參數(shù)資料
型號(hào): MAX6469UT15BD3
廠(chǎng)商: MAXIM INTEGRATED PRODUCTS INC
元件分類(lèi): 基準(zhǔn)電壓源/電流源
英文描述: 300mA LDO Linear Regulators with Internal Microprocessor Reset Circuit
中文描述: FIXED/ADJUSTABLE POSITIVE LDO REGULATOR, PDSO6
封裝: MO-178AB, SOT-23, 6 PIN
文件頁(yè)數(shù): 10/20頁(yè)
文件大小: 556K
代理商: MAX6469UT15BD3
M
300mA LDO Linear Regulators with Internal
Microprocessor Reset Circuit
10
______________________________________________________________________________________
remotely sense the output voltage of the device. Using
FB with an external NPN transistor, the current drive
capability can be increased according to the following
equation (Figure 2):
I
OUT(TOTAL)
= I
OUT
(
β
+1)
The external NPN pass transistor must meet specifica-
tions for current gain, power dissipation, and collector
current. The beta influences the maximum output cur-
rent the circuit can deliver. The largest guaranteed out-
put current is given by I
LOAD
(max) = 300mA
×
beta
(min). The transistor
s rated power dissipation must
exceed the actual power dissipated in the transistor.
The power dissipated (PD) equals the maximum load
current (I
LOAD
(max)) times the maximum input-to-out-
put voltage differential: PD = I
LOAD
(max)
×
(V
IN
(max) -
V
OUT
). The rated transistor collector current must
exceed the maximum load current.
Reverse Leakage Protection
Reverse OUT to IN Current
An internal circuit monitors the MAX6469
MAX6484
input and output voltages. When the output voltage is
greater than the input voltage, the internal IN-to-OUT
pass transistor and parasitic diode turn off. An external
voltage applied to OUT does not reverse charge a bat-
tery or power source applied to IN (the leakage path
from OUT to IN is 0.01μA typ). When the output voltage
exceeds the input voltage, OUT powers the device and
shutdown must be logic high (greater than 0.7
V
OUT
).
RESET
asserts until IN exceeds OUT and OUT is above
the specified V
THOUT
threshold (based on the selected
or adjusted regulator OUT nominal voltage).
Reverse OUT to Ground Current
The MAX6469
MAX6484 maintain a low OUT-to-GND
reverse-current flow when the IN power source is
removed. When IN floats (input battery removed) and
SHDN
is pulled up to V
OUT
(by an external diode), the
OUT-to-GND current through the LDO is 40μA (typ). The
regulator output can be held up with an external super
capacitor or backup battery at OUT until the IN battery is
replaced. The
RESET
output is asserted while the IN bat-
tery is removed to place the system in a low-power
mode. Volatile memory content is maintained until the
super capacitor or battery voltage drops below RAM
standby specifications.
RESET
deasserts when the IN
battery has been replaced and OUT exceeds the
desired reset threshold. For nonrechargeable backup
battery applications, place a reverse diode between
OUT and the backup battery (to prevent battery charg-
ing). The external diode does not affect the regulator
s
dropout voltage because it is not between the LDO out-
put and the processor/memory Vcc supply. The diode
can be replaced with a current-limiting resistor for
rechargeable backup battery applications.
Current Limit
The MAX6469
MAX6484 include an internal current-
limit circuit that monitors and controls the pass transis-
tor
s gate voltage, limiting the output current to 450mA
(min). The output can be shorted to ground indefinitely
without damaging the part.
Thermal Shutdown
When the junction temperature (T
J
) exceeds +180
°
C
(typ), the thermal sensor signals the shutdown logic,
turning off the pass transistor and allowing the IC to
Figure 3. Battery Backup
MAX6469
MAX6484
μ
P
MEMORY
OUT
IN
SHDN
3.0V
LITHIUM
REMOVABLE
LITHIUM ION OR
3-CELL
ALKALINE
REMOVABLE
LITHIUM ION OR
3-CELL
ALKALINE
MAX6469
MAX6484
μ
P
MEMORY
OUT
IN
SHDN
SUPERCAP
3.3
μ
F
3.3
μ
F
Figure 2. High-Current, External Transistor Application
MAX6475/MAX6476
MAX6483/MAX6484
R
PULLUP
0.1
μ
F
3.3
μ
F
330
μ
P
5.0V
OUT
FB
RESET
GND
IN
V
CC
= 3.3V
1A TOTAL CURRENT
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX6469UT15BD3-T 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓(最大值):307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20
MAX6469UT15BD4 制造商:Maxim Integrated Products 功能描述:300MA LDO LINEAR REGULATORS WITH IN - Rail/Tube
MAX6469UT15BD4-T 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓(最大值):307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20
MAX6469UT16AD1 制造商:Maxim Integrated Products 功能描述:300MA LDO LINEAR REGULATORS WITH IN - Rail/Tube
MAX6469UT16AD1-T 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓(最大值):307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20