MAX978 [MAXIM]

Single/Dual/Quad, SOT23, Single-Supply, High-Speed, Low-Power Comparators; 单/双/四路, SOT23封装,单电源,高速,低功耗比较器
MAX978
型号: MAX978
厂家: MAXIM INTEGRATED PRODUCTS    MAXIM INTEGRATED PRODUCTS
描述:

Single/Dual/Quad, SOT23, Single-Supply, High-Speed, Low-Power Comparators
单/双/四路, SOT23封装,单电源,高速,低功耗比较器

比较器
文件: 总8页 (文件大小:122K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
19-1299; Rev 1; 1/98  
S in g le /Du a l/Qu a d , S OT2 3 , S in g le -S u p p ly,  
Hig h -S p e e d , Lo w -P o w e r Co m p a ra t o rs  
67/MAX98  
________________Ge n e ra l De s c rip t io n  
____________________________Fe a t u re s  
Single-Supply Operation Down to 2.7V  
20ns Propagation Delay  
The MAX976/MAX978/MAX998 dual/quad/single, high-  
s p e e d , low-p owe r c omp a ra tors a re op timize d for  
+3V/+5V single-supply applications. They achieve a  
20ns propagation delay while consuming only 225µA  
supply current per comparator. The MAX998 features a  
low-power shutdown mode that places the output in a  
high-impedance state and reduces supply current to  
1nA.  
225µA Supply Current  
1nA Shutdown Supply Current  
Rail-to-Rail Outputs  
Ground-Sensing Inputs  
The MAX976/MAX978/MAX998 inputs have a common-  
mode voltage range that extends 200mV below ground.  
Their outputs are capable of Rail-to-Rail® operation  
without external pull-up circuitry, making these devices  
ideal for interface with CMOS/TTL logic. All inputs and  
outputs can tolerate a continuous short-circuit fault con-  
dition to either rail. The comparators’ internal hysteresis  
ensures clean output switching, even with slow-moving  
input signals.  
Internal Hysteresis Ensures Clean Switching  
Available in Space-Saving Packages:  
SOT23-6 (MAX998)  
µMAX (MAX976)  
QSOP-16 (MAX978)  
For space-critical applications, the single MAX998 is  
available in a 6-pin SOT23 package, the dual MAX976  
is available in an 8-pin µMAX package, and the quad  
MAX978 is available in a 16-pin QSOP package.  
_______________Ord e rin g In fo rm a t io n  
SOT  
PART  
TEMP. RANGE PIN-PACKAGE  
TOP MARK  
MAX976ESA -40°C to +85°C 8 SO  
________________________Ap p lic a t io n s  
Battery-Powered Systems  
Threshold Detectors/Discriminators  
3V Systems  
MAX976EUA -40°C to +85°C 8 µMAX  
MAX978ESE  
-40°C to +85°C 16 Narrow SO  
-40°C to +85°C 16 QSOP  
MAX978EEE  
MAX998ESA -40°C to +85°C 8 SO  
IR Receivers  
MAX998EUT-T -40°C to +85°C 6 SOT23-6  
AAAO  
Digital Line Receivers  
___________Typ ic a l Op e ra t in g Circ u it  
__________________P in Co n fig u ra t io n s  
V
CC  
TOP VIEW  
V
CC  
MAX998  
OUT  
GND  
IN+  
1
2
3
6
5
4
V
CC  
0.1µF  
V
CC  
OUT  
R
D
SHDN  
IN-  
GND  
SHDN  
+
-
MAX998  
V
CC  
R1  
R2  
V
CC  
SOT23-6  
IR RECEIVER  
Pin Configurations continued at end of data sheet  
Rail-to-Rail is a registered trademark of Nippon Motorola Ltd.  
________________________________________________________________ Maxim Integrated Products  
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.  
For small orders, phone 408-737-7600 ext. 3468.  
S in g le /Du a l/Qu a d , S OT2 3 , S in g le -S u p p ly,  
Hig h -S p e e d , Lo w -P o w e r Co m p a ra t o rs  
ABSOLUTE MAXIMUM RATINGS  
Supply Voltage (V ).............................................................+6V  
SHDN (MAX998).........................................................-0.3V to 6V  
8-Pin SO (derate 5.88mW/°C above +70°C).................471mW  
16-Pin Narrow SO (derate 8.70mW/°C above +70°C) ..696mW  
16-Pin QSOP (derate 8.33mW/°C above +70°C)..........667mW  
Operating Temperature Range ..........................-40°C to +85°C  
Storage Temperature Range .............................-65°C to +160°C  
Lead Temperature (soldering, 10sec) .............................+300°C  
CC  
All Other Pins ..............................................-0.3V to (V + 0.3V)  
CC  
Duration of Output Short Circuit to GND or V ........Continuous  
CC  
Continuous Power Dissipation (T = +70°C)  
A
6-Pin SOT23-6 (derate 7.1mW/°C above +70°C) .........571mW  
8-Pin µMAX (derate 4.10mW/°C above +70°C) ............330mW  
Stresses beyond those listed under Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional  
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to  
absolute maximum rating conditions for extended periods may affect device reliability.  
ELECTRICAL CHARACTERISTICS  
(V = +2.7V to +5.5V, V = 0V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)  
CC  
CM  
A
A
PARAMETER  
Supply Voltage Range  
SYMBOL  
CONDITIONS  
Inferred from PSRR test  
MIN  
TYP  
MAX  
5.5  
UNITS  
V
CC  
2.7  
V
V
= 5.5V  
= 2.7V  
300  
225  
1
650  
CC  
Supply Current per Comparator  
I
µA  
CC  
V
CC  
Shutdown Supply Current  
I
SD  
500  
nA  
dB  
V
MAX998 only, SHDN = GND  
Power-Supply Rejection Ratio  
Common-Mode Voltage Range  
Common-Mode Rejection Ratio  
PSRR  
2.7V < V < 5.5V  
CC  
63  
-0.2  
66  
100  
V
CMR  
(Note 2)  
V
CC  
- 1.2  
CMRR  
-0.2V V (V - 1.2V)  
95  
dB  
CM  
CC  
T
= +25°C  
0.2  
±2  
±3  
A
67/MAX98  
Input Offset Voltage  
V
V
= 5V (Note 3)  
= 5V (Note 4)  
mV  
OS  
CC  
T
A
= T to T  
MIN MAX  
MAX976EUA, MAX998EUT  
All others  
0.3  
0.5  
1.5  
1.5  
75  
±5  
0.1  
0.1  
74  
90  
3
5
mV  
Input-Referred Hysteresis  
V
HYS  
V
CC  
4
Input Bias Current  
I
300  
±100  
0.4  
0.4  
nA  
nA  
V
B
Input Offset Current  
I
OS  
OUT Output Voltage High  
OUT Output Voltage Low  
V
OH  
I
= 2mA, V  
- V  
CC OH  
SOURCE  
V
OL  
I
= 2mA  
V
SINK  
Sinking  
OUT Short-Circuit Current  
I
SH  
V
CC  
= 5.5V  
mA  
Sourcing  
Input Capacitance  
C
pF  
V
IN  
V
MAX998 only  
MAX998 only  
0.65 x V  
CC  
SHDN Input Voltage High  
SHDN Input Voltage Low  
IH  
V
0.2 x V  
V
IL  
CC  
MAX998 only, SHDN = GND,  
= 0V to V  
OUT Leakage Current  
SHDN Input Current  
Propagation Delay  
I
1
200  
200  
nA  
nA  
ns  
OUT  
V
OUT  
CC  
I
t
MAX998 only  
1
28  
20  
2
SHDN  
Overdrive = 5mV  
Overdrive = 50mV  
C
V
CC  
=10pF,  
= 5V (Note 5)  
LOAD  
t
PD  
SKEW  
40  
Propagation-Delay Skew  
C
=10pF (Note 6)  
ns  
LOAD  
Propagation-Delay Matching  
Between Channels  
t  
MAX976/MAX978 only  
=10pF  
1
ns  
PD  
Output Rise/Fall Time  
Shutdown Delay Time  
t /t  
R
C
LOAD  
1.6  
5
ns  
µs  
F
t
MAX998 only, V = 5V, I = 10% of typical  
CC CC  
SD  
2
_______________________________________________________________________________________  
S in g le /Du a l/Qu a d , S OT2 3 , S in g le -S u p p ly,  
Hig h -S p e e d , Lo w -P o w e r Co m p a ra t o rs  
67/MAX98  
ELECTRICAL CHARACTERISTICS (continued)  
(V = +2.7V to +5.5V, V = 0V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)  
CC  
CM  
A
A
PARAMETER  
SYMBOL  
CONDITIONS  
MAX998 only, V = 5V, I = 90% of typical  
MIN  
TYP  
15  
MAX  
UNITS  
µs  
CC  
CC  
Wake-Up from Shutdown  
Power-Up Delay  
t
t
EN  
(Note 7)  
V
CC  
= 0V to 5V step, output valid  
3
µs  
PU  
Note 1: The MAX998EUT specifications are 100% tested at T = +25°C. Limits over the extended temperature range are guaran-  
A
teed by design, not production tested.  
Note 2: Inferred from CMRR test. Either input can be driven to the absolute maximum limit without false output inversion, as long as  
the other input is within the common-mode voltage range.  
Note 3: V is defined as the mean of trip points. The trip points are the extremities of the differential input voltage required to make  
OS  
the comparator output change state (Figure 1).  
Note 4: The difference between the upper and lower trip points is equal to the width of the input-referred hysteresis zone (Figure 1).  
Note 5: Propagation Delay is guaranteed by design. For low overdrive conditions, V  
(Figure 1) is added to the overdrive.  
TRIP  
Note 6: Propagation-Delay Skew is the difference between the positive-going and the negative-going propagation delay.  
Note 7: For design purposes, the t can be as high as 60µs.  
EN  
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s  
(V = +5V, V = 0V, T = +25°C, unless otherwise noted.)  
CC  
CM  
A
SHORT-CIRCUIT OUTPUT CURRENT  
vs. TEMPERATURE  
SUPPLY CURRENT PER COMPARATOR  
vs. TEMPERATURE  
OUTPUT LOW VOLTAGE vs.  
OUTPUT SINK CURRENT  
110  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
1.6  
1.4  
1.2  
375  
V
CC  
= 5.5V, SOURCING  
V
CC  
= 5.5V,  
V
OUT  
= HIGH  
325  
275  
225  
175  
125  
V
V
OUT  
= 2.7V,  
= HIGH  
CC  
1.0  
0.8  
0.6  
0.4  
V
CC  
= 5.5V, SINKING  
V
CC  
= 2.7V  
V
CC  
= 2.7V, SOURCING  
V
V
OUT  
= 5.5V,  
= LOW  
CC  
V
CC  
= 5.5V  
0.2  
0
V
CC  
= 2.7V,  
V
CC  
= 2.7V, SINKING  
V
OUT  
= LOW  
-60 -40 -20  
0
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
0.1  
1
10  
100  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
OUTPUT CURRENT (mA)  
PROPAGATION DELAY  
vs. TEMPERATURE  
OUTPUT HIGH VOLTAGE vs.  
OUTPUT SOURCE CURRENT  
PROPAGATION DELAY  
vs. CAPACITIVE LOAD  
27  
26  
25  
24  
23  
22  
21  
20  
19  
18  
17  
6
5
4
3
2
1
0
40  
35  
30  
25  
20  
15  
10  
V
C
LOAD  
= 50mV  
= 15pF  
OD  
V
CC  
= 5.5V  
V = 50mV  
OD  
V
= 2.7V  
CC  
V
CC  
= 2.7V  
V
CC  
= 5.5V  
0.1  
1
10  
100  
-60 -40 -20  
0
20 40 60 80 100  
10  
100  
1000  
OUTPUT CURRENT (mA)  
TEMPERATURE (°C)  
CAPACITIVE LOAD (pF)  
_______________________________________________________________________________________  
3
S in g le /Du a l/Qu a d , S OT2 3 , S in g le -S u p p ly,  
Hig h -S p e e d , Lo w -P o w e r Co m p a ra t o rs  
______________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )  
(V = +5V, V = 0V, T = +25°C, unless otherwise noted.)  
CC  
CM  
A
INPUT BIAS CURRENT  
vs. TEMPERATURE  
PROPAGATION DELAY  
vs. INPUT OVERDRIVE  
TRIP POINTS AND OFFSET VOLTAGE  
vs. TEMPERATURE  
2.0  
1.5  
1.0  
0.5  
0
90  
80  
70  
100  
90  
80  
70  
60  
50  
40  
C
LOAD  
= 15pF  
V
TRIP+  
60  
50  
V
CC  
= 5.5V  
V
OS  
40  
30  
20  
10  
-0.5  
-1.0  
-1.5  
-2.0  
V
TRIP-  
V
= 2.7V  
0
CC  
0
1
10  
INPUT OVERDRIVE (mV)  
100  
-60 -40 -20  
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
INPUT BIAS CURRENT vs.  
INPUT COMMON-MODE VOLTAGE  
PROPAGATION DELAY  
PROPAGATION DELAY  
(t = 3V)  
(t  
V
= 3V)  
V
PD+, CC  
PD-, CC  
MAX976 TOC11  
MAX976 TOC12  
100  
10  
1
V
C
LOAD  
= 50mV  
= 15pF  
OD  
67/MAX98  
V
CC  
= 2.7V  
V = 5.5V  
CC  
V
V
IN+  
IN+  
50mV/div  
50mV/div  
0.1  
V
1V/div  
V
1V/div  
OUT  
OUT  
C
V
OD  
= 15pF  
= 50mV  
LOAD  
0.01  
-1  
0
1
2
3
4
5
6
10ns/div  
10ns/div  
INPUT COMMON-MODE VOLTAGE (V)  
PROPAGATION DELAY  
PROPAGATION DELAY  
(t  
V
= 5V)  
10MHz RESPONSE  
PD+, CC  
(t  
V
= 5V)  
PD-, CC  
MAX976 TOC13  
MAX976 TOC14  
MAX976 TOC15  
V
OD  
= 50mV  
C
LOAD  
= 15pF  
INPUT  
50mV/div  
V
OS  
V
IN+  
V
IN+  
50mV/div  
50mV/div  
V
CC  
OUTPUT  
2V/div  
V
2V/div  
OUT  
V
2V/div  
GND  
OUT  
V
OD  
= 50mV  
C
LOAD  
= 15pF  
10ns/div  
10ns/div  
20ns/div  
4
_______________________________________________________________________________________  
S in g le /Du a l/Qu a d , S OT2 3 , S in g le -S u p p ly,  
Hig h -S p e e d , Lo w -P o w e r Co m p a ra t o rs  
67/MAX98  
______________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )  
(V = +5V, V = 0V, T = +25°C, unless otherwise noted.)  
CC  
CM  
A
SHUTDOWN DELAY TIME  
WAKE-UP FROM SHUTDOWN  
MAX976 TOC17  
MAX976 TOC16  
V
IN+  
> V  
IN-  
V > V  
IN+ IN-  
SHDN  
2V/div  
SHDN  
2V/div  
V
OUT  
V
OUT  
2V/div  
2V/div  
200ns/div  
5µs/div  
______________________________________________________________P in De s c rip t io n  
PIN  
MAX976  
MAX978  
MAX998  
NAME  
FUNCTION  
SO/µMAX SO/QSOP SOT23-6  
SO  
3
1, 3  
2, 4  
5
1, 3, 5, 7  
2, 4, 6, 8  
9, 13  
3
4
2
IN_+  
IN_-  
Comparator Noninverting Input  
2
Comparator Inverting Input  
Ground  
4
GND  
10, 11,  
14, 15  
6, 7  
1
6
OUT_  
Comparator Output  
8
12, 16  
6
7
V
Supply Voltage, +2.7V to +5.5V  
CC  
1, 5  
N.C.  
No Connection. Not internally connected.  
Shutdown Input. Drive low for shutdown mode. Drive high or con-  
nect to V for normal operation.  
CC  
5
8
SHDN  
Either input can be driven to the Absolute Maximum  
Ratings limit without false output inversion, as long as  
the other input is within the Common-Mode Voltage  
Range. Their push/pull output structure is capable of  
rail-to-rail operation without external pull-up circuitry,  
ma king the s e d e vic e s id e a l for inte rfa c ing with  
CMOS/TTL logic. All inputs and outputs can tolerate a  
continuous short-circuit fault condition to either supply.  
The comparators internal hysteresis ensures clean out-  
put switching, even with slow-moving input signals.  
__________________De t a ile d De s c rip t io n  
The MAX976/MAX978/MAX998 dual/quad/single com-  
parators operate from a single +2.7V to +5.5V supply.  
They achieve a 20ns propagation delay while consum-  
ing only 225µA of supply current per comparator. The  
MAX998 features a low-power shutdown mode that  
p la c e s the outp ut in a hig h-imp e d a nc e s ta te a nd  
re d uc e s s up p ly c urre nt to 1nA. Ac tiva te s hutd own  
mode by driving SHDN low.  
The MAX976/MAX978/MAX998 comparator inputs have  
a common-mode voltage range of -0.2V to (V - 1.2V).  
CC  
_______________________________________________________________________________________  
5
S in g le /Du a l/Qu a d , S OT2 3 , S in g le -S u p p ly,  
Hig h -S p e e d , Lo w -P o w e r Co m p a ra t o rs  
affecting comparator operation. Likewise, do not three-  
Hys t e re s is  
High-speed comparators can oscillate in the linear  
operating region because of noise or undesired para-  
sitic feedback. This tends to occur when the voltage on  
one input is equal to or very close to the voltage on the  
other input. The MAX976/MAX978/MAX998 have inter-  
nal hysteresis to counter parasitic effects and noise.  
The hysteresis in a comparator creates two trip points:  
one for the rising input voltage and one for the falling  
input voltage (Figure 1). The difference between the trip  
points is the hysteresis. When the comparator input  
voltages are equal, the hysteresis effectively causes  
one comparator input voltage to move quickly past the  
other, taking the input out of the region where oscilla-  
tion occurs.  
state SHDN. Due to the output leakage currents of  
three-state devices and the small internal current for  
SHDN, three-stating this pin could also result in indeter-  
minate logic levels.  
The maximum input voltage for SHDN is 6V, referred to  
GND, and is not limited by V . This allows the use of  
CC  
5V logic to drive SHDN while V  
operates at a lower  
volta g e , s uc h a s 3V. The log ic thre s hold limits for  
CC  
SHDN a re p rop ortiona l to V  
(s e e Ele c tric a l  
CC  
Characteristics).  
_____________Ap p lic a t io n s In fo rm a t io n  
Circ u it La yo u t a n d Byp a s s in g  
The MAX976/MAX978/MAX998 have a high-gain band-  
width and require careful board layout. We recommend  
the following design guidelines:  
Figure 1 illustrates the case where IN- has a fixed volt-  
a g e a p p lie d a nd IN+ is va rie d . If the inp uts we re  
reversed, the figure would be the same, except with an  
inverted output.  
1) Use a printed circuit board with an unbroken, low-  
inductance ground plane. Surface-mount compo-  
nents are recommended.  
In p u t -S t a g e Circ u it ry  
The MAX976/MAX978/MAX998 input common-mode  
2) Pla c e a d e c oup ling c a p a c itor (a 0.1µF c e ra mic  
voltage range is from -0.2V to (V - 1.2V). The voltage  
CC  
c a p a c itor is a g ood c hoic e ) b e twe e n V  
ground as close to the pins as possible.  
a nd  
CC  
range for each comparator input extends to both V  
CC  
and GND. The output remains in the correct logic state  
while one or both of the inputs are within the common-  
mode range. If both input levels are out of the common-  
mode range, input-stage current saturation occurs, and  
the output becomes unpredictable.  
67/MAX98  
3) Keep lead lengths short on the inputs and outputs  
to avoid unwanted parasitic feedback around the  
comparators.  
4) Solder the devices directly to the printed circuit  
board instead of using a socket.  
S h u t d o w n Mo d e  
The MAX998 features a low-power shutdown mode,  
which is activated by forcing SHDN low. Shutdown  
mode reduces the supply current to 1nA (typical), dis-  
ables the comparator, and places the output in a high-  
imp e d a nc e s ta te . Drive SHDN hig h to e na b le the  
comparator. Do not leave SHDN unconnected. Since it  
is a high-impedance input, leaving SHDN unconnected  
could result in indeterminate logic levels, adversely  
5) Minimize input impedance.  
6) For slowly varying inputs, use a small capacitor  
(~1000pF) across the inputs to improve stability.  
Ad d it io n a l Hys t e re s is  
Ge ne ra te a d d itiona l hys te re s is with thre e re s is tors  
using positive feedback, as shown in Figure 2. This  
p os itive fe e d b a c k me thod s lows the hys te re s is  
response time. Calculate resistor values as follows:  
1) Select R3. The leakage current of IN+ is typically  
75nA, so the current through R3 should be at least  
1.0µA to minimize errors caused by leakage current.  
V
HYST  
V
TRIP+  
The current through R3 at the trip point is (V  
-
REF  
V
+ V  
TRIP-  
TRIP+  
V
=
OS  
V
IN+  
V ) / R3. Consider the two possible output states  
OUT  
2
V
TRIP-  
V = 0  
IN-  
when solving for R3. The two formulas are:  
R3 = V / 1.0µA  
REF  
or  
R3 = (V - V ) / 1.0µA  
V
OH  
COMPARATOR  
OUTPUT  
CC  
REF  
V
OL  
Use the smaller of the two resulting resistor values.  
For example, if V = 1.2V and V = 5.0V, the two  
REF  
CC  
resistor values are 1.2Mand 3.8M. Choose a  
standard value for R3 of 1.2M.  
Figure 1. Input and Output Waveforms, Noninverting Input  
Varied  
6
_______________________________________________________________________________________  
S in g le /Du a l/Qu a d , S OT2 3 , S in g le -S u p p ly,  
Hig h -S p e e d , Lo w -P o w e r Co m p a ra t o rs  
67/MAX98  
Win d o w Co m p a ra t o r  
V
CC  
R3  
The MAX976 is ideal for making a window detector  
(undervoltage/overvoltage detector). The schematic  
shown in Figure 3 uses a MAX6120 reference and com-  
ponent values selected for a 2.0V undervoltage thresh-  
old and a 2.5V overvoltage threshold. Choose different  
thresholds by changing the values of R1, R2, and R3.  
OUTA provides an active-low undervoltage indication,  
and OUTB gives an active-low overvoltage indication.  
ANDing the two outp uts p rovid e s a n a c tive -hig h,  
power-good signal. The design procedure is as follows:  
R1  
0.1µF  
V
IN  
V
CC  
OUT  
R2  
GND  
MAX976  
MAX978  
MAX998  
V
REF  
1) Select R1. The leakage current into INB- is normally  
75nA, so the current through R1 should exceed  
1.0µA for the thresholds to be accurate. R1 values in  
the 50kto 100krange are typical.  
Figure 2. Additional Hysteresis  
2) Choose the hysteresis band required (V ). For this  
HB  
example, choose 100mV.  
2) Choose the overvoltage threshold (V ) when V  
OTH IN  
is rising, and calculate R2 and R3 with the following  
formula:  
3) Calculate R1. R1 = R3 x (V / V ). Plugging in the  
HB  
CC  
values for this example,  
R
= R2 + R3 = R1 x [V  
/ (V  
+ V ) - 1]  
R1 = 1.2Mx (100mV / 5.0V) = 24kΩ  
SUM  
OTH  
REF H  
where V = 1/2V  
.
4) Choos e the trip p oint for V ris ing . This is the  
IN  
HYST  
H
threshold voltage at which the comparator switches  
3) Choose the undervoltage threshold (V  
) when V  
IN  
UTH  
from low to high as V rises above the trip point. In  
IN  
is falling, and calculate R2 with the following formula:  
this example, choose 3.0V.  
5) Calculate R2 as follows:  
R2 = (R1 + R ) x [(V - V ) / V ] - R1  
SUM  
REF  
H
UTH  
where V = 1/2V  
.
H
HYST  
1
4) Calculate R3 with the following formula:  
R3 = (R ) - R2  
R2 =  
V
1
1
THR  
x R1  
SUM  
V
R1  
R3  
REF  
5) Verify the resistor values. The equations are as follows:  
= (V + V ) x (R1 + R2 + R3) / R1  
1
V
OTH  
REF  
H
R2 =  
= 16.2kΩ  
3.0V  
1.2 x 24kΩ  
1
1
V
UTH  
= (V  
- V ) x (R1 + R2 + R3) / (R1 + R2)  
REF H  
24kΩ  
1.2M  
V
CC  
R3  
82.1k, 1%  
Choose a standard value for R2 of 16k.  
6) Verify the trip voltage and hysteresis as follows:  
1
2
0.1µF  
V
IN  
8
1/2  
UNDERVOLTAGE  
R2  
1
1
1
24.9k,  
1%  
MAX976  
7
V
rising : V  
= V  
x R1 x  
+
+
IN  
THR  
REF  
5
V
CC  
R1  
R2  
R3  
1
R1 x V  
POWER GOOD  
CC  
V
falling : V  
= V  
IN  
THF  
THR  
R3  
3
4
2
MAX6120  
3
Hysteresis = V  
V  
THF  
THR  
1/2  
6
OVERVOLTAGE  
MAX976  
IR Re c e ive r  
The Typical Operating Circuit shows an application using  
the MAX998 as an infrared receiver. The infrared photo-  
diode creates a current relative to the amount of infrared  
R1  
100k,  
1%  
light present. This current creates a voltage across R .  
D
When this voltage level crosses the voltage applied by the  
voltage divider to the inverting input, the output transitions.  
Figure 3. Window Comparator  
_______________________________________________________________________________________  
7
S in g le /Du a l/Qu a d , S OT2 3 , S in g le -S u p p ly,  
Hig h -S p e e d , Lo w -P o w e r Co m p a ra t o rs  
______________________________________________P in Co n fig u ra t io n s (c o n t in u e d )  
TOP VIEW  
MAX978  
MAX976  
MAX998  
INA+  
INA-  
INB+  
INB-  
INC+  
INC-  
IND+  
IND-  
1
2
3
4
5
6
7
8
16 V  
CC  
+
-
15 OUTA  
14 OUTB  
13 GND  
INA+  
INA-  
INB+  
INB-  
1
2
3
4
8
7
6
5
V
CC  
N.C.  
IN-  
1
2
3
4
8
7
6
5
SHDN  
+
-
+
-
OUTA  
OUTB  
GND  
V
CC  
+
-
-
+
IN+  
OUT  
N.C.  
12  
V
CC  
+
-
GND  
11 OUTC  
10 OUTD  
+
-
SO/µMAX  
SO  
9
GND  
SO/QSOP  
___________________Ch ip In fo rm a t io n  
TRANSISTOR COUNT: 415 (MAX976)  
830 (MAX978)  
300 (MAX998)  
67/MAX98  
________________________________________________________P a c k a g e In fo rm a t io n  
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are  
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.  
8 _____________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 4 0 8 -7 3 7 -7 6 0 0  
© 1998 Maxim Integrated Products  
Printed USA  
is a registered trademark of Maxim Integrated Products.  

相关型号:

MAX9787

2.2W Stereo Audio Power Amplifier with Analog Volume Control
MAXIM

MAX9787ETI

2.2W Stereo Audio Power Amplifier with Analog Volume Control
MAXIM

MAX9787ETI+

Audio Amplifier, 2 Channel(s), BICMOS, 5 X 5 MM, 0.80 MM HEIGHT, LEAD FREE, MO-220WHHD-1, TQFN-28
MAXIM

MAX9787_V01

2.2W Stereo Audio Power Amplifier with Analog Volume Control
MAXIM

MAX9788

14VP-P,Class G Ceramic Speaker Driver
MAXIM

MAX9788EBP+T

14VP-P,Class G Ceramic Speaker Driver
MAXIM

MAX9788EBP+T*

14VP-P,Class G Ceramic Speaker Driver
MAXIM

MAX9788ETI+

14VP-P,Class G Ceramic Speaker Driver
MAXIM

MAX9788ETI+C6F

Audio Amplifier, 2.4W, 1 Channel(s), 1 Func, BICMOS, 4 X 4 MM, 0.80 MM HEIGHT, ROHS COMPLIANT, TQFN-28
MAXIM

MAX9788EVKIT

Delivers Greater than 14VP-P into a Ceramic Speaker
MAXIM

MAX9788EVKIT+

Delivers Greater than 14VP-P into a Ceramic Speaker
MAXIM

MAX9788EWP+TG45

14VP-P,Class G Ceramic Speaker Driver
MAXIM