LM134Z

LM134-LM234 STMICROELECTRONICS | Alldatasheet

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Technical content

Z TO92 (Plastic Package) .OPERATES from 1V to 40V .0.02% V CURRENT REGULATION .PROGRAMMABLE from 1 µA to 10mA .±3% INITIAL ACCURACY

DESCRIPTION

The LM134/LM234/LM334 are 3-terminal adjust- able current sources characterized by : - an operating current range of 10000 : 1 - an excellent current regulation - a wide dynamic voltage range of 1V to 40V The current is determined by an external resistor without requiring other external components. Reverse voltages of up to 20V will only draw a cur- rent of several microamperes. This enables the circuit tooperate asa rectifierand as a sourceofcur- rent in a.c. applications. For the LM134/LM234/LM334, the voltage on the control pin is 64mV at +25 oC and is directly propor- tionaltothe absolutetemperature(oK). The simplest external resistor connection generates a current with≈ 0.33%/oC temperature dependence. Zero drift can be obtainedby adding an additionalresistor and a diode to the external circuit. PIN CONNECTIONS D SO8 (Plastic Micropackage) V + ADJ V - 21 3 TO92 (Bottom view) LM134-LM234 LM334 THREE TERMINAL ADJUSTABLE CURRENT SOURCES 876 5 123 4 NC NC V NC- ADJ NC NC V+ SO8 (Top view) ORDER CODES Part Num- ber Temperature Range Package ZD LM134 –55 oC, +125oC •• LM234 –25 oC, +100oC •• LM334 0 oC, +70oC •• Example :LM134Z October 1997 1/10

V V SCHEMATIC DIAGRAM ABSOLUTE MAXIMUM RATING Symbol Parameter LM134 - LM234 LM334 Unit Voltage V+ to V– Forward Reverse V VADJ - ADJ Pin to V– Voltage 5 5 V ISET Set Current 10 10 mA Ptot Power Dissipation 400 400 mW Tstg Storage Temperature Range –65 to +150 oC Toper Operating Free-air Temperature Range LM134 LM234 LM334 –55 to +125 –25 to +100 0 to +70 oC LM134-LM234-LM334

ELECTRICAL CHARACTERISTICS

Tj= +25oC with pulse testing so that junction temperature does not change during testing (unless otherwise specified) Parameter LM134 - LM234 LM334 Unit Set Current Error (V+ = +2.5V) - (note 1) 10µA ≤ ISET ≤ 1mA 1mA ≤ ISET ≤ 5mA 2µA ≤ ISET ≤ 10µA Ratio of Set Current to V – Current 10µA ≤ ISET ≤ 1mA 1mA ≤ ISET ≤ 5mA 2µA ≤ ISET ≤ 10µA 14 18 23 14 18 Minimum Operating Voltage 2µA ≤ I SET ≤ 100µA 100µA ≤ ISET ≤ 1mA 1mA ≤ ISET ≤ 5mA 0.8 0.9 0.8 0.9 V Average change in set current with input voltage 2µA ≤ ISET ≤ 1mA +1.5V ≤ V+ ≤ +5V +5V ≤ V+ ≤ +40V 1mA ≤ ISET ≤ 5mA +1.5V ≤ V+ + ≤ +5V +5V ≤ V+ ≤ +40V 0.02 0.01 0.03 0.02 0.05 0.03 0.02 0.01 0.03 0.02 0.1 0.05 %/V Temperature Dependence of set current - (note 2) 25µA ≤ ISET ≤ 1mA 0.96 T T 1.04 T 0.96 T T 1.04 T Effective Shunt Capacitance 15 15 pF Notes : 1. Set current is the current flowing into theV+ pin. It is determined by the following formula Iset = 67.7mV/Rset (Tj =+ 2 5oC). Set current error is expressed as a percent deviation from this amount. 2. Iset is directly proportional to absolute temperature (oK). Iset at any temperature can be calculated from Iset =I O (T/TO ) where IO is Iset measured at TO (oK). LM134-LM234-LM334

At slew rates above a threshold (see curve) the LM134, LM234, LM334 can have a non-linear cur- rent characteristic. The slew rate at which this takes place is directly proportional to I set.A tIset=1 0µA, dv/dt max. = 0.01V/µS ; at Iset= 1mA, dv/dt max. = 1V/µS. Slew rates of more than 1V/µSd on o td a m - age the circuit nor do they produce high currents. THERMAL EFFECTS Internalheatingcan have a significant effect on cur- rent regulation for an Isetabove 100µA. For exam- ple, each increase of 1V in the voltage across the LM134 at Iset= 1mA will increase the junction tem- peratureby≈ 0.4oC (in still air). The output current (Iset) has a temperature coefficient of about 0.33%/oC. Thus the change in current due to the in- crease in temperaturewill be (0.4) (0.33) =0.132%. This is a degradation of 10 : 1 in regulation versus the true electrical effects.Thermal effectsshould be taken into account when d.c. regulation is critical and Isetis higher than 100µA. The dissipation of the connectionsof CB-97 packagecan reduce this ther- mal effect by a coefficient of more than 3. SHUNT CAPACITANCE In certain applications, the 15pF value for the shunt capacitance should be reduced : - because of loading problems, - because of limitation of the output impedance of the current source in a.c. applications. This reduc- tion of the capacitance can be easily carried out by addingaFET as indicatedin thetypical applications. The value of this capacitance can be reduced by at least 3pF and regulation can be improved by an or- der ofmagnitude without anymodificationof the d.c. characteristics (except for the minimum input volt- age). NOISE The current noise produced by LM134, LM234, LM334 is about 4 times that of a transistor. If the LM134, LM234, LM334 is utilized as an active load for a transistor amplifier, the noise at the input will increase by about 12dB. In most cases this is ac- ceptable, and a single amplifier can be built with a voltage gain higher than 2000. LEAD RESISTANCE The sense voltage which determines the current of the LM134, LM234, LM334, is less than 100mV. At this level, the effects of the thermocouple and the connectionresistance should be reduced by locat- ing the current setting resistor close to the device. Do not use sockets for the ICs. A contactresistance of 0.7Ω is sufficient to decrease the output current by 1% at the 1mA level. SENSING TEMPERATURE The LM134, LM234, LM334 are excellent remote controlled temperature sensors because their op- eration as sources of current preserves their accu- racy even in the case of long connecting wires. The outputcurrent is directly proportional tothe absolute temperaturein degrees Kelvin according to the fol- lowing equation. I set= (227µV/oK)(T) R set The calibration of the LM134,LM234, LM334 is sim- plified by the fact that most of the initial accuracy is due to gain limitation (slope error) and not an offset. Gainadjustment is a one point trim becausethe out- put of the device extrapolates to zero at 0 oK. This particularity of the LM134, LM234, LM334 is il- lustrated in the above diagram. Line abc represents the sensor current before adjustment and line a’b’c’ representsthe desired output. An adjustment of the gain provided at T2 will move the output from b to b’ and will correct the slope at the same time so that the output at T1 and T3 will be correct. This gain ad- justment can be carried out by means of R setor the load resistor utilized in the circuit. After adjustment, the slope error should be less than 1%. A low tem- peraturecoefficientforR setis necessary to keep this accuracy. A 33ppm/oC temperaturedrift of Rsetwill give an error of 1% on the slope because the resis- tance follows the same temperature variations as the LM134, LM234, LM334. Three wires are re- quired to isolate Rset from the LM134, LM234, LM334. Since this solution is not recommended. Metal-film resistors with a drift less than 20ppm/oC are now available. Wirewound resistors can be util- ized when very high stability is required. T1 T2 T30°K Iset Desired output Initial output c b a LM134-LM234-LM334

PM-SO8.EPS PACKAGE MECHANICAL DATA

8 PINS - PLASTIC MICROPACKAGE (SO)

Dimensions Millimeters Inches A 1.75 0.069 a1 0.1 0.25 0.004 0.010 a2 1.65 0.065 a3 0.65 0.85 0.026 0.033 b 0.35 0.48 0.014 0.019 b1 0.19 0.25 0.007 0.010 C 0.25 0.5 0.010 0.020 c1 45 o (typ.) D 4.8 5.0 0.189 0.197 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 3.81 0.150 F 3.8 4.0 0.150 0.157 L 0.4 1.27 0.016 0.050 M 0.6 0.024 o (max.) SO8.TBL LM134-LM234-LM334

PM-TO92.IMG PACKAGE MECHANICAL DATA

3 PINS - PLASTIC PACKAGE TO92

Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsi- bility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics.  1997 SGS-THOMSON Microelectronics – Printed in Italy – All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. ORDER CODE : Dimensions Millimeters Inches L 1.27 0.05 K 12.7 0.5 a 0.35 0.0138 TO92.TBL LM134-LM234-LM334