1. Features (for outside view, see Fig. 1) of Synchro/Resolver-Digital Converter (HSDC/HRDC1459 Series)
Internal differential isolation conversion |
![]() |
16-bit resolution |
|
Accuracy: 2 angular minutes |
|
Three-state latch output |
|
High continuous tracking speed |
|
36-wire salt fog resistant metal sealed DDIP package |
|
Pin-To-Pin compatible with Model SDC14560 of DDC company |
2. Scope of application of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)
Military servo control system; antenna monitoring; radar control system; navigation system for naval vessels; cannon control system; flight instrument system; aviation electronic system; computerized numeric control (CNC) machine; robot technology.3. General of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)
HSDC/HRDC1459 series synchro/resolver-digital converter is a hybrid integrated conversion device for continuous tracking designed on the principle of model II servo. This series products are designed and manufactured by MCM process, the core elements adopt special chip developed independently by our institute. The pin arrangement is compatible with SDC14560 series products of American DDC company, 16-bit parallel natural binary code data latch output, 36-line DIP totally sealed metal package, have the advantages of high precision, small volume, low power consumption, light weight and high reliability etc., and can be widely used in important strategic and tactic weapons such as aircraft, naval vessel, cannon, missile, radar, tank, etc.4. Electric performance (Table 1, Table 2) of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)
Table 1 Rated conditions and recommended operating conditionsAbsolute max. rated value | Logical supply voltage VL: +7V |
Supply voltage Vs: ± 17.5V | |
Signal voltage V1: rated value ±20% | |
Reference voltage VRef: rated value ±20% | |
Operating frequency f: rated value ±20% | |
Storage temperature Tstg: -65~150℃ | |
Recommended operating conditions | Logical supply voltage VL: 5±0.5V |
Supply voltage Vs: 15± 0.75V | |
Signal voltage V1: rated value ±10% | |
Reference voltage VRef: rated value ±20% | |
Operating frequency f: rated value ±20% | |
Range of operating temperature (TA): -55℃~125℃ |
Note: * indicates it can be customized as per user’s requirement.
Table 2 Electric characteristics
Parameter | Conditions | HSDC14569 Series | |
(VS=15V, VL=+5V) | Military standard (Q/HW20725-2006) | ||
Min. | Max. | ||
Resolution | Binary system parallel digital code | 16 bits | — |
Accuracy | ± 10% of signal voltage, reference voltage and fluctuation range of operating frequency | -2 angular minutes | +2 angular minutes |
Range of reference frequency | — | 50Hz | 2600Hz |
Range of reference voltage | — | 2V | 115V |
Reference input impedance | — | 4.4kΩ | 129.2 kΩ |
Range of signal voltage | — | 2V | 90V |
Signal input impedance | — | 4.4kΩ | 102.2 kΩ |
Signal/reference phase shift | — | —70° | +70° |
Input logic level | — | Logic “1” ≥3.3V | Logic “0” ≤0.8V |
![]() |
— | 0 | 0.8V |
![]() |
— | 0 | 0.8V |
![]() |
— | 0 | 0.8V |
Output logic level | — | Logic “1” ≥3.3V | Logic “0” ≤0.8V |
Digital angle code output | — | Logic “1” ≥3.3V | Logic “0” ≤0.8V |
Converting busy signal (CB) output | — | 200ns | 600ns |
Fault detection Bit output | — | Logic “0” indicates fault |
|
Loading capacity | — | — | 3TTL |
Tracking speed | — | — | 2.5rps |
Acceleration constant | — | — | 12500 |
Settling time | — | — | 850ms |
Angular velocity voltage (Vel) output | — | —10V | +10V |
Current | VS=+15V | — | 10mA |
VS =—15V | 15 mA | ||
VL=+15V | 20 mA |
5. Step response of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)
When a step or initial power-on happens in the input signal, the response will be inhibited due to the limitation of maximum tracking speed. The oscillation process of the output digital angle is shown in Fig. 2:
6. Operating principle (Fig. 3) of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)
The input signal of synchro (or resolver) is converted into the orthogonal signal through the internal differential isolation: Vsin=KE0sin (ωt+α) sinθ (sin) Vcos=KE0sin (ωt+α) cosθ (cos) Where, θ is the analog input angle. |
![]() Fig.2 Curve of step response |
KE0sin (ωt+α)(sinθ cosϕ-cosθ sinϕ), i.e. KE0sin (ωt+α) sin(θ-ϕ)
The signals are sent to voltage controlled oscillator after amplification, phase discrimination and integration filtration, if θ-φ≠0, the voltage controlled oscillator will output the pulses, and the reversible counter counts, till θ-φ becomes zero within the accuracy of the converter, during this process, the conversion tracks the change of input angle all the time.
Reading method:
Following two methods are available for data transfer:
(1) Inhibit method:
After 640ns of



(2) Bust mode: At the rising edge of Busy pulse, the three-state reversible counter counts; at the descending edge of Busy pulse, it internally generates a latch pulse with a width equal to Busy pulse for updating the data of three-state latch, the time sequence of data transfer is shown in Fig.4, in other words, after 600ns of Busy logic low, the stable transfer of data is valid. In the asynchronous reading mode, the Busy output is CMOS-level pulse train. The width of its high and low level depends on operating frequency and rotational speed of the selected device. |
|

Fig.4 Time sequence of data transfer
7. MTBF curve (Fig.5) of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)![]() Fig.5 MTBF-temperature curve |
8.Pin designation (Fig.6, Table 3) of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)![]() Fig.6 Pin designation (Bottom view) |
(Note: according to GJB/Z299B-98, envisaged good ground condition)
Table 3 Pin designation
Pin | Symbol | Meaning | Pin | Symbol | Meaning |
1 | S1 | Resolver input S1 (or synchro input S1) | 25 |
![]() |
Digital Enabled control of lower 8 bits |
2 | S2 | Resolver input S2 (or synchro input S2) | 26 |
![]() |
Digital Enabled control of higher 8 bits |
3 | S3 | Resolver input S3 (or synchro input S3) | 27 | RIPCLK | Zero-bit signal output |
4 | S4 | Resolver input S4 (leave unconnected) | 28 | VL | +5V power supply |
5月18日 | D1-D14 | Digital output 1(MSB)-14 | 29 | GND | Ground |
19 | RHi | High end of reference signal input | 30 | NC | No connection |
20 | RL | Low end of reference signal input | 31 | -VS | -15V Power supply |
21 | D15 | Digital output 15 | 32 | VS | +15V Power supply |
22 | D16 | Digital output 16 (LSB) | 33 | Inhibit | Static signal input |
23 | Vel | Angular velocity voltage signal output | 34 |
bit |
Fault detection bit output |
24 | CB | Busy signal output | 35-36 | NC | No connection |
Notes: D1~D16 | Parallel binary system digital angle code output end |
S1, S2, S3, S4 | Signal input of Resolver (or synchro) |
RHi | High end of reference signal input |
RL | Low end of reference signal input |
Lower
8-bit digit enabled signal input, this pin is the logic input pin of
data gating control, its function is to carry out three-state control
externally on the lower 8-bit output data of the converter. Low level is
valid, the lower 8-bit output data of the converter occupies the data
bus; At high level, the pin of lower 8-bit output data is in high
resistance state, and the device does not occupy the data bus. Enable
and release delay time is 600ns(max).
higher
8-bit digit enabled signal input, this pin is the logic input pin of
data gating control, its function is to carry out three-state control
externally on the higher 8-bit output data of the converter. Low level
is valid, the higher 8-bit output data of the converter occupies the
data bus; At high level, the pin of higher 8-bit output data is in high
resistance state, and the device does not occupy the data bus. Enable
and release delay time is 600ns(max).
Inhibit static
signal input, this pin is the input pin of control logic, its function
is to output data externally to the converter to realize optional
latching or bypass control. At high level, the output data of the
converter directly outputs without latching; at low level, the output
data of the converter is latched, the data is not updated, but the
internal loop is not interrupted, and tracking is operating all the
time, Inhibit has connected pull-up resistance internally. After 600ns (max) delay of
descending edge of static signal, the data becomes stable (whether the
device occupies the data bus, i.e. when does it output the data depends
on the state of and
).
CB “Busy” signal output, this signal indicates whether the binary code
output of the converter is valid or not. When the change of angle input
reaches 0.33 angular minute, CB end outputs a positive pulse with a
width of 400ns(typical). When CB is at high level, it indicates the
converter is carrying out data conversion, the data output at this time
is invalid; after 600ns (max) delay of descending edge of CB signal, the
data becomes stable and the updated data output at this time is valid.
bit fault
detection bit output, high level indicates normal operation of the
converter, in the event that the signal wire is broken or the converter
fails to track normally, this bit changes into low level from high
level.
RIPCLK zero-bit signal input, when the output data increment to all “0”
from all “1” or decrement from all “1” from all “0”, a positive pulse
with a width of 200us is output.
VL, +VS, -VS Incoming terminal of power supply
GND Ground wire incoming terminalReference signals are connected to RHi
and RLo. In the case of synchro, signals are connected to S1, S2, and
S3 as per the following conventions.
Notes:
- Pin voltage shall not exceed 20% of rated value.
- The voltage of power supply shall not exceed the specified range.
- Do not connect reference RHi and RLo to other pins.
- For the power supply connected to +VS and -VS pin, its voltage shall be ±15V, and shall not be reversely connected. The digital logic power supply VL is connected to +5V. Between the power supply and ground, 0.1µF ceramic capacitance and 6.8µF electrolytic capacitance shall be connected in parallel.
- Reference signals are connected to RHi and RLo. In the case of synchro, signals are connected to S1, S2, and S3 as per the following conventions.

- In the case of resolver, signals are connected to S1, S2, S3 and S4 as per the following conventions:

Pins of CB,

9. Table of weight values(Table 4) of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)
Table 4 Table of weight values
10. Connection diagram for typical application (Fig. 7) of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series) |
11. Package specifications (unit: mm) (Fig. 8, Table 5) of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series) |
![]() |
![]() |
Fig. 7 Connection diagram for typical application |
Fig.8 Outside view and dimensions of package |
Table 5 Case materials
Case model |
Header |
Header plating |
Cover |
Covering plating |
Pin material |
Pin plating |
Sealing style |
Notes |
UP4820-36A |
4J42 |
Ni plating |
4J42 |
Chemical Ni plating |
4J42 |
Au plating |
Matched seal |
Header plus three solid glass beads |
12. Part numbering key (Fig. 9) of Synchro to Digital Converters or Resolver to Digital Converters (HSDC/HRDC1459 Series)

Fig.9 Part numbering key
Note: when the above signal voltage and reference voltage (Z) are non-standard, they shall be given as follows:

(e.g. reference voltage 5V and signal voltage 3V are expressed as -5/3)
Application notes:
Supply the power correctly, upon power-on, be sure to correctly connect the positive and negative pole of the power supply for fear of burnout.
Upon assembly, the bottom of the product shall fit to the circuit board closely so as to avoid damage of pins, and shockproof provision shall be added, if necessary.
Do not bend the pinouts to prevent the insulator from breaking, which affects the sealing property.