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Rev 0; 1/06
KIT ATION EVALU E AILABL AV
Sample-and-Infinite Hold Voltage Reference
General Description Features
Precise Electronically Adjustable Voltage Reference Enables Automated Factory Trimming of Devices Needing Voltage Adjustment Can be Adjusted to Within 1.5mV Wide Adjustable Output Voltage Range Within 300mV of the Supply Rails Low Temperature Coefficient 1mA of Output-Current Drive NV Memory Stores the Voltage Indefinitely Output Short-Circuit Protection Low Cost
DS4305
The DS4305 is a nonvolatile (NV) sample-and-infinitehold adjustable voltage reference. The reference voltage is programmed in-circuit during factory calibration/ programming. Programming the reference voltage, VOUT, is as simple as applying the desired voltage on VIN and toggling the adjust pin (ADJ) to lock the VOUT voltage level indefinitely, even if the device is power cycled. The DS4305 replaces current cumbersome factory adjustment arrangements with a low-cost solution that can be adjusted using automated techniques. In addition, the DS4305 has the ability to be readjusted after the unit has been fully assembled and tested. This results in a much more flexible manufacturing arrangement, lower inventory costs, and a quicker time-to-market.
Applications
Power-Supply Calibration Threshold Setting Offset Nulling Bias Adjusting Power Amps Pressure Bridges Factory-Calibrated Equipment
Low Power Consumption 4.0V to 5.5V Single-Supply Operation Small 5-Lead SOT23 Package -40C to +125C Temperature Operation DS4305K Evaluation Kit is Available
Ordering Information
PART DS4305R+T&R TEMP RANGE -40C to +125C PINPACKAGE 5 SOT23 SOT MARK 4305+
+Denotes lead-free package.
Typical Operating Circuit
EXISTING SOLUTION VCC DS4305 SOLUTION
Pin Configuration
TOP VIEW
ADJ 1 5 VCC
REFERENCE VOLTAGE
VCC
SHUNT VOLTAGE REFERENCE
DS4305
GND HAND-SELECTED 0.1% RESISTOR OR MECHANICAL POT VIN ADJ
VOUT
REFERENCE VOLTAGE
GND
2
DS4305
VIN
ACCESS FOR AUTOMATED ALIGNMENT
3
4
VOUT
SOT23
______________________________________________ Maxim Integrated Products
1
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Sample-and-Infinite Hold Voltage Reference DS4305
ABSOLUTE MAXIMUM RATINGS
Voltage on VCC Relative to GND ...........................-0.5V to +6.0V Voltage on VIN, ADJ, and VOUT Relative to GND ...-0.5V to (VCC + 0.5V), not to exceed +6.0V Operating Temperature Range .........................-40C to +125C EEPROM Programming Adjust Temperature..........0C to +70C VOUT to GND Short-Circuit Duration .........................Continuous Storage Temperature Range .............................-55C to +125C Soldering Temperature ...See IPC/JEDEC J-STD-020 Specification
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED OPERATING CONDITIONS
(TA = -40C to +125C)
PARAMETER Supply Voltage VIN Voltage Range ADJ Logic 0 VOUT Current VOUT Load SYMBOL VCC VIN VIL VOUTI VOUTL (Note 1) CONDITIONS MIN 4.0 0.3 -0.3 -1 TYP MAX 5.5 VCC - 0.3 0.3 x VCC +1 100 UNITS V V V mA pF
ELECTRICAL CHARACTERISTICS
(VCC = +4.0V to +5.5V, TA = -40C to +125C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS -40C to +85C; VIN, ADJ, and VOUT = open circuit +85C to +125C; VIN, ADJ, and VOUT = open circuit 95 18 (Note 1) (Note 2) (Note 3) -40C to +85C, VOUT = 0.7V VOUT Temperature Coefficient VOUT TC -40C to +25C, VOUT = 5.0V, VCC 5.3V +25C to +85C, VOUT = 5.0V, VCC 5.3V +85C to +125C, VOUT = 5.0V, VCC 5.3V VOUT Line Regulation VOUT Load Regulation Long-Term Stability VOUT Noise VOUT LN VOUT LD VOUTLTS en1 en2 -40C to +85C +85C to +125C -40C to +85C, -1mA VOUT I +1mA +85C to +125C, -1.0mA VOUT I +1.0mA 1000 hours at +25C 0.1Hz f 10Hz 10Hz f 1kHz 160 23 7 -24 -43 -1.6 -1.6 56 34 -7 -23 60 +10 -3 +1.8 +1.8 2.0 2.5 mV/V mV/mA ppm VP-P VRMS ppm/C 0.3 VCC - 0.3 20 1.5 MIN TYP 1.4 MAX 2.0 mA 2.1 k k V mV mV V/C UNITS
Supply Current
IIN
VIN Resistance ADJ Pullup Resistance VOUT Voltage Range VOUT Tracking Accuracy VOUT Quantization
RPD RPU VOUTR VOUTTA VOUTQ
2
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Sample-and-Infinite Hold Voltage Reference
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +4.0V to +5.5V, TA = -40C to +125C, unless otherwise noted.)
PARAMETER VOUT PSRR VOUT Self-Adjust Settling Time EEPROM Programming Time Turn-On Time ADJ Toggle Low Time VOUT Factory-Trimmed Value SYMBOL VOUTPSRR tST tW tON tADJ VOUT FT +25C, VCC = 5.8V (Note 7) f = 200kHz (Note 4) (Note 5) VIN and ADJ = open circuit (Note 6) 100 1200 CONDITIONS MIN TYP 28 7 9 10 12 10 MAX UNITS dB ms/V ms s ns mV
DS4305
NONVOLATILE MEMORY CHARACTERISTICS
(VCC = +4.0V to 5.5V, unless otherwise noted.)
PARAMETER Programming Cycles SYMBOL +70C (Note 8) CONDITIONS MIN 50,000 TYP MAX UNITS Cycles
Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8:
All voltages referenced to ground. Tracking accuracy is defined as VOUT - VIN after the DS4305 has completed self-adjustment. Quantization refers to the size of the voltage steps used to track the input signal. Settling time is the maximum amount of time VOUT requires to self-adjust. The settling time is determined by the following formula: VOUT x tST. EEPROM programming time is the hold time required after the DS4305 has completed self-adjustment before VIN or VCC can be removed or before ADJ can be toggled low once again. Turn-on time is defined as the time required for VOUT to reach its specified accuracy after the required supply voltage is applied. VOUT not loaded. Guaranteed by design.
Typical Operating Characteristics
(VCC = 5.0V, TA = +25C, unless otherwise noted.)
ACTIVE SUPPLY CURRENT vs. TEMPERATURE (VOUT = 0.3V)
DS4305 toc01
ACTIVE SUPPLY CURRENT vs. TEMPERATURE (VOUT = 3.5V)
DS4305 toc02
ACTIVE SUPPLY CURRENT vs. SUPPLY VOLTAGE (VOUT = 0.3V)
DS4305 toc03
1.6 1.5 SUPPLY CURRENT (mA) VCC = 5.0V 1.4 1.3 1.2 1.1 IL = 0mA 1.0 -40 -10 20 50 80 TEMPERATURE (C) 110 ADJ = VCC VCC = 4.0V VCC = 5.5V
1.8 1.7 SUPPLY CURRENT (mA) 1.6 VCC = 5.5V 1.5 VCC = 5.0V 1.4 1.3 1.2 IL = 0mA 1.1 -40 -10 20 50 80 110 TEMPERATURE (C) ADJ = VCC VCC = 4.0V
1.6 1.5 SUPPLY CURRENT (mA) TA = +125C 1.4 1.3 1.2 1.1 IL = 0mA 1.0 4.0 4.3 4.6 4.9 5.2 TA = +25C TA = -40C TA = +85C
5.5
SUPPLY VOLTAGE (V)
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Sample-and-Infinite Hold Voltage Reference DS4305
Typical Operating Characteristics (continued)
(VCC = 5.0V, TA = +25C, unless otherwise noted.)
LOAD REGULATION (VOUT = 0.3V)
DS4305 toc04
LOAD REGULATION (VOUT = 5.2V)
DS4305 toc05
LINE REGULATION (VOUT = 0.3V)
DS4305 toc06
2.0 OUTPUT VOLTAGE CHANGE (mV) 1.5 1.0 0.5 0 TA = -40C -0.5 TA = +25C -1.0 -1.5 -1.0 -0.5 0 0.5 VCC = 4.0V TA = +125C TA = +85C
1.0 OUTPUT VOLTAGE CHANGE (mV) 0.5 0 -0.5 -1.0 -1.5 TA = +125C -2.0 VCC = 5.5V -2.5 TA = -40C TA = +25C TA = +85C
0 -100 -200 TA = +125C -300 TA = -40C -400 TA = +85C -500 -600
1.0
-1.0
-0.5
0
0.5
-1.0
OUTPUT VOLTAGE CHANGE (V)
4.0
4.3
4.6
4.9
5.2
5.5
LOAD CURRENT (mA)
LOAD CURRENT (mA)
SUPPLY VOLTAGE (V)
LINE REGULATION (VOUT = 3.5V)
DS4305 toc07
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY (VCC = 5.0V)
DS4305 toc08
DS4305 OUTPUT NOISE (0.1Hz TO 10Hz)
DS4305 toc09
20 TA = -40C OUTPUT VOLTAGE CHANGE (V) 0 -20 TA = +85C
80 70 60 PSRR (dB) VOUT = 0.3V, VCC-AC = 300mVRMS
300 200 100
TA = +125C -40 -60 -80 -100 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V)
40 30 20 10 0 1
VOUT = 4.5V, VCC-AC = 300mVRMS
VOUT (V)
50
0 -100 -200 VCC = 5.5V -300 VOUT = 5V 1.5 2.0 TIME (s) 2.5 3.0 3.5 4.0
10
100
1000
0
0.5
1.0
FREQUENCY (kHz)
DS4305 OUTPUT NOISE (10Hz TO 1kHz)
DS4305 toc10
DS4305 TURN-ON TRANSIENT
4.5 4.0 3.5 VOLTAGE (V) 3.0 2.5 2.0 1.5 1.0 VOUT VCC
DS4305 toc11
DS4305 LOAD TRANSIENT (VOUT = 3.0V, VCC = 5.0V)
4.5 4.0 3.5 VOUT NOISE / (VHz) 3.0 2.5 2.0 1.5 1.0 0.5 0 10 100 FREQUENCY (Hz) VCC = 5.5V VOUT = 5V
5.0
DS4305 toc12
+1mA IOUT -1mA VOUT AC-COUPLED 300mV/div COUT =100pF 1s/div
0.5 0 1000
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Sample-and-Infinite Hold Voltage Reference DS4305
Typical Operating Characteristics (continued)
(VCC = 5.0V, TA = +25C, unless otherwise noted.)
DS4305 LINE TRANSIENT (VOUT = 3.0V)
DS4305 toc13
DS4305 SHUTDOWN TRANSIENT (VOUT = 4.0V)
DS4305 toc14
5.5V VCC 4.0V 1.1V/div VCC VOUT
VOUT AC-COUPLED 300mV/div
COUT = 100pF
DS4305 VOUT ADJUST TRANSIENT (VIN = 0.3V TO 4.0V, VCC = 5.0V)
DS4305 toc15
DS4305 NORMALIZED VOUT vs. TEMPERATURE (VOUT = 0.7V)
1.008
DS4305 toc16
1.010
2V/div
ADJ VOUT (V/V)
1.006 1.004 1.002 1.00 0.998 0.996 0.994 0.992 0.990 -40 -10 20 50 VCC = 5.0V 80 110
1V/div
VOUT
TEMPERATURE (C)
DS4305 NORMALIZED VOUT vs. TEMPERATURE (VOUT = 5.0V)
DS4305 toc17
1.001 1.000 0.999 VOUT (V/V) 0.998 0.997 0.996 0.995 -40 -10 20 50 VCC = 5.5V 80 110
TEMPERATURE (C)
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Sample-and-Infinite Hold Voltage Reference DS4305
Pin Description
PIN 1 2 3 4 5 NAME ADJ GND VIN VOUT VCC Ground Sample Voltage Input Voltage Output Power-Supply Voltage FUNCTION Adjust Control Input
Detailed Description
The DS4305 provides a precise, NV output voltage, VOUT, making it an ideal solution for factory calibration of embedded systems. The DS4305 output voltage can be adjusted over almost the entire operating supply range of the device, and it can be precisely set to within 1.5mV. A graphical description of the DS4305 is provided in the block diagram. During factory calibration, a simple adjustment procedure must be followed. This entire procedure includes setting VIN, toggling ADJ, waiting as VOUT self-adjusts, and waiting for the completion of the EEPROM storage cycle (see the timing diagram in Figure 1). At the start of calibration, a voltage must be placed on VIN. This voltage needs to be completely stable before the adjustment procedure begins, and it must remain stable throughout the entire adjustment procedure. The DS4305 starts its self-adjust procedure when the ADJ pin is pulled low and held low for at least tADJ, after which it can be released at any time. Once ADJ has been released, it should not be toggled again for the remainder of the adjustment procedure. After the falling edge on ADJ and the wait time, tADJ, the VOUT selfadjust period begins. The length of the VOUT self-adjust period can be determined using the formula V x tST, where V is | VOUT OLD - VOUT NEW |.
Block Diagram
VCC
DS4305
RPU ADJ ADC AND CONTROL VIN VCC VCC GND RPD EEPROM VREF 12-BIT DAC VOUT
VOUT
VOUT VOUT x tST
VOUT
VOUT x tST
VIN tW tW
ADJ tADJ tADJ tADJ
FIRST PROGRAMMING CYCLE
ADDITIONAL PROGRAMMING CYCLES (IF REQUIRED)
Figure 1. Timing Diagram 6 _____________________________________________________________________
Sample-and-Infinite Hold Voltage Reference DS4305
AUTOMATED TEST EQUIPMENT DEVICE-UNDER-TEST (DUT)
DS4305 STEP 1: SET REFERENCE VOLTAGE STEP 2: TOGGLE ADJ DIGITALLY CONTROLLED VOLTAGE SOURCE EEPROM VIN ADJ DIGITAL PIN DRIVER GND BED-OF-NAILS TEST ACCESS DIGITALLY CONTROLLED MEASUREMENT PARAMETER MEASURED DURING CALIBRATION VOLTAGE SAMPLE-ANDINFINITEHOLD VOUT CIRCUITRY REQUIRING VOLTAGE ADJUSTMENT 4.0V TO 5.5V VCC
STEP 3: DETERMINE IF THE REFERENCE VOLTAGE NEEDS ADJUSTMENT
Figure 2. Application Circuit
During the VOUT self-adjust period, the DS4305 internally adjusts the on-board DAC until VOUT matches VIN. After VOUT has stabilized to within the tracking accuracy, VOUTTA, of VIN, it will be automatically stored in EEPROM. The storage period lasts for the duration of the EEPROM write time, tW. After the first adjustment procedure has completed, V OUT can be measured, and if necessary VIN can be readjusted and the entire adjustment procedure can be repeated to fine-tune VOUT within the VOUTQ range. Following each self-adjust procedure, VOUT is saved indefinitely, even if the DS4305 is power cycled.
circuit. VOUT can be readjusted at any time by following the same procedure. The closed-loop nature of the adjustment process removes all the system inaccuracies such as resistor tolerances, amplifier offsets, gain mismatches, and even the inaccuracies in the automated equipment that provides the reference voltage.
Typical Operating Circuit
The Typical Operating Circuit shows an example of how the DS4305 can replace most existing calibration solutions. Many power supplies use a shunt voltage reference to provide the internal reference voltage, and fine-tune adjustments are often made with hand-selected discrete resistors. The DS4305 replaces this cumbersome arrangement with a solution that is capable of being adjusted by automated techniques. An additional benefit of the DS4305 is the ability to provide a much lower voltage (down to 300mV) than is possible with shunt voltage references. Another benefit of the DS4305 is the ability to be adjusted after the unit has been fully assembled and tested, resulting in a much more flexible manufacturing arrangement, lower inventory costs, and a quicker time-to-market.
Automated Programming Procedure
Figure 2 details an example of how the DS4305 can be adjusted in an application. During factory alignment, a three/four-node bed-of-nails is used to: (1) provide the adjustment voltage through the VIN pin, (2) control the ADJ input, and (3) sense the needed feedback parameter. During manufacture, an automated test procedure adjusts VOUT, by changing VIN, until the feedback parameter is optimized. After the bed-of-nails operation is complete, both the VIN and ADJ inputs are left open
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Sample-and-Infinite Hold Voltage Reference DS4305
Layout Considerations
To prevent an inadvertent programming cycle from occurring during power-up, minimize capacitive loading on the ADJ pin. A large capacitance on this pin could potentially hold ADJ in a low state long enough that a programming cycle is initiated.
Chip Topology
TRANSISTOR COUNT: 6016 SUBSTRATE CONNECTED TO GROUND
Power-Supply Decoupling
To achieve best results, it is highly recommended that a decoupling capacitor is used on the IC power-supply pin. Typical values of decoupling capacitors are 0.01F or 0.1F. Use a high-quality, ceramic, surface-mount capacitor, and mount it as close as possible to the VCC and GND pins of the IC to minimize lead inductance.
Package Information
For the latest package outline information, go to www.maxim-ic.com/DallasPackInfo.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2006 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
is a registered trademark of Dallas Semiconductor Corporation.
Heaney

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