NSC LM117HVKGMW8, LM117HVK-MLS, LM117HVH-883, LM117HVH-MLS, LM117HVK-883 Datasheet

April 2000

LM117HV/LM317HV

3-Terminal Adjustable Regulator

General Description

The LM117HV/LM317HV are adjustable 3-terminal positive voltage regulators capable of supplying in excess of 1.5A over a 1.2V to 57V output range. They are exceptionally easy to use and require only two external resistors to set the output voltage. Further, both line and load regulation are better than standard fixed regulators. Also, the LM117HV is packaged in standard transistor packages which are easily mounted and handled.

In addition to higher performance than fixed regulators, the LM117HV series offers full overload protection available only in IC's. Included on the chip are current limit, thermal overload protection and safe area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is disconnected.

Normally, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors in which case an input bypass is needed. An optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejections ratios which are difficult to achieve with standard 3-terminal regulators.

Besides replacing fixed regulators, the LM117HV is useful in a wide variety of other applications. Since the regulator is ªfloatingº and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded, i.e. do not short the output to ground.

Also, it makes an especially simple adjustable switching regulator, a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM117HV can be used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping the adjustment terminal to ground which programs the output to 1.2V where most loads draw little current.

The LM117HVK STEEL and LM317HVK STEEL are packaged in standard TO-3 transistor packages, while the LM117HVH and LM317HVH are packaged in a solid Kovar base TO-39 transistor package. The LM317HVT uses a TO220 plastic package. The LM117HV is rated for operation from −55ÊC to +150ÊC, and the LM317HV from 0ÊC to +125ÊC.

Features

nAdjustable output down to 1.2V

nGuaranteed 1.5A output current

nLine regulation typically 0.01%/V

nLoad regulation typically 0.1%

nCurrent limit constant with temperature

n100% electrical burn-in

nEliminates the need to stock many voltages

nStandard 3-lead transistor package

n80 dB ripple rejection

nOutput is short-circuit protected

nP+ Product Enhancement tested

Typical Applications

1.2V-45V Adjustable Regulator

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Full output current not available at high input-output voltages

²Optional Ð improves transient response. Output capacitors in the range of 1 µF to 1000 µF of aluminum or tantalum electrolytic are commonly used to provide improved output impedance and rejection of transients.

*Needed if device is more than 6 inches from filter capacitors.

Regulator Adjustable Terminal-3 LM117HV/LM317HV

© 2000 National Semiconductor Corporation

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LM117HV/LM317HV

Typical Applications (Continued)

Digitally Selected Outputs	5V Logic Regulator with
	Electronic Shutdown*

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*Min. output ≈ 1.2V

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*Sets maximum VOUT

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Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

(Note 4)

Power Dissipation	Internally limited
Input Ð Output Voltage Differential	+60V, −0.3V

Operating Junction Temperature Range
LM117HV	−55ÊC to +150ÊC
LM317HV	0ÊC to +125ÊC
Storage Temperature	−65ÊC to +150ÊC
Lead Temperature (Soldering, 10 sec.)	300ÊC
ESD Tolerance (Note 5)	2000V

Electrical Characteristics (Note 2)

Parameter	Conditions		LM117HV				LM317HV			Units
		Min	Typ		Max	Min	Typ		Max
Line Regulation	TJ = 25ÊC, 3V ≤ VIN − V OUT ≤ 60V		0.01		0.02		0.01		0.04	%/V
	(Note 3) IL = 10 mA
Load Regulation	TJ = 25ÊC, 10 mA ≤ IOUT ≤ IMAX		0.1		0.3		0.1		0.5	%
Thermal Regulation	TJ = 25ÊC, 20 ms Pulse		0.03		0.07		0.04		0.07	%/W
Adjustment Pin Current			50		100		50		100	µA
Adjustment Pin Current Change	10 mA ≤ IL ≤ IMAX		0.2		5		0.2		5	µA
	3.0 V ≤ (VIN − V OUT) ≤ 60V
Reference Voltage	3.0 V ≤ (VIN − V OUT) ≤ 60V, (Note 4)	1.20	1.25		1.30	1.20	1.25		1.30	V
	10 mA ≤ IOUT ≤ IMAX, P ≤ PMAX
Line Regulation	3.0V ≤ (VIN − V OUT) ≤ 60V,		0.02		0.05		0.02		0.07	%/V
	IL = 10 mA, (Note 3)
Load Regulation	10 mA ≤ IOUT ≤ IMAX (Note 3)		0.3		1		0.3		1.5	%
Temperature Stability	TMIN ≤ TJ ≤ TMAX		1				1			%
Minimum Load Current	(VIN − V OUT) = 60V		3.5		7		3.5		12	mA
Current Limit	(VIN − V OUT) ≤ 15V
	K, T Packages	1.5	2.2		3.5	1.5	2.2		3.7	A
	H Package	0.5	0.8		1.8	0.5	0.8		1.9	A
	(VIN − V OUT) ≤ 60V
	K, T Packages		0.3				0.3			A
	H Package		0.03				0.03			A
RMS Output Noise, % of VOUT	TJ = 25ÊC, 10 Hz ≤ f ≤ 10 kHz		0.003				0.003			%
Ripple Rejection Ratio	VOUT = 10V, f = 120 Hz		65				65			dB
	CADJ = 10 µF	66	80			66	80			dB
Long-Term Stability	TJ = 125ÊC		0.3		1		0.3		1	%
Thermal Resistance,	H Package		12		15		12		15	ÊC/W
Junction to Case	T Package						4		5	ÊC/W
	K Package		2.3		3		2.3		3	ÊC/W
Thermal Resistance,	H Package		140				140			ÊC/W
Junction to Ambient	T Package						50			ÊC/W
(no heat sink)	K Package		35				35			ÊC/W

Note 1: ªAbsolute Maximum Ratingsº indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the devicesi functional, but do not guarantee specific performance limits.

Note 2: Unless otherwise specified, these specifications apply: −55ÊC ≤ TJ ≤ +150ÊC for the LM117HV, and 0ÊC ≤ TJ ≤ +125ÊC for the LM317HV; VIN − V OUT = 5V and IOUT = 0.1A for the TO-39 package and IOUT = 0.5A for the TO-3 and TO-220 packages. Although power dissipation is internally limited, these specifications are applicable for power dissipations of 2W for the TO-39 and 20W for the TO-3 and TO-220. IMAX is 1.5A for the TO-3 and TO-220 and 0.5A for the TO-39 package. Note 3: Regulation is measured at constant junction temperature. Changes in output voltage due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used.

Note 4: Refer to RETS117HVH for LM117HVH or RETS117HVK for LM117HVK military specificatioins.

Note 5: Human body model, 1.5 kΩ in series with 100 pF.

LM117HV/LM317HV

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LM117HV/LM317HV

Typical Performance Characteristics Output capacitor = 0 µF unless otherwise noted.

Load Regulation

Current Limit

Adjustment Current

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Dropout Voltage		Temperature Stability	Minimum Operating Current

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Ripple Rejection Ripple Rejection Ripple Rejection

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Output Impedance	Line Transient Response		Load Transient Response

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Application Hints

In operation, the LM117HV develops a nominal 1.25V reference voltage, VREF, between the output and adjustment terminal. The reference voltage is impressed across program resistor R1 and, since the voltage is constant, a constant current I1 then flows through the output set resistor R2, giving an output voltage of

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FIGURE 1.

Since the 100 µA current from the adjustment terminal represents an error term, the LM117HV was designed to minimize IADJ and make it very constant with line and load changes. To do this, all quiescent operating current is returned to the output establishing a minimum load current requirement. If there is insufficient load on the output, the output will rise.

External Capacitors

An input bypass capacitor is recommended. A 0.1 µF disc or 1 µF solid tantalum on the input is suitable input bypassing for almost all applications. The device is more sensitive to the absence of input bypassing when adjustment or output capacitors are used but the above values will eliminate the possiblity of problems.

The adjustment terminal can be bypassed to ground on the LM117HV to improve ripple rejection. This bypass capacitor prevents ripple from being amplified as the output voltage is increased. With a 10 µF bypass capacitor 80 dB ripple rejection is obtainable at any output level. Increases over 10 µF do not appreciably improve the ripple rejection at frequencies above 120 Hz. If the bypass capacitor is used, it is sometimes necessary to include protection diodes to prevent the capacitor from discharging through internal low current paths and damaging the device.

In general, the best type of capacitors to use are solid tantalum. Solid tantalum capacitors have low impedance even at high frequencies. Depending upon capacitor construction, it takes about 25 µF in aluminum electrolytic to equal 1 µF solid tantalum at high frequencies. Ceramic capacitors are also good at high frequencies; but some types have a large decrease in capacitance at frequencies around 0.5 MHz. For this reason, 0.01 µF disc may seem to work better than a 0.1 µF disc as a bypass.

Although the LM117HV is stable with no output capacitors, like any feedback circuit, certain values of external capacitance can cause excessive ringing. This occurs with values between 500 pF and 5000 pF. A 1 µF solid tantalum (or 25 µF aluminum electrolytic) on the output swamps this effect and

insures stability. Any increase of load capacitance larger than 10 µF will merely improve the loop stability and output impedance.

Load Regulation

The LM117HV is capable of providing extremely good load regulation but a few precautions are needed to obtain maximum performance. The current set resistor connected between the adjustment terminal and the output terminal (usually 240Ω) should be tied directly to the output of the regulator rather than near the load. This eliminates line drops from appearing effectively in series with the reference and degrading regulation. For example, a 15V regulator with 0.05Ω resistance between the regulator and load will have a load regulation due to line resistance of 0.05Ω x IL. If the set resistor is connected near the load the effective line resistance will be 0.05Ω (1 + R2/R1) or in this case, 11.5 times worse.

Figure 2 shows the effect of resistance between the regulator and 240Ω set resistor.

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FIGURE 2. Regulator with Line

Resistance in Output Lead

With the TO-3 package, it is easy to minimize the resistance from the case to the set resistor, by using two separate leads to the case. However, with the TO-5 package, care should be taken to minimize the wire length of the output lead. The ground of R2 can be returned near the ground of the load to provide remote ground sensing and improve load regulation.

Protection Diodes

When external capacitors are used with any IC regulator it is sometimes necessary to add protection diodes to prevent the capacitors from discharging through low current points into the regulator. Most 10 µF capacitors have low enough internal series resistance to deliver 20A spikes when shorted. Although the surge is short, there is enough energy to damage parts of the IC.

When an output capacitor is connected to a regulator and the input is shorted, the output capacitor will discharge into the output of the regulator. The discharge current depends on the value of the capacitor, the output voltage of the regulator, and the rate of decrease of VIN. In the LM117HV, this discharge path is through a large junction that is able to sustain 15A surge with no problem. This is not true of other types of positive regulators. For output capacitors of 25 µF or less, there is no need to use diodes.

The bypass capacitor on the adjustment terminal can discharge through a low current junction. Discharge occurs when either the input or output is shorted. Internal to the LM117HV is a 50Ω resistor which limits the peak discharge current. No protection is needed for output voltages of 25V

LM117HV/LM317HV

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