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CS3524A
CS3524A
Voltage Mode PWM Control Circuit with 200mA Output Drivers
Description
The CS3524A PWM control circuit retains the same versatile architecture of the industry standard CS3524 (SG3524) while adding substantial improvements. The CS3524 is pin-compatible with "non-A" versions, and in most applications can be directly interchanged. The CS3524A, however, eliminates many of the design restrictions which had previously required additional external circuitry. The CS3524A includes a precision 5V reference trimmed to 1% accuracy (eliminating the need for potentiometer adjustments), an error amplifier with an output voltage swing extending to 5V, and a current sense amplifier useful in either the ground or power supply output lines. The uncommitted 60V, 200mA NPN output pair greatly enhances the output drive capability. The CS3524A features an undervoltage lockout circuit which disables all internal circuitry (except the reference) until the input voltage has risen to 8V. This holds standby current low until turnon, and greatly simplifies the design of low power, off-line supplies. The turnon circuit has approximately 600mV of hysteresis for jitter free activation. Other improvements include a PWM latch that insures freedom from multiple pulsing within a period, even in noisy environments; logic to eliminate double pulsing on a single output, a 200ns external shutdown capability, and automatic thermal protection from excessive chip temperature. The oscillator circuit is usable to 500kHz and is easier to synchronize with an external clock pulse.
Features
s Precision Reference Internally Trimmed to 1% s Current Limit s Undervoltage Lockout s Start-up Supply Current < 4mA s Output to 200mA s 60V Output Capability s Wide Common-mode Input Range for Error and Current Limit Amplifiers s PWM Latch Insures Single Pulse per Period s Double Pulse Suppression s 200ns Shutdown s Guaranteed Frequency s Thermal Shutdown
Block Diagram
V IN
5V Reference Regulator Power to Internal Circuitry T
V REF
Package Options
16 Lead PDIP & SO Wide
EA- 1 EA+ 2
16 15 14 13 12 11 10 9
SYNC
UV Sense CLOCK
V OUTA Flip Flop EA
RT OSC CT RAMP
VREF VIN EB VOUTB VOUTA EA SHUTDOWN COMP
+
COMP
S S
R V OUTB PWM Latch EB
SYNC 3 ISENSE+ 4 ISENSERT
5 6 7
COMP V IN EAEA+ 200mV I SENSE + CL I SENSE -
EA
+
V IN
1k SHUTDOWN 10k Gnd
CT
Gnd 8
Cherry Semiconductor Corporation 2000 South County Trail, East Greenwich, RI 02818 Tel: (401)885-3600 Fax: (401)885-5786 Email: info@cherry-semi.com Web Site: www.cherry-semi.com
Rev. 10/28/96
1
A
(R)
Company
CS3524A
Absolute Maximum Ratings Supply Voltage (VIN) .................................................................................................................................................................40V Collector Supply Voltage (VCC) ...............................................................................................................................................60V Output Current (Each Output)...........................................................................................................................................200mA Reference Output Current.....................................................................................................................................................50mA Oscillator Charging Current ..................................................................................................................................................5mA Power Dissipation at TA=25C.........................................................................................................................................1000mW Power Dissipation at TJ=+25C........................................................................................................................................2000mW Derate for Case Temperature above +25C........................................................................................................16mW/C Storage Temperature Range ................................................................................................................................-65C to +150C Lead Temperature Soldering: Wave Solder (through hole styles only)..........................................10 sec. max, 260C peak Reflow (SMD styles only) ......................................................................................60 sec. max above 183C, 230C peak Electrical Characteristics: 0C TA +70C for the CS3524A; VIN = VCC = 20V; unless otherwise stated.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
s Turn-on Characteristics Input Voltage Turn-on Threshold Turn-on Current Operating Current Turn-on Hysteresis* s Reference Section Output Voltage Line Regulation Load Regulation Temperature Stability* Short Circuit Current Output Noise Voltage* Long Term Stability* TA = 25C VIN = 10 to 40V IL = 0 to 20mA Over Operating Range VREF = 0, TA = 25C 10Hz f 10kHz, TA = 25C TA = 125C; 1000 Hrs. 4.90 5.00 10 20 20 80 40 20 50 5.20 30 50 50 100 V mV mA mV mA Vrms mV VIN Turn-on - 100mV VIN = 8 to 40V Operating range after Turn-on 8 5.5 7.5 2.5 5 0.6 40 8.5 4.0 10 V V mA mA V
s Oscillator Section (Unless otherwise specified, RT = 2700, CT = 0.01F) Initial Accuracy Temperature Stability* Minimum Frequency Maximum Frequency Output Amplitude* Output Pulse Width* Ramp Peak Ramp Valley s Error Amplifier Section (Unless otherwise specified, VCM = 2.5V) Input Offset Voltage Input Bias Current Input Offset Current Common Mode Rejection Ratio Output Swing VCM = 1.5 to 5.5V Minimum Total Range 2 60 50 0.5 2 1 0.5 75 60 5.0 10 10 1.0 mV A A dB dB V TA = 25C Over Operating Temperature Range RT = 150k, CT = 0.1F RT = 2.0k, CT = 470pF TA = 25C TA = 25C 3.3 0.7 500 3.5 0.5 3.5 0.9 3.7 1.0 39 43 1 47 2 120 kHz % Hz kHz V s V V
Power Supply Rejection Ratio VIN = 10 to 40V
* These parameters are guaranteed by design but not 100% tested in production.
CS3524A
Electrical Characteristics: continued
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
s Error Amplifier Section (Unless otherwise specified, VCM = 2.5V): continued Open Loop Voltage Gain Gain-Bandwidth* VOUT = 1 to 4V, RL 10 M TA = 25C, AV = 0dB 60 80 3 dB MHz
s Current Limit Amplifier (Unless otherwise specified, VSENSE = VO) Input Offset Voltage Input Offset Voltage Input Bias Current Common Mode Rejection Ratio Output Swing Open Loop Voltage Gain Delay Time* s Output Section (Each Output) Collector Emitter Voltage Collector Leakage Current Saturation Emitter Output Voltage Rise Time* Fall Time* Comparator Delay* Shutdown Delay* Shutdown Threshold Thermal Shutdown* * These parameters are guaranteed by design but not 100% tested in production. Typical Performance Characteristics Error Amplifier Voltage Gain vs. Frequency Over RF
50 80
TA = 25C, EA Set for Max. Output Over Operating Temperature Range
180 170
200 -1
220 230 -10
mV mV A dB dB
VSENSE = 0 to 15V Minimum Total Range VOUT = 1 to 4V, RL 10M VIN = 300mV
50 50 0.5 70
60 60 5.0 80 300
Power Supply Rejection Ratio VIN = 10 to 40V
V dB ns
IC = 100A VCE = 50V IC = 20mA IC = 200mA IE = 50mA TA = 25C, R = 2k TA = 25C, R = 2k TA = 25C, VCOMP to VOUT TA = 25C, VSHUT to VOUT TA = 25C, RC = 2k
60
80 0.1 0.2 1.0 20.0 0.4 2.2
V A V V V ns ns ns ns 1.0 V C
17
18 200 100 300 200
0.5
0.7 165
Duty Cycle vs. Input Voltage
OPEN VOLTAGE GAIN (dB)
RF = 1M 60 RF = 300k RF = 100k 40 RF = 30k
VIN = 20V TA = 25C
DUTY-CYCLE (ONE OUTPUT) - %
RF =
40 VIN = 20V RT = 2700 TA = 25C
F =1 0 CT
20 Note: Duty-Cycle is percent of two clock periods that one output conducts 0 1 2 3 4 5
20
0
RF is impedance to ground. Values below 30k will begin to limit the maximum duty-cycle.
10
0 100 1k 10k 100k 1M
FREQUENCY (Hz)
INPUT VOLTAGE VIN
3
CT
=
1
F
30
CS3524A
Typical Performance Characteristics continued Quiescent Supply Current vs. Supply Voltage Over Temperature
10
Shutdown Delay From PWM Comparator
OUTPUT (V)
QUIESCENT CURRENT (mA)
9 8 7 6 5 TA = -55C TA = 25C TA = 125C
20 15 10 5 0 5 4 3 2 1 0 0 VIN = 20V RL = 2k TA = 25C OUTPUT at VOA or VOB
3 2 Note: Outputs off. RT = 1 0 0 10 20 30 40 50
INTPUT (V)
4
INPUT at VOB
Note: Minimum input pulse width to latch is 200ns 1 2 3
SUPPLY VOLTAGE VIN (V)
DELAY TIME (s)
Oscillator Frequency vs. Timing Components Resistor Over Timing Capacitance
1M
Output Dead Time vs. Timing Capacitor Value
10
OSCILLATOR FREQUENCY (Hz)
OUTPUT DEAD TIME (s)
VIN = 20V TA = 25C 100k
5.0 VIN = 20V RT = 2700 TA = 25C 2.0 1.0 0.5
CT CT
=1 =3 =1 =3 =1
.0n .0n 0nf 0nf
f f
10k
CT CT
1k f 1.15 RTCT 100 1 2 5 10
CT
00n
f
0.2 0.1
Note: Dead time = osc output pulse width plus output delay 1 2 5 10 20 50 100
20
50
100
TIMING RESISTOR - RT (k)
TIMING CAPACITOR - CT (nf)
Current Limit Amplifier Delay
OUTPUT at COMP
Turn-Off Delay From Shutdown
OUTPUT (V)
20 15 10 5 0 OUTPUT at VOA OR VOB VIN = 20V RL = 2k TA = 25C
6 5 4 3 2 1 0
OUTPUT (V)
Overdrive 5% 10% 20% 50%
INTPUT (V)
INPUT at ISENSE+ 0.2 0.1 0.0 0 1 2 VIN 20V TA 25C EA+ = VREF ISENSE- = Gnd
INTPUT (V)
1.0 0.5 0.0 Note: Minimum input pulse width to latch is 200ns 0 1 2 3 INPUT at SHUTDOWN
3
4
DELAY TIME (s)
DELAY TIME (s)
4
CS3524A
Typical Performance Characteristics continued Output Saturation Voltage vs. Output Current Over Temperature
5
4
VCE SAT (V)
3 TA = 125C 2 TA = 25C 1 TA = -55C 0 0 50 100 150 200 250
OUTPUT COLLECTOR CURRENT (mA)
Open Loop Test Circuit
V CC
IS VIN VOUTA VOUTB SYNC
2k 1W
2k 1W
SHUTDOWN
CS3524A
ISENSE+ ISENSECOMP EA+ EA-
EA
100k 100k SHUTDOWN
2k
0.1
RT
CT
2k 10k 0.1
10k 1k
Note: The CS3524A should be able to be tested in any 3524 test circuit with two possible exceptions: 1. The higher gain-bandwidth of the current limit amplifier in the CS 3524A may cause oscillations in an uncompensated 3524 test circuit. 2. The effect of the shutdown, cannot be seen at the compensation terminal, but must be observed at the outputs. 5
Gnd
VREF
EB
RT
CT
CS3524A
Package Specification
PACKAGE DIMENSIONS IN mm (INCHES) PACKAGE THERMAL DATA
D Lead Count 16 Lead PDIP 16L SO Wide Metric Max 19.69 10.50 Min 18.67 10.10 English Max .775 .413 Min .735 .398
Thermal Data RJC RJA typ typ
16 Lead PDIP 42 80
16L SO Wide 23 105 C/W C/W
Plastic DIP (N); 300 mil wide
7.11 (.280) 6.10 (.240)
8.26 (.325) 7.62 (.300) 3.68 (.145) 2.92 (.115)
1.77 (.070) 1.14 (.045)
2.54 (.100) BSC
.356 (.014) .203 (.008)
0.39 (.015) MIN. .558 (.022) .356 (.014) Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same.
REF: JEDEC MS-001
D
Surface Mount Wide Body (DW); 300 mil wide
7.60 (.299) 7.40 (.291)
10.65 (.419) 10.00 (.394)
0.51 (.020) 0.33 (.013)
1.27 (.050) BSC
2.49 (.098) 2.24 (.088)
2.65 (.104) 2.35 (.093)
1.27 (.050) 0.40 (.016)
REF: JEDEC MS-013
0.32 (.013) 0.23 (.009) D 0.30 (.012) 0.10 (.004)
Ordering Information Part Number CS3524AGN16 CS3524AGDW16 CS3524AGDWR16
Rev. 10/28/96
Description 16 Lead PDIP 16 Lead SO Wide 16 Lead SO Wide (tape & reel) 6
Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information.
(c) 1999 Cherry Semiconductor Corporation

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