LM2907M-8EP [NSC]
IC VOLTAGE-FREQUENCY CONVERTER, PDSO8, 0.150 INCH, PLASTIC, SOP-8, Analog Special Function Converter;
| 型号： | LM2907M-8EP |
| 厂家： | 
National Semiconductor |
| 描述： | IC VOLTAGE-FREQUENCY CONVERTER, PDSO8, 0.150 INCH, PLASTIC, SOP-8, Analog Special Function Converter 光电二极管 转换器 |
| 文件： | 总21页 (文件大小：715K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
June 2004
LM2907EP/LM2917EP
Enhanced Plastic Frequency to Voltage Converter
General Description
Features
n Ground referenced tachometer input interfaces directly
with variable reluctance magnetic pickups
n Op amp/comparator has floating transistor output
n 50 mA sink or source to operate relays, solenoids,
meters, or LEDs
The LM2907EP, LP2917EP series are monolithic frequency
to voltage converters with a high gain op amp/comparator
designed to operate a relay, lamp, or other load when the
input frequency reaches or exceeds a selected rate. The
tachometer uses a charge pump technique and offers fre-
quency doubling for low ripple, full input protection in two
versions (LM2907-8EP, LM2917-8EP) and its output swings
to ground for a zero frequency input.
n Frequency doubling for low ripple
n Tachometer has built-in hysteresis with either differential
input or ground referenced input
The op amp/comparator is fully compatible with the tachom-
eter and has a floating transistor as its output. This feature
allows either a ground or supply referred load of up to 50 mA.
The collector may be taken above VCC up to a maximum VCE
of 28V.
n Built-in zener on LM2917EP
n
0.3% linearity typical
n Ground referenced tachometer is fully protected from
damage due to swings above VCC and below ground
The two basic configurations offered include an 8-pin device
with a ground referenced tachometer input and an internal
connection between the tachometer output and the op amp
non-inverting input. This version is well suited for single
speed or frequency switching or fully buffered frequency to
voltage conversion applications.
Advantages
n Output swings to ground for zero frequency input
n Easy to use; VOUT = fIN x VCC x R1 x C1
n Only one RC network provides frequency doubling
n Zener regulator on chip allows accurate and stable
frequency to voltage or current conversion (LM2917EP)
The more versatile configurations provide differential ta-
chometer input and uncommitted op amp inputs. With this
version the tachometer input may be floated and the op amp
becomes suitable for active filter conditioning of the tachom-
eter output.
Applications
n Selected Military Applications
n Selected Avionics Applications
Both of these configurations are available with an active
shunt regulator connected across the power leads. The
regulator clamps the supply such that stable frequency to
voltage and frequency to current operations are possible
with any supply voltage and a suitable resistor.
ENHANCED PLASTIC
•
•
•
•
•
•
Extended Temperature Performance of −40˚C to +85˚C
Baseline Control - Single Fab & Assembly Site
Process Change Notification (PCN)
Qualification & Reliability Data
Solder (PbSn) Lead Finish is standard
Enhanced Diminishing Manufacturing Sources (DMS)
Support
Ordering Information
PART NUMBER
LM2907MX-8EP
LM2917MXEP
(Notes 1, 2)
VIN PART NUMBER
V62/04635-01
V62/04635-02
TBD
NS PACKAGE NUMBER (Note 3)
M08A
M14A
TBD
Note 1: For the following (Enhanced Plastic) versions, check for availablility: LM2907M-8EP, LM2907MEP, LM2907MXEP, LM2907N-8EP, LM2907NEP
and LM2917M-8EP, LM2917MX-8EP, LM2917MEP, LM2917N-8EP, LM2917NEP. Parts listed with an "X" are provided in Tape & Reel and parts without
an "X" are in Rails.
Note 2: FOR ADDITIONAL ORDERING AND PRODUCT INFORMATION, PLEASE VISIT THE ENHANCED PLASTIC WEB SITE AT: www.national.com/
mil
Note 3: Refer to package details under Physical Dimensions
© 2004 National Semiconductor Corporation
DS200906
www.national.com
Block and Connection Diagrams Dual-In-Line and Small Outline Packages, Top Views
20090601
LM2907-8
20090602
See NS Package Number M08A or N08E
LM2917-8
See NS Package Number M08A or N08E
20090603
20090604
LM2907
See NS Package Number M14A or N14A
LM2917
See NS Package Number M14A or N14A
www.national.com
2
Absolute Maximum Ratings (Note 4)
Op Amp/Comparator
0.0V to +28V
Power Dissipation (Note 4)
LM2907-8EP, LM2917-8EP
LM2907-14EP, LM2917-14EP
Operating Temperature Range
Storage Temperature Range
Soldering Information
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
1200 mW
1580 mW
Supply Voltage
28V
28V
−40˚C to +85˚C
−65˚C to +150˚C
Collector Voltage
Differential Input Voltage
Tachometer
28V
28V
Dual-In-Line Package
Op Amp/Comparator
Input Voltage Range
Tachometer
Soldering (10 seconds)
Small Outline Package
260˚C
Vapor Phase (60 seconds)
Infrared (15 seconds)
215˚C
220˚C
LM2907-8EP, LM2917-8EP
LM2907EP, LM2917EP
28V
0.0V to +28V
Electrical Characteristics VCC = 12 VDC, TA = 25˚C, see test circuit
Symbol
Parameter
Conditions
Min
Typ
Max
Units
TACHOMETER
@
Input Thresholds
VIN = 250 mVp-p 1 kHz (Note 5)
10
25
30
40
mV
mV
@
VIN = 250 mVp-p 1 kHz (Note 5)
Hysteresis
@
VIN = 250 mVp-p 1 kHz (Note 5)
Offset Voltage
LM2907EP/LM2917EP
LM2907-8EP/LM2917-8EP
Input Bias Current
Pin 2
3.5
5
10
15
1
mV
mV
µA
V
VIN
=
50 mVDC
0.1
8.3
2.3
180
VOH
VOL
I2, I3
I3
VIN = +125 mVDC (Note 6)
VIN = −125 mVDC (Note 6)
V2 = V3 = 6.0V (Note 7)
I2 = 0, V3 = 0
Pin 2
V
Output Current
Leakage Current
Gain Constant
Linearity
140
240
0.1
µA
µA
K
(Note 6)
0.9
1.0
0.3
1.1
fIN = 1 kHz, 5 kHz, 10 kHz (Note 8)
−1.0
+1.0
%
OP/AMP COMPARATOR
VOS
VIN = 6.0V
VIN = 6.0V
3
10
mV
nA
V
IBIAS
50
500
Input Common-Mode Voltage
0
V
CC−1.5V
Voltage Gain
200
50
V/mV
mA
mA
V
Output Sink Current
Output Source Current
Saturation Voltage
VC = 1.0
40
VE = VCC −2.0
ISINK = 5 mA
ISINK = 20 mA
ISINK = 50 mA
10
0.1
0.5
1.0
1.5
V
1.0
V
ZENER REGULATOR
Regulator Voltage
Series Resistance
Temperature Stability
Total Supply Current
RDROP = 470Ω
7.56
10.5
+1
V
Ω
15
6
mV/˚C
mA
3.8
Note 4: For operation in ambient temperatures above 25˚C, the device must be derated based on a 150˚C maximum junction temperature and a thermal resistance
of 101˚C/W junction to ambient for LM2907-8EP and LM2917-8EP, and 79˚C/W junction to ambient for LM2907-14EP and LM2917-14EP.
Note 5: Hysteresis is the sum +V − (−V ), offset voltage is their difference. See test circuit.
TH
TH
3
1
4
Note 6: V
is equal to
⁄4
x V
− 1 V , V is equal to
⁄
x V
− 1 V therefore V
− V = V /2. The difference, V
− V , and the mirror gain, I /I ,
OH OL 2 3
OH
CC
BE
OL
CC
BE
OH
OL
CC
are the two factors that cause the tachometer gain constant to vary from 1.0.
Note 7: Be sure when choosing the time constant R1 x C1 that R1 is such that the maximum anticipated output voltage at pin 3 can be reached with I x R1. The
3
maximum value for R1 is limited by the output resistance of pin 3 which is greater than 10 MΩ typically.
@
@
@
10 kHz. C1 = 1000 pF,
OUT
Note 8: Nonlinearity is defined as the deviation of V
(
pin 3) for f = 5 kHz from a straight line defined by the V
IN
1 kHz and V
OUT
OUT
R1 = 68k and C2 = 0.22 mFd.
3
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Test Circuit and Waveform
20090606
Tachometer Input Threshold Measurement
20090607
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4
Typical Performance Characteristics
Zener Voltage vs
Temperature
Total Supply Current
20090640
20090641
Normalized Tachometer
Output vs Temperature
Normalized Tachometer
Output vs Temperature
20090643
20090642
Tachometer Currents I2
and I3 vs Supply Voltage
Tachometer Currents I2
and I3 vs Temperature
20090644
20090645
5
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Typical Performance Characteristics (Continued)
Tachometer Linearity
vs Temperature
Tachometer Linearity
vs Temperature
20090647
20090646
Tachometer Input Hysteresis
vs Temperature
Tachometer Linearity vs R1
20090649
20090648
Op Amp Output Transistor
Characteristics
Op Amp Output Transistor
Characteristics
20090651
20090650
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6
CHOOSING R1 AND C1
Applications Information
There are some limitations on the choice of R1 and C1 which
should be considered for optimum performance. The timing
capacitor also provides internal compensation for the charge
pump and should be kept larger than 500 pF for very accu-
rate operation. Smaller values can cause an error current on
R1, especially at low temperatures. Several considerations
must be met when choosing R1. The output current at pin 3
is internally fixed and therefore VO/R1 must be less than or
equal to this value. If R1 is too large, it can become a
significant fraction of the output impedance at pin 3 which
degrades linearity. Also output ripple voltage must be con-
sidered and the size of C2 is affected by R1. An expression
that describes the ripple content on pin 3 for a single R1C2
combination is:
The LM2907EP series of tachometer circuits is designed for
minimum external part count applications and maximum ver-
satility. In order to fully exploit its features and advantages
let’s examine its theory of operation. The first stage of op-
eration is a differential amplifier driving a positive feedback
flip-flop circuit. The input threshold voltage is the amount of
differential input voltage at which the output of this stage
changes state. Two options (LM2907-8EP, LM2917-8EP)
have one input internally grounded so that an input signal
must swing above and below ground and exceed the input
thresholds to produce an output. This is offered specifically
for magnetic variable reluctance pickups which typically pro-
vide a single-ended ac output. This single input is also fully
protected against voltage swings to 28V, which are easily
attained with these types of pickups.
The differential input options (LM2907EP, LM2917EP) give
the user the option of setting his own input switching level
and still have the hysteresis around that level for excellent
noise rejection in any application. Of course in order to allow
the inputs to attain common-mode voltages above ground,
input protection is removed and neither input should be
taken outside the limits of the supply voltage being used. It is
very important that an input not go below ground without
some resistance in its lead to limit the current that will then
flow in the epi-substrate diode.
It appears R1 can be chosen independent of ripple, however
response time, or the time it takes VOUT to stabilize at a new
voltage increases as the size of C2 increases, so a compro-
mise between ripple, response time, and linearity must be
chosen carefully.
As a final consideration, the maximum attainable input fre-
quency is determined by VCC, C1 and I2:
Following the input stage is the charge pump where the input
frequency is converted to a dc voltage. To do this requires
one timing capacitor, one output resistor, and an integrating
or filter capacitor. When the input stage changes state (due
to a suitable zero crossing or differential voltage on the input)
the timing capacitor is either charged or discharged linearly
between two voltages whose difference is VCC/2. Then in
one half cycle of the input frequency or a time equal to 1/2 fIN
the change in charge on the timing capacitor is equal to
VCC/2 x C1. The average amount of current pumped into or
out of the capacitor then is:
USING ZENER REGULATED OPTIONS (LM2917EP)
For those applications where an output voltage or current
must be obtained independent of supply voltage variations,
the LM2917EP is offered. The most important consideration
in choosing a dropping resistor from the unregulated supply
to the device is that the tachometer and op amp circuitry
alone require about 3 mA at the voltage level provided by the
zener. At low supply voltages there must be some current
flowing in the resistor above the 3 mA circuit current to
operate the regulator. As an example, if the raw supply
varies from 9V to 16V, a resistance of 470Ω will minimize the
zener voltage variation to 160 mV. If the resistance goes
under 400Ω or over 600Ω the zener variation quickly rises
above 200 mV for the same input variation.
The output circuit mirrors this current very accurately into the
load resistor R1, connected to ground, such that if the pulses
of current are integrated with a filter capacitor, then VO = ic x
R1, and the total conversion equation becomes:
VO = VCC x fIN x C1 x R1 x K
Where K is the gain constant—typically 1.0.
The size of C2 is dependent only on the amount of ripple
voltage allowable and the required response time.
7
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Typical Applications
Minimum Component Tachometer
20090608
20090609
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8
Typical Applications (Continued)
Zener Regulated Frequency to Voltage Converter
20090610
Breaker Point Dwell Meter
20090611
9
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Typical Applications (Continued)
Voltage Driven Meter Indicating Engine RPM
@
VO = 6V 400 Hz or 6000 ERPM (8 Cylinder Engine)
20090612
Current Driven Meter Indicating Engine RPM
@
IO = 10 mA 300 Hz or 6000 ERPM (6 Cylinder Engine)
20090613
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10
Typical Applications (Continued)
Capacitance Meter
VOUT = 1V–10V for CX = 0.01 to 0.1 mFd
(R = 111k)
20090614
Two-Wire Remote Speed Switch
20090615
11
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Typical Applications (Continued)
100 Cycle Delay Switch
20090616
Variable Reluctance Magnetic Pickup Buffer Circuits
20090639
20090617
Precision two-shot output frequency
equals twice input frequency.
Pulse height = V
ZENER
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12
Typical Applications (Continued)
Finger Touch or Contact Switch
20090619
20090618
Flashing LED Indicates Overspeed
20090620
Flashing begins when f ≥ 100 Hz.
IN
Flash rate increases with input frequency
increase beyond trip point.
13
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Typical Applications (Continued)
Frequency to Voltage Converter with 2 Pole Butterworth Filter to Reduce Ripple
20090621
Overspeed Latch
20090623
20090622
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14
Typical Applications (Continued)
Some Frequency Switch Applications May Require Hysteresis in the
Comparator Function Which can be Implemented in Several Ways:
20090624
20090625
20090626
20090627
20090628
15
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Typical Applications (Continued)
Changing the Output Voltage for an Input Frequency of Zero
20090630
20090629
Changing Tachometer Gain Curve or Clamping the Minimum Output Voltage
20090632
20090631
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16
Anti-Skid Circuit Functions
“Select-Low” Circuit
20090634
V
is proportional to the lower of the two input wheel speeds.
OUT
20090633
“Select-High” Circuit
20090636
V
is proportional to the higher of the two input wheel speeds.
OUT
20090635
“Select-Average” Circuit
20090637
17
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Equivalent Schematic Diagram
20090638
*This connection made on LM2907-8EP and LM2917-8EP only.
**This connection made on LM2917EP and LM2917-8EP only.
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18
Physical Dimensions inches (millimeters) unless otherwise noted
8-Lead (0.150" Wide) Molded Small Outline Package, JEDEC
NS Package Number M08A
14-Lead Molded SO Package
NS Package Number M14A
19
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Molded Dual-In-Line Package (N)
NS Package Number N08E
Molded Dual-In-Line Package (N)
NS Package Number N14A
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20
Notes
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
BANNED SUBSTANCE COMPLIANCE
National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products
Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification
(CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2.
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