feature

• Internal frequency compensated unity gain

• Large DC voltage gain: 100dB

• Very low supply current drain ( 500µA ) - essentially independent of supply voltage

• Broadband (unity gain): 1 MHz (temperature compensated)

• Input common mode voltage range including ground

• Differential input voltage range equals power; supply voltage

• Low input offset voltage: 2mV

• Wide power supply range: single supply: 3V to 32V; or dual supply: ±1.5V to ±6V

• The output voltage fluctuates greatly: 0V to V+-1.5V

•8-pin SOP, PDIP package

• Pb-free finish / RoHS compliant Pb-free and "green" products (Note 1)

•SOP-8L: "green" molding compound (Br, Sb free)

Advantage

• No dual power supply required

• Compatible with all forms of logic

• Two internally compensated op amps

• Low power consumption suitable for battery operation

• Allows direct sensing near GND and VOUT also goes to GND

General Instructions

The AP358 family includes two independent high gain, internal frequency compensated operational amplifiers specifically designed to operate over a wide voltage range from a single supply. It is also possible to run the power supply at split power, with low supply current consumption independent of the magnitude of the supply voltage.

Application areas include sensor amplifiers, DC gain blocks, and all conventional op-amp circuits that are easily implemented in single-supply systems. For example, the AP358 series can easily provide the required interface electronics directly from the standard +5V supply voltage for digital systems, without the need for an additional ±15V supply.

Pin Description

Ordering Information

Note: 1. RoHS version 13.2.2003 . Exemptions for glass and high temperature solders apply, see Notes 5 and 7 of the EU Directive Annex.

2. Green represents SOP-8L.

unique features

• In linear mode, the input common-mode voltage range includes ground, and the output voltage can swing to ground even when operating from only a single supply voltage.

• The unity-gain crossover frequency is temperature compensated.

• The input bias current is also temperature compensated.

pin assignment

block diagram

Voltage Controlled Oscillator

Absolute Maximum Ratings

Notes: 1. For devices operating at high temperatures, AP358 must be based on a maximum junction temperature of +125°C with a thermal resistance (DIP) of 120°C/W and a small outline package of 189°C/W (suitable for soldering on printed device on the circuit board) for derating. The loss is the sum of the two amplifiers using external resistors, where possible, to allow the amplifier to saturate or reduce the power dissipated in the integrated circuit.

2. A short circuit from the output to V+ can cause overheating and eventual damage. When considering a short to ground, the maximum output current is about 40 mA, independent of the magnitude of V+. When the supply voltage value exceeds +15V, a sustained short circuit may exceed the power loss rating and cause eventual destruction. Simultaneous shorting of all amplifiers can result in destructive losses.

3. This input current exists only when the voltage of any input lead is negative. This is due to the collector-base junction of the input PNP transistor becoming forward biased, acting as an input diode clamp. In addition to the role of this diode, there are also lateral NPN parasitic transistors acting on the IC chip. This transistor action can cause the output voltage of the op amp to reach the V+ voltage level for the duration that the input is driven negative (or ground for large overspeeds). This is not destructive, when the input voltage is negative, the normal output state will again revert to a value greater than -0.3V (at 25°C).

Typical Single Supply Circuit (Continued) (V+=5.0 VDC)

Non-inverting DC gain (0V output)

Typical Characteristics (TA=25oC)

application information

The AP358 series are operational amplifiers that operate only from a single supply voltage, have true differential inputs, and remain in linear mode with an input common-mode voltage of 0 VDC. These amplifiers operate over a wide range of supply voltages with little change in performance characteristics. The amplifier's operating voltage can be reduced to a minimum of 2.3 VDC at 25°C.

Precautions should be taken to ensure that the power supply to the integrated circuit is never reversed in polarity, or that the device cannot be accidentally installed backwards in the test socket due to an infinite current wave through the forward diode generated within the integrated circuit Surge can cause internal conductors to fuse and cause damage to the unit.

Large differential input voltages can be easily accommodated, and since input differential voltage protection diodes are not required, large differential input voltages do not result in large input currents. The differential input voltage may be greater than V+ without damaging the device. Protection should be provided to prevent input voltages going negative beyond -0.3 VDC (25°C). An input clamp diode with a resistor to the IC input terminal can be used.

To reduce supply current consumption, the amplifier has a Class A output stage for small signal levels, which converts to Class B in large signal mode. This enables the amplifier to source and sink large output currents simultaneously. Therefore, both NPN and PNP external current boost transistors can be used to extend the power capability of the basic amplifier. The output voltage needs to be raised about 1 diode drop from ground to bias the on-chip vertical PNP transistors for output current sinking applications.

For AC applications, when the load is capacitively coupled to the amplifier's output, a resistor should be used from the amplifier's output to ground to increase class-a bias current and prevent crossover distortion. In the case of direct coupling of the load, as in DC applications, there is no crossover distortion.

A capacitive load applied directly to the amplifier output reduces the loop stability margin. The 50pF value can be adjusted using a worst case non-inverting unity gain connection. If the amplifier must drive a larger load capacitance, a larger closed-loop gain or resistive isolation should be used.

The bias network of the AP358 establishes a drain current that is independent of the supply voltage in the range of 3 VDC to 30 VDC.

The duration of the output short circuit to ground or to the positive supply should be short. Cells can be destroyed, not because of metal melting due to short-circuit currents, but because of a large increase in IC chip losses, which will cause the function to overheat and eventually fail. Direct shorting of more than one amplifier at a time, if not properly protected by external dissipation limiting resistors in series with the output leads of the amplifiers, can increase the overall power dissipation of the integrated circuit to destructive levels. The greater the value of output source current available at 25°C, the greater the output current capability available at high temperature (see Typical Performance Characteristics) rather than a standard IC op amp.

The circuits presented in the Typical Applications chapter emphasize operation on a single supply voltage only. All standard op amp circuits can be used if complementary power supplies are available. In general, in a single-supply system, introducing a pseudo-ground (bias voltage reference of V+/2) will allow operation above or below this value. A number of application circuits are presented that take advantage of a wide input common-mode voltage range including ground. In most cases, the input bias is not needed and the input voltage range to ground can be easily accommodated.

tag information

Packaging Information (all dimensions in mm)