參數(shù)資料
型號(hào)： ADP1108AN-12
廠商： ANALOG DEVICES INC
元件分類： 穩(wěn)壓器
英文描述： Circular Connector; No. of Contacts:128; Series:LJT06R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:25; Circular Contact Gender:Pin; Circular Shell Style:Straight Plug; Insert Arrangement:25-1
中文描述： 1.5 A SWITCHING REGULATOR, 25 kHz SWITCHING FREQ-MAX, PDIP8
封裝： PLASTIC, DIP-8
文件頁(yè)數(shù)： 11/12頁(yè)
文件大小： 234K
代理商： ADP1108AN-12
ADP1108
–11–
REV. 0
PROGRAMMING T HE GAIN BLOCK
T he gain block of the ADP1108 can be used as a low battery de-
tector, error amplifier or linear post regulator. T he gain block
consists of an op amp with PNP inputs and an open-collector
NPN output. T he inverting input is internally connected to the
ADP1108’s 1.245 V reference, while the noninverting input is
available at the SET Pin. T he NPN output transistor will sink
about 300
μ
A.
Figure 24a shows the gain block configured as a low-battery
monitor. Resistors R1 and R2 should be set to high values to re-
duce quiescent current, but not so high that bias current in the
SET input causes large errors. A value of 33 k
V
for R2 is a good
compromise.
T he value for R1 is then calculated from the formula:
R
1
=
V
LOBATT
±1.245
V
1.245
V
R
2
where V
LOBAT T
is the desired low battery trip point. Since the
gain block output is an open-collector NPN, a pull-up resistor
should be connected to the positive logic power supply.
2
V
IN
+5V
GND
ADP1108
R1
AO
SET
5
R2
33k
47k
TO
PROCESSOR
6
1.245V
REF
7
V
BAT
V
LB
–1.245V
37.7μA
V
LB
= BATTERY TRIP POINT
R1 =
Figure 24a. Setting the Low Battery Detector Trip Point
T he circuit of Figure 24a may produce multiple pulses when ap-
proaching the trip point, due to noise coupled into the SET in-
put. T o prevent multiple interrupts to the digital logic, hysteresis
can be added to the circuit (Figure 24b). Resistor R3, with a
value of 1 M
V
to 10 M
V
, provides the hysteresis. T he addition
of R3 will change the trip point slightly, so the new value for R1
will be:
V
LOBATT
±1.245
V
1.245
V
R
2
R
1
=
±
V
L
±1.245
V
R
L
+
R
3
where V
L
is the logic power supply voltage, R
L
is the pull-up
resistor and R3 creates the hysteresis.
2
V
IN
+5V
GND
ADP1108
R1
AO
SET
5
R2
33k
47k
TO
PROCESSOR
6
1.245V
REF
7
V
BAT
R3
1.6M
Figure 24b. Adding Hysteresis to the Low Battery Detector
L1*
100
m
H
5V
OUT
200mA AT 6.5V
500mA AT 8V
100
0.22
ZETEX
ZTX749
*L1 = COILTRONICS CTX100-4
100
5
8
2
I
LIM
V
IN
SW1
SW2
4
GND
ADP1108-5
D1
1N5818
C2
V
IN
6.5V TO 20V
3
C1
220
1
SENSE
Figure 25. 6.5 V to 5 V Step-Down Converter
I
LIM
V
IN
SW1
ADP1108-5
L1*
300μH
220
SENSE
SW2
4
GND
5
1
2
3
8
*L1 = COILTRONICS CTX300-4
–5V OUTPUT
150mA
+
C2
V
IN
6.5V TO 20V
MBRS130T3
+
330μF
Figure 26. Positive to –5 V Converter
相關(guān)PDF資料
PDF描述
ADP1108AN-33 Circular Connector; No. of Contacts:128; Series:LJT06R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:25; Circular Contact Gender:Socket; Circular Shell Style:Straight Plug; Insert Arrangement:25-1
ADP1108AN-5 Circular Connector; No. of Contacts:30; Series:LJT06R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:25; Circular Contact Gender:Socket; Circular Shell Style:Straight Plug; Insert Arrangement:25-20
ADP1108AR Circular Connector; No. of Contacts:24; Series:LJT06R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:25; Circular Contact Gender:Socket; Circular Shell Style:Straight Plug; Insert Arrangement:25-24
ADP1108AR-12 Circular Connector; No. of Contacts:128; Series:LJT06R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:25; Circular Contact Gender:Pin; Circular Shell Style:Straight Plug; Insert Arrangement:25-35
ADP1108AR-33 Circular Connector; No. of Contacts:128; Series:LJT06R; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:25; Circular Contact Gender:Pin; Circular Shell Style:Straight Plug; Insert Arrangement:25-35
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ADP1108AN-3.3 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Analog Devices 功能描述:IC MICROPROCESSOR DC/DC CONVERTER ((NS))
ADP1108AN-33 制造商:AD 制造商全稱:Analog Devices 功能描述:Micropower DC-DC Converter Adjustable and Fixed 3.3 V, 5 V, 12 V
ADP1108AN-5 制造商:AD 制造商全稱:Analog Devices 功能描述:Micropower DC-DC Converter Adjustable and Fixed 3.3 V, 5 V, 12 V
ADP1108AR 制造商:Rochester Electronics LLC 功能描述:- Bulk
ADP1108AR-12 制造商:Rochester Electronics LLC 功能描述:- Bulk
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