LT3751EUFD#PBF Linear Technology, LT3751EUFD#PBF Datasheet - Page 26

• Manufacturer Part Number: LT3751EUFD#PBF
• Description: IC CAPACITOR CHRG 20-QFN
• Manufacturer: Linear Technology

Specifications of LT3751EUFD#PBF

• Applications: Photoflash Capacitor Charger
• Current - Supply: 5.5mA
• Voltage - Supply: 4.75 V ~ 24 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 20-QFN
• Primary Input Voltage: 24V
• No. Of Outputs: 1
• No. Of Pins: 20
• Operating Temperature Range: -40°C To +125°C
• Msl: MSL 1 - Unlimited
• Supply Voltage Range: 4.75V To 24V
• Termination Type: SMD
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TYPICAL APPLICATIONS
LT3751
Suggested Component Values
†
and R
26
5V TO 24V
5V TO 24V
Transformer primary inductance limits V
V
500
100
200
300
400
V
(V)
90
85
80
75
70
65
60
OUT
TRANS
BG
0
V
†
Effi ciency (V
CC
should be tied to ground when operating V
5% V
V
V
TRANS
AT V
TRANS
I
50
V
OUT(MAX)
OUT
CC
C1
10μF
OFF ON
TRANS
= 5V
DEFLECTION
180
110
OUT
75
55
40
MICRO
I
LOAD
R1, 69.8k
R3, 69.8k
R2, 475k
R4, 475k
DANGER HIGH VOLTAGE! OPERATION BY HIGH VOLTAGE TRAINED PERSONNEL ONLY
TO
+
(mA)
100
= 5V,
= 500V)
(mA)
V
TRANS
C3
680μF
CHARGE
CLAMP
V
DONE
FAULT
UVLO1
OVLO1
UVLO2
OVLO2
CC
V
GND RBG
150
TRANS
= 12V
5% V
RV
LT3751
AT V
TRANS
I
OUT(MAX)
= 24V
3751 TA03c
OUT
OUT
R6
40.2k
R9
TRANS
HVGATE
LVGATE
RV
200
RDCM
270
315
245
200
170
comparator operation to V
DEFLECTION
3751 TA04
CSN
CSP
OUT
FB
(mA)
= 24V,
OUT
R7, 18.2k
R8, 40.2k
515
510
505
500
495
C2
5 2.2μF
V
above 400V.
CC
Load Regulation (V
0
C6
10nF
Tie to GND
0.825
(kΩ)
3.32
1.65
1.10
High Voltage Regulator
R9
•
1:10
T1*
V
M1*
R5
6mΩ
TRANS
50
•
D1
OUT
= 5V
I
LOAD
+
0.383
0.768
= 400V
(kΩ)
1.13
1.54
1.74
100
R11
(mA)
V
C4***
100μF
TRANS
OUT
V
TRANS
MAX
= 500V)
= 12V
150
. RV
= 24V
C5
0.47μF
(kΩ)
30.9
R10
124
274
499
715
OUT
3751 TA03d
200
R10**
R11
V
100V TO 500V
OUT
AC COUPLED
*** C4 MUST BE SIZED TO MEET LARGE SIGNAL
** DEPENDING ON DESIRED OUTPUT VOLTAGES,
* M1 AND T1 REQUIRE PROPER
COUPLED
C1: 25V X5R OR X7R CERAMIC
C2: 25V X5R OR X7R CERAMIC
C3: 25V ELECTROLYTIC
C5: TDK CKG57NX7R2J474M
D1: VISHAY US1M 1000V
M1: FAIRCHILD FQP34N20L
R1 THRU R4, R6 THRU R9, R11: USE 1% 0805
R5: IRC LR SERIES 2512 RESISTORS
R10: USE 200V 1206 RESISTOR(S)
T1: COILCRAFT GA3459-AL
HEATSINK/THERMAL DISSIPATION
TO MEET MANUFACTURER’S SPECIFICATIONS
R10 MUST BE SPLIT INTO MULTIPLE RESISTORS,
TO MEET MANUFACTURER’S VOLTAGE SPECIFICATION.
STABILITY CRITERIA DESCRIBED IN THE
APPLICATIONS INFORMATION SECTION
50V/DIV
10A/DIV
50V/DIV
10A/DIV
V
2V/DIV
V
2V/DIV
DRAIN
DRAIN
V
V
I
OUT
OUT
I
PRI
PRI
Steady-State Operation with
100mA Load Current
Steady-State Operation with
1.1mA Load Current
10μs/DIV
10μs/DIV
3751 TA03b
3751 TA03e
3751fb