIN + 0.3) w/ 6 V
maximum
–0.3
V
Continuous power dissipation
Junction temperature, TJ-MAX
Maximum lead temperature (soldering)
Storage temperature, Tstg
150
°C
°C
See(4)
–65°C
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) If Military/Aerospace specified devices are required, contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
(3) All voltages are with respect to the potential to the GND pin.
(4) For detailed soldering specifications and information, see AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009).
6.2 ESD Ratings
VALUE
±2000
±200
UNIT
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)
Charged-device model (CDM), per JEDEC specification JESD22-C101(2)
V(ESD)
Electrostatic discharge
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.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)(1)
MIN
MAX
5.5
UNIT
Input voltage
2.7
–40
–40
V
Junction temperature, TJ
Ambient temperature, TA
125
85
°C
°C
(2)
(1) All voltages are with respect to the potential at the GND pin.
(2) 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 operation 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).
6.4 Thermal Information
LM2758
THERMAL METRIC(1)
YZR (DSBGA)
12 PINS
93.6
UNIT
RθJA
RθJC(top)
RθJB
ψJT
Junction-to-ambient thermal resistance
°C/W
°C/W
°C/W
°C/W
°C/W
Junction-to-case (top) thermal resistance
Junction-to-board thermal resistance
0.7
16.1
Junction-to-top characterization parameter
Junction-to-board characterization parameter
2.9
ψJB
16.0
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report, SPRA953.
4
Copyright © 2008–2016, Texas Instruments Incorporated
LM2758
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ZHCSF17E –APRIL 2008–REVISED MAY 2016
6.5 Electrical Characteristics
Unless otherwise specified, aspecifications apply to the Figure 8 with VIN = 3.6 V, VEN1 = VIN, VEN2 = 0 V,
C1 = C2 = 1 µF, CIN = COUT = 2.2 µF, RSET = 20 kΩ, TJ = 25°C.(1)(2)(3)
PARAMETER
TEST CONDITIONS
ILED = 500 mA, flash mode
MIN
TYP
MAX
UNIT
ILED
LED current accuracy
500
ILED = 500 mA, flash mode
–40°C ≤ TJ ≤ 125°C
450
550
mA
V
VSET
ISET pin voltage
1.3
7650
1639
ID/ISET
LED current to set current
ratio
Flash mode
Torch mode
ILED-IND
1/32 ×
ILED-
Indicator mode
32-kHZ PWM mode
Indicator current level
mA
mV
TORCH
VGDX
1× to 1.5× gain transition
voltage threshold on VLED
IOUT = 500 mA
300
–
1× mode, IOUT = 0 mA
1.5× mode, IOUT = 0 mA(4)
VIN
4.8
VOUT
Output voltage
V
1.5× mode, IOUT = 0 mA
5.3
–40°C ≤ TJ ≤ 125°C(4)
IOUT = 200 mA, VIN = 3.3 V
0.33
–40°C ≤ TJ ≤ 125°C
1× mode output impedance
ROUT
IOUT = 200 mA, VIN = 3.3 V(5)
IOUT = 500 mA, VIN = 3.3 V(5)
0.53
2.0
Ω
1.5× mode output
impedance
1.5
1.25
FSW
Switching frequency
MHz
mA
–40°C ≤ TJ ≤ 125°C
0.8
1.5
0.8
5
IOUT = 0 mA 1× mode, –40°C ≤ TJ ≤ 125°C
IOUT = 0 mA 1x mode
0.7
4
IQ
Quiescent current
IOUT = 0 mA 1.5× mode
IOUT = 0 mA 1.5× mode, –40°C ≤ TJ ≤ 125°C
Device disabled(6)
Device disabled, –40°C ≤ TJ ≤ 125°C(6)
–40°C ≤ TJ ≤ 125°C, see(7)
See(7)
0.01
814
µA
ISD
Shutdown current
Timeout duration
1
TOUT
msec
640
1.2
1000
0.4
VIH
VIL
Input logic high
Input logic low
Pins: EN1, EN2, –40°C ≤ TJ ≤ 125°C
Pins: EN1, EN2, –40°C ≤ TJ ≤ 125°C
V
V
(1) All voltages are with respect to the potential at the GND pin.
(2) Minimum (MIN) and maximum (MAX) limits are specified by design, test, or statistical analysis. Typical (TYP) numbers are not ensured,
but do represent the most likely norm. Unless otherwise specified, conditions for TTYP specifications are: VIN = 3.6 V and TA = 25°C.
(3) CIN, COUT, C1, C2: Low-ESR surface-mount ceramic capacitors (MLCCs) used in setting electrical characteristics.
(4) Output voltage is internally limited not to exceed maximum specified value.
(5) These table entries are specified by design. These parameters are not ensured by production testing. The temperature limits for test are
(–40°C ≤ TA ≤ +85°C).
(6) The temperature limits for ISD (shutdown current) test are -40°C ≤ TA ≤ +85°C, as in shutdown mode ambient temperature is equal to
junction temperature.
(7) The timeout specifications are calculated values based on the switching frequency spread.
Copyright © 2008–2016, Texas Instruments Incorporated
5
LM2758
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6.6 Typical Characteristics
Unless otherwise specified: TA = 25°C, VIN = 3.6 V, CIN = COUT = 2.2 µF, C1 = C2 = 1 µF. Capacitors are low-ESR multi-layer
ceramic capacitors (MLCCs). Luxeon PWF1 Flash LED.
110
90
70
50
30
10
1.15
1.13
1.11
1.09
1.07
1.05
2.7
3.2
3.7
4.2
(V)
4.7
5.2
2.7
3.2
3.7
4.2
(V)
4.7
5.2
V
V
IN
IN
Figure 1. Efficiency vs VIN
Figure 2. Oscillator Frequency vs VIN
5.000
4.000
3.000
2.000
1.000
0.000
0.04
0.03
0.02
0.01
0.00
EN1 = EN2 = 0V
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
V
(V)
V
(V)
IN
IN
Figure 3. Quiescent Current vs VIN
Figure 4. Shutdown Current vs VIN
800
700
600
500
400
300
200
100
0
1k
900
800
700
600
500
400
300
200
100
0
700 mA
0.0
0.5
1.0
LED- (V)
1.5
10
15
20
25
30
35
V
R
(kW)
SET
Figure 5. ILED vs VLED–
Figure 6. LED Current vs RSET
6
Copyright © 2008–2016, Texas Instruments Incorporated
LM2758
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ZHCSF17E –APRIL 2008–REVISED MAY 2016
7 Detailed Description
7.1 Overview
The LM2758 is an adaptive 1× and 1.5× CMOS charge pump, optimized for driving flash LEDs in camera phones
and other portable applications. It provides a constant current of 500 mA (typical) for flash mode and 107 mA
(typical) for torch mode with RSET = 20 kΩ. These current can change (see Setting LED Currents).
There are four modes of operation for LM2758: the flash mode, torch mode, indicator mode, and shutdown mode
(see Table 1). Torch and flash modes sink a constant DC current while indicator mode operates in pulsating DC
at 1/32 positive duty cycle with same current magnitude as torch mode. The LED is driven from CPOUT and
connected to the current sink. LED drive current mode is programmed by connecting a resistor, RSET, to the
current set pin, ISET. The LM2758 device also controls CPOUT with variable gain (1× or 1.5×) and adjustable
impedance (ROUT) to provide an output voltage that would account for LED forward voltage drop and headroom
for the current sink to drive desired current through LED.
7.2 Functional Block Diagram
LED
C
OUT
= 2.2 µF
CP
OUT
LED-
V
IN
Gain Control
GND
EN1
EN2
Ind.
Torch
Flash
C
IN = 2.2 µF
Flash, Torch
Mode
Control
C1+
Current
Control
1 µF
C1-
1x, 1.5x
Charge Pump
VREF
C2+
1 µF
OSC
C2-
I
SET
R
SET
Copyright © 2016, Texas Instruments Incorporated
7.3 Feature Description
7.3.1 Charge Pump and Gain Transitions
The input to the 1×/1.5× charge pump is connected to the VIN pin, and the loosely regulated output of the charge
pump is connected to the CPOUT pin. In 1× mode, as long as the input voltage is less than 4.7 V, the output
voltage is approximately equal to the input voltage. When input voltage is over 4.7 V the output voltage is
regulated to 4.7 V. In 1.5× mode, the output voltage is always less than or equal to 4.7 V over entire input
voltage range.
The gain of the charge pump is selected depending on the headroom voltage across the current sink of LM2758.
When headroom voltage VLED– (at the LED pin) drops below 300 mV (typical) the charge-pump gain transition
happens from 1× to 1.5× to maintain current regulation across the LED. Once the charge pump transition to a
higher gain, it remains at that gain for as long as the device remains enabled. Shutting down and then re-
enabling the device resets the gain mode to the minimum gain required to maintain the load.
Copyright © 2008–2016, Texas Instruments Incorporated
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ZHCSF17E –APRIL 2008–REVISED MAY 2016
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Feature Description (continued)
7.3.2 Soft Start
The LM2758 contains internal soft-start circuitry to limit inrush currents when the part is enabled. Soft start is
implemented internally with a controlled turnon of the internal voltage reference.
7.3.3 Current Limit Protection
The LM2758 charge pump contains current limit protection circuitry that protects the device during VOUT fault
conditions where excessive current is drawn. Output current is limited to 1.2 A typically.
7.3.4 Flash Time-out Feature
Flash time-out protection circuitry disables the current sinks when the signal on EN1 and EN2 is held high for
more than 814 msec (typical). This prevents the device from self-heating due to the high power dissipation during
flash conditions. During the time-out condition, voltage is still present on CPOUT but the current sinks are shut off,
resulting in no current through the flash LED. When the device goes into a time-out condition, placing a logic low
signal on EN1 and EN2 resets the timeout; a subsequent logic high signal on EN1 or EN2 returns the device to
normal operation.
7.3.5 Setting LED Currents
The current through the LED can be set by connecting an appropriately sized resistor RSET between the ISET pin
of the LM2758 and GND.
The LED current in torch mode is approximately 1639 times greater than the current of ISET, while the LED
current in flash mode is approximately 7650 times of the same ISET current. The feedback loop of an internal
amplifier sets the voltage of the ISET pin to 1.3 V (typical). The statements above are simplified in Equation 1:
ILED = GAINFLASH/TORCH × (1.3 / RSET
)
(1)
The maximum recommended current through LED is 500 mA in torch mode / 700 mA in flash mode.
NOTE
If the ISET for torch mode setting at 500 mA, the flash mode would be over 700 mA
(maximum). See Figure 6. Using the device in conditions where the junction temperature
might rise above the rated maximum requires that the operating ranges and/or conditions
be de-rated. The printed circuit board also must be carefully laid out to account for high
thermal dissipation in the part.
8
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LM2758
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ZHCSF17E –APRIL 2008–REVISED MAY 2016
Feature Description (continued)
7.3.6 Analog Brightness Control
C1
1 µF
C2
1 µF
C1-
C2-
CPOUT
C2+
C1+
VIN
COUT
2.2 µF
CIN
2.2 µF
+
-
LM2758
EN1
EN2
LED-
PGND SGND
ISET
VA
RA
RSET
Copyright © 2016, Texas Instruments Incorporated
Figure 7. Analog Brightness Control
The current through the LED can be varied dynamically by changing the ISET current. Figure 7 shows the circuit.
The current though the LED can be calculated with Equation 2:
VA - 1.3V
1.3V
RSET
ILED = GainTORCH/FLASH
-
RA
(2)
7.3.7 Thermal Protection
Internal thermal protection circuitry disables the LM2758 when the junction temperature exceeds 150°C (typical).
This feature protects the device from being damaged by high die temperatures that might otherwise result from
excessive power dissipation. The device recovers and operates normally when the junction temperature falls
below 140°C (typical). It is important that the board layout provide good thermal conduction to keep the junction
temperature within the specified operating ratings.
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7.4 Device Functional Modes
7.4.1 Modes
There are four modes of operation for LM2758: the flash mode, torch mode, indicator mode and shutdown mode
(see Table 1). Torch and flash modes sink a constant DC current while indicator mode operates in pulsating DC
at 1/32 positive duty cycle with same current magnitude as torch mode.
7.4.2 Logic Control Pins
The LM2758 has two logic pins, EN1 and EN2. There is a 500-kΩ (typical) pulldown resistor connected from EN1
to GND and from EN2 to GND. The operating modes of the part function according to Table 1:
Table 1. EN1 and EN2 Truth Table
EN1
EN2
MODE
Shutdown
Indicator
Torch
0
1
0
1
0
0
1
1
Flash
10
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LM2758
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ZHCSF17E –APRIL 2008–REVISED MAY 2016
8 Application 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.
8.1 Application Information
The LM2758 can drive one flash LED at currents up to 700 mA. The multi-gain charge-pump boost regulator
allows for the use of small value discrete external components.
8.2 Typical Application
C1
C2
C1-
C2-
CPOUT
C2+
C1+
VIN
2.7 V to 5.5 V
CIN
COUT
+
-
LM2758
EN1
EN2
LED-
PGND SGND
ISET
RSET
Copyright © 2016, Texas Instruments Incorporated
Figure 8. LM2758 Typical Application
8.2.1 Design Requirements
For typical switched-capacitor LED-driver applications, use the parameters listed in Table 2.
Table 2. Design Parameters
DESIGN PARAMETER
Minimum input voltage
Maximum output current
EXAMPLE VALUE
2.7 V
700 mA
8.2.2 Detailed Design Procedure
8.2.2.1 Capacitor Selection
The LM2758 device requires 4 external capacitors for proper operation. Surface-mount multi-layer ceramic
capacitors are recommended. These capacitors are small, inexpensive and have very low equivalent series
resistance (ESR < 20 mΩ typical). Tantalum capacitors, OS-CON capacitors, and aluminum electrolytic
capacitors are not recommended for use with the LM2758 due to their high ESR compared to ceramic
capacitors. For most applications, ceramic capacitors with X7R or X5R temperature characteristic are preferred
for use with the LM2758. Ceramic capacitors have tight capacitance tolerance (as good as ±10%) and hold their
value over temperature (X7R: ±15% over –55°C to +125°C; X5R: ±15% over –55°C to +85°C). Capacitors with
Y5V or Z5U temperature characteristic are generally not recommended for use with the LM2758. Capacitors with
these temperature characteristics typically have wide capacitance tolerance (+80%, –20%) and vary significantly
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over temperature (Y5V: 22%, –82% over –30°C to +85°C range; Z5U: 22%, –56% over 10°C to 85°C range).
Under some conditions, a nominal 1 μF Y5V or Z5U capacitor could have a capacitance of only 0.1 μF. Such
detrimental deviation is likely to cause Y5V and Z5U capacitors to fail to meet the minimum capacitance
requirements of the LM2758. The voltage rating of the output capacitor must be 6.3 V or more. For example, a
6.3-V, 0603, 2.2-μF output capacitor (TDK C1608X5R0J225) is acceptable for use with the LM2758, as long as
the capacitance on the output does not fall below a minimum of 1 μF in the intended application. All other
capacitors must have a voltage rating at or above the maximum input voltage of the application and a minimum
capacitance of 1 μF.
Table 3. Suggested Capacitors And Suppliers
MANUFACTURER
PART NUMBER
CASE SIZE
INCH (mm)
TYPE
MANUFACTURER
VOLTAGE RATING
2.2 µF for CIN and COUT
C1608X5R0J225
JMK107BJ225
Ceramic X5R
Ceramic X5R
TDK
6.3 V
6.3 V
0603 (1608)
0603 (1608)
Taiyo-Yuden
1 µF for C1 and C2
C1608X5R0J105
JMK107BJ105M
Ceramic X5R
Ceramic X5R
TDK
6.3 V
6.3 V
0603 (1608)
0603 (1608)
Taiyo-Yuden
8.2.2.2 Power Efficiency
Efficiency of LED drivers is commonly taken to be the ratio of power consumed by the LEDs (PLED) to the power
drawn at the input of the part (PIN). With a 1×/1.5× charge pump, the input current is equal to the charge pump
gain times the output current (total LED current). The efficiency of the LM2758 can be predicted as follows:
PLED = VLED × ILED
PIN = VIN × IIN
(3)
(4)
(5)
(6)
PIN = VIN × (Gain × ILED + IQ)
E = (PLED ÷ PIN)
For a simple approximation, the current consumed by internal circuitry (IQ) can be neglected, and the resulting
efficiency will become:
E = VLED ÷ (VIN × Gain)
(7)
Neglecting IQ results in a slightly higher efficiency prediction, but this impact will be negligible due to the value of
IQ being very low compared to the typical torch and flash current levels (100 mA to 500 mA). It is also worth
noting that efficiency as defined here is in part dependent on LED voltage. Variation in LED voltage does not
affect power consumed by the circuit and typically does not relate to the brightness of the LED. For an advanced
analysis, it is recommended that power consumed by the circuit (VIN × IIN) be evaluated rather than power
efficiency.
12
Copyright © 2008–2016, Texas Instruments Incorporated
LM2758
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ZHCSF17E –APRIL 2008–REVISED MAY 2016
8.2.3 Application Curves
110
2V/DIV
90
GAIN = 1.5x
V
OUT
70
2V/DIV
200 mA/DIV
50
EN1,
EN2
200 mA/DIV
30
I
10
2.7
IN
I
3.2
3.7
4.2
(V)
4.7
5.2
LED
400 µs/DIV
V
IN
VIN = 3.6 V
ILED = 500 mA
Figure 10. Shutdown to Flash Mode
Figure 9. Efficiency vs VIN
2V/DIV
V
OUT
2V/DIV
2V/DIV
GAIN = 1.5x
V
OUT
EN1
2V/DIV
EN2
100 mA/DIV
100 mA/DIV
100 mA/DIV
100 mA/DIV
I
LED
I
IN
I
IN
1 ms/DIV
I
LED
100 µs/DIV
VIN = 3.6 V
EN1 = 0 V
ILED = 108 mA
Gain = 1×
VIN = 3.6 V
EN2 = 0 V
ILED (torch) = 108 mA
Figure 11. Shutdown to Torch Mode
Figure 12. Shutdown to Indicator Mode
2V/DIV
2V/DIV
2V/DIV
EN1
V
OUT
V
OUT
200 mA/DIV
200 mA/DIV
I
100 mA/DIV
LED
I
IN
I
LED
20 mA/DIV
I
IN
200 ms/DIV
10 µS/DIV
EN1 = VIN = 3.6 V
EN2 = 0 V
ILED (torch) = 108 mA
Gain = 1×
EN2 = VIN = 3.6 V
ILED (flash) = 500 mA
Gain = 1.5×
Figure 13. Indicator Mode
Figure 14. Torch to Flash Mode Transition
Copyright © 2008–2016, Texas Instruments Incorporated
13
LM2758
ZHCSF17E –APRIL 2008–REVISED MAY 2016
www.ti.com.cn
2V/DIV
2V/DIV
EN2
V
OUT
200 mA/DIV
200 mA/DIV
I
IN
I
LED
200 ms/DIV
EN1 = VIN = 3.6 V
ILED (flash) = 500 mA
Gain = 1.5×
Figure 15. Indicator to Flash Mode Transition
9 Power Supply Recommendations
The LM2758 is designed to operate from an input voltage supply range from 2.7 V to 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
device, additional bulk capacitance may be required in addition to the ceramic bypass capacitors.
9.1 Power Dissipation
The power dissipation (PDISSIPATION) and junction temperature (TJ) can be approximated with the equations
below. PIN is the power generated by the 1×/1.5× charge pump, PLED is the power consumed by the LEDs, TA is
the ambient temperature, and RθJA is the junction-to-ambient thermal resistance for the 12-pin DSBGA package.
VIN is the input voltage to the LM2758, VLED is the nominal LED forward voltage, and ILED is the programmed
LED current.
PDISSIPATION = PIN – PLED
(8)
(9)
= (Gain × VIN × ILED) − (VLED × ILED
)
TJ = TA + (PDISSIPATION × RJθA
)
(10)
The junction temperature rating takes precedence over the ambient temperature rating. The LM2758 may be
operated outside the ambient temperature rating, so long as the junction temperature of the device does not
exceed the maximum operating rating of 125°C. The maximum ambient temperature rating must be derated in
applications where high power dissipation and/or poor thermal resistance causes the junction temperature to
exceed 125°C.
14
Copyright © 2008–2016, Texas Instruments Incorporated
LM2758
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ZHCSF17E –APRIL 2008–REVISED MAY 2016
10 Layout
10.1 Layout Guidelines
PC board layout is an important part of DC-DC converter design. Poor board layout can disrupt the performance
of a DC-DC converter and surrounding circuitry by contributing to EMI, ground bounce, and resistive voltage loss
in the traces. These can send erroneous signals to the DC-DC converter device, resulting in poor regulation or
instability. Poor layout can also result in re-flow problems leading to poor solder joints between the DSBGA
package and board pads. Poor solder joints can result in erratic or degraded performance.
10.2 Layout Example
GND
EN1
SGND
ISET
EN2
C1+
CPOUT
VIN
C2+
VIN
C2-
LED-
PGND
C1-
GND
GND
Figure 16. LM2758 Layout Example
Copyright © 2008–2016, Texas Instruments Incorporated
15
LM2758
ZHCSF17E –APRIL 2008–REVISED MAY 2016
www.ti.com.cn
10.3 DSBGA Package Assembly and Use
Use of the DSBGA package requires specialized board layout, precision mounting and careful re-flow techniques
as detailed in AN-1112 DSBGA Wafer Level Chip Scale Package (SNVA009). Refer to the section Surface
Mount Assembly Considerations" For best results in assembly, use alignment ordinals on the PC board to
facilitate placement of the device. The pad style used with the DSBGA package must be the NSMD (non-solder
mask defined) typical. This means that the solder-mask opening is larger than the pad size. This prevents a lip
that otherwise forms if the solder mask and pad overlap, from holding the device off the surface of the board and
interfering with mounting. See SNVA009 for specific instructions how to do this. The 12-pin package used for
LM2758 has 300 micron solder balls and requires 10.82 mils pads for mounting on the circuit board. The trace to
each pad should enter the pad with a 90° entry angle to prevent debris from being caught in deep corners.
Initially, the trace to each pad should be 7 mil. wide, for a section approximately 7 mil. long or longer, as a
thermal relief. Then each trace should neck up or down to its optimal width. The important criteria is symmetry.
This ensures the solder bumps on the LM2758 re-flow evenly and that the device solders level to the board. In
particular, special attention must be paid to the pads for bumps C1 and D3, because VIN and GND are typically
connected to large copper planes, thus inadequate thermal relief can result in late or inadequate re-flow of these
bumps.
The DSBGA package is optimized for the smallest possible size in applications with red or infrared opaque
cases. Because the DSBGA package lacks the plastic encapsulation characteristic of larger devices, it is
vulnerable to light. Backside metallization and/or epoxy coating, along with front side shading by the printed
circuit board, reduce this sensitivity. However, the package has exposed die edges. In particular, DSBGA
devices are sensitive to light, in the red and infrared range, shining on the exposed die edges of the package.
16
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LM2758
www.ti.com.cn
ZHCSF17E –APRIL 2008–REVISED MAY 2016
11 器件和文档支持
11.1 器件支持
11.1.1 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.
11.2 文档支持
11.2.1 相关文档
更多信息，请参见以下文档：
AN-1112《DSBGA 晶圆级芯片规模封装》（文献编号：SNVA009）
11.3 社区资源
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.4 商标
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.5 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。
11.6 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 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 © 2008–2016, Texas Instruments Incorporated
17
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)
LM2758TL/NOPB
LM2758TLX/NOPB
ACTIVE
ACTIVE
DSBGA
DSBGA
YZR
YZR
12
12
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
Level-1-260C-UNLIM
-40 to 85
-40 to 85
2758
2758
3000 RoHS & Green
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
9-Aug-2022
TAPE AND REEL INFORMATION
REEL DIMENSIONS
TAPE DIMENSIONS
K0
P1
W
B0
Reel
Diameter
Cavity
A0
A0 Dimension designed to accommodate the component width
B0 Dimension designed to accommodate the component length
K0 Dimension designed to accommodate the component thickness
Overall width of the carrier tape
W
P1 Pitch between successive cavity centers
Reel Width (W1)
QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE
Sprocket Holes
Q1 Q2
Q3 Q4
Q1 Q2
Q3 Q4
User Direction of Feed
Pocket Quadrants
*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)
LM2758TL/NOPB
LM2758TLX/NOPB
DSBGA
DSBGA
YZR
YZR
12
12
250
178.0
178.0
8.4
8.4
1.68
1.68
2.13
2.13
0.76
0.76
4.0
4.0
8.0
8.0
Q1
Q1
3000
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
9-Aug-2022
TAPE AND REEL BOX DIMENSIONS
Width (mm)
H
W
L
*All dimensions are nominal
Device
Package Type Package Drawing Pins
SPQ
Length (mm) Width (mm) Height (mm)
LM2758TL/NOPB
LM2758TLX/NOPB
DSBGA
DSBGA
YZR
YZR
12
12
250
210.0
210.0
185.0
185.0
35.0
35.0
3000
Pack Materials-Page 2
MECHANICAL DATA
YZR0012xxx
0.600±0.075
D
E
TLA12XXX (Rev C)
D: Max = 2.022 mm, Min =1.962 mm
E: Max = 1.527 mm, Min =1.466 mm
4215049/A
12/12
A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994.
B. This drawing is subject to change without notice.
NOTES:
www.ti.com
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