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: D Output Swing to GND for Zero Frequency Input D Easy to Use: VOUT = fIN x VCC x R1 x C1 D Only One RC Network Provides Frequency Doubling D Zener Regulator On Chip Allows Accurate and Stable Frequency to Voltage or Current Conversion Features: D Ground Referenced Tachometer Input Interfaces Directly with Variable Reluctance Magnetic Pickups D OP Amp/Comparator has Floating Transistor Output D 50mA Sink or Source to Operate Relays, Solenoids, Meters, or LEDs D Frequency Doubling for Low Ripple D Tachometer has Built–In Hysteresis with Either Differential Input or Ground Referenced Input D Built–In Zener Diode D ±0.3% Linearity Typical D Ground Referenced Tachometer is Fully Protected from damage Due to Swings Above VCC and Below GND Applications: D Over/Under Speed Sensing D Frequency to Voltage Conversion (Tachometer) D Speedometers D Breaker Point Dwell Meters D Hand–Held Tachometer D Speed Governors D D D D D Cruise Control Automotive Door Lock Control Clutch Control Horn Control Touch or Sound Switches Absolute Maximum Ratings: Supply Voltage, 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 – 5.0 15 mV VIN = ±50mV – 0.1 1.0 µA NTE995M Input Bias Current 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 – – 0.1 µA Leakage Current I3 I2 = 0, V3 = 0 Gain Constant K Note 3 0.9 1.0 1.1 fIN = 1kHz, 5kHz, 10kHz, Note 5 –1.0 0.3 +1.0 Linearity % 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 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 Zener Regulator Regulator Voltage Pin Connection Diagram NTE995 NTE995M + Comparator 1 14 N.C. Charge Pump Cap 2 13 N.C. Charge Pump Out 3 12 GND + Op Amp In 4 Output Emitter 5 11 – Comparator In 10 – Op Amp In N.C. 6 9 Vcc N.C. 7 8 Output Collector + Comparator In 1 Charge Pump Cap 2 8 GND/ Frequency Input 7 – Op Amp In Charge Pump 3 Output 6 Vcc Emitter Output 4 5 Collector Output NTE995 14 8 1 7 .785 (19.95) Max .300 (7.62) .200 (5.08) Max .100 (2.45) .099 (2.5) Min .600 (15.24) NTE995M 8 5 .256 (6.52) Max 1 4 .393 (10.0) Max .300 (7.62) .150 (3.81) .100 (2.54) .070 (1.77) Min .300 (7.62)