LT1389 Nanopower Precision Shunt Voltage Reference U FEATURES DESCRIPTIO Initial Voltage Accuracy: 0.05% Low Operating Current: 800nA Low Drift: 10ppm/C Max Less Than 1 Dynamic Impedance Available in 1.25V, 2.5V, 4.096V and 5V SO-8 Packages U APPLICATIO S The LT (R)1389 is a nanopower, precision shunt voltage reference. The bandgap reference uses trimmed precision thin-film resistors and improved curvature correction techniques to achieve 0.05% initial voltage accuracy with guaranteed 10ppm/C maximum temperature drift. Voltage regulation is maintained to an ultralow 800nA operating current. Advances in design, processing and packaging achieve low temperature cycling hysteresis. The LT1389 does not require an output compensation capacitor, but is stable with capacitive loads. Low dynamic impedance makes the LT1389 reference easy to use from unregulated supplies. Portable Meters Precision Regulators A/D and D/A Converters Calibrators The LT1389 reference can be used as a high performance upgrade to the LM185/LM385, LT1004, LT1034 and LT1634 where lowest power and guaranteed temperature drift are required. , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO Temperature Drift 5V 4.7M VOUT 1.25V LT1389-1.25 1389 TA01 REFERENCE VOLTAGE CHANGE (mV) 2.0 IR = 0.8A VOUT = 1.25V 1.5 1.0 0.5 0 - 0.5 -1.0 -1.5 - 2.0 0 10 20 40 50 30 TEMPERATURE (C) 60 70 1389 TA02 1 LT1389 W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) Operating Current 1.25V ............................................................... 20mA 2.5V ................................................................. 20mA 4.096V ............................................................. 10mA 5V .................................................................... 10mA Forward Current .................................................. 20mA Operating Temperature Range ..................... 0C to 70C Storage Temperature Range (Note 2) ... - 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C ORDER PART NUMBER TOP VIEW DNC* 1 8 DNC* DNC* 2 7 DNC* DNC* 3 6 VOUT GND 4 5 GND S8 PACKAGE 8-LEAD PLASTIC SO LT1389ACS8-1.25 LT1389BCS8-1.25 LT1389BCS8-2.5 LT1389BCS8-4.096 LT1389BCS8-5 S8 PART MARKING TJMAX = 125C, JA = 190C/ W 1389B4 1389B5 389A12 389B12 389B25 *Connected internally. Do Not Connect external circuitry to these pins. Consult factory for Industrial and Military grade parts. U AVAILABLE OPTIO S TEMPERATURE 0C to 70C OUTPUT VOLTAGE ACCURACY (%) TEMPERATURE COEFFICIENT (ppm/C) PART TYPE PART MARKING 1.250 0.05 10 LT1389ACS8-1.25 389A12 1.250 0.05 20 LT1389BCS8-1.25 389B12 2.500 0.05 20 LT1389BCS8-2.5 389B25 4.096 0.075 50 LT1389BCS8-4.096 1389B4 5.000 0.075 50 LT1389BCS8-5 1389B5 1.25V ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 3) PARAMETER CONDITIONS Reverse Breakdown Voltage LT1389ACS8/LT1389BCS8 (IR = 0.8A) Reverse Breakdown Change with Current (Note 4) MAX UNITS 1.24937 - 0.05 1.250 1.25062 0.05 V % 1.24849 - 0.12 1.250 1.25149 0.12 V % LT1389BCS8 (IR = 0.8A) 1.24762 - 0.19 1.250 1.25237 0.19 V % 0.20 0.20 0.4 1.0 mV mV 0.3 0.3 1.0 2.0 mV mV 0.6 A 0.8A IR 200A Minimum Operating Current Temperature Coefficient LT1389ACS8 (IR = 0.8A) LT1389BCS8 (IR = 0.8A) Reverse Dynamic Impedance (Note 5) 0.8A IR 2mA 2 TYP LT1389ACS8 (IR = 0.8A) 200A IR 2mA Low Frequency Noise (Note 6) MIN IR = 0.8A, 0.1Hz f 10Hz 4 4 10 20 ppm/C ppm/C 0.25 0.25 0.7 1.5 25 VP-P LT1389 2.5V ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 3) PARAMETER CONDITIONS Reverse Breakdown Voltage LT1389BCS8 (IR = 0.9A) LT1389BCS8 (IR = 0.9A) Reverse Breakdown Change with Current (Note 4) MIN TYP MAX 2.49875 - 0.05 2.500 2.50125 0.05 V % 2.49525 - 0.19 2.500 2.50475 0.19 V % 0.2 0.2 0.5 1.5 mV mV 0.3 0.3 1.0 2.5 mV mV 0.7 A ppm/C 0.9A IR 200A 200A IR 2mA Minimum Operating Current Temperature Coefficient IR = 0.9A Reverse Dynamic Impedance (Note 5) 0.9A IR 2mA Low Frequency Noise (Note 6) 8 20 0.25 0.25 0.75 2 IR = 0.9A, 0.1Hz f 10Hz UNITS VP-P 50 4.096V ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 3) PARAMETER CONDITIONS Reverse Breakdown Voltage LT1389BCS8 (IR = 1.5A) LT1389BCS8 (IR = 1.5A) Reverse Breakdown Change with Current (Note 4) MIN TYP MAX 4.09293 - 0.075 4.096 4.09907 0.075 V % 4.0788 - 0.42 4.096 4.1132 0.42 V % 0.2 0.2 1.5 3 mV mV 0.3 0.3 4 6 mV mV 1 A 1.5A IR 200A 200A IR 2mA Minimum Operating Current Temperature Coefficient IR = 1.5A Reverse Dynamic Impedance (Note 5) 1.5A IR 2mA Low Frequency Noise (Note 6) IR = 1.5A, 0.1Hz f 10Hz UNITS 12 50 ppm/C 0.75 0.75 2 3 80 VP-P 3 LT1389 5V ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 3) PARAMETER CONDITIONS Reverse Breakdown Voltage LT1389BCS8 (IR = 1.5A) LT1389BCS8 (IR = 1.5A) Reverse Breakdown Change with Current (Note 4) MIN TYP MAX 4.99625 - 0.075 5.000 5.00375 0.075 V % 4.979 - 0.42 5.000 5.021 0.42 V % 0.2 0.2 1.5 3 mV mV 0.3 0.3 4 6 mV mV 1 A 1.5A IR 200A 200A IR 2mA Minimum Operating Current Temperature Coefficient IR = 1.5A Reverse Dynamic Impedance (Note 5) 1.5A IR 2mA Low Frequency Noise (Note 6) IR = 1.5A, 0.1Hz f 10Hz Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: If the part is stored outside of the specific operating temperature range, the output may shift due to hysteresis. Note 3: ESD (Electrostatic Discharge) sensitive device. Use proper ESD handling precautions. 4 UNITS 12 50 ppm/C 0.75 0.75 2 3 100 VP-P Note 4: Output requires 0.1F for operating current greater than 1mA. Note 5: This parameter is guaranteed by "reverse breakdown change with current" test. Note 6: Peak-to-peak noise is measured with a single highpass filter at 0.1Hz and 2-pole lowpass filter at 10Hz. LT1389 U W 1.25V TYPICAL PERFOR A CE CHARACTERISTICS Reverse Characteristics TA = - 40C TO 85C 0.8 0.6 0.4 0.2 0.8 0.4 1.2 REVERSE VOLTAGE (V) 1.0 0.5 0 IR = 250A - 0.5 -1.0 IR = 0.8A -1.5 - 2.0 - 40 1.6 -20 60 0 40 20 TEMPERATURE (C) Reverse Dynamic Impedance 100 DYNAMIC IMPEDANCE (k) DYNAMIC IMPEDANCE () TA = 25C f = 25Hz 100 10 1 0.01 0.1 1 REVERSE CURRENT (mA) 10 NOISE VOLTAGE (V/DIV) 0.2 15 0.1 1 0.01 REVERSE CURRENT (mA) 10 Forward Characteristics 0.9 TA = 25C 0.8 IR = 0.8A COUT = 0F 1 IR = 0.8A COUT = 0.047F IR = 10A COUT = 0.1F 0.1 0.1 1 FREQUENCY (kHz) 0.6 0.5 0.4 0.3 0.2 IR = 10A COUT = 0F 0.01 0.01 0.7 0.1 10 0 0.001 0.01 0.1 1 10 FORWARD CURRENT (mA) 100 1389-1.25 G06 1389-1.25 G05 Response Time Response Time 10 85C 1389-1.25 G03 TA = 25C 10 0.1Hz to 10Hz Noise IR = 0.8A 25C 0.4 1.0 1389-1.25 G04 20 - 40C 0.6 Dynamic Impedance vs Frequency 1000 25 0.8 1389-1.25 G02 1389-1.25 G01 0.1 0.001 1.0 0 0.001 80 FORWARD VOLTAGE (V) 0 1.5 REVERSE VOLTAGE CHANGE (mV) REFERENCE VOLTAGE CHANGE (mV) REVERSE CURRENT (A) 1.2 2.0 1.0 0 Reverse Voltage Change vs Current Temperature Drift 1.5V 1V 1.5V 1V 0.5V 0.5V 0V 0V 5V 0V 5V 0V 5 0 -5 -10 IR = 0.8A COUT = 0F -15 1ms/DIV 1389-1.25 G08 IR = 0.8A COUT = 0.1F 200ms/DIV 1389-1.25 G09 - 20 - 25 0 10 20 30 40 50 TIME (SEC) 60 70 1389-1.25 G07 5 LT1389 U W 2.5V TYPICAL PERFOR A CE CHARACTERISTICS Reverse Characteristics 4.0 1000 600 400 200 0.8 1.2 1.6 2.0 REVERSE VOLTAGE (V) 2.4 2.0 1.0 0 IR = 250A -1.0 IR = 0.9A - 2.0 - 3.0 - 4.0 - 40 2.8 -20 0 40 20 Reverse Dynamic Impedance DYNAMIC IMPEDANCE (k) DYNAMIC IMPEDANCE () 1.2 0.8 25C 0.4 85C 0 0.001 80 100 10 1 0.01 0.1 1 REVERSE CURRENT (mA) 10 TA = 25C 0.9 IR = 0.9A COUT = 0F 1 IR = 0.9A COUT = 0.033F 0.1 IR = 10A COUT = 0.22F IR = 10A COUT = 0F 0.01 0.01 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.1 1 FREQUENCY (kHz) 10 0 0.001 100 1389-2.5 G06 Response Time 3V 2V 3V 2V 1V 1V 0V 0V 0 5V - 20 0V 5V 0V 60 0.01 0.1 1 10 FORWARD CURRENT (mA) 1389-2.5 G05 Response Time 40 TA = 25C 0.8 10 0.1Hz to 10Hz Noise IR = 0.9A 10 Forward Characteristics 1.0 1389-2.5 G04 80 0.01 0.1 1 REVERSE CURRENT (mA) 1389-2.5 G03 Dynamic Impedance vs Frequency 100 TA = 25C f = 25Hz NOISE VOLTAGE (V/DIV) - 40C 1389-2.5 TA02 1000 100 1.6 TEMPERATURE (C) 1389-2.5 G01 0.1 0.001 60 FORWARD VOLTAGE (V) 0.4 0 3.0 REVERSE VOLTAGE CHANGE (mV) REVERSE VOLTAGE CHANGE (mV) REVERSE CURRENT (nA) 2.0 TA = - 40C TO 85C 800 0 Reverse Voltage Change vs Current Temperature Drift 20 - 40 IR = 0.9A COUT = 0F - 60 - 80 -100 0 10 20 30 40 50 TIME (SEC) 60 70 1389-2.5 G07 6 1ms/DIV 1389-2.5 G08 IR = 0.9A COUT = 0.1F 200ms/DIV 1389-2.5 G09 LT1389 U W 4.096V TYPICAL PERFOR A CE CHARACTERISTICS Reverse Characteristics 600 400 200 6 4 2 0 IR = 250A -2 IR = 1.5A -4 -6 -8 - 40 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 REVERSE VOLTAGE (V) REVERSE VOLTAGE CHANGE (mV) REFERENCE VOLTAGE CHANGE (mV) REVERSE CURRENT (nA) 800 0 2.0 8 TA = -40C TO 85C -20 0 40 20 TEMPERATURE (C) 60 Reverse Dynamic Impedance DYNAMIC IMPEDANCE (k) TA = 25C f = 25Hz DYNAMIC IMPEDANCE () 0.8 25C 100 10 1 10 10 Forward Characteristics TA = 25C 0.9 TA = 25C 0.8 10 1 IR = 1.5A COUT = 0.047F IR = 1.5A COUT = 0F 0.1 0.7 0.6 0.5 0.4 0.3 0.2 0.01 0.01 IR = 10A COUT = 0.68F 0.1 1 FREQUENCY (kHz) 1389-4 G04 0.1 0 0.001 10 0.01 0.1 1 10 FORWARD CURRENT (mA) 100 1389-4 G06 1389-4 G05 Response Time Response Time 4V 4V 0V 0V 10V 10V 0V 0V 2ms/DIV 0.1 1 0.01 REVERSE CURRENT (mA) 1389-4 G03 1.0 IR = 10A COUT = 0F 0.01 0.1 1 REVERSE CURRENT (mA) 85C 0.4 Dynamic Impedance vs Frequency 100 1000 IR = 1.5A COUT = 0F - 40C 1.2 1389-4 G02 1389-4 G01 0.1 0.001 1.6 0 0.001 80 FORWARD VOLTAGE (V) 1000 Reverse Voltage Change vs Current Temperature Drift 1389-4 G08 IR = 1.5A COUT = 0.1F 200ms/DIV 1389-4 G09 7 LT1389 U W 5V TYPICAL PERFOR A CE CHARACTERISTICS Reverse Characteristics 600 400 200 0 6 4 2 0 -2 IR = 250A -4 IR = 1.5A -6 -8 - 40 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 REVERSE VOLTAGE (V) REVERSE VOLTAGE CHANGE (mV) 800 -20 0 40 20 TEMPERATURE (C) 60 1389-4 G01 Reverse Dynamic Impedance DYNAMIC IMPEDANCE (k) DYNAMIC IMPEDANCE () TA = 25C f = 25Hz 100 10 1 0.01 0.1 1 REVERSE CURRENT (mA) 10 0 0.001 0.1 1 0.01 REVERSE CURRENT (mA) 10 1389-4 G03 Forward Characteristics TA = 25C 0.9 TA = 25C 0.8 10 1 IR = 1.5A COUT = 0F IR = 1.5A COUT = 0.047F 0.1 0.7 0.6 0.5 0.4 0.3 0.2 0.01 0.01 IR = 10A COUT = 0.1F 0.1 1 FREQUENCY (kHz) 0.1 0 0.001 10 1389-5 G04 0.01 0.1 1 10 FORWARD CURRENT (mA) Response Time 4V 2V 4V 2V 0V 0V 10V 10V 0V 0V 1389-5 G08 IR = 1.5A COUT = 0.1F 100 1389-5 G06 1389-4 G05 Response Time 2ms/DIV 85C 0.4 1.0 IR = 10A COUT = 0F 8 25C 0.8 Dynamic Impedance vs Frequency 100 IR = 1.5A COUT = 0F - 40C 1.2 1389-5 G02 1000 0.1 0.001 1.6 80 FORWARD VOLTAGE (V) REVERSE CURRENT (nA) 2.0 8 TA = -40C TO 85C REFERENCE VOLTAGE CHANGE (mV) 1000 Reverse Voltage Change vs Current Temperature Drift 200ms/DIV 1389-5 G09 LT1389 U W U U APPLICATIO S I FOR ATIO The reverse characteristics of the LT1389 resembles a simple resistor Zener diode parallel connection. This well behaved characteristic is important to the proper operation of circuits like Figure 1. The adjustable output voltage reference depends upon positive feedback from the LT1495's output to start-up and regulate the bias current for the LT1389. The LT1389 has no negative resistance regions that can interfere with the proper start-up of the buffered reference. Board leakage is a concern for a nanopower precision shunt voltage reference. The LT1389 requires attention to detail in board layout in order to maximize its performance. 1.5G of leakage between a DNC pin and a 5V supply will conduct 2.5nA which induces a 0.2% error in VOUT. Board leakage can be minimized by encircling the DNC pins with a guard ring operated at a potential of VOUT. By tying the guard ring to VOUT as shown in Figure 2, leakage paths are eliminated. VIN 10.5V - 1.25V V RB = OUT 0.8A + LT1389-1.25 VOUT 1.5V TO 10V LT1495 - R1 249k TO 8.66M R2 1.24M 1389 F01 Figure 1. Adjustable Output Voltage Reference BOARD METAL TRACE DNC 1 8 DNC DNC 2 7 DNC VOUT LT1389 DNC 3 6 GND 4 5 GND 1389 F02 Figure 2. Guard Ring to Reduce Board Leakage 9 LT1389 U TYPICAL APPLICATIO S 2.5V Output, Low Noise Reference 1F VIN 3V 10k - 510k 10k 1k + LT1495 2.5V + 20F* 100k + LT1389-2.5 20F* *WET SLUG TANTALUM 1389 TA04 Micropower Voltage and Current Reference R3 249k 0.1% 2 AAA ALKALINE CELLS - ZTX214C R4 300k 5% 1/2 LT1495 + 1/2 LT1495 + - R2 1M 0.1% LT1389-1.25 IOUT = 1A R1 TO R3: MAR5 SERIES, IRC (512) 992-7900 10 R1 200k 0.1% COM VOUT = 1.5V 1389 TA03 LT1389 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.189 - 0.197* (4.801 - 5.004) 8 7 6 5 0.150 - 0.157** (3.810 - 3.988) 0.228 - 0.244 (5.791 - 6.197) 1 0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0.053 - 0.069 (1.346 - 1.752) 0- 8 TYP 0.016 - 0.050 (0.406 - 1.270) 0.014 - 0.019 (0.355 - 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 2 3 4 0.004 - 0.010 (0.101 - 0.254) 0.050 (1.270) BSC Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. SO8 1298 11 LT1389 U TYPICAL APPLICATIO S Single Cell Li-Ion Battery Supervisory Circuit, IQ = 10A OFF CHARGER VBAT SW T0 LOAD 1.75V - A2 1/4 LT1496 RS 620k 5% + + A1 1/4 LT1496 R1 500k 0.1% - VBAT + 1.25V A3 1/4 LT1496 RH1 10M 5% D1 RH2 10M 5% D2 A RSW 1M 5% BATTERY - A4 1/4 LT1496 - + R2 1.25M 0.1% LT1389-1.25 R3 1.75M 0.1% R4 1.25M 0.1% 1389 TA05 D1, D2: 1N458 R1 TO R4: CAR6 SERIES IRC (512) 992-7900 SW: PMOS SPECIFIED FOR MAXIMUM LOAD CURRENT Precision Undervoltage Lockout Circuit SW1 VBATT R1 3.57M B 0.1% Li-Ion CELL A 4.1V R2 3M 0.1% R3 2.05M 1% RSW 1M 5% + U1 1/2 LT1495 U2 LT1389 1.250V R4 150k 1% TO LOAD - R5 10M 5% 1389 TA06 R1, R2: IRC CAR6 SERIES (512) 992-7900 SW1: PMOS SPECIFIED FOR MAXIMUM LOAD CURRENT RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC 1440 Micropower Comparator with Reference 3.7A Max Supply Current, 1% 1.182V Reference, MSOP, PDIP and SO-8 Packages LT1460 Micropower Series Reference 0.075% Max, 10ppm/C Max Drift, 2.5V, 5V and 10V Versions, MSOP, PDIP, SO-8, SOT-23 and TO-92 Packages LT1461 Micropower Precision LDO Series Reference 3ppm/C Max Drift, 0C to 70C, -40C to 85C, -40C to 125C Options in SO-8 LT1495 1.5A Precision Rail-to-Rail Dual Op Amp 1.5A Max Supply Current, 100pA Max IOS LTC1540 Nanopower Comparator with Reference 600nA Max Supply Current, 2% 1.182V Reference, MSOP and SO-8 Packages LT1634 Micropower Precision Shunt Voltage Reference 0.05% Max, 10ppm/C Max Drift, 1.25V, 2.5V, 4.096V, 5V, 10A Maximum Supply Current LTC1798 6A Low Dropout Series Reference Available in Adjustable, 2.5V, 3V, 4.096V and 5V (R) 12 Linear Technology Corporation 1389fa LT/TP 0200 2K REV A * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 FAX: (408) 434-0507 www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1998