HIGH PERFORMANCE CURRENT MODE CONTROLLERS Power Management Power Manag

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HIGH PERFORMANCE CURRENT MODE CONTROLLERS Power Management Power Manag

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GM38C42, GM38C43, GM38C44, GM38C45
HIGH PERFORMANCE CURRENT MODE CONTROLLERS Power Management Power Management
GM38C4x fixed frequency, high performance, current- mode controllers. Gamma's BiCMOS devices compatible with standard 384x bipolar devices with several improvements. Undervoltage lockout circuitry allows versions start 14.5V operate down versions start 8.4V with operation down 7.6V. versions operate 16V. When compared bipolar 384x devices operating from supply, start-up current been reduced 50µA typical operating current been reduced typical. Decreased output rise fall times drive larger MOSFETs, rail-to-rail output capability increases efficiency, especially lower supply voltages. GM38C4x also features trimmed oscillator discharge current bandgap reference. GM38C4x denotes 8-pin plastic packages.
Features
40ns output rise 30ns output fall times -40° +85°C temp. range same standard UC284x Low-power BiCMOS Process Very start-up current (50µA typical) operating current (4mA typical) CMOS outputs with rail-to-rail swing 500kHz current-mode operation Pin-for-pin compatible with UC3842/ 3843 3844/ 3845(A) Trimmed oscillator discharge current UVLO with hysteresis cross-conduction currents
Application
Current-mode, off-line, switched-mode power supplies Current-mode, dc-to-dc converters. Step-down "buck" regulators Step-up "boost" regulators Flyback, isolated regulators Forward converters Synchronous converters
GM38C42, GM38C43, GM38C44, GM38C45
www.gammamicro.com
PRELIMINARY
Revision May. 2004
GM38C42, GM38C43, GM38C44, GM38C45 MARKING INFORMATION CONFIGURATIONS (TOP VIEW)
(SO-8)
VREF
VREF
GM38CXX AYWW
GM38CXX
AYWW
COMP ISNS COMP
ISNS
Assembly Location Year Work Week
GM38C42, GM38C43, GM38C44, GM38C45
ORDERING INFORMATION
Ordering Number
GM38C42S8T GM38C42S8R GM38C42D8T GM38C43S8T GM38C43S8R GM38C43D8T GM38C44S8T GM38C44S8R GM38C44D8T GM38C45S8T GM38C45S8R GM38C45D8T
Package
DIP-8 DIP-8 DIP-8 DIP-8
Shipping
Units/ Tube 2,500 Units/ Tape Reel Units/ Tube Units/ Tube 2,500 Units/ Tape Reel Units/ Tube Units/ Tube 2,500 Units/ Tape Reel Units/ Tube Units/ Tube 2,500 Units/ Tape Reel Units/ Tube
detail Ordering Number identification, please last page.
GM38C42, GM38C43, GM38C44, GM38C45
ABSOLUTE MAXIMUM RATINGS
PARAMETER
Zener Current Operation require special precautions(Note6) Supply Voltage(Note Switch Supply Voltage Current Sense Voltage Feedback Voltage Output Current Storage Temperature
SYMBOL
VISNS IOUT
VALUE
UNIT
OPERATING RATINGS
PARAMETER
Junction Temperature
SYMBOL
VALUE
UNIT
PACKAGE DESCRIPTION
Compensation Connect external Compensation network modify error amplifier output. Feedback (Input): Error amplifier input .Feedback 2.5Vat desired output voltage. Current Sense (Input): Current sense comparator input. Connect current sensing resistor current transformer. Timing Resistor Timing Capacitor: Connect external network select switching frequency. Ground: Combined analog power ground. Power Output: Totem pole output. Analog Supply (Input): Controller circuitry supply input. Return analog ground (AGND). Reference (Output): Connect external network.
COMP ISNS VREF
BLOCK DIAGRAM
Reference UVLO
VREF
Oscillator
OUTPUT
2.5V
COMP
GND*
ISNS
lead versions only
GM38C42, GM38C43, GM38C44, GM38C45
LEAD
FUNCTION
FUNCTION
GM38C42, GM38C43, GM38C44, GM38C45
Power Management
ELECTRICAL CHARACTERISTICS
-40°C 85°C, Note 15V, CT=3.3 RT=10kW, unless otherwise noted
CHARACTERISTICS
Reference Section
Output Voltage Line Regulation Load Regulation Temp. Stability Total Output Variation Output Noise Voltage Long Term Stability Output Short Circuit
TEST CONDITIONS
UNIT
25°C, 16V, 5µA, (Note 20mA
(Note Line, Load, Temp.,Note 10Hz 10kHz, 25°C, (Note 4.82
5.18 -180
125°C, 1000hrs., (Note
Oscillator Section
Initial Accuracy Voltage Stability Temp. Stability
25°C, (Note TMIN 16V, (Note TMAX, (Note
0.04
GM38C42, GM38C43, GM38C44, GM38C45
Clock Ramp Reset Current Amplitude
25°C, VRT/CT TMIN TMAX VRT/CT (Peak Peak)
Vp-p
Error Amplifier Section
Input Bias Current Input Voltage Open Loop Voltage Gain Power Supply Rejection Ratio Output Sink Current Output Source Current High Output Voltage Output Voltage Unity Gain Bandwidth
VCOMP 2.5V 2.42 -0.5
-0.1
2.58
2.7V, VCOMP 1.1V 2.3V, VCOMP 2.3V, 2.7V, VREF (Note
Current Sense Section
Gain Maximum Threshold PSRR Input Bias Current Delay Output
Note VCOMP (Note 16V, (Note
2.85
-1.0
3.15
GM38C42, GM38C43, GM38C44, GM38C45
ELECTRICAL CHARACTERISTICS
-40°C 85°C, Note 15V, CT=3.3 RT=11kW, unless otherwise noted
CHARACTERISTICS
Output Section RDS(ON) High RDS(ON) Rise Time Fall Time Undervoltage Lockout Section
TEST CONDITIONS
UNIT
ISOURCE 200mA ISINK 200mA 25°C, 25°C,
GM3438C42, GM38C44 Start Threshold GM3438C43, GM38C45 GM3438C42, GM38C44 Minimum Operating Voltage GM3438C43, GM38C45 Section Maximum Duty Cycle Minimum Duty Cycle Total Standby Current Start Current GM38C42, GM38C44 7.5V GM38C43, GM38C45 Operating Supply Current Zener Voltage VISNS Note GM3438C42, GM38C43 GM3438C44, GM38C45
13.5
14.5
15.5
Note These parameters, although guaranteed, 100% tested production. Note Parameter measured trip point latch with Note Gain defined DVPIN1 (ISNS) (ISNS) 0.8V
Note Adjust above start threshold before setting 15V. Note Output frequency equals oscillator frequency GM38C42 GM38C43. Output frequency GM38C44, GM38C45 equals half oscillator frequency. Note 8-pin version, maximum input this also supply output stage.
GM38C42, GM38C43, GM38C44, GM38C45
GM38C42, GM38C43, GM38C44, GM38C45
TYPICAL PERFORMANCE CHARACTERISTICS
200pF OUTPUT DEAD TIME
RESISTANCE (kW)
470pF
4.7nF
18nF
1.8nF 10nF 4.7nF
10nF
470pF 200pF
1x104
1x105
OSCILLATOR FREQUENCY (Hz)
5x105
1x104
1x105
FREQUENCY (Hz)
1x106
Figure Oscillator Frequency Configuration
Figure GM38C42, GM38C43 Output Dead Time Oscillator Frequency
CURRENT SENSE THRESHOLD
OSC. DISCHARGE CURRENT(mA)
VOSC
-50°C
125°C 25°C
GM38C42, GM38C43, GM38C44, GM38C45
TEMPERATURE (°C)
ERROR AMPLIFIER OUTPUT
Figure Oscillator Discharge Current Temperature
VREF SHORT CURCUIT CURRENT (mA)
Figure Current Sense Amplifier Error Amplifier Output
OUTPUT VOLTAGE
TEMPERATURE (°C)
TIME (µS)
Figure Short Circuit Reference Current Temperature
Figure GM38C4X Output Waveform
GM38C42, GM38C43, GM38C44, GM38C45
Application Information
Familiarity with 384x converter designs assumed. GM38C4x been designed compatible with 384xA series controllers. GM38C4x Advantages Start-up Current Start-up current been reduced ultra-low 50µA(typical) permitting higher-valued, lower-wattage, start-up resistors (power controller during power supply start-up). reduced resistor wattage reduces cost printed circuit space. Operating Current Operating current been reduced compared 11mA typical bipolar controller. controller runs cooler hold-up capacitance required during start-up reduced. Output Driver Complementary internal P-and N-channel MOSFETs produce rail-to rail output voltages better performance driving external power MOSFETs. driver transistor's resistance high peak current capability drive gate capacitances greater than 1000pF. value output capacitance which driven determined only rise/fall time requirements. Within restrictions output capacity controller power dissipation, maximum switching frequency approach 500kHz. Design Precautions When operating near 20V, circuit transients easily exceed absolute maximum rating, permanently damaging controller's CMOS construction. reduce transients, 0.1µF low-ESR capacitor next controller's supply '-1' versions)and ground connections. Film type capacitors, such Wima MKS2, recommended. When designing high -frequency converters, avoid capacitive inductive coupling switching waveform into high impedance circuitry such error amplifier, oscillator, current sense amplifier. Avoid long printed-circuit traces component leads. Locate oscillator compensation circuitry neat high frequency decoupling capacitors VERF, necessary, VDD. Return high di/dt currents directly their source large ground planes. Buck Converter Refer Figure When lest applied input, charged through until voltage greater than 14.5V(the undervoltage lockout value GM38C42). Output switching begins when Q1is turned gate drive transformer charging output filter capacitor through supplies regulated +12V once circuit running. Current sense transformer provides current feedback ISNS current-mode operation cycle-by-cycle current limiting. This more efficient than high- power sense resistor provides required groundreferenced level shift. When turns off, current flow continues from ground through until turned again. 100V Schottky diode reduces forward voltage drop main current path, resulting higher efficiency than could accomplished using ultra-fast recovery diode. suppress parasitic oscillations from Using high-value inductance low-ESR capacitor permits small capacitance with minimum output ripple. This inductance value also improves circuit efficiency reducing flux swing Magnetic components carefully chosen minimal loss 500kHz.
GM38C42, GM38C43, GM38C44, GM38C45
GM38C42, GM38C43, GM38C44, GM38C45
M17Z105 1/4W MBR030 6.8k 0.22µF
IRF820 1N765B
1/2W
48µH 31DQ10
VOUT 12V, 0.1µF
3.3µF
0.1µF*
MKS2
100k GM38C42 VREF COMP
ISNS RT/CT
4.7W 4.7µF 0.1µF
1000pF
0.1µF 0.1µF
1N4001 6.19k 1.62k
200pF
Locate near GM38C42 supply pins Figure 500kHz, 25W, Buck Converter
GM38C42, GM38C43, GM38C44, GM38C45
Test
Line Regulation Load Regulation Efficiency Output Ripple
Conditions
VIN= 80V, VIN= 48V, 0.2A VIN= 48V, VIN= 48V, (20MHz
Results
0.5% 0.6% 100mV
GM38C42, GM38C43, GM38C44, GM38C45
SOP-8(SO-8) PACKAGE OUTLINE DIMENSIONS
0.008 +0.0018 -0.0005
0.028
+0.022 -0.013 +0.56 -0.33
(0.20
+0.05 -0.01
(0.71
Layout
0.060 1.52
(5.99
+0.21 -0.20
0.236 0.008
0.275
0.155
0.154
+0.003 -0.004
INDENT
(3.91 0.1)
0.024
0.050 1.270
Inches
0.191
+0.004 -0.002 +0.10 -0.05
(4.85
0.063 0.005 (1.60 0.13)
0.057 (1.45)
Inches
0.0025 0.0015 (0.175 0.075)
0.050 (1.270)
0.016
+0.004 -0.003 +0.10 -0.08
(0.41
DIP-8 PACKAGE OUTLINE DIMENSIONS
0.26 0.006 (6.60
+0.16 -0.15
0.30
+0.015 -0.010
(7.62 +0.38 -0.25
0.36 0.01 (9.14
+0.26 -0.25
0.13
+0.006 -0.002
0.01
+0.003 -0.002
(0.25 +0.08 -0.05
0.365 0.02 9.27 0.51
(3.30 +0.15 -0.05
0.180 4.570
0.015 0.380
0.125 3.180
0.018 0.004 0.46 0.10 0.039 0.07 0.99 0.18
0.06 0.01 (1.52 +0.26 -0.25
0.100 2.540
0.021 0.005 (0.53 +0.13 -0.12
Inches
GM38C42, GM38C43, GM38C44, GM38C45
GM34063/ GM38C43, GM38C42, GM34063E GM38C44, GM38C45
ORDERING NUMBER
Gamma Micro. Shipping Tube Tape Reel
Circuit Type
BiCOMS Process
GM38C42, GM38C43, GM38C44, GM38C45
Package SO-8 DIP-8

HIGH PERFORMANCE CURRENT MODE CONTROLLERS Power Management Power Manag

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