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參數(shù)資料
| 型號： | LM5110-2SD |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 外設及接口 |
| 英文描述： | Dual 5A Compound Gate Driver with Negative Output Voltage Capability |
| 中文描述： | 5 A 2 CHANNEL, BUF OR INV BASED PRPHL DRVR, QCC10 |
| 封裝： | LLP-10 |
| 文件頁數(shù)： | 10/13頁 |
| 文件大?。?/td> | 269K |
| 代理商： | LM5110-2SD |
Thermal Performance
(Continued)
The schematic above shows a conceptual diagram of the
LM5110 output and MOSFET load. Q1 and Q2 are the
switches within the gate driver. R
G
is the gate resistance of
the external MOSFET, and C
IN
is the equivalent gate capaci-
tance of the MOSFET. The gate resistance Rg is usually very
small and losses in it can be neglected. The equivalent gate
capacitance is a difficult parameter to measure since it is the
combination of C
(gate to source capacitance) and C
(gate to drain capacitance). Both of these MOSFET capaci-
tances are not constants and vary with the gate and drain
voltage. The better way of quantifying gate capacitance is
the total gate charge Q
G
in coloumbs. Q
combines the
charge required by C
GS
and C
GD
for a given gate drive
voltage V
GATE
.
Assuming negligible gate resistance, the total power dissi-
pated in the MOSFET driver due to gate charge is approxi-
mated by
P
DRIVER
= V
GATE
x Q
G
x F
SW
Where
F
SW
= switching frequency of the MOSFET.
As an example, consider the MOSFET MTD6N15 whose
gate charge specified as 30 nC for V
GATE
= 12V.
The power dissipation in the driver due to charging and
discharging of MOSFET gate capacitances at switching fre-
quency of 300 kHz and V
GATE
of 12V is equal to
P
DRIVER
= 12V x 30 nC x 300 kHz = 0.108W.
If both channels of the LM5110 are operating at equal fre-
quency with equivalent loads, the total losses will be twice as
this value which is 0.216W.
In addition to the above gate charge power dissipation, -
transient power is dissipated in the driver during output
transitions. When either output of the LM5110 changes state,
current will flow from V
to V
for a very brief interval of
time through the output totem-pole N and P channel
MOSFETs. The final component of power dissipation in the
driver is the power associated with the quiescent bias cur-
rent consumed by the driver input stage and Under-voltage
lockout sections.
Characterization of the LM5110 provides accurate estimates
of the transient and quiescent power dissipation compo-
nents. At 300 kHz switching frequency and 30 nC load used
in the example, the transient power will be 8 mW. The 1 mA
nominal quiescent current and 12V V
GATE
supply produce a
12 mW typical quiescent power.
Therefore the total power dissipation
P
D
= 0.216 + 0.008 + 0.012 = 0.236W.
We know that the junction temperature is given by
T
J
= P
D
x
θ
JA
+ T
A
Or the rise in temperature is given by
T
RISE
= T
J
T
A
= P
D
x
θ
JA
For SOIC-8 package
θ
is estimated as 170C/W for the
conditions of natural convection.
Therefore T
RISE
is equal to
T
RISE
= 0.236 x 170 = 40.1C
For LLP-10 package, the integrated circuit die is attached to
leadframe die pad which is soldered directly to the printed
circuit board. This substantially decreases the junction to
ambient thermal resistance (
θ
).
θ
as low as 40C/W is
achievable with the LLP10 package. The resulting T
for
the dual driver example above is thereby reduced to just 9.5
degrees.
CONTINUOUS CURRENT RATING OF LM5110
The LM5110 can deliver pulsed source/sink currents of 3A
and 5A to capacitive loads. In applications requiring continu-
ous load current (resistive or inductive loads), package
power dissipation, limits the LM5110 current capability far
below the 5A sink/3A source capability. Rated continuous
current can be estimated both when sourcing current to or
sinking current from the load. For example when sinking, the
maximum sink current can be calculated as
where R
DS
(on) is the on resistance of lower MOSFET in the
output stage of LM5110.
Consider T
J
(max) of 125C and
θ
JA
of 170C/W for an SO-8
package under the condition of natural convection and no air
flow. If the ambient temperature (T
A
) is 60C, and the R
D-
20079207
FIGURE 2.
L
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相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM5110-2SDX | Dual 5A Compound Gate Driver with Negative Output Voltage Capability |
| LM5110-3M | Dual 5A Compound Gate Driver with Negative Output Voltage Capability |
| LM5110-1MX | MC 1,5/16-ST-3,5 |
| LM5110-1SD | MC 1,5/17-ST-3,5 |
| LM5110-1SDX | MC 1,5/18-ST-3,5 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM5110-2SD/NOPB | 功能描述:功率驅(qū)動器IC RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| LM5110-2SDX | 功能描述:功率驅(qū)動器IC RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| LM5110-2SDX/NOPB | 功能描述:功率驅(qū)動器IC RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| LM5110-3M | 功能描述:功率驅(qū)動器IC RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| LM5110-3M/HALF | 制造商:Texas Instruments 功能描述:DRIVER GATE DUAL 5A COMPOUND 5110 |
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