2008-08-11T17:26:00.000-07:00

NTE995 & NTE995M
Integrated Circuit
Frequency–to–Voltage Converter
Description:
The NTE995 (14–Lead DIP) and NTE995M (8–Lead DIP) 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 frequency doubling for low ripple, full input protection, and its output swings to GND
for a zero frequency input.
Advantages:
Output Swing to GND for Zero Frequency Input
Easy to Use: VOUT = fIN x VCC x R1 x C1
Only One RC Network Provides Frequency Doubling
Zener Regulator On Chip Allows Accurate and Stable Frequency to Voltage or Current Conversion
Features:
Ground Referenced Tachometer Input Interfaces Directly with Variable Reluctance Magnetic
Pickups
OP Amp/Comparator has Floating Transistor Output
50mA Sink or Source to Operate Relays, Solenoids, Meters, or LEDs
Frequency Doubling for Low Ripple
Tachometer has Built–In Hysteresis with Either Differential Input or Ground Referenced Input
Built–In Zener Diode
±0.3% Linearity Typical
Ground Referenced Tachometer is Fully Protected from damage Due to Swings Above VCC
and Below GND
Applications:
Over/Under Speed Sensing
Frequency to Voltage Conversion (Tachometer)
Speedometers
Breaker Point Dwell Meters
Hand–Held Tachometer
Speed Governors
Cruise Control
Automotive Door Lock Control
Clutch Control
Horn Control
Touch or Sound Switches
Absolute Maximum Ratings:
Supply Voltage, oltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28V
Supply Current (Zener Options) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25mA
Collector Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28V
Differential Input Voltage
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28V
OP Amp/Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28V
Input Voltage Range
Tachometer
NTE995M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±28V
NTE955 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0V to +28V
OP Amp/Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0V to +28V
Power Dissipation (Note 1), PD
NTE995M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1200mW
NTE995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1580mW
Operating Temperature Range, Topr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40° to +85°C
Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65° to +150°C
Lead Temperature, TL
NTE995, NTE995M (During Soldering, 10sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +260°C
NTE995M
(Vapor Phase, 60sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +215°C
(Infrared, 15sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +220°C
Note 1. 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 the NTE995M, and +79°C/W junction to ambient for the NTE995.
Electrical Characteristics: (VCC = 12V, TA = +25°C unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
Tachometer
Input Thresholds VIN = 250mVP–P @ 1kHz, Note 2 ±10 ±25 ±40 mV
Hysteresis VIN = 250mVP–P @ 1kHz, Note 2 – 30 – mV
Offset Voltage
NTE995 VIN = 250mVP–P @ 1kHz, Note 2 – 3.5 10 mV
NTE995M – 5.0 15 mV
Input Bias Current VIN = ±50mV – 0.1 1.0 μA
Output Voltage (High Level, Pin2) VOH VIN = +125mV, Note 3 – 8.3 – V
Output Voltage (Low Level, Pin2) VOL VIN = –125mV, Note 3 – 2.3 – V
Output Current I2, I3 V2 = V3 = 6V, Note 4 140 180 240 μA
Leakage Current I3 I2 = 0, V3 = 0 – – 0.1 μA
Gain Constant K Note 3 0.9 1.0 1.1
Linearity fIN = 1kHz, 5kHz, 10kHz, Note 5 –1.0 0.3 +1.0 %
Note 2. Hysteresis is the sum + VTH – (–VTH), offset voltage is their difference.
Note 3. VOH is equal to 3/4 x VCC – 1 VBE, VOL is equal to 1/4 x VCC – 1 VBE therefore VOH – VOL = VCC/2.
The difference, VOH – VOL, and the mirror gain, I2/I3, are two factors that cause the tachometer
gain constant to vary from 1.0.
Note 4. Be sure when choosing the time constant R1 x C1 that R1 is such that the maximum anticipated
output voltage at Pin3 can be reached with I3 x R1. The maximum value for R1 is limited
by the output resistance of Pin3 which is greater than 10MΩ typically.
Note 5. Nonlinearity is defined as the deviation of VOUT (@ Pin3) for fIN = 5kHz from a straight line
defined by the VOUT @ 1kHz and VOUT @ 10kHz. C1 = 1000pF, R1 = 68k and C2 = 0.22mFd.
Electrical Characteristics (Cont’d): (VCC = 12V, TA = +25°C unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
OP Amp/Comparator
VOS VIN = 6V – 3 10 mV
IBIAS VIN = 6V – 50 500 nA
Input Common–Mode Voltage 0 – VCC–1.5V V
Voltage Gain – 200 – V/mV
Output Sink Current VC = 1.0 40 50 – mA
Output Source Current VE = VCC – 2.0 – 10 – mA
Saturation Voltage ISINK = 5mA – 0.1 0.5 V
ISINK = 20mA – – 1.0 V
ISINK = 50mA – 1.0 1.5 V
Zener Regulator
Regulator Voltage RDROP = 470Ω – 7.56 – V
Series Resistance – 10.5 15.0 Ω
Temperature Stability – +1 – mV/°C
Total Supply Current – 3.8 6.0 mA
Pin Connection Diagram
NTE995 NTE995M
– Op Amp In
+ Comparator N.C.
– Comparator In
GND
+ Op Amp In
Charge Pump Out
Output Collector
Vcc
N.C.
N.C.
N.C.
Output Emitter
Charge Pump Cap
1
2
3
4
5
6
7
14
13
12
11
10
9
8
GND/
– Op Amp In
Emitter Output
Vcc
1
2
3
4
+ Comparator In
Charge Pump Cap
Charge Pump
8
7
6
5 Collector Output
Output
Frequency Input
NTE995
NTE995M
.600 (15.24)
1 7
14 8
.300
(7.62)
.200 (5.08)
Max
.100 (2.45) .099 (2.5) Min
.785 (19.95)
Max
8 5
.256 (6.52) Max
.393 (10.0)
Max
1 4
.300 (7.62)
.300
(7.62)
.150
(3.81)
.100 (2.54) .070 (1.77) Min

Prueba

2008-08-11T17:08:00.000-07:00

Entrada de prueba 11/8/2008

Fernando Martí Vega

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