LM2907D14 [TI]
VOLTAGE-FREQUENCY CONVERTER, PDSO14;
| 型号： | LM2907D14 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | VOLTAGE-FREQUENCY CONVERTER, PDSO14 光电二极管 转换器 |
| 文件： | 总7页 (文件大小：102K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LM2907, LM2917
FREQUENCY-TO-VOLTAGE CONVERTERS
SLFS011A – MARCH 1986 – REVISED JULY 1993
LM2907, LM2917 . . . D OR P PACKAGE
(TOP VIEW)
Output Swings to Ground for
Zero-Frequency Input
Only One RC Network Provides Frequency
Doubling for Low Ripple
TACH+
CAP1
GND
IN–
1
2
3
4
8
7
6
5
8-Pin Versions Interface Directly to
Variable-Reluctance Magnetic Pickups
CPO/IN+
E
V
CC
C
Uncommitted Collector and Emitter
Outputs Provide 40-mA Sink or Source
Current to Operate Relays, Solenoids,
Meters, or LEDs
LM2907, LM2917 . . . D OR N PACKAGE
(TOP VIEW)
TACH+
CAP1
CPO
IN+
NC
1
2
3
4
5
6
7
14
13
12
11
10
9
Built-In Hysteresis for Noise Immunity
NC
Linearity Typically ±0.3%
GND
TACH–
IN–
8-Pin Versions Are Fully Protected From
Damage Due to TACH Input Swing Above
E
V
and Below Ground
CC
NC
V
CC
NC
8
C
applications
NC – No internal connection
Over/under speed sensing
Frequency-to-voltage conversion
Speedometers
Breaker-point dwell meters
Hand-held tachometers
Speed governors
AVAILABLE OPTIONS
PACKAGED DEVICES
SMALL PLASTIC PLASTIC
T
A
OUTLINE
(D)
DIP
(N)
DIP
(P)
Cruise controls
Automotive door-lock controls
Clutch controls
L2907D8
L2907D14
L2917D8
L2917D14
—
LM2907P
—
LM2907N
—
–40°C to 85°C
LM2917P
—
Horn controls
LM2917N
Touch or sound switches
description
The LM2907 and LM2917 are monolithic frequency-to-voltage converters. Each device has an output circuit
that activates loads such as relays and lamps when the input frequency reaches or exceeds a selected rate.
The converter (tachometer) section consists of a comparator driving a charge pump and offers frequency
doubling for low ripple, full input protection in 8-pin versions, and an output swing to ground for a zero-frequency
input. The output section consists of an operational amplifier, normally operating as a comparator, that drives
an output transistor with both the collector and emitter floating. The circuit can either sink or source 40 mA of
load current.
Two basic configurations are offered: 8-pin devices and 14-pin devices. Each 8-pin version has a ground-
referenced tachometer input and an internal connection between the tachometer output and the operational
amplifier input. The 8-pin versions are suited to single-speed or single-frequency switching or fully buffered
frequency-to-voltage conversion applications. The more versatile 14-pin versions provide differential
tachometer inputs and uncommitted operational amplifier inputs. The tachometer input can be floated, and the
operational amplifier becomes suitable for active filter conditioning of the tachometer output.
The LM2917 has an active shunt regulator connected across the power leads. The regulator clamps the supply
voltage so that stable frequency-to-voltage and frequency-to-current conversions are possible with any supply
voltage and a suitable resistor.
The LM2907 and LM2917 are designed for operation from –40°C to 85°C.
Copyright 1993, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
LM2907, LM2917
FREQUENCY-TO-VOLTAGE CONVERTERS
SLFS011A – MARCH 1986 – REVISED JULY 1993
functional block diagrams
8
5
5
C
E
10
C
E
7
IN–
–
+
IN–
–
+
1
1
6
4
TACH+
TACH–
TACH+
Charge
Pump
Charge
Pump
11
3
3
4
CAP1 CPO
CPO/IN+
CAP1
9
V
CC
IN +
V
CC
(LM2917 only)
14-PIN VERSIONS
(LM2917 only)
8-PIN VERSIONS
†
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V : LM2907 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 V
CC
Supply current, I : LM2917 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 mA
CC
Collector-to-emitter voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 V
Operational amplifier input voltage range, IN+ and IN– . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to V
CC
Tachometer input voltage range: 8-pin version TACH+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to 28 V
14-pin version TACH+ and TACH– . . . . . . . . . . . . . . . . . . . . . . . . 0 V to V
CC
Continuous total dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Dissipation Rating Table
Operating free-air temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to 85°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C
†
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 recommended operating conditions section of
this specification is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
DISSIPATION RATING TABLE
T
≤ 25°C
DERATING FACTOR
T = 85°C
A
POWER RATING
A
PACKAGE
POWER RATING
ABOVE T = 25°C
A
D (8 pin)
725 mW
5.8 mW/°C
7.6 mW/°C
9.2 mW/°C
8.0 mW/°C
377 mW
D (14 pin)
950 mW
494 mW
N
P
1150 mW
598 mW
1000 mW
520 mW
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
LM2907, LM2917
FREQUENCY-TO-VOLTAGE CONVERTERS
SLFS011A – MARCH 1986 – REVISED JULY 1993
†
electrical characteristics, V
= 12 V (LM2907), V+ = 12 V through 470 Ω (LM2917), T = 25°C
A
CC
converter (tachometer) section
LM2907
TYP
±15
30
LM2917
TYP
±15
30
PARAMETER
TEST CONDITIONS
UNIT
MIN
MAX
MIN
MAX
V
V
Input threshold voltage
V = 250 mV,
f = 1 kHz
f = 1 kHz
f = 1 kHz
±8.5
±40
±8.5
±40
mV
mV
IT
I
Input hysteresis (see Note 1)
V = 250 mV,
I
hys
8-pin versions
V = 250 mV,
5
15
10
1
5
15
10
1
Input offset voltage
(see Note 1)
I
V
IO
mV
14-pin versions
V
= 250 mV, f = 1 kHz
ID
V = ±50 mV
3.5
3.5
I
IB
Input bias current
0.1
0.1
µA
I
High-level output
voltage
V
CAP1
CAP1
V or V = 125 mV
ID
8.3
5
V
OH
OL
I
Low-level output
voltage
V
V or V = – 125 mV
I ID
2.3
1.2
V
CAP1 and CPO at 6 V
CAP1 and CPO at 3.8 V
140
0.9
200
240
0.1
I
O
Output current
CAP1, CPO
CPO
µA
140
0.9
200
240
0.1
CAP1 open,
CPO at 0 V,
See Note 3
Leakage current
µA
Gain constant
1
1.1
1
1.1
Nonlinearity (see Note 2)
f = 1 kHz, 5 kHz, or 10 kHz
0.3
±1
0.3
±1
%
output section
LM2907
TYP
3
LM2917
TYP
PARAMETER
TEST CONDITIONS
UNIT
mV
MIN
MAX
MIN
MAX
10
V = 6 V,
See Note 3
10
I
V
IO
Input offset voltage
V = 3.8 V, See Note 3
3
I
V = 6 V
50
500
I
I
Input bias current
nA
IB
V = 3.8 V
I
50
200
50
500
A
Voltage amplification
200
50
V/mV
mA
V
I
I
Collector output (sink) current
Emitter output (source) current
V
V
= 1 V,
V
V
= 0
= V
40
40
C
C
E
= V
,
–2
CC
–10
0.1
–10
0.1
mA
E
C
CC
E
I
C
I
C
I
C
= 5 mA
0.5
1
0.5
1
V
Collector-emitter saturation voltage
= 20 mA
= 50 mA
V
CE(sat)
1
1.5
1
1.5
†
V+ is the symbol for voltage applied to a series resistor to create a current source.
NOTES: 1. Hysteresis is the algebraic difference V
measurement information test circuit.
– V
IT–
; offset voltage is the difference in magnitudes |V
| – |V
IT+
|. See parameter
IT–
IT+
2. Nonlinearity is defined as the deviation of V at CPO for f = 5 kHz from a straight line defined by the V at 1 kHz and V at 10 kHz,
O
O
O
with C1 = 1000 pF, R1 = 68 Ω, C2 = 0.22 µF.
3. CAP1 must be bypassed with a 0.001-µF capacitor to prevent oscillation for these tests.
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
LM2907, LM2917
FREQUENCY-TO-VOLTAGE CONVERTERS
SLFS011A – MARCH 1986 – REVISED JULY 1993
†
zener regulator (LM2917 only), V+ = 12 V through 470 Ω, T = 25°C
A
PARAMETER
MIN
TYP
7.56
1
MAX
UNIT
V
V
Z
Regulated supply voltage
α
Temperature coefficient of regulated supply voltage
Series resistance
mV/°C
VZ
r
10.5
15
Ω
s
†
V+ is the symbol for voltage applied to a series resistor to create a current source.
total device (LM2907 only), V
= 12 V, T = 25°C
CC
A
PARAMETER
MIN
TYP
MAX
UNIT
I
Supply current
3.8
6
mA
CC
PARAMETER MEASUREMENT INFORMATION
TACH+
Charge
Pump
CAP1
C1
CPO
R1
TEST CIRCUIT
≈ 15 mV
≈ –15 mV
TACH+
CAP1
V
CC
2
V
OH
V
OL
I × R1 (I ≈ 200 µA)
CPO
WAVEFORMS
Figure 1. Test Circuit and Waveforms
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
LM2907, LM2917
FREQUENCY-TO-VOLTAGE CONVERTERS
SLFS011A – MARCH 1986 – REVISED JULY 1993
APPLICATION INFORMATION
The LM2907 and LM2917 frequency-to-voltage converter circuits provide maximum versatility with a minimum
of external parts. The first stage of each device is a differential comparator. The single-input 8-pin versions have
one input grounded so that an input signal must swing above and below GND and exceed the input thresholds
to produce an output. This version is specifically for magnetic variable-reluctance pickups, which typically
provide a single-ended ac output. These single-ended inputs are fully protected against voltage swings to
±28 V, which are easily attained by this type of pickup.
The differential-input 14-pin versions provide the option of setting the input reference level, maintaining
hysteresis around that level to provide excellent noise rejection in any application. The input protection is
removedinthe14-pinversions. Therefore, neitherofthedifferentialinputsshouldexceedthelimitsofthesupply
voltage. An input must not go below GND without a resistance in the lead to limit the current that flows in the
episubstrate diode. The charge-pump circuit that follows the input state produces a dc output voltage
proportional to the input frequency. The charge-pump circuit (see Figures 1 and 2) consists of a timing capacitor
(C1), an output resistor (R1), and an integrating or filter capacitor (C2). When the input changes state (due to
a suitable zero crossing or differential voltage on the input), the timing capacitor is either charged or discharged
linearlywithaconstantcurrentof200µAthroughCAP1betweentwovoltageswhosedifferenceisV /2.Within
CC
one-half cycle of the input frequency or a time equal to 1/2f, the change in charge on C1 is equal to (V /2)C1.
CC
The average amount of current pumped into or out of the capacitor is:
V
Q
T
CC
CAP1 current (average)
C1 •
• 2f
V
• f • C1
CC
2
The output of the charge pump accurately mirrors the CAP1 current into the load resistor (R1) connected to
CPO. If the pulses of current are integrated with a filter capacitor, the output voltage is the average CAP1 current
times R1 and the total equation becomes:
V
V
• f • C1 • R1 • K
CC
O
where K is the gain factor, which is typically one.
The size of C2 is dependent only on the amount of ripple allowable and the required response time.
selection of R1, C1, and C2
To achieve optimum performance, there are some limitations to be considered in the selection of R1 and C1.
The timing capacitor controls the RC time and provides internal compensation for the charge-pump circuit. For
very accurate operation, it should be 100 pF or greater. Smaller values, especially at lower temperatures, can
cause an error current through R1. V /R1 must be less than or equal to the output current at CPO, which is fixed
O
typically at 200 µA. If R1 is too large, it becomes a significant fraction of the output impedance at CPO, which
degrades the linearity. In addition, ripple voltage must be considered when selecting R1. The size of C2 is
directly affected by the size of R1. An expression that describes the ripple content at CPO is:
V
CC
2
C1
C2
C1
200
•
•
•
•
volts peak-to-peak
)
V
(1
V
f
ripple
CC
where:
C1 and C2 are in farads,
is in volts, and
V
CC
f is in hertz.
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
LM2907, LM2917
FREQUENCY-TO-VOLTAGE CONVERTERS
SLFS011A – MARCH 1986 – REVISED JULY 1993
APPLICATION INFORMATION
R1 cannot be chosen independent of ripple because response time or the time it takes V to stabilize at a new
O
level increases as the size of C2 increases. A compromise between ripple, response time, and linearity must
be chosen carefully. As a final consideration, the maximum attainable input frequency is determined by V
,
CC
C1, and I
(current through CAP1).
cap
I
cap
f
hertz
max
C1 • V
CC
where:
I
is typically 200 µA,
cap
C1 is in farads, and
is in volts.
V
CC
zener regulator options (LM2917)
For those applications in which an output voltage or current must be obtained independent of supply voltage
variations, the LM2917 can be used. The most important factor in selecting a dropping resistor for the
unregulated supply is that the frequency-to-voltage converter circuit and the operational amplifier alone require
approximately 3 mA at the voltage level set by the zener diode. At low supply voltages, there must be some
currentflowingintheresistorabovethe3-mAcircuitcurrenttooperatetheregulator. Asanexample, ifthesupply
voltage varies between 9 V and 16 V, a resistance of 470 Ω minimizes the zener voltage variation to typically
160 mV. If the resistance goes under 400 Ω or above 600 Ω, the zener variation quickly rises above 200 mV
for the same input variation.
V
CC
TACH+
Charge
Pump
+
–
CAP1 CAPO/IN+
IN–
R1
E
Emitter/Follower
Output
C1
C2
10 kΩ
Figure 2. Minimum-Component Tachometer
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
IMPORTANT NOTICE
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO
BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 1998, Texas Instruments Incorporated
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