AB-005 [ETC]

AB-005 - Make A Precision -10V Reference ; AB - 005 - 使一个精密-10V参考


型号：	AB-005
厂家：	ETC
描述：	AB-005 - Make A Precision -10V Reference AB - 005 - 使一个精密-10V参考
文件：	总2页 (文件大小：32K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

AP P LICATION BULLETIN

Mailing Address: PO Box 11400 • Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd. • Tucson, AZ 85706

Tel: (520) 746-1111 • Twx: 910-952-111 • Telex: 066-6491 • FAX (520) 889-1510 • Immediate Product Info: (800) 548-6132

Ma ke A Pre c ision ±10V Re fe re nc e

By R. Mark Stitt, (520) 746-7445

Many systems require the combination of both a positive and

Both of the V_OUTerrors are adjustable to zero as shown in

Figure 2. Because the adjustment range is small, instability

in the trim components is negligible. Since the +V_OUTadjust-

ment affects –V_OUT, adjust +V_OUTfirst.

a negative precision 10.0V reference. ADI offers several

hybrid ±10V references. Although Burr-Brown offers no

±10V reference at this time, we do have some simple two-

chip solutions which are accurate and can be more cost

effective. (The lowest cost grades of ADI’s ±10V references

are priced at $37.25 (AD2702) and $42.10 (AD2712) each in

25+ quantities.)

If you need a 1ppm/°C reference, use the REF101 as shown

in Figure 3. The REF101 contains the precision resistors

needed for the –10V inverter. For a ±10.0V reference, the

only additional component needed is an op amp. The 0.6µV/

°C V_OS/dT of the OPA27AM adds a negligible 0.06ppm/°C

drift to the negative reference.

Figure 1 shows one two-chip solution. It uses the super-

stable REF102 +10.0V precision reference and an INA105

difference amplifier connected as a precision unity gain

inverting amplifier. The REF102CM has 2.5ppm/°C max

drift. The INA105BM adds drift to the –10.0V output of

1ppm/°C max due to V_OS/dT and 5ppm/°C due to gain drift.

The V_OUTerror of the REF102CM is ±2.5mV max. The

INA105BM adds ±10mV max error to the –10.0V reference.

For lowest parts cost, consider the ±10V reference shown in

Figure 4. The unity-gain-inverting amplifier in this circuit

uses 1% resistors and a 100Ω pot to trim the –10.0V

reference output. When using standard 1% film resistors, a –

V_OUTdrift of 50ppm/°C or more should be expected.

TheREF101 and REF102 are buried-zener-based references.

They have better stability and much lower noise than stan-

dard band-gap-based voltage references. Still, there are in-

stances when even lower noise is required. The standard way

to lower noise is to lower the noise bandwidth at the output

of the reference by filtering (see Application Bulletin 3).

+15V

V+

REF102

10V

Out

+10V Out

–10V Out

The circuit shown in Figure 5 includes noise reduction filters

on both the +10V and –10V reference outputs. The improved

filter design shown has several advantages:

1) low output impedance at high frequency for driving

dynamic loads,

25kΩ

Com

25kΩ

2) improved noise filtering, and

3) ability to drive large capacitive loads.

INA105

FIGURE 1. Precision Two-Chip ±10.0V Reference.

+15V

V+

10V

Out

REF102

Trim

+10V Out

–10V Out

10kΩ

20kΩ

25kΩ

+10V

Adj

20Ω

Com

25kΩ

1kΩ

–10V

Adj

INA105

10kΩ

FIGURE 2. Precision Two-Chip ±10V Reference with ±V_OUTTrim.

AB-005

Printed in U.S.A. June, 1995

+15V

0.01µF

V+

+15V

OPA27

–10V Out

REF102

10V

Out

V+

+10V Out

–10V Out

R₁

R₂

100Ω

+10V Out

Com

10kΩ

10V

Out

REF101

Com

OPA27

FIGURE 3. Precision 1ppm/°C ±10V Reference.

FIGURE 4. ±10V Reference Using 1% Resistors.

R_2A

10kΩ

C_2A

+15V

0.01µF

OPA27

V+

R_1A

REF102

+10V Out

10V

Out

50Ω

1µF

Tantalum

C_1A

10.0kΩ

0.01%

R₃

Com

R_2B

10.0kΩ

0.01%

C_2B

0.01µF

OPA27

R_1B

–10V Out

50Ω

1µF

Tantalum

C_1B

FIGURE 5. Precision ±10.0V Reference with Output

Filtering.

The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes

no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change

without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant

any BURR-BROWN product for use in life support devices and/or systems.

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