LM2907EP/LM2917EP
Enhanced Plastic Frequency to Voltage Converter
General Description
Features
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 frequency 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.
The op amp/comparator is fully compatible with the tachometer 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.
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.
The more versatile configurations provide differential tachometer 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 tachometer output.
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
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
n Frequency doubling for low ripple
n Tachometer has built-in hysteresis with either differential
input or ground referenced input
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
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Advantages
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Output swings to ground 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 (LM2917EP)
Applications
n Selected Military Applications
n Selected Avionics Applications
Process Change Notification (PCN)
Qualification & Reliability Data
Solder (PbSn) Lead Finish is standard
Enhanced Diminishing Manufacturing Sources (DMS)
Support
Ordering Information
PART NUMBER
VIN PART NUMBER
NS PACKAGE NUMBER (Note 3)
LM2907MX-8EP
V62/04635-01
M08A
LM2917MXEP
V62/04635-02
M14A
(Notes 1, 2)
TBD
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
LM2907EP/LM2917EP Enhanced Plastic Frequency to Voltage Converter
June 2004
