LM5035AMHX/NOPB National Semiconductor, LM5035AMHX/NOPB Datasheet
LM5035AMHX/NOPB
Specifications of LM5035AMHX/NOPB
Available stocks
Related parts for LM5035AMHX/NOPB
LM5035AMHX/NOPB Summary of contents
Page 1
... The differences between LM5035, LM5035A, LM5035B, and LM5035C are summarized in Table 2. Simplified Application Diagram © 2010 National Semiconductor Corporation LM5035A/LM5035A-1 Features ■ 105V / 2A Half-Bridge Gate Drivers ■ Synchronous Rectifier Control Outputs with Programmable Delays ■ ...
Page 2
Connection Diagrams www.national.com Top View LM5035A 20-Lead TSSOP EP Top View LM5035A 30034103 20-Lead TSSOP EP 2 30034102 ...
Page 3
Top View LM5035A–1 28-Lead TSSOP EP 3 30034149 www.national.com ...
Page 4
Ordering Information Order Number Package Type LM5035AMH TSSOP-20EP LM5035AMHX TSSOP-20EP LM5035ASQ LLP-24 LM5035ASQX LLP-24 LM5035AMH-1 TSSOP-28EP LM5035AMHX-1 TSSOP-28EP Pin Descriptions for LM5035A and LM5035A–1 TSSOP 20 PIN LLP PIN TSSOP 28 PIN LM5035A LM5035A LM5035A ...
Page 5
TSSOP 20 PIN LLP PIN TSSOP 28 PIN LM5035A LM5035A LM5035A ...
Page 6
TSSOP 20 PIN LLP PIN TSSOP 28 PIN LM5035A LM5035A LM5035A www.national.com Name Description 21 VCC Output of the high voltage start-up regulator.The VCC ...
Page 7
... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VIN to GND HS to GND HB to GND VCC to GND CS, RT, DLY to GND COMP Input Current Electrical Characteristics apply over full Operating Junction Temperature range. V 27.4kΩ ...
Page 8
Symbol Parameter Soft-Start (SS Pin) I Charging current in normal SS operation Charging current during a hiccup mode restart Soft-stop Current Sink Oscillator (RT Pin) F Frequency 1 (at HO, half oscillator SW1 frequency) F Frequency 2 (at HO, half ...
Page 9
Symbol Parameter Thermal Shutdown T Shutdown temperature SD Hysteresis Thermal Resistance θ Junction to ambient, 0 LFPM Air JA Flow θ Junction to Case (EP) Thermal JC resistance θ Junction to ambient, 0 LFM Air Flow LLP- ...
Page 10
Typical Performance Characteristics V and V VCC REF REF REF Oscillator Frequency vs Temperature www.national.com vs V VIN 30034105 30034107 Soft-Start & Stop Current vs Temperature 30034109 VCC VCC 30034106 Frequency vs RT ...
Page 11
Effective Comp Input Impedance 30034111 SR "T1" Parameter vs Temperature 30034113 R vs Deadtime DLY SR "T2" Parameter vs Temperature 11 30034112 30034114 www.national.com ...
Page 12
Block Diagram www.national.com FIGURE 1. 12 30034104 ...
Page 13
Functional Description The LM5035A PWM controller contains all of the features necessary to implement half-bridge voltage-mode controlled power converters. The LM5035A provides two gate driver outputs to directly drive the primary side power MOSFETs and two signal level outputs to ...
Page 14
Cycle-by-Cycle Current Limit The CS pin is driven by a signal representative of the trans- former primary current. If the voltage sensed at CS pin ex- ceeds 0.25V, the current sense comparator terminates the output driver pulse. ...
Page 15
FIGURE 2. Current Limit Restart Circuit FIGURE 3. Current Limit Restart Timing 15 30034115 30034116 www.national.com ...
Page 16
Soft-Start The soft-start circuit allows the regulator to gradually reach a steady state operating point, thereby reducing start-up stress- es and current surges. When bias is supplied to the LM5035A, the SS pin capacitor is discharged by an internal MOSFET. ...
Page 17
VIN while the threshold of the clamp fixed voltage (2.5V). An example will illustrate the use of the Volt • Second Clamp comparator to achieve a 50% duty cycle limit at 200kHz ...
Page 18
Synchronous Rectifier Control Outputs (SR1 & SR2) Synchronous rectification (SR) of the transformer secondary provides higher efficiency, especially for low output voltage converters. The reduction of rectifier forward voltage drop (0.5V - 1.5V) to 10mV - 200mV V DS significantly ...
Page 19
Applications Information The following information is intended to provide guidelines for the power supply designer using the LM5035A. VIN The voltage applied to the VIN pin, which may be the same as the system voltage applied to the power transformer’s ...
Page 20
FIGURE 9. Current Sense Using Current Sense Resistor (R1) If the current sense resistor method is used, the over-current condition will only be sensed while LO is driving the low-side MOSFET. Over-current while HO is driving the high-side MOSFET will ...
Page 21
T2 = .0007 10.01 ns DLY T1 and T2 can be set to minimum by not connecting a resistor to DLY, connecting a resistor greater than 300kΩ from DLY to ground, or connecting DLY to the REF ...
Page 22
The impedance seen looking into the resistor divider from the UVLO and OVP pins determines the hysteresis level. UVLO and OVP enable and disable thresholds are calculated using Outputs disabled due to VIN falling below UVLO threshold Outputs enabled due ...
Page 23
FIGURE 13. Remote Standby and Disable Control To maintain the threshold’s accuracy, a resistor tolerance better is recommended. The design process starts with the choice of the voltage dif- ference between the UVLO enabling and disabling thresh- ...
Page 24
Figure 15 shows an application of the OVP comparator for Remote Thermal Protection using a thermistor (or multiple thermistors) which may be located near the main heat sources of the power supply. The negative temperature co- efficient (NTC) thermistor is ...
Page 25
If the application requires no delay from the first detection of a current limit condition to ...
Page 26
Printed Circuit Board Layout The LM5035A Current Sense and PWM comparators are very fast, and respond to short duration noise pulses. The compo- nents at the CS, COMP, SS, OVP, UVLO, DLY and the RT pins should be as physically ...
Page 27
27 www.national.com ...
Page 28
Physical Dimensions www.national.com inches (millimeters) unless otherwise noted Molded TSSOP-20 NS Package Number MXA20A Molded TSSOP-28 NS Package Number MXA28A 28 ...
Page 29
LLP Package NS Package Number SQA24B 29 www.national.com ...
Page 30
... For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www ...