NTE995 & NTE995M Integrated Circuit FrequencytoVoltage Converter Description: The NTE995 (14Lead DIP) and NTE995M (8Lead DIP) are monolithic frequency to voltage con- verters 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 tech- nique 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: V = f x V x R1 x C1 OUT IN CC 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 BuiltIn Hysteresis with Either Differential Input or Ground Referenced Input BuiltIn Zener Diode 0.3% Linearity Typical Ground Referenced Tachometer is Fully Protected from damage Due to Swings Above V CC and Below GND Applications: Over/Under Speed Sensing Cruise Control Frequency to Voltage Conversion (Tachometer) Automotive Door Lock Control Speedometers Clutch Control Breaker Point Dwell Meters Horn Control HandHeld Tachometer Touch or Sound Switches Speed GovernorsAbsolute Maximum Ratings: Supply Voltage, V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28V CC 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), P D NTE995M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1200mW NTE995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1580mW Operating Temperature Range, T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 to +85C opr Storage Temperature Range, T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 to +150C stg Lead Temperature, T L NTE995, NTE995M (During Soldering, 10sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +260C NTE995M (Vapor Phase, 60sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +215C (Infrared, 15sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +220C Note 1. For operation in ambient temperatures above 25C, the device must be derated based on a +150C maximum junction temperature and a thermal resistance of +101C/W junction to ambient for the NTE995M, and +79C/W junction to ambient for the NTE995. Electrical Characteristics: (V = 12V, T = +25C unless otherwise specified) CC A Parameter Symbol Test Conditions Min Typ Max Unit Tachometer Input Thresholds V = 250mV 1kHz, Note 2 10 25 40 mV IN PP Hysteresis V = 250mV 1kHz, Note 2 30 mV IN PP Offset Voltage NTE995 V = 250mV 1kHz, Note 2 3.5 10 mV IN PP NTE995M 5.0 15 mV Input Bias Current V = 50mV 0.1 1.0 A IN Output Voltage (High Level, Pin2) V V = +125mV, Note 3 8.3 V OH IN Output Voltage (Low Level, Pin2) V V = 125mV, Note 3 2.3 V OL IN Output Current I , I V2 = V3 = 6V, Note 4 140 180 240 A 2 3 Leakage Current I I2 = 0, V3 = 0 0.1 A 3 Gain Constant K Note 3 0.9 1.0 1.1 Linearity f = 1kHz, 5kHz, 10kHz, Note 5 1.0 0.3 +1.0 % IN Note 2. Hysteresis is the sum + V (V ), offset voltage is their difference. TH TH 3 1 Note 3. V is equal to / x V 1 V , V is equal to / x V 1 V therefore V V = V /2. OH 4 CC BE OL 4 CC BE OH OL CC The difference, V V , and the mirror gain, I /I , are two factors that cause the tachometer OH OL 2 3 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 antici- pated output voltage at Pin3 can be reached with I x R1. The maximum value for R1 is lim- 3 ited by the output resistance of Pin3 which is greater than 10M typically. Note 5. Nonlinearity is defined as the deviation of V ( Pin3) for f = 5kHz from a straight line OUT IN defined by the V 1kHz and V 10kHz. C1 = 1000pF, R1 = 68k and C2 = 0.22mFd. OUT OUT