PT7750 Datasheet, PDF (1/3 Pages) Texas Instruments – 15 AMP 24V INPUT “BIG-HAMMER III” PROGRAMMABLE ISR

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PT7750
Series
15 AMP 24V INPUT “BIG-HAMMER III”
PROGRAMMABLE ISR
Revised 1/12/99
Application Notes
Mechanical Outline
Product Selector Guide
The PT7750 series is a new +24V
input, 15 Amp output, high-perfor-
mance Integrated Switching Regulator
(ISR) housed in a 27-pin SIP package.
The 15A capability allows easy integra-
tion of the latest high-speed,
low-voltage µPs and bus drivers into
+24V distributed power systems.
The PT7750 series has been de-
signed to work in parallel with one or
more of the PT7747 current boosters for
increased Iout in increments of 15A.
The output voltage of the PT7750
series can be easily programmed over a
wide range with a 5-bit input. A differ-
ential remote sense is provided which
automatically compensates for any
voltage drop from the ISR to the load.
2000µF of output capacitance is
required for proper operation.
Standard Application
PROGRAMMING PINS
VID0
VID1
VID2
VID3
VID4
V_IN
L1
1µH
SYNC OUT
GND
STBY*
+
C_IN
6432 1
26
7 - 11 _PT7750
REMOTE SENSE (+)
20 - 25
V_OUT
27
13 - 19 5 12
+
C_OUT
LOAD
GND
REMOTE SENSE (-)
Cin = Required 560µF electrolytic
(See input filter note)
Cout = Required 2000µF electrolytic
L1 = Optional 1µH input choke
Specifications
Pin-Out Information
Pin Function
Pin Function
1 VID0
2 VID1
3 VID2
4 VID3
5 STBY* - Stand-by
6 VID4
7 V_in
8 Vin
9 Vin
10 V_in
11 Vin
12 Remote Sense Gnd
13 GND
For STBY* pin:
open = output enabled
ground = output disabled.
14 GND
15 GND
16 GND
17 GND
18 GND
19 GND
20 Vout
21 V_out
22 Vout
23 Vout
24 V_out
25 Vout
26 Remote Sense Vout
27 Sync Out
Features
• +24V bus input
• High Efficiency
• Differential Remote
Sense
• 27-pin SIP Package
• Parallelable with
PT7747 15A current boosters
Characteristics
(T_a = 25°C unless noted)
Symbols
Conditions
PT7750 SERIES
Min
Typ
Max
Units
Output Current
Io
Input Voltage Range
Vin
Undervoltage Lockout Threshold Vuvl
Output Voltage Tolerance
∆V_o
Line Regulation
Load Regulation
Vo Ripple/Noise
Transient Response
with Cout = 2000µF
Efficiency
Reg_line
Regload
Vn
t_tr
Vos
η
Switching Frequency
ƒo
Ta = +60°C, 200 LFM
T_a = +25°C, natural convection
0.1^*
—
0.1^*
—
15^**
A
15^**
A
0.1A ≤ Io ≤ Io max
20.0
—
28.0
V
0.1A ≤ Io ≤ Io max
—
18.7
—
V
V_in = +24V, I_o = 15A PT7751
0°C ≤ Ta ≤ +55°C PT7756
—
—
±80
mV
—
—
±160
mV
20V ≤ V_in ≤ 28V, I_o = I_{o max (w/remote sense)} —
±15
—
mV
Vin = +24V, 0.1 ≤ Io ≤ Io max (w/remote sense) —
±10
—
mV
Vin = +24V, Io = Io max
—
75
—
mV
I_o step between 7.5A and 15A
Vo over/undershoot
—
100
—
µSec
—
200
—
mV
V_in = +24V, I_o = 10A
V_o = 5.0V —
88
—
%
Vo = 3.3V —
84
—
%
Vo = 2.5V —
80
—
%
20V ≤ Vin ≤ 28V
0.1A ≤ Io ≤ 15A
300
350
400
kHz
Absolute Maximum
Ta
Operating Temperature Range
0
—
+85
°C
Recommended Operating
T_a
Temperature Range
Forced Air Flow = 200 LFM
At Vin = +24V, Io = 12A
0
—
+65*** °C
Storage Temperature
Ts
Weight
—
—
Vertical/Horizontal
-40
—
+125
°C
—
53/66
—
grams
* ISR-will operate down to no load with reduced specifications. Please note that this product is not short-circuit protected.
** The PT7750 series can be easily paralleled with one or more of the PT7747 Current Boosters to provide increased output current in increments of 15A.
*** See safe operating area chart.
Output Capacitors: The PT7750 series requires a minimum output capacitance of 2000µF for proper operation. Do not use Oscon type capacitors. The maximum allowable
output capacitance is (42,000 ÷ Vout)µF for the PT7751, (96,000 ÷ Vout)µF for the PT7756, or 15,000µF, whichever is less.
Input Filter: An input inductor is optional for most applications. The input inductor must be sized to handle 9ADC with a typical value of 1µH. The input capacitance
must be rated for a minimum of 8.0 Arms of ripple current when operated at maximum output current and maximum output voltage. Contact an applications engi-
neer for input capacitor selection for applications at other output voltages and output currents.
56
Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 [phone] Fax: [phone] http://www.powertrends.com