MAX1978ETM+ ,Integrated Temperature Controllers for Peltier ModulesApplicationsPV 2 7 30 PV 1DD MAX1979 DDN.C. 8 29 N.C.Fiber Optic Laser Modules28LX2 9 LX1PV 2 10 27 ..
MAX1979ETM+ ,Integrated Temperature Controllers for Peltier ModulesFeatures♦ Smallest, Safest, Most Accurate CompleteThe MAX1978/MAX1979 are the smallest, safest, mos ..
MAX197ACAI ,Multi-Range (【10V, 【5V, +10V, +5V), Single +5V, 12-Bit DAS with 8+4 Bus Interfacefeatures include a 5MHz bandwidth track/hold, a100ksps throughput rate, software-selectable interna ..
MAX197ACAI+ ,Multi-Range (±10V, ±5V, +10V, +5V), Single +5V, 12-Bit DAS with 8+4 Bus InterfaceFeatures♦ 12-Bit Resolution, 1/2LSB LinearityThe MAX197 multi-range, 12-bit data-acquisition sys-te ..
MAX197ACAI+T ,Multi-Range (±10V, ±5V, +10V, +5V), Single +5V, 12-Bit DAS with 8+4 Bus InterfaceGeneral Description ________
MAX197ACNI ,Multi-Range (【10V, 【5V, +10V, +5V), Single +5V, 12-Bit DAS with 8+4 Bus InterfaceELECTRICAL CHARACTERISTICS(V = 5V ±5%; unipolar/bipolar range; external reference mode, V = 4.096V; ..
MAX497CPE+ ,375MHz Quad Closed Loop Video Buffers, AV = +1 and +2ELECTRICAL CHARACTERISTICS(V = +5V, V = -5V, V = 0V, R = 150Ω, T = T to T , unless otherwise noted. ..
MAX497CSE ,375MHz Quad Closed-Loop Video Buffers, AV = +1 and +2MAX496/MAX49719-0373; Rev 1; 12/98375MHz Quad Closed-Loop Video Buffers, A = +1 and +2V____________ ..
MAX497CSE+ ,375MHz Quad Closed Loop Video Buffers, AV = +1 and +2Applications♦ Low Distortion: 64dBc (f = 10MHz)Computer Workstations♦ Directly Drives 50Ω or 75Ω B ..
MAX4981ETA+T ,Overvoltage Protector with Active Current LimitApplications*EPCell Phones PDAs and PalmtopDevicesMP3 Players13 2 4Digital Still CamerasSDT(BAT)IN ..
MAX4983EEVB+ ,High-Speed USB 2.0 Switches with ±15kV ESDfeatures an active-high enableActive-High (EN) MAX4984Einput (EN) that when driven low sets the dev ..
MAX4983EEVB+T ,High-Speed USB 2.0 Switches with ±15kV ESDFeaturesThe MAX4983E/MAX4984E are high ESD-protected♦ USB Hi-Speed Switchinganalog switches that co ..
MAX1978ETM+-MAX1979ETM+
Integrated Temperature Controllers for Peltier Modules
AVAILABLE
General DescriptionThe MAX1978/MAX1979 are the smallest, safest, most
accurate complete single-chip temperature controllers for
Peltier thermoelectric cooler (TEC) modules. On-chip power
FETs and thermal control-loop circuitry minimize external
components while maintaining high efficiency. Selectable
500kHz/1MHz switching frequency and a unique ripple-can-
cellation scheme optimize component size and efficiency
while reducing noise. Switching speeds of internal
MOSFETs are optimized to reduce noise and EMI. An ultra-
low-drift chopper amplifier maintains ±0.001°C temperature
stability. Output current, rather than voltage, is directly con-
trolled to eliminate current surges. Individual heating and
cooling current and voltage limits provide the highest level of
TEC protection.
The MAX1978 operates from a single supply and provides
bipolar ±3A output by biasing the TEC between the outputs
of two synchronous buck regulators. True bipolar operation
controls temperature without “dead zones” or other nonlin-
earities at low load currents. The control system does not
hunt when the set point is very close to the natural operating
point, where only a small amount of heating or cooling is
needed. An analog control signal precisely sets the TEC
current. The MAX1979 provides unipolar output up to 6A.
A chopper-stabilized instrumentation amplifier and a high-
precision integrator amplifier are supplied to create a pro-
portional-integral (PI) or proportional-integral-derivative (PID)
controller. The instrumentation amplifier can interface to an
external NTC or PTC thermistor, thermocouple, or semicon-
ductor temperature sensor. Analog outputs are provided to
monitor TEC temperature and current. In addition, separate
overtemperature and undertemperature outputs indicate
when the TEC temperature is out of range. An on-chip volt-
age reference provides bias for a thermistor bridge.
The MAX1978/MAX1979 are available in a low-profile
48-lead thin QFN-EP package and is specified over the
-40°C to +85°C temperature range. The thermally
enhanced QFN-EP package with exposed metal pad
minimizes operating junction temperature. An evaluation
kit is available to speed designs.
ApplicationsFiber Optic Laser Modules
WDM, DWDM Laser-Diode Temperature Control
Fiber Optic Network Equipment
EDFA Optical Amplifiers
Telecom Fiber Interfaces
ATE
FeaturesSmallest, Safest, Most Accurate Complete
Single-Chip ControllerOn-Chip Power MOSFETS—No External FETsCircuit Footprint < 0.93in2Circuit Height < 3mmTemperature Stability to 0.001°CIntegrated Precision Integrator and Chopper
Stabilized Op AmpsAccurate, Independent Heating and Cooling
Current LimitsEliminates Surges By Directly Controlling
TEC CurrentAdjustable Differential TEC Voltage LimitLow-Ripple and Low-Noise DesignTEC Current MonitorTemperature MonitorOver- and Undertemperature AlarmBipolar ±3A Output Current (MAX1978)Unipolar +6A Output Current (MAX1979)
Integrated Temperature
Controllers for Peltier Modules
Ordering InformationFREQ
N.C
LX1
PGND1
N.C.
LX1
PVDD1
GND
GND
LX1
PVDD1
PGND1PGND2
LX2
PGND2
LX2
PVDD2
N.C.
LX2
N.C.
OS21
DIFOUT
FB-
FB+
BFB+AOUT
AIN-
AIN+
GNDINT-
INTOUTREFCTLIV
GNDGNDMAXVMAXINMAXIPITECCOMPOS1
TQFN-EPMAX1978
MAX1979
BFB-
TOP VIEW
*ELECTRICALLY CONNECTED TO THE UNDERSIDE METAL SLUG.47464544434241403938371415161718192021222324
PVDD2
SHDN
Pin Configuration
Typical Operating Circuit appears at end of data sheet.
PARTT EM P R A N G EPIN-PACKAGE
MAX1978ETM+- 40°C to + 85°C 48 Thin QFN-EP*
MAX1979ETM+- 40°C to + 85°C 48 Thin QFN-EP*
*EP = Exposed pad.
+Denotes a lead(Pb)-free/RoHS-compliant package.
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VDD= PVDD1 = PVDD2 = VSHDN= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA
= 0°C to +85°C,unless otherwise noted. Typical values at TA= +25°C.)
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.
VDDto GND..............................................................-0.3V to +6V
SHDN, MAXV, MAXIP, MAXIN,
CTLI, OT, UTto GND............................................-0.3V to +6V
FREQ, COMP, OS1, OS2, CS, REF, ITEC, AIN+, AIN-,
AOUT, INT-, INTOUT, BFB+, BFB-, FB+, FB-,
DIFOUT to GND......................................-0.3V to (VDD+ 0.3V)
PVDD1, PVDD2 to VDD...........................................-0.3V to +0.3V
PVDD1, PVDD2 to GND...............................-0.3V to (VDD+ 0.3V)
PGND1, PGND2 to GND.......................................-0.3V to +0.3V
COMP, REF, ITEC, OT, UT, INTOUT, DIFOUT,
BFB-, BFB+, AOUT Short to GND.............................Indefinite
Peak LX Current (MAX1978) (Note 1).................................±4.5A
Peak LX Current (MAX1979) (Note 1)....................................+9A
Continuous Power Dissipation (TA= +70°C)
48-Lead Thin QFN-EP
(derate 26.3mW/°C above +70°C) (Note 2).................2.105W
Operating Temperature Ranges
MAX1978ETM..................................................-40°C to +85°C
MAX1979ETM..................................................-40°C to +85°C
Maximum Junction Temperature.....................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSInput Supply RangeVDD3.05.5V
VDD = 5V, ITEC = 0 to ±3A,
VOUT = VOS1 - VOS2 (MAX1978)-4.3+4.3
VDD = 5V, ITEC = 0 to 6A,
VOUT = VOS1 (MAX1979)4.3
VDD = 3V, ITEC = 0 to ±3A,
VOUT = VOS1 - VOS2 (MAX1978)-2.3+2.3
Output Voltage RangeVOUT
VDD = 3V, ITEC = 0 to 6A,
VOUT = VOS1 (MAX1979)2.3
MAX1978±3Maximum TEC CurrentITEC(MAX)MAX19796A
Reference VoltageVREFVDD = 3V to 5.5V, IREF = 150µA1.4851.5001.515V
Reference Load Regulation∆VREFVDD = 3V to 5.5V, IREF = +10µA to -1mA1.25mV
VMAXI_ = VREF135150160VOS1 < VCSVMAXI_ = VREF/3405060
VMAXI_ = VREF135150160Current-Sense Threshold
VOS1 > VCSVMAXI_ = VREF/3405060
VDD = 5V, I = 0.5A0.040.07NFET On-ResistanceRDS(ON-N)VDD = 3V, I = 0.5A0.060.08Ω
VDD = 5V, I = 0.5A0.060.10PFET On-ResistanceRDS(ON-P)VDD = 3V, I = 0.5A0.090.12Ω
VLX = VDD = 5V, TA = +25°C0.0210NFET LeakageILEAK(N)VLX = VDD = 5V, TA = +85°C1µA
Note 1:LX has internal clamp diodes to PGND and PVDD. Applications that forward bias these diodes should not exceed the IC’s
package power dissipation limits.
Note 2:Solder underside metal slug to PCB ground plane.
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD1 = PVDD2 = VSHDN= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA
= 0°C to +85°C,unless otherwise noted. Typical values at TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSVLX = 0, TA = +25°C0.0210PFET LeakageILEAK(P)VLX = 0, TA = +85°C1µA
VDD = 5V3050No-Load Supply CurrentIDD(NO
LOAD)VDD = 3.3V1530mA
Shutdown Supply CurrentIDD-SDSHDN = GND, VDD = 5V (Note 3)23mA
Thermal ShutdownTS H U TD OWN Hysteresis = 15°C165°C
VDD rising2.42.62.8UVLO ThresholdVUVLOVDD falling2.252.52.75V
FREQ = GND450500650Switching Frequency Internal
OscillatorfSW-INTFREQ=VDD80010001200kHz
OS1, OS2, CS Input CurrentIOS1, IOS2,
ICS0 or VDD-100+100µA
SHDN, FREQ Input CurrentISHDN,
IFREQ0 or VDD-5+5µA
SHDN, FREQ Input Low VoltageVILVDD = 3V to 5.5V0.25 ×
VDDV
SHDN, FREQ Input High VoltageVIHVDD = 3V to 5.5V0.75 ×
VDDV
VMAXV = VREF ✕ 0.67,
VOS1 to VOS2 = ±4V, VDD = 5V-1+1
MAXV Threshold Accuracy
VMAXV = VREF ✕ 0.33,
VOS1 to VOS2 = ±2V, VDD = 3V-2+2
MAXV, MAXIP, MAXIN
Input Bias Current
IMAXV-BIAS,
IMAXI_-BIASVMAXV = VMAXI_ = 0.1V or 1.5V-0.1+0.1µA
CTLI GainACTLIVCTLI = 0.5V to 2.5V (Note 4)9.51010.5V/V
CTLI Input ResistanceRCTLI1MΩ terminated at REF0.51.02.0MΩ
Error Amp Transconductancegm50100175µS
ITEC AccuracyVOS1 to VCS = +100mV or -100mV-10+10%
ITEC Load Regulation∆VITECVOS1 to VCS = +100mV or -100mV,
IITEC = ±10µA-0.1+0.1%
Instrumentation Amp Input Bias
CurrentIDIF-BIAS-100+10nA
Instrumentation Amp Offset
VoltageVDIF-OSVDD = 3V to 5.5V-200+20+200µV
Instrumentation Amp Offset-
Voltage Drift with TemperatureVDD = 3V to 5.5V0.1µV/°C
Instrumentation Amp Preset
GainADIFRLOAD = 10kΩ to REF455055V/V
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD1 = PVDD2 = VSHDN= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA
= 0°C to +85°C,unless otherwise noted. Typical values at TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSIntegrator Amp Open-Loop GainAOL-INTRLOAD = 10kΩ to REF120dB
Integrator Amp CMRRCMRRINT100dB
Integrator Amp Input Bias CurrentIINT-BIASVDD = 3V to 5.5V1nA
Integrator Amp Voltage OffsetVINT-OSVDD = 3V to 5.5V-3+0.1+3mV
Integrator Amp Gain BandwidthGBWINT100kHz
Undedicated Chopper Amp
Open-Loop GainAOL-AINRLOAD = 10kΩ to REF120dB
Undedicated Chopper Amp
CMRRCMRRAIN85dB
Undedicated Chopper Amp Input
Bias CurrentIAIN-BIASVDD = 3V to 5.5V-100+10nA
Undedicated Chopper Amp
Offset VoltageVAIN-OSVDD = 3V to 5.5V-200+10+200µV
Undedicated Chopper Amp Gain
BandwidthGBWAIN100kHz
Undedicated Chopper Amp
Output RippleVRIPPLEA = 520mV
BFB_ Buffer ErrorC L OA D < 100p F-2000+200µV
UT and OT Leakage CurrentILEAKV UT = V OT = 5.5V 1µA
UT and OT Output Low VoltageVOLSinking 4mA50150mV
UT Trip ThresholdFB+ - FB- (see Typical Application Circuit)-20mV
OT Trip ThresholdFB+ - FB- (see Typical Application Circuit)20mV
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
ELECTRICAL CHARACTERISTICS(VDD= PVDD1 = PVDD2 = VSHDN= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA
= -40°C to +85°C,unless otherwise noted.) (Note 5)
PARAMETERSYMBOLCONDITIONSMINMAXUNITSInput Supply RangeVDD35.5V
VDD = 5V, ITEC = 0 to ±3A,
VOUT = VOS1 -VOS2 (MAX1978)-4.3+4.3
VDD = 5V, ITEC = 0 to 6A,
VOUT = VOS1 (MAX1979)4.3
VDD = 3V, ITEC = 0 to ±3A,
VOUT = VOS1 - VOS2 (MAX1978)-2.3+2.3
Output Voltage RangeVOUT
VDD = 3V, ITEC = 0 to 6A,
VOUT = VOS1 (MAX1979)2.3
MAX1978±3Maximum TEC CurrentITEC(MAX)MAX19796A
Reference VoltageVREFVDD = 3V to 5.5V, IREF = 150µA1.4751.515V
Reference Load Regulation∆VREFVDD = 3V to 5.5V,
IREF = 10µA to -1mA5mV
VMAXI_ = VREF135160VOS1 < VCSVMAXI_ = VREF/34060
VMAXI_ = VREF135160Current-Sense Threshold
VOS1 > VCSVMAXI_ = VREF/34060
VDD = 5V50No-Load Supply CurrentIDD(NO
LOAD)VDD = 3.3V30mA
Shutdown Supply CurrentIDD-SDSHDN = GND, VDD = 5V (Note 3)3mA
VDD rising2.42.8UVLO ThresholdVUVLOVDD falling2.252.75V
FREQ = GND450650Switching Frequency Internal
OscillatorfSW-INTFREQ = VDD8001200kHz
OS1, OS2, CS Input CurrentIOS1, IOS2,
ICS0 or VDD-100+100µA
SHDN, FREQ Input CurrentI SHDN,
I F REQ0 or VDD-5+5µA
SHDN, FREQ Input Low VoltageVILVDD = 3V to 5.5V0.25 ✕
VDDV
SHDN, FREQ Input High VoltageVIHVDD = 3V to 5.5V0.75 ✕
VDDV
MAX1978/MAX1979
Note 3:Includes power FET leakage.
Note 4:CTLI gain is defined as:
Note 5:Specifications to -40°C are guaranteed by design, not production tested.
ACTLIVV
CTLIREF
OSICS=−()()
Integrated Temperature
Controllers for Peltier Modules
ELECTRICAL CHARACTERISTICS (continued)(VDD= PVDD1 = PVDD2 = VSHDN= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA
= -40°C to +85°C,unless otherwise noted.) (Note 5)
PARAMETERSYMBOLCONDITIONSMINMAXUNITSVMAXV = VREF ✕ 0.67,
VOS1 to VOS2 = ±4V, VDD = 5V-1+1
MAXV Threshold Accuracy
VMAXV = VREF ✕ 0.33, VOS1 to VOS2 = ±2V,
VDD = 3V-2+2
MAXV, MAXIP, MAXIN
Input Bias Current
IMAXV-BIAS,
IMAXI_-BIASVMAXV = VMAXI_ = 0.1V or 1.5V-0.1+0.1µA
CTLI GainACTLIVCTLI = 0.5V to 2.5V (Note 4)9.510.5V/V
CTLI Input ResistanceRCTLI1MΩ terminated at REF0.52.0MΩ
Error Amp Transconductancegm50175µS
ITEC AccuracyVOS1 to VCS = +100mV or -100mV-10+10%
ITEC Load Regulation∆VITECVOS1 to VCS = +100mV or
-100mV, IITEC = ±10µA-0.125+0.125%
Instrumentation Amp
Input Bias CurrentIDIF-BIAS-10+10nA
Instrumentation Amp
Offset VoltageVDIF-OSVDD = 3V to 5.5V-200+200µV
Instrumentation Amp
Preset GainADIFRLOAD = 10kΩ to REF4555V/V
Integrator Amp Input Bias CurrentIINT-BIASVDD = 3V to 5.5V1nA
Integrator Amp Voltage OffsetVINT-OSVDD = 3V to 5.5V-3+3mV
Undedicated Chopper Amp Input
Bias CurrentIAIN-BIASVDD = 3V to 5.5V-10+10nA
Undedicated Chopper Amp
Offset VoltageVAIN-OSVDD = 3V to 5.5V-200+200µV
BFB_ Buffer ErrorCLOAD < 100pF-200+200µV
UT and OT Leakage CurrentILEAKV UT = V OT = 5.5V 1µA
UT and OT Output Low VoltageVOLSinking 4mA150mV
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
EFFICIENCY vs. TEC CURRENT
VDD = 5VMAX1978 toc01
TEC CURRENT (A)
EFFICIENCY (%)
RTEC = 1.1Ω
EFFICIENCY vs. TEC CURRENT
VDD = 3.3VMAX1978 toc02
TEC CURRENT (A)
RTEC = 0.855Ω
EFFICIENCY (%)
OUTPUT-VOLTAGE
RIPPLE WAVEFORMSMAX1978 toc03
400ns/div
VOS2
100mV/div
AC-COUPLED
VOS1
100mV/div
AC-COUPLED
VOS1 - VOS1
50mV/div
INPUT SUPPLY RIPPLEMAX1978 toc04
200ns/div
VDD
20mV/div
AC-COUPLED
TEC CURRENT vs. CTLI VOLTAGEMAX1978 toc05
20ms/div
VCTLI
1V/div
ITEC
2A/div
-0V
-0A
ZERO-CROSSING TEC CURRENTMAX1978 toc06
1ms/div
VCTLI
200mV/div
ITEC
500mA/div
1.5V
VITEC vs. TEC CURRENTMAX1978 toc07
TEC CURRENT (A)
ITEC
(V)10-1-2
TEC CURRENT vs. TEMPERATURE
MAX1978 toc08
TEMPERATURE (°C)
ITEC
(A)6040200-20
ITEC = 1A
RSENSE = 0.68Ω
SWITCHING FREQUENCY
vs. TEMPERATURESWITCHING FREQUENCY (kHz)
MAX1978 toc09
TEMPERATURE (°C)6040200-20-40
VCTLI = 1.5V
RTEC = 1Ω
Typical Operating Characteristics(VDD= 5V, VCTLI= 1V, VFREQ= GND, RTEC = 1Ω, circuit of Figure 1, TA= +25°C, unless otherwise noted.)
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
SWITCHING FREQUENCY CHANGE
vs. INPUT SUPPLYMAX1978 toc10
VDD (V)
SWITCHING FREQUENCY CHANGE (kHz)
REFERENCE VOLTAGE CHANGE
vs. INPUT SUPPLY
REFERENCE VOLTAGE CHANGE (mV)-2.5
MAX1978 toc11
VDD (V)
REFERENCE VOLTAGE CHANGE
vs. TEMPERATURE
TEMPERATURE (°C)
REFERENCE VOLTAGE CHANGE (mV)40200-20
REFERENCE LOAD REGULATION
MAX1978 toc13
REFERENCE LOAD CURRENT (mA)
REFERENCE VOLTAGE CHANGE (mV)
SINKSOURCE
ATO VOLTAGE
vs. THERMISTOR TEMPERATUREMAX1978 toc14
THERMISTOR TEMPERATURE (°C)
ATO VOLTAGE (V)20010
NTC, 10kΩ THERMISTOR
CIRCUIT IN FIGURES 1 AND 2
STARTUP AND SHUTDOWN WAVEFORMSMAX1978 toc15
100μs/div
VSHDN
5V/div
ITEC
500mA/div
IDD
200mA/div
CTLI STEP RESPONSEMAX1978 toc16
1ms/div
1.5V
VCTLI
1V/div
ITEC
1A/div
INPUT SUPPLY STEP RESPONSEMAX1978 toc17
VDD
2V/div
ITEC
20mA/div
10ms/div
THERMAL STABILITY,
COOLING MODEMAX1978 toc18
4s/div
TEMPERATURE
0.001°C/div
ITEC = +25°C
TA = +45°C
Typical Operating Characteristics (continued)(VDD= 5V, VCTLI= 1V, VFREQ= GND, RTEC = 1Ω, circuit of Figure 1, TA= +25°C, unless otherwise noted.)
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
Pin Description
THERMAL STABILITY,
ROOM TEMPERATUREMAX1978 toc19
4s/div
MPERATURE
0.001°C/div
ITEC = +25°C
TA = +25°C
THERMAL STABILITY,
HEATING MODEMAX1978 toc20
4s/div
TEMPERATURE
0.001°C/div
TTEC = +25°C
TA = +5°C
TEMPERATURE ERROR
vs. AMBIENT TEMPERATUREMAX1978 toc21
AMBIENT TEMPERATURE (°C)
TEMPERATURE ERROR (4010200-10
Typical Operating Characteristics (continued)
(VDD= 5V, VCTLI= 1V, VFREQ= GND, RTEC = 1Ω, circuit of Figure 1, TA= +25°C, unless otherwise noted.)
PINNAMEFUNCTIONOS2Output Sense 2. OS2 senses one side of the differential TEC voltage. OS2 is a sense point, not a power
output.
2, 8, 29,N.C.Not Internally Connected
3, 5PGND2Power Ground 2. Internal synchronous rectifier ground connections. Connect all PGND pins together at
power ground plane.
4, 6, 9LX2Inductor 2 Connection. Connect all LX2 pins together. Connect LX2 to LX1 when using the MAX1979.
7, 10PVDD2Power 2 Inputs. Must be same voltage as VDD. Connect all PVDD2 inputs together at the VDD power plane.
Bypass to PGND2 with a 10µF ceramic capacitor.SHDNShutdown Control Input. Active-low shutdown control.OTOver-Temperature Alarm. Open-drain output pulls low if temperature feedback rises 20mV
(typically +1.5°C) above the set-point voltage.UTUnder-Temperature Alarm. Open-drain output pulls low if temperature feedback falls 20mV
(typically +1.5°C) below the set-point voltage.INTOUTIntegrator Amp Output. Normally connected to CTLI.INT-Integrator Amp Inverting Input. Normally connected to DIFOUT through thermal-compensation network.
16, 25,
26, 42, 43GNDAnalog Ground. Connect all GND pins to analog ground plane.DIFOUTChopper-Stabilized Instrumentation Amp Output. Differential gain is 50 ✕ (FB+ - FB-).FB-Chopper-Stabilized Instrumentation Amp Inverting Input. Connect to thermistor bridge.FB+Chopper-Stabilized Instrumentation Amp Noninverting Input. Connect to thermistor bridge.BFB-Chopper-Stabilized Buffered FB- Output. Used to monitor thermistor bridge voltage.BFB+Chopper-Stabilized Buffered FB+ Output. Used to monitor thermistor bridge voltage.AIN+Undedicated Chopper-Stabilized Amplifier Noninverting Input
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
Pin Description (continued)
PINNAMEFUNCTIONAIN-Undedicated Chopper-Stabilized Amplifier Inverting InputAOUTUndedicated Chopper-Stabilized Amplifier Output
27, 30PVDD1Power 1 Inputs. Must be same voltage as VDD. Connect all PVDD1 inputs together at the VDD power plane.
Bypass to PGND1 with a 10µF ceramic capacitor.
28, 31, 33LX1Inductor 1 Connection. Connect all LX1 pins together. Connect LX1 to LX2 when using the MAX1979.
32, 34PGND1Power Ground 1. Internal synchronous-rectifier ground connections. Connect all PGND pins together at
power ground plane.FREQSwitching-Frequency Select. Low = 500kHz, high = 1MHz.ITECTEC Current Monitor Output. The ITEC output voltage is a function of the voltage across the TEC current-
sense resistor. VITEC = 1.50V + (VOS1 - VCS) ✕ 8.COMPCurrent-Control Loop Compensation. For most designs, connect a 10nF capacitor from COMP to GND.MAXIPMaximum Positive TEC Current. Connect MAXIP to REF to set default positive current limit +150mV/RSENSE.MAXINMaximum Negative TEC Current. Connect MAXIN to REF to set default negative current limit -150mV /
RSENSE. Connect MAXIN to MAXIP when using the MAX1979.MAXVMaximum Bipolar TEC Voltage. Connect an external resistive divider from REF to GND to set the maximum
voltage across the TEC. The maximum TEC voltage is 4 ✕ VMAXV.VDDAnalog Supply Voltage Input. Bypass to GND with a 10µF ceramic capacitor.CTLI
TEC Current-Control Input. Sets differential current into the TEC. Center point is 1.50V (no TEC current).
Connect to INTOUT when using the thermal control loop. ITEC = (VOS1 - VCS)/RSENSE = (VCTLI - 1.50)/(10 ✕
RSENSE). When (VCLTI - VREF) > 0, VOS2 > VOS1 > VCS.REF1.5V Reference Voltage Output. Bypass REF to GND with a 1µF ceramic capacitor.CSCurrent-Sense Input. The current through the TEC is monitored between CS and OS1. The maximum TEC
current is given by 150mV/RSENSE and is bipolar for the MAX1978. The MAX1979 TEC current is unipolar.OS1Output Sense 1. OS1 senses one side of the differential TEC voltage. OS1 is a sense point, not a power
output.EPExposed Pad. Solder evenly to the PCB ground plane to maximize thermal performance.
MAX1978/MAX1979
