SLLSEQ1A September   2016  – December 2016 ISO5851-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Function
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Power Ratings
    6. 7.6  Insulation Characteristics
    7. 7.7  Safety-Related Certifications
    8. 7.8  Safety Limiting Values
    9. 7.9  Electrical Characteristics
    10. 7.10 Switching Characteristics
    11. 7.11 Insulation Characteristics Curves
    12. 7.12 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Supply and Active Miller Clamp
      2. 9.3.2 Active Output Pulldown
      3. 9.3.3 Undervoltage Lockout (UVLO) With Ready (RDY) Pin Indication Output
      4. 9.3.4 Fault (FLT) and Reset (RST)
      5. 9.3.5 Short Circuit Clamp
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1  Recommended ISO5851-Q1 Application Circuit
        2. 10.2.2.2  FLT and RDY Pin Circuitry
        3. 10.2.2.3  Driving the Control Inputs
        4. 10.2.2.4  Local Shutdown and Reset
        5. 10.2.2.5  Global-Shutdown and Reset
        6. 10.2.2.6  Auto-Reset
        7. 10.2.2.7  DESAT Pin Protection
        8. 10.2.2.8  DESAT Diode and DESAT Threshold
        9. 10.2.2.9  Determining the Maximum Available, Dynamic Output Power, POD-max
        10. 10.2.2.10 Example
        11. 10.2.2.11 Higher Output Current Using an External Current Buffer
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 PCB Material
    3. 12.3 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Community Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DW|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings

Over operating free-air temperature range (unless otherwise noted)(1)
MIN MAX UNIT
VCC1 Supply voltage input side GND1 - 0.3 6 V
VCC2 Positive supply voltage output side VCC2 – GND2 –0.3 35 V
VEE2 Negative supply voltage output side VEE2 – GND2 –17.5 0.3 V
V(SUP2) Total supply output voltage VCC2 – VEE2 –0.3 35 V
VOUT Gate driver output voltage VEE2 – 0.3 VCC2 + 0.3 V
I(OUTH) Gate driver high output current Gate driver high output current
max pulse width = 10 μs, max duty cycle = 0.2%		 2.7 A
I(OUTL) Gate driver low output current Gate driver high output current
max pulse width = 10 μs, max duty cycle = 0.2%		 5.5 A
V(LIP) Voltage at IN+, IN–,FLT, RDY, RST GND1 – 0.3 VCC1 + 0.3 V
I(LOP) Output current of FLT, RDY 10 mA
V(DESAT) Voltage at DESAT GND2 – 0.3 VCC2 + 0.3 V
V(CLAMP) Clamp voltage VEE2 – 0.3 VCC2 + 0.3 V
TJ Junction temperature –40 150 °C
TSTG Storage temperature –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per AEC Q100-002(1) ±4000 V
Charged-device model (CDM), per AEC Q100-011 ±1500
(1) AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

7.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
VCC1 Supply voltage input side 3 5.5 V
VCC2 Positive supply voltage output side (VCC2 – GND2) 15 30 V
VEE2 Negative supply voltage output side (VEE2 – GND2) –15 0 V
V(SUP2) Total supply voltage output side (VCC2 – VEE2) 15 30 V
VIH High-level input voltage (IN+, IN–, RST) 0.7 × VCC1 VCC1 V
VIL Low-level input voltage (IN+, IN–, RST) 0 0.3 × VCC1 V
tUI Pulse width at IN+, IN– for full output (CLOAD = 1 nF) 40 ns
tRST Pulse width at RST for resetting fault latch 800 ns
TA Ambient temperature –40 25 125 °C

7.4 Thermal Information

THERMAL METRIC(1) ISO5851-Q1 UNIT
DW (SOIC)
16 PINS
RθJA Junction-to-ambient thermal resistance 99.6 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 48.5 °C/W
RθJB Junction-to-board thermal resistance 56.5 °C/W
ψJT Junction-to-top characterization parameter 29.2 °C/W
ψJB Junction-to-board characterization parameter 56.5 °C/W
(1) For more information about traditional and new thermal metrics, see Semiconductor and IC Package Thermal Metrics (SPRA953).

7.5 Power Ratings

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
PD Maximum power dissipation(1) 1255 mW
PID Maximum input power dissipation 175 mW
POD Maximum output power dissipation 1080 mW
(1) Full chip power dissipation is de-rated 10.04 mW/°C beyond 25°C ambient temperature. At 125°C ambient temperature, a maximum of 251 mW total power dissipation is allowed. Power dissipation can be optimized depending on ambient temperature and board design, while ensuring that Junction temperature does not exceed 150°C.

7.6 Insulation Characteristics

PARAMETER TEST CONDITIONS SPECIFICATION UNIT
CLR External clearance(1) Shortest terminal-to-terminal distance through air 8 mm
CPG External creepage(1) Shortest terminal-to-terminal distance across the package surface 8 mm
DTI Distance through the insulation Minimum internal gap (internal clearance) 21 μm
CTI Comparative tracking index DIN EN 60112 (VDE 0303-11); IEC 60112 >600 V
Material group According to IEC 60664-1 I
Overvoltage category per IEC 60664-1 Rated mains voltage ≤ 600 VRMS I-IV
Rated mains voltage ≤ 1000 VRMS I-III
DIN V VDE V 0884-10 (VDE V 0884-10):2006-12(2)
VIORM Maximum repetitive peak isolation voltage AC voltage (bipolar) 2121 VPK
VIOWM Maximum isolation working voltage AC voltage. Time dependent dielectric breakdown (TDDB) Test, see Figure 1 1500 VRMS
DC voltage 2121 VDC
VIOTM Maximum Transient isolation voltage VTEST = VIOTM, t = 60 sec (qualification), t = 1 sec (100% production) 8000 VPK
VIOSM Maximum surge isolation voltage(3) Test method per IEC 60065, 1.2/50 μs waveform,
VTEST = 1.6 x VIOSM = 12800 VPK (qualification)		 8000
qpd Apparent charge(4) Method a: After I/O safety test subgroup 2/3,
Vini = VIOTM, tini = 60 s;
Vpd(m) = 1.2 × VIORM = 2545 VPK,
tm = 10 s		 ≤5 pC
Method a: After environmental tests subgroup 1,
Vini = VIOTM, tini = 60 s;
Vpd(m) = 1.6 × VIORM = 3394 VPK,
tm = 10 s		 ≤5
Method b1: At routine test (100% production) and preconditioning (type test)
Vini = VIOTM, tini = 60 s;
Vpd(m) = 1.875× VIORM = 3977 VPK,
tm = 10 s		 ≤5
RIO Isolation resistance, input to output(5) VIO = 500 V at TS > 109 Ω
VIO = 500 V, TA = 25°C >1012 Ω
VIO = 500 V, 100°C ≤ TA ≤ 125°C >1011 Ω
CIO Barrier capacitance, input to output(5) VIO = 0.4 x sin (2πft), f = 1 MHz 1 pF
Pollution degree 2
UL 1577
VISO Withstanding Isolation voltage VTEST = VISO, t = 60 sec (qualification),
VTEST = 1.2 × VISO = 6840 VRMS, t = 1 sec (100% production)		 5700 VRMS
(1) Creepage and clearance requirements should be applied according to the specific equipment isolation standards of an application. Care should be taken to maintain the creepage and clearance distance of a board design to ensure that the mounting pads of the isolator on the printed-circuit board do not reduce this distance. Creepage and clearance on a printed-circuit board become equal in certain cases. Techniques such as inserting grooves and/or ribs on a printed circuit board are used to help increase these specifications.
(2) This coupler is suitable for safe electrical insulation only within the safety ratings. Compliance with the safety ratings shall be ensured by means of suitable protective circuits.
(3) Testing is carried out in air or oil to determine the intrinsic surge immunity of the isolation barrier.
(4) Apparent charge is electrical discharge caused by a partial discharge (pd).
(5) All pins on each side of the barrier tied together creating a two-terminal device.

7.7 Safety-Related Certifications

VDE CSA UL CQC TUV
Certified according to
DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 and DIN EN 60950-1 (VDE 0805 Teil 1):2011-01		 Certified according to CSA Component Acceptance Notice 5A, IEC 60950-1, and IEC 60601-1 Certified according to UL 1577 Component Recognition Program Certified according to GB 4943.1-2011 Certified according to
EN 61010-1:2010 (3rd Ed) and
EN 60950-1:2006/A11:2009/A1:2010/
A12:2011/A2:2013
Reinforced Insulation Maximum Transient isolation voltage, 8000 VPK;
Maximum surge isolation voltage, 8000 VPK,
Maximum repetitive peak isolation voltage, 2121 VPK		 Isolation Rating of 5700 VRMS;
Reinforced insulation per CSA 60950-1- 07+A1+A2 and IEC 60950-1 (2nd Ed.), 800 VRMS max working voltage (pollution degree 2, material group I) ;

2 MOPP (Means of Patient Protection) per CSA 60601-1:14 and IEC 60601-1 Ed. 3.1, 250 VRMS (354 VPK) max working voltage		 Single Protection, 5700 VRMS (1) Reinforced Insulation, Altitude ≤ 5000m, Tropical climate, 400 VRMS maximum working voltage 5700 VRMS Reinforced insulation per
EN 61010-1:2010 (3rd Ed) up to working voltage of 600 VRMS

5700 VRMS Reinforced insulation per
EN 60950-1:2006/A11:2009/A1:2010/
A12:2011/A2:2013 up to working voltage of 800 VRMS
Certification completed
Certificate number: 40040142		 Master contract number: 220991 Certification completed
File number: E181974		 Certification completed
Certificate number: CQC16001141761		 Certification completed
Client ID number: 77311
(1) Production tested ≥6840 VRMS for 1 second in accordance with UL 1577.

7.8 Safety Limiting Values

Safety limiting intends to minimize potential damage to the isolation barrier upon failure of input or output circuitry. A failure of the I/O can allow low resistance to ground or the supply and, without current limiting, dissipate sufficient power to overheat the die and damage the isolation barrier, potentially leading to secondary system failures.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
IS Safety input, output or supply current RθJA = 99.6°C/W, VI = 3.6 V, TJ = 150°C, TA = 25°C 349 mA
RθJA = 99.6°C/W, VI = 5.5 V, TJ = 150°C, TA = 25°C 228
RθJA = 99.6°C/W, VI = 15 V, TJ = 150°C, TA = 25°C 84
RθJA = 99.6°C/W, VI = 30 V, TJ = 150°C, TA = 25°C 42
PS Safety input, output, or total power RθJA = 99.6°C/W, TJ = 150°C, TA = 25°C 1255(1) mW
TS Maximum ambient safety temperature 150 °C
(1) Input, output, or the sum of input and output power should not exceed this value

The safety-limiting constraint is the maximum junction temperature specified in the data sheet. The power dissipation and junction-to-air thermal impedance of the device installed in the application hardware determines the junction temperature. The assumed junction-to-air thermal resistance in the Thermal Information table is that of a device installed on a high-K test board for leaded surface-mount packages. The power is the recommended maximum input voltage times the current. The junction temperature is then the ambient temperature plus the power times the junction-to-air thermal resistance.

7.9 Electrical Characteristics

Over recommended operating conditions unless otherwise noted. All typical values are at TA = 25°C, VCC1 = 5 V,
VCC2 – GND2 = 15 V, GND2 – VEE2 = 8 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VOLTAGE SUPPLY
VIT+(UVLO1) Positive-going UVLO1 threshold voltage input side (VCC1 – GND1) 2.25 V
VIT-(UVLO1) Negative-going UVLO1 threshold voltage input side (VCC1 – GND1) 1.7 V
VHYS(UVLO1) UVLO1 Hysteresis voltage (VIT+ – VIT–) input side 0.24 V
VIT+(UVLO2) Positive-going UVLO2 threshold voltage output side (VCC2 – GND2) 12 13 V
VIT-(UVLO2) Negative-going UVLO2 threshold voltage output side (VCC2 – GND2) 9.5 11 V
VHYS(UVLO2) UVLO2 Hysteresis voltage (VIT+ – VIT–) output side 1 V
IQ1 Input supply quiescent current 2.8 4.5 mA
IQ2 Output supply quiescent current 3.6 6 mA
LOGIC I/O
VIT+(IN,RST) Positive-going input threshold voltage (IN+, IN–, RST) 0.7 × VCC1 V
VIT-(IN,RST) Negative-going input threshold voltage (IN+, IN–, RST) 0.3 × VCC1 V
VHYS(IN,RST) Input hysteresis voltage (IN+, IN–, RST) 0.15 × VCC1 V
IIH High-level input leakage at (IN+) IN+ = VCC1 100 µA
IIL Low-level input leakage at (IN–, RST) IN– = GND1, RST = GND1 –100 µA
IPU Pull-up current of FLT, RDY V(RDY) = GND1, V(FLT) = GND1 100 µA
VOL Low-level output voltage at FLT, RDY I(FLT) = 5 mA 0.2 V
GATE DRIVER STAGE
V(OUTPD) Active output pulldown voltage IOUT = 200 mA, VCC2 = open 2 V
V(OUTH) High-level output voltage IOUT = –20 mA VCC2 – 0.5 VCC2 – 0.24 V
V(OUTL) Low-level output voltage IOUT = 20 mA VEE2 + 13 VEE2 + 50 mV
I(OUTH) High-level output peak current IN+ = high, IN– = low,
VOUT = VCC2 - 15 V		 1.5 2.5 A
I(OUTL) Low-level output peak current IN+ = low, IN– = high,
VOUT = VEE2 + 15 V		 3.4 5 A
ACTIVE MILLER CLAMP
V(CLP) Low-level clamp voltage I(CLP) = 20 mA VEE2 + 0.015 VEE2 + 0.08 V
I(CLP) Low-level clamp current V(CLAMP) = VEE2 + 2.5 V 1.6 2.5 A
V(CLTH) Clamp threshold voltage 1.6 2.1 2.5 V
SHORT CIRCUIT CLAMPING
V(CLP_OUT) Clamping voltage
(VOUT - VCC2)		 IN+ = high, IN– = low, tCLP = 10 µs, I(OUTH) = 500 mA 0.8 1.3 V
V(CLP_CLAMP) Clamping voltage
(VCLP - VCC2)		 IN+ = high, IN– = low, tCLP = 10 µs, I(CLP) = 500 mA 1.3 V
V(CLP_CLAMP) Clamping voltage at CLAMP IN+ = High, IN– = Low, I(CLP) = 20 mA 0.7 1.1 V
DESAT PROTECTION
I(CHG) Blanking capacitor charge current V(DESAT) - GND2 = 2 V 0.42 0.5 0.58 mA
I(DCHG) Blanking capacitor discharge current V(DESAT) - GND2 = 6 V 9 14 mA
V(DSTH) DESAT threshold voltage with respect to GND2 8.3 9 9.5 V
V(DSL) DESAT voltage with respect to GND2, when OUT is driven low 0.4 1 V

7.10 Switching Characteristics

Over recommended operating conditions unless otherwise noted. All typical values are at TA = 25°C, VCC1 = 5 V, VCC2 – GND2 = 15 V, GND2 – VEE2 = 8 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
tr Output signal rise time CLOAD = 1 nF, see Figure 38, Figure 39, and Figure 40 12 20 35 ns
tf Output signal fall time 12 20 37 ns
tPLH, tPHL Propagation Delay 76 110 ns
tsk-p Pulse Skew |tPHL – tPLH| 20 ns
tsk-pp Part-to-part skew 30(1) ns
tGF Glitch filter on IN+, IN–, RST 20 30 40 ns
tDESAT (10%) DESAT sense to 10% OUT delay 300 415 500 ns
tDESAT (GF) DESAT glitch filter delay 330 ns
tDESAT (FLT) DESAT sense to FLT-low delay see Figure 40 2000 2420 ns
tLEB Leading edge blanking time see Figure 38 and Figure 39 330 400 500 ns
tGF(RSTFLT) Glitch filter on RST for resetting FLT 300 800 ns
CI Input capacitance(2) VI = VCC1 /2 + 0.4 x sin (2πft), f = 1 MHz, VCC1 = 5 V 2 pF
CMTI Common-mode transient immunity VCM = 1500 V, see Figure 41 100 120 kV/μs
(1) Measured at same supply voltage and temperature condition
(2) Measured from input pin to ground.

7.11 Insulation Characteristics Curves

ISO5851-Q1 tddb_curve_reinforced_dw.gif
TA upto 150°C Stress-voltage frequency = 60 Hz
Figure 1. Reinforced High-Voltage Capacitor Life Time Projection
ISO5851-Q1 D100_SLLSEN5.gif Figure 2. Thermal Derating Curve for Limiting Current per VDE
ISO5851-Q1 D101_SLLSEN5.gif Figure 3. Thermal Derating Curve for Limiting Power per VDE

7.12 Typical Characteristics

ISO5851-Q1 D001_SLLSEO1.gif
VCC2 = 30 V
Figure 4. Output High Drive Current vs Temperature
ISO5851-Q1 D003_SLLSEO1.gif
Figure 6. Output High Drive Current vs Output Voltage
ISO5851-Q1 D005_SLLSEO1.gif
Unipolar: VCC2 – VEE2 = VCC2 – GND2
Figure 8. DESAT Threshold Voltage vs Temperature
ISO5851-Q1 D002_SLLSEO1.gif
VCC2 = 30 V
Figure 5. Output Low Drive Current vs Temperature
ISO5851-Q1 D004_SLLSEO1.gif
Figure 7. Output Low Drive Current vs Output Voltage
ISO5851-Q1 G001_SLLSEN5.gif
CL = 1 nF RG = 0 Ω
VCC2 – VEE2 = VCC2 – GND2 = 20 V
Figure 9. OUT Transient Waveform
ISO5851-Q1 G003_SLLSEN5.gif
CL = 10 nF RG = 0 Ω
VCC2 – VEE2 = VCC2 – GND2 = 20 V
Figure 11. OUT Transient Waveform
ISO5851-Q1 G005_SLLSEN5.gif
CL = 100 nF RG = 0 Ω
VCC2 – VEE2 = VCC2 – GND2 = 20 V
Figure 13. OUT Transient Waveform
ISO5851-Q1 G007_SLLSEN5.gif
CL = 100 nF RG = 10 Ω
VCC2 – VEE2 = VCC2 – GND2 = 20 V
Figure 15. OUT Transient Waveform DESAT and FLT
ISO5851-Q1 D007_SLLSEO1.gif
IN+ = Low IN– = Low
Figure 17. ICC1 Supply Current vs Temperature
ISO5851-Q1 D009_SLLSEO1.gif
Figure 19. ICC1 Supply Current vs Input Frequency
ISO5851-Q1 D025_SLLSEO1.gif
RG = 10 Ω, 20 kHz
Figure 21. ICC2 Supply Current vs Load Capacitance
ISO5851-Q1 D013_SLLSEO1.gif
CL = 1 nF RG = 0 Ω VCC2 = 15 V
Figure 23. VCC2 Propagation Delay vs Temperature
ISO5851-Q1 D022_SLLSEO1.gif
RG = 0 Ω VCC1 = 5 V
Figure 25. tr Rise Time vs Load Capacitance
ISO5851-Q1 D023_SLLSEO1.gif
RG = 10 Ω VCC1 = 5 V
Figure 27. tr Rise Time vs Load Capacitance
ISO5851-Q1 D014_SLLSEO1.gif
Figure 29. Leading Edge Blanking Time With Temperature
ISO5851-Q1 D016_SLLSEO1.gif
CL = 1 nF
Figure 31. DESAT Sense to FLT Low Delay vs Temperature
ISO5851-Q1 D018_SLLSEO1.gif
Figure 33. Miller Clamp Current vs Temperature
ISO5851-Q1 D021_SLLSEQ3.gif
Figure 35. VCLP_CLAMP - Short Circuit Clamp Voltage on Clamp Across Temperature
ISO5851-Q1 D011_SLLSEO1.gif
VCC2 = 15 V DESAT = 6 V
Figure 37. Blanking Capacitor Charging Current vs Temperature
ISO5851-Q1 G002_SLLSEN5.gif
CL = 1 nF RG = 10 Ω
VCC2 – VEE2 = VCC2 – GND2 = 20 V
Figure 10. OUT Transient Waveform
ISO5851-Q1 G004_SLLSEN5.gif
CL = 10 nF RG = 10 Ω
VCC2 – VEE2 = VCC2 – GND2 = 20 V
Figure 12. OUT Transient Waveform
ISO5851-Q1 G006_SLLSEN5.gif
CL = 100 nF RG = 10 Ω
VCC2 – VEE2 = VCC2 – GND2 = 20 V
Figure 14. OUT Transient Waveform
ISO5851-Q1 D006_SLLSEO1.gif
IN+ = High IN– = Low
Figure 16. ICC1 Supply Current vs Temperature
ISO5851-Q1 D008_SLLSEO1.gif
Input Frequency = 1 kHz
Figure 18. ICC2 Supply Current vs Temperature
ISO5851-Q1 D010_SLLSEO1.gif
no CL
Figure 20. ICC2 Supply Current vs Input Frequency
ISO5851-Q1 D012_SLLSEO1.gif
CL = 1nF RG = 0 Ω VCC1 = 5 V
Figure 22. VCC1 Propagation Delay vs Temperature
ISO5851-Q1 D024_SLLSEO1.gif
RG = 10 Ω VCC1 = 5 V
Figure 24. Propagation Delay vs Load Capacitance
ISO5851-Q1 D026_SLLSEO1.gif
RG = 0 Ω VCC1 = 5 V
Figure 26. tf Fall Time v. Load Capacitance
ISO5851-Q1 D027_SLLSEO1.gif
RG = 10 Ω VCC1 = 5 V
Figure 28. tf Fall Time vs Load Capacitance
ISO5851-Q1 D015_SLLSEO1.gif
CL = 10 nF
Figure 30. DESAT Sense to VOUT 10% Delay vs Temperature
ISO5851-Q1 D017_SLLSEO1.gif
Figure 32. Reset to Fault Delay Across Temperature
ISO5851-Q1 D019_SLLSEO1.gif
Figure 34. Active Pulldown Voltage vs Temperature
ISO5851-Q1 D020_SLLSEQ3.gif
Figure 36. VOUT_CLAMP - Short Circuit Clamp Voltage on OUT Across Temperature