A275 Pulse Amplifier

The A275 is a high performance hybrid differential op-amp developed as a pulse amplifier for instrumentation.

Its low power dissipation (15 mW), high slew rate (100 V/µs), and low input noise (4 nV/? Hz) make it ideal for use in a wide range of op-amp applications. The A275 is packaged in a standard 14 Pin hybrid DIP and is also available in a SIP as the A275F.

A275 high-performance pulse amplifier module for detector signal processing applications.

Product Details

Features

Power 15 mW
Slew Rate 100 V/µs
Input Noise 4 nV/√Hz
Stable DC Operation
200 MHz Gain-Bandwidth Product
High Reliability Screening
Unity Gain Stable

Specifications

Absolute Maximum Ratings

Supply Voltage	±8 V
Input Voltage	±VS
Operating Temperature	-55 °C to +125 °C
Storage Temperature	-65 °C to +150 °C
Lead Temperature Range (Soldering, 10 sec.)	+300 °C

General

Screening	Amptek High Reliability
Mean Time Between Failure (MTBF)	1.6/106 hrs @ +60 °C
Package	14 Pin hybrid DIP, also available in a SIP as the A275F.
Weight	3.8 g

Electrical Characteristics

VS = ±6 V, TA = +25 °C

Parameter	Symbol	Conditions	Min	Typ	Max	Units
Input Offset Voltage Uncompensated/Compensated	V_os			2	5/7	mV
Input Offset Current	I_os			0.1	0.6	µA
Input Bias Current	I_B			1.5	4	µA
Input Capacitance	C_IN			4		pF
Differential Input Resistance	R_IN			44		kΩ
Common-Mode Input Resistance	R_IN		>5	8		MΩ
Common-Mode Rejection Ratio	CMRR		90	95		dB
Common-Mode Input Range	IVR			±4.5		V
Power Supply Rejection Ratio	PSRR			60		dB
Large-Signal Voltage Gain @5kHz @5kHz @10MHz @10MHz	A_LFC	compensated	64	66		dB
	A_LF	uncompensated	72	74
	A_HFC	compensated	16	20
	A_HF	uncompensated	24	28
Pulse Risetime (AV = 10)	trc	compensated		15	22	ns
Pulse Risetime (AV = 10)	tr	uncompensated		9	15	ns
Output Voltage Swing	V_OP	positive	+4.2	+4.4	-5.5	V
Output Voltage Swing	V_ON	negative		-5.0		V
Open Loop Output Resistance	R_O			750		Ω
Output Short-Circuit Current	I_OSC	source		11		mA
Output Short-Circuit Current	I_OSC	sink		-4		mA
Slew Rate	S_RP	positive	65	100		V/µs
Slew Rate	S_RN	negative	35	40		V/µs
Input Noise Voltage Density	e_N			4		nV/√Hz
Supply Current	I_S		±1.1	±1.25	±1.4	mA
Power Consumption	P_D			15		mW

Connection Diagram and Pin Out

A275 connection diagram and pin configuration for pulse amplifier applications.

Pin	Function
1	Inverting input
2	Non-inverting input
3	Bias adjust to Pin 4 (R > 3 kΩ) Frequency De-Compensation This resistor will increase the current to the input stage and increase the bandwidth
4	-Vs direct
5	-Vs through 50 ohms
6	Compensation to Pin 7 (C = 0 to 5 pF) Frequency Compensation to decrease the bandwidth
7	Case and Ground
8	Output through 50 ohms
9	Output direct
10	+Vs through 50 ohms
11	+Vs direct
12, 13, 14	Compensation (leave open for gain < 10, short for gain > 10)

The A275 is also available in a SIP package as the A275F.

Operating Notes

A275 gain & phase

A275 gain and phase response graph across frequency range.

A275 pulse characteristics

A275 pulse amplifier waveform showing pulse shaping and signal response characteristics.

Upper: Input pulse First output: 3 pole Second output: 5 pole

Circuit Layout Considerations

Due to the high bandwidth of the A275, care should be taken in circuit layout. In general, ground plane construction is recommended. Input and output lines should be well separated and in most cases shielding will be necessary. Grounding the physical case of the A275 (in addition to Pin 7) to the ground plane can be used to avoid oscillations or electronic pick-up.

Applications

PC275 Test Board

PC-275

The A275 can be tested as a shaping amplifier by using the circuit shown below.

The PC-275 Test Board accommodates three (3) A275s and a BLR1 and produces a 5-pole pulse with 1 µs risetime (2.3 µs peaking time).

PC-275 test board layout for A275 pulse amplifiers and BLR1 baseline restorer.

Figure 4. PC-275 layout. Dimensions: 3.5 in X 1.75 in (88.9 mm X 44.45 mm)

A250 solid-state detector system with five-pole pulse shaping and BLR1 baseline restoration.

Figure 5. The A250 connected to a solid state detector with 5-pole shaping and active baseline restoration (BLR1). The PC-275 Schematic begins at the output of A250.

Mechanicals

Downloads

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