ST LM2903 User Manual

LM2903

Low-power dual voltage comparator

Features

■Wide single supply voltage range or dual supplies +2 V to +36 V or ±1 V to ±18 V

■Very low supply current (0.4 mA) independent of supply voltage (1 mW/comparator at +5 V)

■Low input bias current: 25 nA typ.

■Low input offset current: ±5 nA typ.

■Input common-mode voltage range includes negative rail

■Low output saturation voltage: 250 mV typ. (IO = 4 mA)

■Differential input voltage range equal to the supply voltage

■TTL, DTL, ECL, MOS, CMOS compatible outputs

Description

This device consists of two independent lowpower voltage comparators designed specifically to operate from a single supply over a wide range of voltages. Operation from split power supplies is also possible.

The device also has a unique characteristic in that the input common-mode voltage range includes the negative rail even though operated from a single power supply voltage.

DIP8

(Plastic package)

SO-8

(Plastic micropackage)

TSSOP8

(Thin shrink small outline package)

Pin connections (top view)

1 - Output 1

2 - Inverting input 1

3- Non-inverting input 1

4- VCC-

5- Non-inverting input 2

6- Inverting input 2

7- Output 2

8- VCC+

February 2012

Doc ID 2470 Rev 9

1/15

www.st.com

Schematic diagram	LM2903

1 Schematic diagram

Figure 1. Schematic diagram (1/2 LM2903)

Non-inverting

input

Inverting

input

3.5 μA

100 μA

3.5 μA

100 μA



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LM2903	Absolute maximum ratings and operating conditions

2 Absolute maximum ratings and operating conditions

Table 1.	Absolute maximum ratings
Symbol		Parameter	Value	Unit

VCC		Supply voltage	±18 to 36	V
Vid		Differential input voltage	±36	V
Vin		Input voltage	-0.3 to +36	V
		Output short-circuit to ground (1)	Infinite
		Thermal resistance junction to ambient(2)
Rthja		DIP8	85	°C/W
Rthja		SO-8	125	°C/W
		SO-8	125
		TSSOP8	120

		Thermal resistance junction to case(2)
Rthjc		DIP8	41	°C/W
Rthjc		SO-8	40	°C/W
		SO-8	40
		TSSOP8	37

Tj		Maximum junction temperature	+150	°C
Tstg		Storage temperature range	-65 to +150	°C
		Human body model (HBM)(3)	800	V
ESD		Machine model (MM)(4)	200	V
		CDM: charged device model(5)	1.5	kV

1.Short-circuits from the output to VCC+ can cause excessive heating and possible destruction. The maximum output current is approximately 20 mA, independent of the magnitude of VCC+.

2.Short-circuits can cause excessive heating and destructive dissipation. Values are typical.

3.Human body model: a 100 pF capacitor is charged to the specified voltage, then discharged through a 1.5 kΩ resistor between two pins of the device. This is done for all couples of connected pin combinations while the other pins are floating.

4.Machine model: a 200 pF capacitor is charged to the specified voltage, then discharged directly between two pins of the device with no external series resistor (internal resistor < 5 Ω). This is done for all couples of connected pin combinations while the other pins are floating.

5.Charged device model: all pins and the package are charged together to the specified voltage and then discharged directly to the ground through only one pin. This is done for all pins.

Table 2.	Operating conditions
Symbol					Parameter	Value		Unit

Vicm		Common mode input voltage range				0 to VCC+ -1.5		V
Vicm		T	≤ T	≤ T	max	0 to V	+ -2	V
		min	amb		max		CC
Toper		Operating free-air temperature range				-40 to +125		°C

Doc ID 2470 Rev 9

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Electrical characteristics	LM2903

3 Electrical characteristics

Table 3.

+ = 5 V, V

- = GND, T

amb

= 25°C (unless otherwise specified)

Symbol

Parameter

Min.

Typ.

Max.

Unit

Vio

Input offset voltage (1)

Tmin

≤ Tamb ≤ Tmax

Iio

Input offset current

Tmin

≤ Tamb ≤ Tmax

150

Iib

Input bias current (2)

250

Tmin

≤ Tamb ≤ Tmax

400

Avd

Large signal voltage gain

200

V/mV

VCC = 15V, RL=15kΩ, Vo=1 to 11V

Supply current (all comparators)

ICC

= 5V, no load

0.4

VCC = 30V, no load

2.5

Vid

Differential input voltage (3)

VCC+

VOL

Low level output voltage (Vid = -1V, Isink = 4mA)

250

400

Tmin

≤ Tamb ≤ Tmax

700

IOH

High level output current (VCC =Vo =30V, Vid = 1V)

0.1

Tmin ≤ Tamb ≤ Tmax

µA

Isink

Output sink current (Vid = -1V, Vo = 1.5V)

res

Small signal response time (4) (R

= 5.1kΩ to V

1.3

µs

Large signal response time (5)

TTL input (V

= +1.4 V, R =5.1kΩ to V

trel

ref

Output signal at 50% of final value

500

Output signal at 95% of final value

µs

1. At output switch point, V

≈ 1.4 V, R

= 0 Ω with V

+ from 5 V to 30 V, and over the full input common-mode range (0 V

to VCC+ –1.5 V).

2.The direction of the input current is out of the IC due to the PNP input stage. This current is essentially constant, independent of the state of the output, so no loading charge exists on the reference of input lines.

3.Positive excursions of input voltage may exceed the power supply level. As long as the other voltage remains within the common-mode range, the comparator will provide a proper output state. The low input voltage state must not be less than –0.3 V (or 0.3 V below the negative power supply, if used).

4.The response time specified is for a 100 mV input step with 5 mV overdrive.

5.Maximum values are guaranteed by design and evaluation.

4/15	Doc ID 2470 Rev 9

LM2903

Electrical characteristics

Figure 2. Supply current vs. supply voltage Figure 3.

Input current vs. supply voltage

Figure 4. Output saturation voltage vs. output current

Figure 5. Response time for various input overdrives - negative transition

Figure 6. Response time for various input overdrives - positive transition

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