LTC1040 LINER
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TECHNOLOGY Dual Micropower Comparator FEATURES DESCRIPTION = Micropower The LTC 1040 is a monolithic CMOS dual comparator manu- 1.5yW (1 Sample/Second) factured using Linear Technology's enhanced LTCMOS™ = Power Supply Flexibility silicon gate process. Extremely low operating power levels Single Supply +2.8V to + 16V are achieved by internally switching the comparator ON fur Split Supply + 2.8V to +8V short periods of time. The CMOS output logic holds the out- = Guaranteed Max. Offset 0.5mV put information continuously while not consuming any = Guaranteed Max. Tracking Error between Input power. Pairs +0.1% at ran . , = Input Common-Mode Range to Both Supply Rails In addition to switching power ON, a switched output is = TTL/CMOS Compatible with + 5V or Single +5V provided to drive external loads during the comparator’s Supply active time. This allows not only low comparator power, = Input Errors are Stable with Time and Temperature but low total system power. Sampling is controlled by an external strobe input or an APPLICATIONS internal oscillator. The oscillator frequency is set by an ex- = Battery Powered Systems ternal RC network. = Remote Sensing Each comparator has a unique input structure, giving two = Window Comparator differential inputs. The output of the comparator will be @ BANG-BANG Controllers high if the algebraic sum of the inputs is positive and low ui the algebraic sum of the inputs is negative. ro | en Window Comparator with Symmetric Window Limits Typical LTC1040 Supply Current vs Sampling Frequency 1000 oe s ese Yerastusvors * 010 —_ EXTERNALLY STROBED 3 wen te oa Vin<Vo~s on 1 40 100 1,000 10,000 L E | La ey SAMPLING FREQUENCY, f5 (Hz) Ltcmos™ is a trademark of Linear Technology Corporation, LT Wee 6-57
Operating Temperature Range on/OFF [2 Ver cno[g] v el Test conditions: V+ =5V, V~ = —5V, Twin <Ta<Tmax unless otherwise specified. UTC1040M/LTC1040C Vos Offset Voltage (Note 1) Split Supplies + 2.8V to + 6V +03 £0.5 mv Single Supply (V~ =GND) +2.8V to 6V Split Supplies + 6V to + 8V +1 £3 mV Single Supply (V~ =GND) +6V to + 15V Tracking Error Split Supplies + 2.8V to + 8V 0.05 0.1 % between Input Pairs Single Supplies (V~ =GND) +2.8 to + 16V (Notes 1 and 2) Naas Ta=25°C, OSC =GND es Rin Average Input fg = 1kHz (Note 3) 20 30 Mo Resistance CMR | Common-Mode Range | EV PSR Power Supply Range Split Supplies [e| +£2.8 +8 Vv Single Supplies (V~ =GND) [e| +28 +16 Vv =e a Current (Note 4 Igcorr) | Power Supply OFF V* =5V.VppOf — LTC1040C 0.001 05 uA Current (Note 4) LTC1040M 0.001 5 vA (Note 5) A, B, A+B and ON/OFF Outputs (Note 6) Vou Logic *1'' Output Voltage | V* =4.75V, loyr= — 360/A 2.4 4.4 Vv Vor Logic ‘0"' Output Voltage | V* =4.75V, Ioyr=1.6mA 0.25 0.4 v STROBE Input (Note 6) Vin Logic ‘1"' Input Voltage vt =5.25V 2.0 1.6 v Vie Logic '0"' Input Voltage | V* =4.75V 1.0 0.8 v Rext Resistor Tied between V* and OSC Pin [| 100 10,000 kQ Resistor "Ts Sampling Frequency T= 25°C, Rex = 1MQ, Cexr=0. 1uF a a
The @ denotes the specifications which apply over the full operating Note 4: Average supply current=tp x IS(on) xf +(1 —-tpxfs)x temperature range. 'S(OFF). Note 1: Applies over input voltage range limit and includes gain vee 5 Res potee time is set by an internal oscillator and is independent uncertainty. overdrive voltage. Note 2: Tracking error =(Vjnq—ViN2)/VIN4 Note 6: Inputs and outputs also capable of meeting EIA/ JEDEC B series Note 3: Ryn is guaranteed by design and is not tested. CMOS specifications. RIN =1/(fs x 33pF). Ee TYPICAL PERFORMANCE CHARACTERISTICS Normalized Sampling Peak Supply Current vs Frequency vs Supply Voltage Supply Voltage and Temperature Sampling Rate vs Rext, Cext 2 22 10 ee [TT TTT Ty Nee SSS —— ae "Li 5 2 PSE ott TA ge SCC TT EES se " 4 go | [le [|] | | 2 Se ae att 4 ee 2 SSR oi z% SEenEy, Yj} iz.-L\\i il tt) 2. CeStee S oy Oe VA WELLE) § === EET IAA) set peeky 2 SSS SSS : Zo = Wo TT) ® | Sir ES o| Lee | | 2 os Sane Sa 6 | Tee), LE res], ESS 2 4 6 8 0 86120 «14 16 0 2 4 6 8 0 12 #14 «16 100k 1M 10M ‘SUPPLY VOLTAGE, V* (V) ‘SUPPLY VOLTAGE, V+ (V) Ret (2) Response Time vs Supply Input Resistance vs Sampling Hid Sutput Voltage vs Load oltage requency B01) eg ree -°? . rT tty S00 LN Tg AWAKE EEE 3 = : = CS 3 SS Og NAS ee ie eee Be ENN FSF SS 18 N «0 PEE TEE Ty 2 CT Te Nn SCs 2 4 6 8 10 12 14 16 < 1 10 102 103 104 o 412 3 4 5 6 7 8 8 10 ‘SUPPLY VOLTAGE, V+ (V) ‘SAMPLING FREQUENCY, fg (Hz) LOAD CURRENT, |, (mA) Owen 6-59
A TYPICAL PERFORMANCE CHARACTERISTICS Response Time vs Quick Hookup Guide . Temperature Self-Oscillating External Strobe ee pe et es [eae Bisa a eo t_tLt tt tT | re ee ra sp -80 -2% 0 8% SH 75 10 125 - - AMBIENT TEMPERATURE, T, (°C) TEST CIRCUIT V+ (18) Vin: a) OUTPUT = V~ (10) ‘ALL INPUTS ON OPPOSITE COMPARATOR AT GROUND SN BLOCK DIAGRAM v+ . { art [5] a Vint [2] tour Vine “Oo } >o ON/OFF De a- i , COMP B 15] Bour 2+ [12} - Vina: cere ose i POWER ON \\e bss] o SE EE ee 6-60 LIT Wee
Functionally, when the sum of inputs is positive, thecom- Y ereasing Us. array. Because of the switching nature of the inputs, the charging and discharging Cin between Vin and ground. between Rs and Rin causing error. Figure 1. Equivalent Input Circuit . . bypass capacitor, Cs , is needed. When switch S1 closes, _is reduced to 66nV.
Cation, to minimize error. because Cjn1 is guaranteed to equal Cin2 to within 0.1%. Figure 2. Dual Differential Equivalent Input Circuit Common-Mode Range _ put common-mode range includes both supply rails. above equation, each method will be at null when: capabilities of the LTC1040. array and even the non-optimum connection will only .
Example: Rext =1M, V+ =5V, Prext =(2.5)2/108 = power is a premium Rext should be made as large as 6.25 x 10- Sw. possible. Note that the power consumed by Rext is not a This is about four times the power consumed by the function of fs or Cexr.. LTC1040 at V+ =5V and fs = 1 sample/second. Where ee TYPICAL APPLICATIONS Complete Heating/Cooling Automatic Thermostat ‘BV AT 0.85yA ae a ( a ae 00 hy wee AARCONDTIONING ON CT /'\\ /\\ HYSTERESIS [7 } coup A mu AIRCONDITIONING OFF t gaa A HEATER OFF G) 3 | 1 za te wg _Seanarion | | 1 4 WA, westlsess , op vor wet NEATERON ren bea cee Gore | Fs ' ' | foto ADJUST: 44 NS gee = HEAT tod | I com it Bae ih, on a oy One TIME 3 7o eye Seon 20M > ‘rHERMISTOR #44007 YELLOW SPRINGS INSTRUMENT CO., INC, “HYSTERESIS =SV x 224 = 20mv Window Comparator with Independent Window Limits and Fully Floating Differential Input ee ee {oy es a vt > i ‘i a are =! APE ha Ne oa Leo eal SY LY Wear 6-65
a TYPICAL APPLICATIONS Hysteresis Comparator with Fully Floating Differential Input ve Vw { Vine WW our OUT =""0" WHEN Viy> Vy = He ae BY 6.996 Vyaip+ 20m 10k2. OUT = "1" WHEN V; Vr Fe =" IN<VI = prep =0.996V rR “TO CENTER HYSTERESIS ABOUT Vrpip FORCE THIS INPUT TO HYSTERESIS/2 (10mV) 2. owe Temperature Controlled Cooling Fan to Reduce Fan Noise, Power Consumption and Wear ve ee oe , 5 ce ea ig | COOLING FAN le] = 39.2k y> " fir) os : : i 100K 34 ey [ees 0 ba Ca Oe 4.72nF f zt *ysi 44034 = 20k 249M The LTC1040 as a Linear Amplifier With a simple RC filter the LTC 1040 can be made to func- v+ tion as a linear amplifier. By filtering the logic output and feeding it back to the negative input, the loop forces the tT Cl a y output duty cycle [ton /(ton + toFF)] so that Vout equals VW 7 on Vin (Figure 10). The RC time constant is set to keep the ripple on the output small. The maximum output ripple is: AV=V* /fsRC and should be set to 0.5mV to 1mV for best results. Notice that ve— | the higher the sampling frequency, fs, the lower RC can vot be. This is important because the RC filter also sets the _| oe vour=v tot loop response. A convenient way to keep fs as high as ‘ow possible under all conditions is to connect a 100k resistor to pin 16 (OSC) with no capacitance to ground. Figure 10. The LTC1040 as a Linear Amplifier SS PTS 6-66 LT We
2-Wire 0°C to 100°C Temperature Transducer with 4mA to 20mA Output 12V TO 40V ve hai 100°C = rr umi34 | &} u LY a a) r a a = I tk | <0 zalust 8 6250 | CT. ur10195 | im | 18, 1M Lit ) é t| 040 NGGS7 4 9 i: lug " = ‘TYELLOW SPRINGS INSTRUMENT PART NO. 44201 RETURN FULL-SCALE ADJUST ACCURACY = £0.1°C + #0.2°C = +£0.3°C CIRCUIT ERROR TRANSDUCER AT 25°C ERROR Analog Multiplier / Divider Single + 5V Voltage-to-Frequency Converter wv
4 Var (5¥)
al 1. 7 lo 18 Ve 2 0 = mae 4 % 7400 | { 10% Vin 4 Basal |) O—> four
5 I 3 Vour iS
vt a? Pyle, wel I 10nF rT oe vA a {LretoM > ucioas | T Vy soe - L 4 tour (AVERAGE) =fyy a 40.1% FS 17. (Wa+V1—V2) x Ve Vout yg ACCURACY = + 10mV NO TRIM “Vg MUST BE >Va+(V1 ~V2) SS
A PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. J Package
18 Lead Hermetic DIP
0.960 oa aaa wax f_ fr [rs]_f) fe)_) fa + 9.025, 0.220-0.310 Os) (5 590-7-870) os JP EE WE eo 10150.060 oae0= 1820) A + aooe-oor rar A | wax (254050258) MIN 150°C 80°C /W N Package
18 Lead Plastic DIP
0.900. Lo aX BAA eeep Teo ooo 0.300-0.20 1085 T=8108) sn 04s 0.065 — 2.000, saciid | | Fae F 175) Min +0025 004520.015 0.018.003 (as 085) vow 110°C 120°C/W SSS