參數(shù)資料
型號： UC3874
廠商： Texas Instruments, Inc.
英文描述： High Efficiency, Synchronous, Step-down (Buck) Controllers
中文描述： 高效率，同步，降壓（降壓）控制器
文件頁數(shù)： 4/10頁
文件大小： 350K
代理商： UC3874
4
UC1874-1,-2
UC2874-1,-2
UC3874-1,-2
ELECTRICAL CHARACTERISTICS:
Unless otherwise stated these specifications apply for T
A
= –55°C to +125°C for
UC1874; T
A
= –25°C to +85°C for UC2874; 0°C to +70°C for UC3874; VCC = 12V, Ct = 680pF, C
CAP
= 1 F; C
BOOT
= 0.1 F;
T
A
= T
J
.
PARAMETER
TEST CONDITIONS
Sleep/Soft start/Bootstrap Section (continued)
Bootstrap Regulation Voltage
UCX874-2, Low Driver ON
UCX874-1, Low Driver ON
Bootstrap Refresh Voltage
UCX874-2, V
CAOUT
> V
CT
PEAK
UCX874-1, V
CAOUT
> V
CT
PEAK
High Side Driver Output Section
Output High Voltage
I
OUT
= –50mA, Boot = 23V
Output Low Voltage
I
OUT
= 50mA
I
OUT
= 10mA
Output Low (UVLO)
I
OUT
= 50mA, VCC = 0V
Output Rise Time
C
OUT
= 1nF
Output Fall Time
C
OUT
= 1nF
Low Side Driver Output Section
Output High Voltage
I
OUT
= –50mA, V
CAP
= 11V
Output Low Voltage
I
OUT
= 50mA
I
OUT
= 10mA
Output Low (UVLO)
I
OUT
= 50mA, VCC = 0V
Output Rise/Fall Time
C
LOAD
= 1nF
Output Fall Time
C
OUT
= 1nF
X10 Amplifier Section
Gain
V
ISNS
±
V
ISNS
= 20mV to 80mV
Slew Rate Rising
T
A
= 25°C
Slew Rate Falling
T
A
= 25°C
Input Resistance
T
A
= 25°C
MIN
TYP
MAX
UNITS
9.5
6
7
2.7
10.2
7.5
8
3.5
12.5
9
9
4
V
V
V
V
21
22.2
1
300
0.9
40
30
V
V
2.2
500
1.5
160
100
mV
V
ns
ns
8.8
9.5
1
300
0.9
40
30
V
V
2.2
500
1.5
160
100
mV
V
ns
ns
9.2
1
2
60
9.8
1.4
3.5
100
10.4
V/V
V/ s
V/ s
k
165
PIN DESCRIPTIONS
BOOT:
This pin provides the high side rail for the
HDRIVE output.
An external capacitor (C
BST
) is
connected between this pin and the drain of the external
low side MOSFET.
When the low side MOSFET is
conducting Cbst is charged to 11V via an external diode
tied to CAP. When the low side MOSFET turns off and
the high side MOSFET turns on, the Cbst bootstraps
itself up with the source of high side MOSFET, ultimately
providing a 10V Vgs for the upper MOSFET. Since this
10V is referenced to the source of the high side
N-channel MOSFET, the actual voltage on BOOT and
HDRIVE is approximately 10V above VCC while the high
side MOSFET is conducting. The voltage on BOOT is
continuously
monitored
during
conditions when the duty cycle equals approximately
100% to insure that a sufficient gate drive level is being
supplied by the UC3874. If the voltage on BOOT falls
below 8V (UC3874-2) or 3.5V (UC3874-1), the IC forces
low
input
voltage
the low side driver to cycle itself on for the few cycles
required to replenish C
BST
. In this way, virtual 100% duty
cycle operation is provided.
CA-:
This is the inverting input to the current amplifier.
Connect a series resistor and capacitor between this pin
and CAOUT to set the current loop compensation. An in-
put resistor between this pin and ISOUT provides the in-
ductor current sense signal to the amplifier and also
sets the high frequency gain of the amplifier. The com-
mon mode operating range for this input is between GND
and 4V. The normal range during operation is between
2V and 3V.
CAOUT:
This is the output of the wide bandwidth current
amplifier and one of the inputs to the PWM duty cycle
comparator. The output signal generated by this amplifier
commands the PWM to force the correct duty cycle to
maintain output voltage in regulation. The output can
swing from 0.1V to 4V.
相關(guān)PDF資料
PDF描述
UC3874Q-1 High Efficiency, Synchronous, Step-down Buck Controllers
UC3874Q-2 High Efficiency, Synchronous, Step-down Buck Controllers
UC2874 High Efficiency, Synchronous, Step-down (Buck) Controllers
UC2874J-1 High Efficiency, Synchronous, Step-down Buck Controllers
UC3874J-1 High Efficiency, Synchronous, Step-down Buck Controllers
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
UC3874DW-1 功能描述:DC/DC 開關(guān)控制器 Hi Eff Synch Step down Buck Cntrlr RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK
UC3874DW-1G4 功能描述:DC/DC 開關(guān)控制器 Hi Eff Synch Step down Buck Cntrlr RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK
UC3874DW-2 功能描述:DC/DC 開關(guān)控制器 Hi Eff Synch Step down Buck Cntrlr RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK
UC3874DW-2G4 功能描述:DC/DC 開關(guān)控制器 Hi Eff Synch Step down Buck Cntrlr RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK
UC3874DWTR-1 功能描述:DC/DC 開關(guān)控制器 Hi Eff Synch Step down Buck Cntrlr RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK
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