AMS421

• Trimmed 0.5% Tolerance • Battery Powered Systems • Wide Operating Current Range 0.1µA to 10mA • Switching Power Supplies • Low Reference Input Current 1.5nA • Isolated Power Supplies • Low Dynamic Output Impedance • Telecommunications • Low Output Noise • Error Amplifiers • Nominal Temperature Range to 125°C • Notebook/Personal Computer • Temperature-Compensated: 50ppm/°C • Monitors/ VCR/ TV • Low supply current: typ. 10µA • Opto-isolator driver

GENERAL DESCRIPTION

The AMS421 is a four-terminal adjustable open collector shunt regulator with guaranteed temperature stability over the entire range of operation. The output voltage can be set to any value between 0.5V (VREF) and 15V by adding two external resistors. The AMS421 features 0.5% initial tolerance, low dynamic output impedance and operates over a wide current range. Due to the sharp turn-on characteristics this device is an excellent replacement for Zener diodes in many applications. AMS421 is available 5 pin SOT-23 packages.

ORDERING INFORMATION: PIN CONNECTIONS

5L SOT-23 TOL. Package OPERATING

(M1) TEMP. RANGE 5 LEAD SOT-23

AMS421AM1 -40 to + 125°C ±0.5% AMS421BM1 -40 to + 125°C ±1.0%

5COLLVCC1AMS421CM1 -40 to + 125°C ±2.0%

GND2BLOCK DIAGRAM

N/C3VCC 15Co4REF

Top View Ref4+

-0.5V

2

GND

1Advanced Monolithic Systems http://www.ams-semitech.comABSOLUTE MAXIMUM RATINGS (Note 1) AMS421Supply Voltage (VCC) 15V Internal Power Dissipation (PD)

10mA SOT-23-5 Package 0.3 W Continuous Collector Current (IC)

Reference Input Current (IREF) 0.5mA

Junction Temperature (TJ) -40°C to +125°C Thermal Resistance (θJA)

Storage temperature SOT-23-5 Package -65°C to +150°C 410°C/W Lead Temperature (Soldering, 10sec.) 265°C Note 1 : Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the

device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed.

ELECTRICAL CHARACTERISTICS

Electrical Characteristics at ICOL =1 mA and TA = +25°C unless otherwise noted. AMS421A AMS421B Parameter Conditions Min Typ Max Min Typ Max

Reference Voltage

AMS421C

Min Typ Max

Units

497.5 500.0 502.25 495.0 500.0 505.0 490.0 500.0 510.0 mV

0.5

0.5

2.5

0.5

3

0.5

5

mV

Deviation of Reference VCOL = VREF

Voltage over TA = -40°C to Temperature +125°C Change in Reference Voltage to Supply Voltage Reference Input Current

Reference Input

Current Deviation over Temperature Off State Collector Current Dynamic Output Impedance Minimum Operating Current

Input Supply Current

ICOL = 100µA Vcc=1.4V to 15V ICOL = 0.1µA to 10mA ICOL = 0.1µA to 10mA

TA = Full Range VREF = 0V

f < 1KHz,

ICOL =1 nA to 10mA VCOL = VREF ICOL = 100 µA

1.0 0.5 1.5 0.5 2 mV 0.5 5 0..5 5 0.5 5 nA

0.1 0.7 0.1 0.7 0.1 0.7 nA

0.04 0.1 0.04 0.1 0.04 0.1 nA

0.35 0.5 0.35 0.5 0.35 0.5 Ω

15

0.1 20

15

0.1 20

15

0.1 20

nA µA

RECOMMENDED OPERATING CONDITIONS:

Min Max Collector Voltage, (VCOL) VREF 15 V Collector Current, (ICOL) 10mA 1µA

2Advanced Monolithic Systems http://www.ams-semitech.com TYPICAL APPLICATIONS

AMS4211.5V ≤ VCC ≤ 15V

1.5V to 15V

0.1µF1510K

Ref4+VO1.000V100K0.47µF-0.5V100K500 pF2

LOW NOISE PRECISSION 1.000V REFERENCE

2.5V ≤ VCC ≤ 15V

Q1

0.1µ

R3

1

54

VO

R10.47µFCo

+ - 0.5VR2

2

Low cost LDO using an External PNP

Set the VOUT according to the following equation:

R1⎞⎛

VOUT= VREF⎜1+⎟+IREFR1

R2⎠⎝

GND

Maximum output current is (PNP Hfe)10mA. The transistor current rating and package depends of the application dropout.

The power dissipation for the PNP transistor is Iout (Vin-Vout). The package type should be selected according to the Power dissipation.

3Advanced Monolithic Systems http://www.ams-semitech.comAMS421 TYPICAL PERFORMANCE CHARACTERISTICS

Output voltage vs. Supply voltage @ 100 µA 10.80.60.60.50.4Vout changeOutput resistance Vs loadmV 0.40.20-0.205Vcc1015Vout change0.30.20.100246810Load step mAoutput resSupply Current vs Input Voltage @100uA load3025 uASupply current vs load2001801601401201008060402001.00E-061.00E-051.00E-041.00E-031.00E-02Load20uA151050010Volts2030IVcc uAIvcc uAVery low current regulation0.510.505Volts ouptutInput output transfer characteristic0.90.80.70.60.50.40.30.20.10012345Volts inputVoutVolts0.50.4950.491.00E-1.00E-1.00E-1.00E-1.00E-1.00E-1.00E-09080706050403loadVout4Advanced Monolithic Systems http://www.ams-semitech.comAMS421 TYPICAL PERFORMANCE CHARACTERISTICS (Continued)

dBdB

PSRR0-10-20-30VoutOutput rejection Load 1k /10n-30-35-40-45-50-55-60-65Vout-40-50-60-70101001000Hz100001000001000000-701.00E+031.00E+04Hz1.00E+051.00E+06Input Bias Current654nA

3210510Volts1520Ibias

2 mA load Transient @ VCC=5V, Output Cap=10 nF

2 mA load Transient at VCC=15V, Output Cap=10nF Fast Start up 0-2V with common supply

5Advanced Monolithic Systems http://www.ams-semitech.comAMS421TYPICAL PERFORMANCE CHARACTERISTICS (Continued)

Slow Start up 0-2V with common supply

6Advanced Monolithic Systems http://www.ams-semitech.comAMS421PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.

5 LEAD SOT-23 PLASTIC PACKAGE (M1)

0.110-0.120 (2.794-3.048)0.102-0.118(2.60-3.00)0.059-0.070(1.50-1.75)0.037(0.95) TYP0.018-0.024(0.457-0.610)0.014-0.020(0.350-0.50)10°NOM0.036-0.051(0.090-1.30)0.0035-0.0080(0.090-0.20)0.003(0.150)MAX0.075(1.90) TYP10°NOM0.018-0.024(0.457-0.610) (SOT-23-5 ) AMS DRW# 051001

7Advanced Monolithic Systems http://www.ams-semitech.com